feat(后端架构): 接入GoGPU渲染，支持后端切换

2026-10-29 13:56:32 +08:00 · 2026-09-23 13:42:55 +08:00
1 parent 87af84e4cd
commit 73472c5d4b
@@ -431,6 +431,26 @@
 						</div>
 					</div>
 				</section>
+				<section id="renderPanel" class="render-panel" aria-label="渲染">
+					<div class="panel-row">
+						<label class="panel-title compact" for="renderBackend">渲染</label>
+						<select id="renderBackend" title="渲染后端" disabled></select>
+					</div>
+					<div class="render-mode-row">
+						<span id="renderModeLabel">显示</span>
+						<div class="render-controls">
+							<div class="render-modes" role="group" aria-labelledby="renderModeLabel">
+								<button id="renderVectorButton" class="small-button" type="button" aria-pressed="true" title="矢量显示" disabled>矢量</button>
+								<button id="renderRasterButton" class="small-button" type="button" aria-pressed="false" title="位图显示" disabled>位图</button>
+							</div>
+							<select id="renderDPI" aria-label="精度" title="位图精度" disabled><option value="96">96 dpi</option><option value="150" selected>150 dpi</option><option value="300">300 dpi</option></select>
+						</div>
+					</div>
+					<details class="render-support">
+						<summary>详情</summary>
+						<dl><div><dt>显示</dt><dd id="renderDisplay">SVG</dd></div><div><dt>编辑</dt><dd>SVG</dd></div><div><dt>编译</dt><dd id="renderCompiler"></dd></div><div><dt>图片</dt><dd id="renderImages"></dd></div><div><dt>SVG</dt><dd id="renderSVG"></dd></div><div><dt>PDF</dt><dd id="renderPDF"></dd></div><div><dt>EPS</dt><dd id="renderEPS"></dd></div></dl>
+					</details>
+				</section>
 				<div class="panel-row">
 					<div class="panel-title compact">文档</div>
 					<button id="infoButton" class="small-button" type="button" aria-label="修改文档信息" aria-haspopup="dialog" aria-controls="infoPanel" hidden>修改</button>
@@ -607,7 +607,8 @@ button:not(:disabled):hover {
 }

 .format-select,
-.order-select {
+.order-select,
+.render-panel select {
 	width: 58px;
 	height: var(--control-height);
 	min-width: 0;
@@ -983,6 +984,104 @@ body[data-hide-meta] .meta-panel {
 	font-size: 12px;
 }

+.render-panel {
+	position: relative;
+	margin-bottom: 12px;
+	padding-bottom: 12px;
+	border-bottom: 1px solid var(--line);
+}
+
+.render-panel select {
+	width: 180px;
+	max-width: calc(100% - 76px);
+	height: 28px;
+	font-size: 12px;
+}
+
+.render-mode-row {
+	display: flex;
+	align-items: center;
+	justify-content: space-between;
+	gap: 8px;
+	font-size: 12px;
+}
+
+.render-panel .panel-row {
+	flex-wrap: nowrap;
+	margin-bottom: 6px;
+}
+
+.render-controls {
+	display: flex;
+	align-items: center;
+	width: 180px;
+	max-width: calc(100% - 76px);
+	gap: 8px;
+}
+
+.render-modes {
+	display: flex;
+	flex: none;
+}
+
+.render-modes .small-button {
+	width: 36px;
+	height: 28px;
+	padding: 0;
+}
+
+.render-modes .small-button + .small-button {
+	margin-left: -1px;
+}
+
+.render-modes .small-button[aria-pressed="true"] {
+	position: relative;
+	border-color: var(--accent);
+	background: var(--accent-soft);
+	color: var(--accent-strong);
+}
+
+.render-controls select {
+	flex: 1;
+	width: 0;
+	min-width: 0;
+	max-width: 100%;
+}
+
+.render-support {
+	font-size: 12px;
+	color: var(--text-muted);
+}
+
+.render-support summary {
+	position: absolute;
+	top: 0;
+	left: 32px;
+	width: fit-content;
+	line-height: 28px;
+	cursor: pointer;
+	color: var(--accent-strong);
+}
+
+.render-support dl {
+	margin: 8px 0 0;
+}
+
+.render-support dl > div {
+	display: flex;
+	justify-content: space-between;
+	gap: 16px;
+	margin-top: 6px;
+}
+
+.render-support dd {
+	min-width: 0;
+	margin: 0;
+	text-align: right;
+	overflow-wrap: anywhere;
+	color: #1f2428;
+}
+
 .app-refresh {
 	width: 26px;
 	padding: 0;
@@ -81,6 +81,10 @@ const state = {
 	fitMode: "width",
 	continuous: false,
 	renderAnnotations: true,
+	renderBackend: "canvas",
+	renderMode: "svg",
+	renderBackends: {},
+	renderDPI: 150,
 	pageCache: new Map(),
 	svgFonts: new Map(),
 	svgImages: new Map(),
@@ -318,6 +322,16 @@ const el = {
 	searchResults: document.querySelector("#searchResults"),
 	metaPanel: document.querySelector(".meta-panel"),
 	appPanel: document.querySelector("#appPanel"),
+	renderBackend: document.querySelector("#renderBackend"),
+	renderDPI: document.querySelector("#renderDPI"),
+	renderVectorButton: document.querySelector("#renderVectorButton"),
+	renderRasterButton: document.querySelector("#renderRasterButton"),
+	renderDisplay: document.querySelector("#renderDisplay"),
+	renderImages: document.querySelector("#renderImages"),
+	renderSVG: document.querySelector("#renderSVG"),
+	renderPDF: document.querySelector("#renderPDF"),
+	renderEPS: document.querySelector("#renderEPS"),
+	renderCompiler: document.querySelector("#renderCompiler"),
 	offlineStatus: document.querySelector("#offlineStatus"),
 	refreshAppButton: document.querySelector("#refreshAppButton"),
 	metaFile: document.querySelector("#metaFile"),
@@ -948,6 +962,10 @@ el.ofdInput.addEventListener("change", () => openOFD(el.ofdInput.files[0]));
 el.fontInput.addEventListener("change", openSelectedFonts);
 el.fontDirectoryInput.addEventListener("change", openSelectedFonts);
 el.prevButton.addEventListener("click", () => renderPage(state.pageIndex - 1));
+el.renderBackend.addEventListener("change", () => changeRenderBackend());
+el.renderDPI.addEventListener("change", () => changeRenderBackend());
+el.renderVectorButton.addEventListener("click", () => changeRenderBackend("svg"));
+el.renderRasterButton.addEventListener("click", () => changeRenderBackend("raster"));
 el.nextButton.addEventListener("click", () => renderPage(state.pageIndex + 1));
 el.zoomOutButton.addEventListener("click", () => setScale(state.scale - 0.1));
 el.zoomInButton.addEventListener("click", () => setScale(state.scale + 0.1));
@@ -1407,6 +1425,16 @@ async function toggleEditor() {
 		}
 		updateControls();
 		renderOutlines(false);
+		if (state.renderMode !== "svg") {
+			try {
+				await refreshRenderBackend(anchor);
+			} catch (err) {
+				state.editing = !state.editing;
+				updateControls();
+				showError(err, false);
+			}
+			return;
+		}
 		renderPageList();
 		applyFit(false);
 		restoreScaleAnchor(anchor);
@@ -2704,6 +2732,14 @@ async function loadWASM() {
 					if (data.phase === "commit") el.importCancel.disabled = el.cancelExportButton.disabled = true;
 				}
 			} else if (data.type === "ready") {
+				state.renderBackends = data.backends;
+				el.renderBackend.replaceChildren();
+				for (const name of Object.keys(data.backends)) {
+					const option = document.createElement("option");
+					option.value = name;
+					option.textContent = renderBackendLabel(name);
+					el.renderBackend.append(option);
+				}
 				state.ready = true;
 				resolve();
 			} else if (data.type === "exit") {
@@ -3091,6 +3127,69 @@ async function toggleAnnotations() {
 	});
 }

+function displayMode() {
+	return state.editing ? "svg" : state.renderMode;
+}
+
+function renderBackendLabel(name) {
+	return { svg: "SVG", canvas: "Canvas", gg: "GoGPU" }[name] || name || "无";
+}
+
+function updateRenderBackend() {
+	el.renderBackend.value = state.renderBackend;
+	el.renderDPI.value = String(state.renderDPI);
+	el.renderBackend.disabled = !state.ready || state.exporting || document.body.hasAttribute("aria-busy");
+	el.renderDPI.disabled = el.renderBackend.disabled || displayMode() === "svg";
+	el.renderVectorButton.disabled = el.renderRasterButton.disabled = el.renderBackend.disabled || state.editing;
+	el.renderVectorButton.setAttribute("aria-pressed", String(displayMode() === "svg"));
+	el.renderRasterButton.setAttribute("aria-pressed", String(displayMode() === "raster"));
+	el.renderVectorButton.title = state.editing ? "编辑使用矢量显示" : "矢量显示";
+	el.renderRasterButton.title = state.editing ? "阅读时可用" : "位图显示";
+	const backend = state.renderBackends[state.renderBackend];
+	el.renderDisplay.textContent = displayMode() === "svg" ? "SVG" : renderBackendLabel(backend?.raster);
+	el.renderImages.textContent = renderBackendLabel(backend?.raster);
+	el.renderSVG.textContent = renderBackendLabel(backend?.svg);
+	el.renderPDF.textContent = renderBackendLabel(backend?.pdf);
+	el.renderEPS.textContent = renderBackendLabel(backend?.eps);
+	el.renderCompiler.textContent = renderBackendLabel(backend?.compiler);
+}
+
+async function refreshRenderBackend(anchor = scaleAnchor(0)) {
+	const selection = state.editing ? { index: canvasEditor.selected?.index ?? state.pageIndex, ids: canvasEditor.items().map(item => item.id) } : null;
+	await openDocument({
+		pageIndex: state.pageIndex, fitMode: state.fitMode, scale: state.scale,
+		skipAutoFonts: true, reuseSession: true, keepPreview: true, keepSearch: true,
+		previewAnchor: anchor, selection, throwError: true,
+	});
+}
+
+async function changeRenderBackend(mode = state.renderMode) {
+	if (document.body.hasAttribute("aria-busy")) return;
+	const backend = el.renderBackend.value, dpi = Number(el.renderDPI.value);
+	if (state.renderBackend === backend && state.renderDPI === dpi && state.renderMode === mode) return;
+	if (state.editing && (!await canvasEditor.commitText() || !await canvasEditor.commitCrop())) {
+		updateRenderBackend();
+		return;
+	}
+	const previous = { backend: state.renderBackend, dpi: state.renderDPI, mode: state.renderMode };
+	state.renderBackend = backend;
+	state.renderDPI = dpi;
+	state.renderMode = mode;
+	updateRenderBackend();
+	if (!state.doc) return;
+	try {
+		await refreshRenderBackend();
+	} catch (err) {
+		state.renderBackend = previous.backend;
+		state.renderDPI = previous.dpi;
+		state.renderMode = previous.mode;
+		resetPageLoading();
+		state.pageCache.clear();
+		updateRenderBackend();
+		showError(err, false);
+	}
+}
+
 async function changeFont(font, changes) {
 	if (document.body.hasAttribute("aria-busy")) {
 		return;
@@ -3215,7 +3314,7 @@ async function openDocument(options = {}) {
 		return;
 	}
 	const resetLocalFonts = !options.skipAutoFonts;
-	resetSearch();
+	if (!options.keepSearch) resetSearch();
 	if (resetLocalFonts) {
 		fontManager.localFonts = [];
 		updateFontSummary();
@@ -3334,6 +3433,7 @@ async function openDocument(options = {}) {
 		if (openSeq !== state.openSeq) {
 			return;
 		}
+		if (options.throwError) throw err;
 		showError(err, true);
 	} finally {
 		if (openSeq === state.openSeq) {
@@ -3536,8 +3636,8 @@ async function exportFile(whole, indices = null, value = el.exportFormat.value)
 			setBusy(true, `正在生成 ${label}`, null, status);
 		}
 		const result = saving ? await callWASM("ofdgoSaveDocument", indices, file) : whole
-			? await callWASM("ofdgoExportDocument", format.value, dpi, indices, file)
-			: await callWASM("ofdgoExportPage", pageIndex, format.value, dpi, file);
+			? await callWASM("ofdgoExportDocument", format.value, dpi, indices, state.renderBackend, file)
+			: await callWASM("ofdgoExportPage", pageIndex, format.value, dpi, state.renderBackend, file);
 		if (openSeq !== state.openSeq) {
 			return;
 		}
@@ -3779,7 +3879,7 @@ async function processPageRenderQueue() {
 					task.resolve(state.pageCache.get(task.index));
 					continue;
 				}
-				const page = await callWASM("ofdgoRenderPage", task.index);
+				const page = await callWASM("ofdgoRenderPage", task.index, state.renderBackend, state.renderDPI, displayMode() === "raster");
 				const scope = state.composite;
 				if (scope?.index === task.index) {
 					const objects = await callWASM("ofdgoCompositeObjects", task.index, scope.key);
@@ -3900,7 +4000,7 @@ function mountPageSVG(index, page, openSeq = state.openSeq) {
 	svg.classList.add("ofd-svg");
 	surface.replaceChildren(svg);
 	surface.append(createTextLayer(page.text));
-	if (state.editorInfo) {
+	if (state.editorInfo && displayMode() === "svg") {
 		mountEditorObjects(index, page, surface);
 	}
 	mountAnnotationNotes(index, surface, page.annotations);
@@ -5956,6 +6056,7 @@ function updateFitSpace() {

 function updateControls() {
 	const hasDoc = Boolean(state.doc);
+	updateRenderBackend();
 	updateEditorTools();
 	const pageCount = state.doc ? state.doc.pageCount : 0;
 	el.prevButton.disabled = !hasDoc || state.pageIndex <= 0;
@@ -6147,6 +6248,7 @@ function showError(err, empty = !state.doc) {

 function setBusy(busy, text = "", percent = 0, status = "") {
 	document.body.toggleAttribute("aria-busy", busy);
+	updateRenderBackend();
 	el.editButton.disabled = busy || !state.doc || !state.ready || state.exporting;
 	el.createForm.inert = busy;
 	el.insertForm.inert = busy;
@@ -114,7 +114,9 @@ async function loadWASM() {
 	self.postMessage({ type: "progress", text: "正在启动引擎", percent: 58 });
 	go.run(instance).then(exitWASM, exitWASM);
 	if (!go.exited) {
-		self.postMessage({ type: "ready" });
+		const backends = JSON.parse(globalThis.ofdgoRenderBackends());
+		if (!backends.ok) throw new Error(backends.error);
+		self.postMessage({ type: "ready", backends: backends.data });
 	}
 }

@@ -4,6 +4,7 @@ go 1.26.0

 require (
 	github.com/go-text/typesetting v0.3.5
+	github.com/gogpu/gg v0.52.5
 	github.com/tdewolff/canvas v0.0.0-20260913163248-dd4999d1c76a
 	github.com/tdewolff/font v0.0.0-20260913163313-54f98bb59ee6
 	github.com/xiaoqidun/jbig2 v1.1.1
@@ -22,6 +23,8 @@ require (
 	github.com/benoitkugler/textlayout v0.3.2 // indirect
 	github.com/benoitkugler/textprocessing v0.0.6 // indirect
 	github.com/go-fonts/latin-modern v0.3.3 // indirect
+	github.com/gogpu/gpucontext v0.28.0 // indirect
+	github.com/gogpu/gputypes v0.5.2 // indirect
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
 	github.com/srwiley/rasterx v0.0.0-20220730225603-2ab79fcdd4ef // indirect
 	github.com/srwiley/scanx v0.0.0-20190309010443-e94503791388 // indirect
@@ -34,6 +34,20 @@ github.com/go-text/typesetting v0.3.5 h1:XZPUooClHY0Vf/rFyUyuPRNEkawARaFzLMQcXLS
 github.com/go-text/typesetting v0.3.5/go.mod h1:XZO1hD+nQVyvVa5IicQk7FsCa4PFQaJ2soWAP1f//68=
 github.com/go-text/typesetting-utils v0.0.0-20260419141703-4ffe8874dabc h1:8FGo2It5K75XkavhTiCKExUfVaVDS1feBnLCru5qeoY=
 github.com/go-text/typesetting-utils v0.0.0-20260419141703-4ffe8874dabc/go.mod h1:3/62I4La/HBRX9TcTpBj4eipLiwzf+vhI+7whTc9V7o=
+github.com/go-webgpu/goffi v0.6.3 h1:p4gKGikHBAQ/8iUiew9MV4C5M1ZGIsk8QGFGuJjMj+A=
+github.com/go-webgpu/goffi v0.6.3/go.mod h1:wfoxNsJkU+5RFbV1kNN1kunhc1lFHuJKK3zpgx08/uM=
+github.com/go-webgpu/webgpu v0.5.5 h1:pIrXzRg0LRlNjNmR+ZNo/ERN88YaObzbCY5oYhir5SA=
+github.com/go-webgpu/webgpu v0.5.5/go.mod h1:vgIuNTa1UlZ4njCGY6Pmp/0c5T5o2Ml2fQ0znLc7B98=
+github.com/gogpu/gg v0.52.5 h1:aDAxjwcUYWTaEcKiAVSX52FPtYKtMhuFYCQYK2SwJwE=
+github.com/gogpu/gg v0.52.5/go.mod h1:mKiEGiR8lT7BCECfSoxRYBQ96HrDc0DHv/CNDxYQG5M=
+github.com/gogpu/gpucontext v0.28.0 h1:W27+0PRnHLVRscDJ2L6r4B1JlaKjlV/EmL0Wxx8vGIc=
+github.com/gogpu/gpucontext v0.28.0/go.mod h1:5rpKj+DpixgAFm8ArBXFXOZQRbeJSFncVMsqyyA9Rhc=
+github.com/gogpu/gputypes v0.5.2 h1:3sbKI0+XW36Ekd3d4QhkbpdY7gbgMVgp8Q4+ZNdGhtE=
+github.com/gogpu/gputypes v0.5.2/go.mod h1:cnXrDMwTpWTvJLW1Vreop3PcT6a2YP/i3s91rPaOavw=
+github.com/gogpu/naga v0.18.0 h1:2y83HUcAnlwEZMuHOiYTMdNYM9J8rev40gkI4zJ96Uk=
+github.com/gogpu/naga v0.18.0/go.mod h1:15sQaHKkbqXcwTN+hHYGLsA0WBBnkmYzne/eF5p5WEg=
+github.com/gogpu/wgpu v0.31.6 h1:WIySgNZHQfUaNRCQ/AzaZpDkcZn5dggqXlRAgpWtVu4=
+github.com/gogpu/wgpu v0.31.6/go.mod h1:r8z3uZOyjl95KXN1eyMxFnwwPMZ0yuBFrLFi8v37QGY=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
 github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
@@ -102,6 +102,7 @@ func RunWASM() {
 	registerCallback("ofdgoConfigure", configureDocument)
 	registerCallback("ofdgoDocumentInfo", documentInfo)
 	registerCallback("ofdgoRenderPage", renderPage)
+	registerCallback("ofdgoRenderBackends", renderBackends)
 	registerCallback("ofdgoSVGFontData", svgFontData)
 	registerCallback("ofdgoSearchPage", searchPage)
 	registerCallback("ofdgoPageTextString", pageTextString)
@@ -181,6 +182,13 @@ func registerCallback(name string, fn func([]js.Value) (any, error)) {
 	js.Global().Set(name, cb)
 }

+// renderBackends 返回库提供的内置后端能力
+// 入参: args 浏览器参数
+// 返回: any 后端能力, error 错误信息
+func renderBackends(args []js.Value) (any, error) {
+	return ofdgo.RenderBackendInfos(), nil
+}
+
 // registerAsyncCallback 注册异步回调，为浏览器处理数据和取消请求让出事件循环
 // 入参: name 回调名称, fn 回调函数
 func registerAsyncCallback(name string, fn func([]js.Value) (any, error)) {
@@ -345,7 +353,7 @@ func svgFontData(args []js.Value) (any, error) {
 }

 // renderPage 渲染OFD页面
-// 入参: args 浏览器参数
+// 入参: args 页面索引、后端组合、DPI和光栅显示开关
 // 返回: any 页面SVG结果, error 错误信息
 func renderPage(args []js.Value) (any, error) {
 	if currentSession == nil {
@@ -354,10 +362,21 @@ func renderPage(args []js.Value) (any, error) {
 	if len(args) == 0 {
 		return nil, fmt.Errorf("missing page index")
 	}
-	page, err := currentSession.RenderPageSVG(args[0].Int())
+	backend, dpi := "canvas", 150.0
+	if len(args) > 1 {
+		backend = args[1].String()
+	}
+	if len(args) > 2 {
+		dpi = args[2].Float()
+	}
+	raster := len(args) > 3 && args[3].Bool()
+	page, err := currentSession.RenderPage(args[0].Int(), backend, dpi, raster)
 	if err != nil {
 		return nil, err
 	}
+	if currentEditor != nil {
+		currentEditor.SetPageCompiler(currentSession.Renderer.Backends().Compiler)
+	}
 	text, err := currentSession.PageText(args[0].Int())
 	if err != nil {
 		return nil, err
@@ -472,8 +491,12 @@ func exportPage(args []js.Value) (any, error) {
 	if len(args) < 4 {
 		return nil, fmt.Errorf("missing export page arguments")
 	}
-	writer := bufio.NewWriterSize(exportWriter{write: args[3]}, 1<<20)
-	format, err := currentSession.ExportPage(args[0].Int(), args[1].String(), args[2].Float(), writer)
+	session, writerIndex, err := exportSession(args)
+	if err != nil {
+		return nil, err
+	}
+	writer := bufio.NewWriterSize(exportWriter{write: args[writerIndex]}, 1<<20)
+	format, err := session.ExportPage(args[0].Int(), args[1].String(), args[2].Float(), writer)
 	if err != nil {
 		return nil, err
 	}
@@ -493,9 +516,13 @@ func exportDocument(args []js.Value) (any, error) {
 	if currentSession == nil {
 		return nil, fmt.Errorf("ofd document is not opened")
 	}
-	renderer := currentSession.Renderer
+	session, writerIndex, err := exportSession(args)
+	if err != nil {
+		return nil, err
+	}
+	renderer := session.Renderer
 	renderer.OnExportProgress = func(completed, total int) error {
-		return awaitExport(args[4], completed, total)
+		return awaitExport(args[writerIndex+1], completed, total)
 	}
 	defer func() { renderer.OnExportProgress = nil }()
 	var indices []int
@@ -505,8 +532,8 @@ func exportDocument(args []js.Value) (any, error) {
 			indices[i] = args[2].Index(i).Int()
 		}
 	}
-	writer := bufio.NewWriterSize(exportWriter{write: args[3]}, 1<<20)
-	format, err := currentSession.ExportDocument(args[0].String(), args[1].Float(), writer, indices...)
+	writer := bufio.NewWriterSize(exportWriter{write: args[writerIndex]}, 1<<20)
+	format, err := session.ExportDocument(args[0].String(), args[1].Float(), writer, indices...)
 	if err != nil {
 		return nil, err
 	}
@@ -519,6 +546,23 @@ func exportDocument(args []js.Value) (any, error) {
 	}), nil
 }

+// exportSession 创建独立导出配置，写入回调前可指定光栅后端
+// 入参: args 浏览器参数
+// 返回: *Session 导出会话, int 写入回调位置, error 错误信息
+func exportSession(args []js.Value) (*Session, int, error) {
+	session := *currentSession
+	renderer := *session.Renderer
+	session.Renderer = &renderer
+	writerIndex := 3
+	if args[3].Type() == js.TypeString {
+		if err := session.SetRenderBackend(args[3].String()); err != nil {
+			return nil, 0, err
+		}
+		writerIndex++
+	}
+	return &session, writerIndex, nil
+}
+
 // successResult 创建成功接口结果
 // 入参: data 返回数据
 // 返回: js.Value 接口结果
@@ -2737,6 +2781,7 @@ func editDocument(args []js.Value) (any, error) {
 	if currentSession.fontFS != nil {
 		editor.SetFontFS(currentSession.fontFS)
 	}
+	editor.SetPageCompiler(currentSession.Renderer.Backends().Compiler)
 	currentEditor = editor
 	currentSession.editing = true
 	copiedObjects = nil
@@ -2758,6 +2803,7 @@ func previewEditor(editor *ofdgo.Editor, annotations bool) (editorInfo, error) {
 	}
 	editor.SetFontFS()
 	if currentSession != nil {
+		ofdgo.WithRenderBackends(currentSession.Renderer.Backends())(session.Renderer)
 		if currentSession.fontFS != nil {
 			session.fontFS = currentSession.fontFS
 			session.Renderer.SetFontFS(session.fontFS)
@@ -2765,6 +2811,7 @@ func previewEditor(editor *ofdgo.Editor, annotations bool) (editorInfo, error) {
 		}
 		_ = currentSession.Close()
 	}
+	editor.SetPageCompiler(session.Renderer.Backends().Compiler)
 	currentSession = session
 	session.editing = true
 	if currentEditor != editor {
@@ -479,6 +479,18 @@ func (s *Session) Info() DocumentInfo {
 // 入参: index 页面索引
 // 返回: PageSVG 页面SVG结果, error 错误信息
 func (s *Session) RenderPageSVG(index int) (PageSVG, error) {
+	return s.RenderPage(index, "", 0, false)
+}
+
+// RenderPage 按显示后端生成页面，光栅结果复用SVG容器和独立交互信息
+// 入参: index 页面索引, backend 后端组合，空值沿用会话配置, dpi 光栅分辨率, raster 是否光栅显示
+// 返回: PageSVG 页面结果, error 错误信息
+func (s *Session) RenderPage(index int, backend string, dpi float64, raster bool) (PageSVG, error) {
+	if backend != "" {
+		if err := s.SetRenderBackend(backend); err != nil {
+			return PageSVG{}, err
+		}
+	}
 	page, err := s.pageContent(index)
 	if err != nil {
 		return PageSVG{}, err
@@ -494,11 +506,10 @@ func (s *Session) RenderPageSVG(index int) (PageSVG, error) {
 			s.textCache[index] = text
 		}
 	}
-	renderSVG := renderer.RenderToSVGWithResources
-	if s.editing {
-		renderSVG = renderer.RenderToSVGWithObjects
+	if raster {
+		renderer.DPI = dpi
 	}
-	resources, err := renderSVG(page, &buf)
+	resources, err := renderer.RenderPreview(page, &buf, ofdgo.PreviewOptions{Raster: raster, Objects: !raster && s.editing})
 	if err != nil {
 		return PageSVG{}, err
 	}
@@ -517,6 +528,21 @@ func (s *Session) RenderPageSVG(index int) (PageSVG, error) {
 	return PageSVG{Index: index, Number: index + 1, ID: page.ID, Width: box.W, Height: box.H, SVG: buf.String(), Links: links, Fonts: resources.Fonts, Images: resources.Images, Annotations: annotations}, nil
 }

+// SetRenderBackend 设置库提供的后端组合，不改变文档数据
+// 入参: name 后端名称
+// 返回: error 错误信息
+func (s *Session) SetRenderBackend(name string) error {
+	backends, err := ofdgo.NewRenderBackends(name)
+	if err != nil {
+		return err
+	}
+	if s.Renderer.Backends().Info().Compiler != backends.Info().Compiler {
+		clear(s.textCache)
+	}
+	ofdgo.WithRenderBackends(backends)(s.Renderer)
+	return nil
+}
+
 // SVGFontData 获取已渲染页面引用的字体数据
 // 入参: name 字体资源标识
 // 返回: []byte 字体数据, error 错误信息
@@ -73,6 +73,7 @@ func NewRenderer(reader *Reader, opts ...RendererOption) *Renderer {
 		CompositeGraphicUnits: reader.compositeGraphicUnitCache,
 		templatePageCache:     make(map[string]*PageContent),
 		imageCache:            make(map[string]image.Image),
+		backends:              defaultRenderBackends(),
 	}
 	r.resetFontCache()
 	for _, opt := range opts {
@@ -0,0 +1,201 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"errors"
+	"fmt"
+	"image"
+	"io"
+)
+
+// ErrBackendUnavailable 表示未配置所需后端，不会自动切换其他实现
+var ErrBackendUnavailable = errors.New("render backend unavailable")
+
+// Backend 提供稳定的后端标识，不包含前端文案
+type Backend interface {
+	Name() string
+}
+
+// RasterBackend 消费只读页面，返回独立图像，不得静默跳过指令或切换其他后端
+type RasterBackend interface {
+	Backend
+	Render(*RasterPage) (image.Image, error)
+}
+
+// PageCompiler 统一页面编译、文字提取和对象度量，不得修改源数据
+// 三项能力需采用相同的字体和几何语义，避免绘制、搜索与选区不一致
+// renderer提供文档、字体配置和文字回调，实现中不得递归调用对应的Renderer方法
+// CompilePage在配置OnPageText时需同步回报文字，PageText和MeasureObject不触发回调
+type PageCompiler interface {
+	Backend
+	CompilePage(renderer *Renderer, page *PageContent) (*RasterPage, error)
+	PageText(renderer *Renderer, page *PageContent) (*PageText, error)
+	MeasureObject(renderer *Renderer, object GraphicObject, options MeasureOptions) (ObjectMeasurement, error)
+}
+
+// MeasureOptions 描述对象度量上下文，坐标以页面左上角为原点，单位为毫米
+// Defaults为继承样式，Parent为父变换，BoundaryInCTM指定边界是否参与父变换
+// Clip为页面坐标中的非零填充裁剪，nil表示不裁剪，空路径表示全部裁去
+// Contours决定是否收集填充轮廓，关闭时文字采用逐字符范围
+type MeasureOptions struct {
+	Defaults      *DrawParam
+	Parent        *Matrix
+	BoundaryInCTM bool
+	Clip          *GeometryPath
+	Contours      bool
+}
+
+// ObjectMeasurement 保存对象在页面坐标中的范围与可选轮廓
+type ObjectMeasurement struct {
+	Bounds   Box
+	Contours []ObjectContour
+}
+
+// SVGMode 指定SVG资源封装方式，Objects模式还需保留稳定的对象分组
+type SVGMode uint8
+
+const (
+	SVGEmbedded SVGMode = iota
+	SVGExternalFonts
+	SVGExternalResources
+	SVGObjects
+)
+
+// SVGBackend 输出SVG及资源，不得修改源页面或省略不支持的内容
+// renderer提供文档和排版能力，输出时不得再次调用RenderToSVG系列方法
+type SVGBackend interface {
+	Backend
+	RenderSVG(renderer *Renderer, page *PageContent, writer io.Writer, mode SVGMode) (SVGResources, error)
+}
+
+// RenderDocumentPage 保存已解析页面和物理区域，不得修改源页面内容
+type RenderDocumentPage struct {
+	Content *PageContent
+	Box     Box
+}
+
+// PDFBackend 输出完整PDF，保留文字、链接、目录和文档信息
+// pages交由后端消费，可逐页清空Content以释放引用，不得改变页面顺序
+// progress返回错误时应停止输出，调用方在失败后丢弃输出
+type PDFBackend interface {
+	Backend
+	RenderPDF(renderer *Renderer, pages []RenderDocumentPage, writer io.Writer, progress func(int, int) error) error
+}
+
+// EPSBackend 输出单页EPS，不得修改源页面
+type EPSBackend interface {
+	Backend
+	RenderEPS(renderer *Renderer, page *PageContent, writer io.Writer) error
+}
+
+// RenderBackends 按职责组合后端，nil表示明确禁用，不隐式回退
+// 实例及其Renderer需串行使用，第三方实现无需引用任何内置绘图库
+type RenderBackends struct {
+	Compiler PageCompiler
+	Raster   RasterBackend
+	SVG      SVGBackend
+	PDF      PDFBackend
+	EPS      EPSBackend
+}
+
+// BackendInfo 描述各项能力实际使用的后端，空标识表示未配置
+type BackendInfo struct {
+	Compiler string `json:"compiler"`
+	Raster   string `json:"raster"`
+	SVG      string `json:"svg"`
+	PDF      string `json:"pdf"`
+	EPS      string `json:"eps"`
+}
+
+// NewRenderBackends 创建内置后端组合，gg仅替换光栅绘制，其他能力通过Info明确报告
+// 入参: name canvas或gg
+// 返回: RenderBackends 后端组合, error 未知后端错误
+func NewRenderBackends(name string) (RenderBackends, error) {
+	backends := defaultRenderBackends()
+	switch name {
+	case "canvas":
+	case "gg":
+		backends.Raster = GGBackend{}
+	default:
+		return RenderBackends{}, fmt.Errorf("unknown render backend %q", name)
+	}
+	return backends, nil
+}
+
+// RenderBackendInfos 列出内置组合及其实际能力，供原生程序和WASM共用
+// 返回: map[string]BackendInfo 后端能力
+func RenderBackendInfos() map[string]BackendInfo {
+	result := make(map[string]BackendInfo, 2)
+	for _, name := range []string{"canvas", "gg"} {
+		backends, _ := NewRenderBackends(name)
+		result[name] = backends.Info()
+	}
+	return result
+}
+
+// defaultRenderBackends 创建独立的默认配置
+// 返回: RenderBackends 默认后端组合
+func defaultRenderBackends() RenderBackends {
+	backend := CanvasBackend{}
+	return RenderBackends{Compiler: backend, Raster: backend, SVG: backend, PDF: backend, EPS: backend}
+}
+
+// Info 返回配置中各能力的提供者，不依赖WebUI推断
+// 返回: BackendInfo 后端能力
+func (b RenderBackends) Info() BackendInfo {
+	return BackendInfo{Compiler: backendName(b.Compiler), Raster: backendName(b.Raster), SVG: backendName(b.SVG), PDF: backendName(b.PDF), EPS: backendName(b.EPS)}
+}
+
+// backendName 获取已配置的后端标识
+// 入参: backend 后端实例
+// 返回: string 后端标识，未配置时为空
+func backendName(backend Backend) string {
+	if backend == nil {
+		return ""
+	}
+	return backend.Name()
+}
+
+// WithRenderBackends 替换完整后端组合，未配置的能力不会沿用默认实现
+// 入参: backends 后端组合
+// 返回: RendererOption 渲染选项
+func WithRenderBackends(backends RenderBackends) RendererOption {
+	return func(r *Renderer) { r.backends = backends }
+}
+
+// Backends 返回当前后端配置副本，可修改后通过WithRenderBackends应用
+// 返回: RenderBackends 后端组合
+func (r *Renderer) Backends() RenderBackends {
+	return r.backends
+}
+
+// WithRasterBackend 选择当前渲染器的图像、PNG和JPEG后端，不改变SVG、PDF或OFD保存
+// 入参: backend 光栅后端，nil禁用图像输出
+// 返回: RendererOption 渲染选项
+func WithRasterBackend(backend RasterBackend) RendererOption {
+	return func(r *Renderer) { r.backends.Raster = backend }
+}
+
+// CompilePage 编译与后端无关的光栅页面，可交给任意RasterBackend绘制
+// 字形、描边、裁剪和底纹沿用文档语义，不交由后端重新排版
+// 入参: page 页面内容
+// 返回: *RasterPage 只读绘制页面, error 编译错误
+func (r *Renderer) CompilePage(page *PageContent) (*RasterPage, error) {
+	if r.backends.Compiler == nil {
+		return nil, fmt.Errorf("page compiler: %w", ErrBackendUnavailable)
+	}
+	return r.backends.Compiler.CompilePage(r, page)
+}
@@ -0,0 +1,106 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+
+	"github.com/tdewolff/canvas"
+	"github.com/tdewolff/canvas/renderers/rasterizer"
+)
+
+// CanvasBackend canvas页面编译与绘制适配器，ColorSpace仅影响光栅输出
+type CanvasBackend struct {
+	ColorSpace canvas.ColorSpace
+}
+
+// Name 返回后端标识
+// 返回: string 后端标识
+func (CanvasBackend) Name() string { return "canvas" }
+
+// Render 绘制已编译页面，不修改输入数据
+// 入参: page 只读页面
+// 返回: image.Image 图像, error 绘制错误
+func (b CanvasBackend) Render(page *RasterPage) (image.Image, error) {
+	w, h, err := page.PixelSize()
+	if err != nil {
+		return nil, err
+	}
+	img := image.NewRGBA(image.Rect(0, 0, w, h))
+	space := b.ColorSpace
+	if space == nil {
+		space = canvas.DefaultColorSpace
+	}
+	r := rasterizer.FromImage(img, canvas.DPMM(page.DPI/25.4), space)
+	for i, cmd := range page.Commands {
+		if cmd.Image != nil {
+			source := cmd.Image
+			if _, linear := space.(canvas.LinearColorSpace); !linear {
+				converted := image.NewRGBA(source.Bounds())
+				for y := source.Bounds().Min.Y; y < source.Bounds().Max.Y; y++ {
+					for x := source.Bounds().Min.X; x < source.Bounds().Max.X; x++ {
+						converted.SetRGBA(x, y, space.ToLinear(color.RGBAModel.Convert(source.At(x, y)).(color.RGBA)))
+					}
+				}
+				source = converted
+			}
+			drawRasterImage(img, source, page.PixelTransform(cmd.Transform, h))
+			continue
+		}
+		p := &canvas.Path{}
+		for _, s := range cmd.Path {
+			switch s.Verb {
+			case RasterMove:
+				p.MoveTo(s.End.X, s.End.Y)
+			case RasterLine:
+				p.LineTo(s.End.X, s.End.Y)
+			case RasterQuad:
+				p.QuadTo(s.Control1.X, s.Control1.Y, s.End.X, s.End.Y)
+			case RasterCubic:
+				p.CubeTo(s.Control1.X, s.Control1.Y, s.Control2.X, s.Control2.Y, s.End.X, s.End.Y)
+			case RasterClose:
+				p.Close()
+			default:
+				return nil, fmt.Errorf("canvas command %d: unsupported path verb %d", i, s.Verb)
+			}
+		}
+		paint := canvas.Paint{Color: cmd.Paint.Color}
+		if g := cmd.Paint.Gradient; g != nil {
+			stops := make(canvas.Grad, len(g.Stops))
+			for j, stop := range g.Stops {
+				stops[j] = canvas.Stop{Offset: stop.Offset, Color: stop.Color}
+			}
+			start, end := canvas.Point{X: g.Start.X, Y: g.Start.Y}, canvas.Point{X: g.End.X, Y: g.End.Y}
+			switch g.Kind {
+			case RasterLinear:
+				paint = canvas.Paint{Gradient: stops.ToLinear(start, end)}
+			case RasterRadial:
+				paint = canvas.Paint{Gradient: stops.ToRadial(start, g.R0, end, g.R1)}
+			default:
+				return nil, fmt.Errorf("canvas command %d: unsupported gradient %d", i, g.Kind)
+			}
+		}
+		style := canvas.Style{Fill: paint, FillRule: canvas.NonZero}
+		if cmd.EvenOdd {
+			style.FillRule = canvas.EvenOdd
+		}
+		m := cmd.Transform
+		r.RenderPath(p, style, canvas.Matrix{{m[0], m[2], m[4]}, {-m[1], -m[3], page.Height - m[5]}})
+	}
+	r.Close()
+	return img, nil
+}
@@ -0,0 +1,164 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"fmt"
+	"image"
+	"image/draw"
+
+	"github.com/tdewolff/canvas"
+)
+
+// CompilePage 使用默认字体和几何解释器生成独立绘制数据
+// 入参: r 渲染器, page 页面内容
+// 返回: *RasterPage 绘制页面, error 编译错误
+func (CanvasBackend) CompilePage(r *Renderer, page *PageContent) (*RasterPage, error) {
+	box, err := r.GetPageBox(page)
+	if err != nil {
+		return nil, err
+	}
+	result := &RasterPage{Width: box.W, Height: box.H, DPI: r.DPI}
+	if _, _, err := result.PixelSize(); err != nil {
+		return nil, err
+	}
+	compiler := &canvasPageCompiler{page: result}
+	if err := r.renderCanvasContext(canvas.NewContext(compiler), page); err != nil {
+		return nil, err
+	}
+	if compiler.err != nil {
+		return nil, compiler.err
+	}
+	return result, nil
+}
+
+// canvasPageCompiler 将已解释的页面绘制转换为自有数据，不保存第三方绘图对象
+type canvasPageCompiler struct {
+	page *RasterPage
+	err  error
+}
+
+// Size 返回物理页面尺寸
+// 返回: float64 宽度, float64 高度
+func (c *canvasPageCompiler) Size() (float64, float64) { return c.page.Width, c.page.Height }
+
+// RenderPath 记录填充并按当前DPI展开描边轮廓
+// 入参: path 路径, style 绘制样式, m 变换矩阵
+func (c *canvasPageCompiler) RenderPath(path *canvas.Path, style canvas.Style, m canvas.Matrix) {
+	if c.err != nil {
+		return
+	}
+	if style.HasFill() {
+		c.fill(path, style.Fill, style.FillRule, m)
+	}
+	if style.HasStroke() {
+		stroke := path
+		if len(style.Dashes) > 0 {
+			offset, dashes := canvas.ScaleDash(style.StrokeWidth, style.DashOffset, style.Dashes)
+			stroke = stroke.Dash(offset, dashes...)
+		}
+		stroke = stroke.Stroke(style.StrokeWidth, style.StrokeCapper, style.StrokeJoiner, canvas.PixelTolerance/(c.page.DPI/25.4))
+		c.fill(stroke, style.Stroke, style.FillRule, m)
+	}
+}
+
+// fill 转换路径和画刷，未知类型返回错误而非丢弃内容
+// 入参: path 路径, paint 画刷, rule 填充规则, m 变换矩阵
+func (c *canvasPageCompiler) fill(path *canvas.Path, paint canvas.Paint, rule canvas.FillRule, m canvas.Matrix) {
+	if c.err != nil || path.Empty() {
+		return
+	}
+	if paint.Pattern != nil {
+		c.err = fmt.Errorf("unsupported raster pattern %T", paint.Pattern)
+		return
+	}
+	cmd := RasterCommand{Paint: RasterPaint{Color: paint.Color}, EvenOdd: rule == canvas.EvenOdd,
+		Transform: RasterMatrix{m[0][0], -m[1][0], m[0][1], -m[1][1], m[0][2], c.page.Height - m[1][2]}}
+	if paint.Gradient != nil {
+		g := &RasterGradient{}
+		var stops canvas.Grad
+		switch source := paint.Gradient.(type) {
+		case *canvas.LinearGradient:
+			g.Kind, g.Start, g.End = RasterLinear, rasterPoint(source.Start), rasterPoint(source.End)
+			stops = source.Grad
+		case *canvas.RadialGradient:
+			g.Kind, g.Start, g.End = RasterRadial, rasterPoint(source.C0), rasterPoint(source.C1)
+			g.R0, g.R1, stops = source.R0, source.R1, source.Grad
+		default:
+			c.err = fmt.Errorf("unsupported raster gradient %T", paint.Gradient)
+			return
+		}
+		g.Stops = make([]RasterStop, len(stops))
+		for i, stop := range stops {
+			g.Stops[i] = RasterStop{Offset: stop.Offset, Color: stop.Color}
+		}
+		cmd.Paint.Gradient = g
+	}
+	path = path.ReplaceArcs()
+	cmd.Path = make([]RasterSegment, 0, path.Len())
+	scanner := path.Scanner()
+	for scanner.Scan() {
+		s := RasterSegment{End: rasterPoint(scanner.End())}
+		switch scanner.Cmd() {
+		case canvas.MoveToCmd:
+			s.Verb = RasterMove
+		case canvas.LineToCmd:
+			s.Verb = RasterLine
+		case canvas.QuadToCmd:
+			s.Verb, s.Control1 = RasterQuad, rasterPoint(scanner.CP1())
+		case canvas.CubeToCmd:
+			s.Verb, s.Control1, s.Control2 = RasterCubic, rasterPoint(scanner.CP1()), rasterPoint(scanner.CP2())
+		case canvas.CloseCmd:
+			s.Verb = RasterClose
+		default:
+			c.err = fmt.Errorf("unsupported raster path command %g", scanner.Cmd())
+			return
+		}
+		cmd.Path = append(cmd.Path, s)
+	}
+	c.page.Commands = append(c.page.Commands, cmd)
+}
+
+// rasterPoint 转换局部坐标点
+// 入参: p 默认引擎坐标点
+// 返回: RasterPoint 独立坐标点
+func rasterPoint(p canvas.Point) RasterPoint { return RasterPoint{X: p.X, Y: p.Y} }
+
+// RenderText 展开已定位字形，使用与目标DPI一致的字形精度
+// 入参: text 文字, m 变换矩阵
+func (c *canvasPageCompiler) RenderText(text *canvas.Text, m canvas.Matrix) {
+	if c.err == nil {
+		text.RenderTo(c, m, canvas.DPMM(c.page.DPI/25.4))
+	}
+}
+
+// RenderImage 记录按像素左上原点定位的图片，旋转或斜切时补充透明采样边距
+// 入参: img 图片, m 变换矩阵
+func (c *canvasPageCompiler) RenderImage(img image.Image, m canvas.Matrix) {
+	if c.err != nil {
+		return
+	}
+	img = imagePixelSource(img)
+	if (m[0][1] != 0 || m[1][0] != 0) && (m[0][0] != 0 || m[1][1] == 0) {
+		bounds := img.Bounds()
+		padded := image.NewRGBA(image.Rect(0, 0, bounds.Dx()+8, bounds.Dy()+8))
+		draw.Draw(padded, image.Rect(4, 4, bounds.Dx()+4, bounds.Dy()+4), img, bounds.Min, draw.Src)
+		img = padded
+		m = m.Translate(-4, -4)
+	}
+	h := float64(img.Bounds().Dy())
+	t := RasterMatrix{m[0][0], -m[1][0], -m[0][1], m[1][1], m[0][2] + m[0][1]*h, c.page.Height - m[1][2] - m[1][1]*h}
+	c.page.Commands = append(c.page.Commands, RasterCommand{Image: img, Transform: t})
+}
@@ -0,0 +1,312 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"fmt"
+	"image"
+
+	"github.com/tdewolff/canvas"
+)
+
+// canvasGeometryPath 将页面坐标路径转换为默认几何引擎的向上纵轴
+// 入参: path 独立几何路径，nil表示不裁剪
+// 返回: *canvas.Path 默认引擎路径, error 不支持的路径指令
+func canvasGeometryPath(path *GeometryPath) (*canvas.Path, error) {
+	if path == nil {
+		return nil, nil
+	}
+	p := &canvas.Path{}
+	for _, segment := range *path {
+		switch segment.Verb {
+		case GeometryMove:
+			p.MoveTo(segment.End.X, -segment.End.Y)
+		case GeometryLine:
+			p.LineTo(segment.End.X, -segment.End.Y)
+		case GeometryQuad:
+			p.QuadTo(segment.Control1.X, -segment.Control1.Y, segment.End.X, -segment.End.Y)
+		case GeometryCubic:
+			p.CubeTo(segment.Control1.X, -segment.Control1.Y, segment.Control2.X, -segment.Control2.Y, segment.End.X, -segment.End.Y)
+		case GeometryArc:
+			p.ArcTo(segment.RadiusX, segment.RadiusY, -segment.Rotation, segment.Large, !segment.Sweep, segment.End.X, -segment.End.Y)
+		case GeometryClose:
+			p.Close()
+		default:
+			return nil, fmt.Errorf("unsupported geometry command %d", segment.Verb)
+		}
+	}
+	return p, nil
+}
+
+// geometryCanvasPath 将默认引擎路径转换为独立的页面坐标路径，保留曲线和椭圆弧
+// 入参: path 默认引擎路径
+// 返回: *GeometryPath 独立路径，nil表示不裁剪
+func geometryCanvasPath(path *canvas.Path) *GeometryPath {
+	if path == nil {
+		return nil
+	}
+	result := make(GeometryPath, 0, path.Len())
+	scanner := path.Scanner()
+	for scanner.Scan() {
+		end := scanner.End()
+		segment := GeometrySegment{End: Point{X: end.X, Y: -end.Y}}
+		switch scanner.Cmd() {
+		case canvas.MoveToCmd:
+			segment.Verb = GeometryMove
+		case canvas.LineToCmd:
+			segment.Verb = GeometryLine
+		case canvas.QuadToCmd:
+			control := scanner.CP1()
+			segment.Verb, segment.Control1 = GeometryQuad, Point{X: control.X, Y: -control.Y}
+		case canvas.CubeToCmd:
+			c1, c2 := scanner.CP1(), scanner.CP2()
+			segment.Verb = GeometryCubic
+			segment.Control1, segment.Control2 = Point{X: c1.X, Y: -c1.Y}, Point{X: c2.X, Y: -c2.Y}
+		case canvas.ArcToCmd:
+			segment.Verb = GeometryArc
+			segment.RadiusX, segment.RadiusY, segment.Rotation, segment.Large, segment.Sweep = scanner.Arc()
+			segment.Rotation, segment.Sweep = -segment.Rotation, !segment.Sweep
+		case canvas.CloseCmd:
+			segment.Verb = GeometryClose
+		}
+		result = append(result, segment)
+	}
+	return &result
+}
+
+// MeasureObject 使用默认解释器度量对象，不分配页面像素
+// 入参: r 渲染器, object 图形对象, options 度量上下文
+// 返回: ObjectMeasurement 度量结果, error 错误信息
+func (CanvasBackend) MeasureObject(r *Renderer, object GraphicObject, options MeasureOptions) (ObjectMeasurement, error) {
+	if object.Type != "TextObject" && object.Type != "PathObject" && object.Type != "ImageObject" && object.Type != "CompositeObject" && object.Type != "CompositeGraphicUnit" {
+		return ObjectMeasurement{}, fmt.Errorf("unsupported object type %q", object.Type)
+	}
+	boundary, ctm := editorGeometry(object)
+	if _, err := creationBox(boundary); err != nil {
+		return ObjectMeasurement{}, err
+	}
+	if ctm != "" {
+		if _, err := creationNumbers(ctm, 6); err != nil {
+			return ObjectMeasurement{}, err
+		}
+	}
+	clip, err := canvasGeometryPath(options.Clip)
+	if err != nil {
+		return ObjectMeasurement{}, err
+	}
+	bounds := &boundsRenderer{collect: options.Contours}
+	renderer := *r
+	renderer.pageText = nil
+	renderer.textOnly = false
+	defaults := options.Defaults
+	ctx := canvas.NewContext(bounds)
+	switch object.Type {
+	case "TextObject":
+		if options.Contours {
+			renderer.renderText(ctx, object.TextObject, 0, defaults, options.Parent, options.BoundaryInCTM, clip)
+			break
+		}
+		renderer.pageText = &PageText{}
+		renderer.textOnly = true
+		renderer.renderText(ctx, object.TextObject, 0, defaults, options.Parent, options.BoundaryInCTM, clip)
+		var box Box
+		for _, run := range renderer.pageText.Runs {
+			for _, glyph := range run.Boxes {
+				box = unionTextBox(box, glyph)
+			}
+		}
+		return ObjectMeasurement{Bounds: box}, nil
+	case "PathObject":
+		obj := object.PathObject
+		defaults = renderer.drawParamDefaults(obj.DrawParam, defaults)
+		obj.DrawParam = ""
+		if defaults != nil {
+			style := *defaults
+			style.FillColor = boundsColor(style.FillColor)
+			style.StrokeColor = (*StrokeColor)(boundsColor((*FillColor)(style.StrokeColor)))
+			defaults = &style
+		}
+		obj.FillColor = boundsColor(obj.FillColor)
+		obj.StrokeColor = (*StrokeColor)(boundsColor((*FillColor)(obj.StrokeColor)))
+		renderer.renderPath(ctx, obj, 0, defaults, options.Parent, options.BoundaryInCTM, clip)
+	case "ImageObject":
+		renderer.measureImage(ctx, object.ImageObject, 0, options.Parent, options.BoundaryInCTM, clip)
+	case "CompositeObject", "CompositeGraphicUnit":
+		renderer.renderCompositeGraphicUnit(ctx, object.CompositeGraphicUnit, 0, defaults, options.Parent, options.BoundaryInCTM, clip)
+	}
+	return ObjectMeasurement{Bounds: bounds.box, Contours: bounds.contours}, nil
+}
+
+// measureImage 复用图片变换与裁剪语义度量范围，不读取像素数据
+// 入参: ctx 度量画布, obj 图片, pageH 页面高度, parentCTM 父变换, boundaryInCTM 边界是否参与变换, parentClip 父裁剪
+func (r *Renderer) measureImage(ctx *canvas.Context, obj ImageObject, pageH float64, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) {
+	if obj.Visible != nil && !*obj.Visible || obj.Alpha != nil && *obj.Alpha == 0 {
+		return
+	}
+	box, _ := ParseBox(obj.Boundary)
+	ctm := NewMatrix(obj.CTM)
+	if obj.CTM == "" {
+		ctm = Matrix{a: box.W, d: box.H}
+	}
+	m := TranslationMatrix(box.X, box.Y).Multiply(ctm)
+	if parentCTM != nil {
+		if boundaryInCTM {
+			m = parentCTM.Multiply(m)
+		} else {
+			m = TranslationMatrix(box.X, box.Y).Multiply(*parentCTM).Multiply(ctm)
+		}
+	}
+	p := canvas.Rectangle(1, 1).Transform(canvas.Matrix{{m.a, m.c, m.e}, {-m.b, -m.d, pageH - m.f}})
+	clip := intersectClipPath(parentClip, r.buildObjectClipPath(obj.Clips, pageH, box.X, box.Y, ctm, parentCTM, boundaryInCTM))
+	ctx.Renderer.(*boundsRenderer).add(applyClipPath(p, clip))
+	if obj.Border != nil {
+		border := *obj.Border
+		border.BorderColor = (*StrokeColor)(boundsColor((*FillColor)(border.BorderColor)))
+		obj.Border = &border
+		r.renderImageBorder(ctx, obj, box, pageH, parentCTM, boundaryInCTM, clip)
+	}
+}
+
+// boundsColor 以底纹的基础颜色和透明度度量轮廓，不修改原画刷
+// 入参: color 填充或描边颜色
+// 返回: *FillColor 用于度量的颜色
+func boundsColor(color *FillColor) *FillColor {
+	if color == nil || color.Pattern == nil {
+		return color
+	}
+	return &FillColor{Value: color.Value, Index: color.Index, ColorSpace: color.ColorSpace, Alpha: color.Alpha}
+}
+
+// boundsRenderer 收集绘制范围，不分配页面像素或合并独立图形轮廓
+type boundsRenderer struct {
+	box      Box
+	collect  bool
+	contours []ObjectContour
+}
+
+// Size 返回不限定边界的度量画布尺寸
+// 返回: float64 宽度, float64 高度
+func (r *boundsRenderer) Size() (float64, float64) {
+	return 0, 0
+}
+
+// add 合并路径的精确曲线范围并转换为向下的纵轴
+// 入参: path 绘制路径
+func (r *boundsRenderer) add(path *canvas.Path) {
+	r.addContour(path, false)
+}
+
+// addContour 合并范围并按需保留独立填充区域
+// 入参: path 绘制路径, evenOdd 是否使用奇偶规则
+func (r *boundsRenderer) addContour(path *canvas.Path, evenOdd bool) {
+	if path.Empty() {
+		return
+	}
+	rect := path.Bounds()
+	r.box = unionTextBox(r.box, Box{X: rect.X0, Y: -rect.Y1, W: rect.W(), H: rect.H()})
+	if r.collect {
+		outline := &canvas.Path{}
+		for _, subpath := range path.Split() {
+			subpath = subpath.Copy()
+			subpath.Close()
+			outline = outline.Append(subpath)
+		}
+		r.contours = append(r.contours, ObjectContour{Path: outline.Transform(canvas.Matrix{{1, 0, 0}, {0, -1, 0}}).ToSVG(), EvenOdd: evenOdd})
+	}
+}
+
+// RenderPath 收集填充与描边范围，保持线帽、连接和虚线语义
+// 入参: path 路径, style 绘制样式, m 变换矩阵
+func (r *boundsRenderer) RenderPath(path *canvas.Path, style canvas.Style, m canvas.Matrix) {
+	if style.HasFill() {
+		r.addContour(path.Copy().Transform(m), style.FillRule == canvas.EvenOdd)
+	}
+	if style.HasStroke() {
+		p := path.Dash(style.DashOffset, style.Dashes...).Stroke(style.StrokeWidth, style.StrokeCapper, style.StrokeJoiner, canvas.Tolerance)
+		r.add(p.Transform(m))
+	}
+}
+
+// RenderText 收集绘制文字范围
+// 入参: text 文字, m 变换矩阵
+func (r *boundsRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
+	text.RenderTo(r, m, 0)
+}
+
+// RenderImage 度量不展开底纹图片
+// 入参: img 图片, m 变换矩阵
+func (r *boundsRenderer) RenderImage(img image.Image, m canvas.Matrix) {}
+
+// PageText 使用默认解释器提取原文与字形位置
+// 入参: r 渲染器, page 页面内容
+// 返回: *PageText 页面文字, error 错误信息
+func (CanvasBackend) PageText(r *Renderer, page *PageContent) (*PageText, error) {
+	box, err := r.GetPageBox(page)
+	if err != nil {
+		return nil, err
+	}
+	renderer := *r
+	renderer.OnPageText = nil
+	renderer.pageText = &PageText{}
+	renderer.textOnly = true
+	if err := renderer.renderPageToContext(canvas.NewContext(canvas.New(box.W, box.H)), page, false); err != nil {
+		return nil, err
+	}
+	return renderer.pageText, nil
+}
+
+// textPathBox 将字形轮廓转换为页面区域
+// 入参: path 字形轮廓, pageH 页面高度
+// 返回: Box 字符区域
+func textPathBox(path *canvas.Path, pageH float64) Box {
+	if path.Empty() {
+		return Box{}
+	}
+	bounds := path.Bounds()
+	return Box{X: bounds.X0, Y: pageH - bounds.Y1, W: bounds.X1 - bounds.X0, H: bounds.Y1 - bounds.Y0}
+}
+
+// addSpan 收集字形选择区域，同一原文区间的多个字形合并为一项
+// 入参: start 起始字符, end 结束字符, bounds 字形布局区域, m 字形变换, clip 裁剪路径, pageH 页面高度
+func (run *TextRun) addSpan(start, end int, bounds canvas.Rect, m canvas.Matrix, clip *canvas.Path, pageH float64) {
+	if m.Det() == 0 {
+		return
+	}
+	if clip != nil {
+		path := canvas.Rectangle(bounds.W(), bounds.H()).Translate(bounds.X0, bounds.Y0).Transform(m)
+		path = applyClipPath(path, clip)
+		if path.Empty() {
+			return
+		}
+		bounds = path.Transform(m.Inv()).Bounds()
+	}
+	if bounds.W() < 0 || bounds.H() <= 0 {
+		return
+	}
+	m = canvas.Matrix{{1, 0, 0}, {0, -1, pageH}}.Mul(m).Translate(bounds.X0, bounds.Y1).Scale(bounds.W(), -bounds.H())
+	span := TextSpan{Start: start, End: end}
+	if n := len(run.Spans); n > 0 && run.Spans[n-1].Start == start && run.Spans[n-1].End == end {
+		span = run.Spans[n-1]
+		v := span.Matrix
+		previous := canvas.Matrix{{v[0], v[2], v[4]}, {v[1], v[3], v[5]}}
+		if previous.Det() != 0 {
+			bounds = canvas.Rect{X1: 1, Y1: 1}.Add(canvas.Rect{X1: 1, Y1: 1}.Transform(previous.Inv().Mul(m)))
+			m = previous.Translate(bounds.X0, bounds.Y0).Scale(bounds.W(), bounds.H())
+		}
+		run.Spans = run.Spans[:n-1]
+	}
+	span.Matrix = [6]float64{m[0][0], m[1][0], m[0][1], m[1][1], m[0][2], m[1][2]}
+	run.Spans = append(run.Spans, span)
+}
@@ -0,0 +1,137 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+
+	"github.com/tdewolff/canvas"
+	"github.com/tdewolff/canvas/renderers/pdf"
+	"github.com/tdewolff/canvas/renderers/ps"
+	"github.com/tdewolff/canvas/renderers/svg"
+)
+
+// RenderSVG 使用canvas输出SVG，按模式保留资源和对象分组
+// 入参: r 渲染器, page 页面内容, writer 输出流, mode 资源模式
+// 返回: SVGResources 外部资源, error 错误信息
+func (CanvasBackend) RenderSVG(r *Renderer, page *PageContent, writer io.Writer, mode SVGMode) (SVGResources, error) {
+	switch mode {
+	case SVGExternalFonts:
+		return r.renderSVGResources(page, writer, false, false)
+	case SVGExternalResources:
+		return r.renderSVGResources(page, writer, true, false)
+	case SVGObjects:
+		return r.renderSVGResources(page, writer, true, true)
+	case SVGEmbedded:
+		c, err := r.renderPage(page)
+		if err != nil {
+			return SVGResources{}, err
+		}
+		buffer := bufio.NewWriter(writer)
+		renderer := svg.New(buffer, c.W, c.H, nil)
+		c.RenderTo(renderer)
+		if err := renderer.Close(); err != nil {
+			return SVGResources{}, err
+		}
+		return SVGResources{}, buffer.Flush()
+	default:
+		return SVGResources{}, fmt.Errorf("unsupported SVG mode %d", mode)
+	}
+}
+
+// RenderEPS 使用canvas输出单页EPS
+// 入参: r 渲染器, page 页面内容, writer 输出流
+// 返回: error 错误信息
+func (CanvasBackend) RenderEPS(r *Renderer, page *PageContent, writer io.Writer) error {
+	c, err := r.renderPage(page)
+	if err != nil {
+		return err
+	}
+	options := ps.DefaultOptions
+	options.Format = ps.EncapsulatedPostScript
+	buffer := bufio.NewWriter(writer)
+	renderer := ps.New(buffer, c.W, c.H, &options)
+	c.RenderTo(renderer)
+	if err := renderer.Close(); err != nil {
+		return err
+	}
+	return buffer.Flush()
+}
+
+// RenderPDF 使用canvas输出PDF，保留导航与文字并复用输出缓冲
+// 入参: r 渲染器, pages 页面列表, writer 输出流, progress 页面处理进度
+// 返回: error 错误信息
+func (CanvasBackend) RenderPDF(r *Renderer, pages []RenderDocumentPage, writer io.Writer, progress func(int, int) error) error {
+	if len(pages) == 0 {
+		return fmt.Errorf("no pages found")
+	}
+	navigation := newPDFNavigation(r, r.Reader.doc, pages)
+	buf, direct := writer.(*bytes.Buffer)
+	if !direct {
+		buf = &bytes.Buffer{}
+	}
+	start := buf.Len()
+	p := pdf.New(buf, pages[0].Box.W, pages[0].Box.H, nil)
+	renderer := &pdfRenderer{PDF: p, glyphPaths: make(map[*canvas.Path]*canvas.Path)}
+	var info DocInfo
+	if docInfo, err := r.Reader.DocInfo(); err == nil {
+		info = *docInfo
+	}
+	p.SetInfo(info.Title, info.Subject, "", info.Author, "xiaoqidun/ofdgo")
+	for i, page := range pages {
+		if i > 0 {
+			p.NewPage(page.Box.W, page.Box.H)
+		}
+		navigation.apply(p, i)
+		if err := r.renderPageToContext(canvas.NewContext(renderer), page.Content, true); err != nil {
+			buf.Truncate(start)
+			return fmt.Errorf("failed to render page %d: %w", i+1, err)
+		}
+		pages[i].Content = nil
+		if progress != nil {
+			if err := progress(i+1, len(pages)); err != nil {
+				buf.Truncate(start)
+				return err
+			}
+		}
+	}
+	if err := p.Close(); err != nil {
+		buf.Truncate(start)
+		return err
+	}
+	data := replacePDFProducer(buf.Bytes()[start:])
+	if direct {
+		return nil
+	}
+	_, err := writer.Write(data)
+	return err
+}
+
+// replacePDFProducer 替换PDF的Producer属性
+// 入参: data PDF字节数据
+// 返回: []byte 替换后的PDF字节数据
+func replacePDFProducer(data []byte) []byte {
+	old := []byte("/Producer(tdewolff/canvas)")
+	idx := bytes.LastIndex(data, old)
+	if idx < 0 {
+		return data
+	}
+	dst := []byte("/Producer(xiaoqidun/ofdgo)")
+	copy(data[idx:idx+len(old)], dst)
+	return data
+}
@@ -42,12 +42,6 @@ func (r *pdfRenderer) glyphPath(path *canvas.Path, matrix canvas.Matrix) *canvas
 	return converted
 }

-// pdfPage PDF页面数据
-type pdfPage struct {
-	Content *PageContent
-	Box     Box
-}
-
 // pdfNavigation PDF导航信息
 type pdfNavigation struct {
 	Anchor  map[int][]pdfAnchor
@@ -78,7 +72,7 @@ type pdfOutline struct {
 // newPDFNavigation 创建PDF导航信息
 // 入参: renderer 渲染器, doc 文档结构, pages 页面数据
 // 返回: *pdfNavigation PDF导航信息
-func newPDFNavigation(renderer *Renderer, doc *Document, pages []pdfPage) *pdfNavigation {
+func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentPage) *pdfNavigation {
 	navigation := &pdfNavigation{
 		Anchor:  make(map[int][]pdfAnchor),
 		Link:    make(map[int][]pdfLink),
@@ -121,7 +115,7 @@ func newPDFNavigation(renderer *Renderer, doc *Document, pages []pdfPage) *pdfNa

 // addAction 添加PDF动作
 // 入参: page 页面索引, rect 动作区域, action 动作, bookmarks 书签, pageIndex 页面索引表, pages 页面数据
-func (n *pdfNavigation) addAction(page int, rect canvas.Rect, action Action, bookmarks map[string]Dest, pageIndex map[string]int, pages []pdfPage) {
+func (n *pdfNavigation) addAction(page int, rect canvas.Rect, action Action, bookmarks map[string]Dest, pageIndex map[string]int, pages []RenderDocumentPage) {
 	if action.Goto != nil {
 		dest := gotoDest(action.Goto, bookmarks)
 		if dest == nil {
@@ -148,7 +142,7 @@ func (n *pdfNavigation) addAction(page int, rect canvas.Rect, action Action, boo

 // addOutlines 添加PDF大纲
 // 入参: outlines 大纲节点, level 节点层级, bookmarks 书签, pageIndex 页面索引表, pages 页面数据
-func (n *pdfNavigation) addOutlines(outlines []OutlineElem, level int, bookmarks map[string]Dest, pageIndex map[string]int, pages []pdfPage) {
+func (n *pdfNavigation) addOutlines(outlines []OutlineElem, level int, bookmarks map[string]Dest, pageIndex map[string]int, pages []RenderDocumentPage) {
 	for _, outline := range outlines {
 		nextLevel := level
 		if dest := outlineDest(outline, bookmarks); dest != nil {
@@ -0,0 +1,211 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/sha256"
+	"fmt"
+	"html"
+	"image"
+	"image/png"
+	"io"
+	"strings"
+
+	"github.com/tdewolff/canvas"
+	canvasimage "github.com/tdewolff/canvas/image"
+	"github.com/tdewolff/canvas/renderers/svg"
+)
+
+// svgResourceRenderer 分离外部资源的SVG渲染器
+type svgResourceRenderer struct {
+	*svg.SVG
+	renderer    *Renderer
+	writer      io.Writer
+	fonts       []SVGFont
+	images      []SVGImage
+	imageNames  map[image.Image]string
+	seen        map[string]bool
+	styles      strings.Builder
+	err         error
+	objects     map[*GraphicObject]string
+	objectStack []svgObjectGroup
+}
+
+// svgObjectGroup 记录编辑分组的稳定路径，不把底纹内部绘制当作成员
+type svgObjectGroup struct {
+	path      string
+	next      int
+	composite bool
+}
+
+// renderSVGResources 渲染SVG并收集外部资源
+// 入参: page 页面内容, writer 输出流, images 是否分离图片, objects 是否标识页面直接对象
+// 返回: SVGResources 外部资源, error 错误信息
+func (r *Renderer) renderSVGResources(page *PageContent, writer io.Writer, images, objects bool) (SVGResources, error) {
+	box, err := r.GetPageBox(page)
+	if err != nil {
+		return SVGResources{}, err
+	}
+	options := svg.DefaultOptions
+	options.EmbedFonts = false
+	buffer := bufio.NewWriter(writer)
+	s := &svgResourceRenderer{
+		SVG:      svg.New(buffer, box.W, box.H, &options),
+		renderer: r,
+		writer:   buffer,
+		seen:     make(map[string]bool),
+	}
+	if images {
+		s.imageNames = make(map[image.Image]string)
+	}
+	if objects {
+		s.objects = make(map[*GraphicObject]string)
+		for i := range page.Content.Layer {
+			for j := range page.Content.Layer[i].Objects {
+				object := &page.Content.Layer[i].Objects[j]
+				s.objects[object] = editorObjectID(*object)
+			}
+		}
+		if err := r.renderPageToContext(canvas.NewContext(s), page, true); err != nil {
+			return SVGResources{}, err
+		}
+	} else {
+		c, err := r.renderPage(page)
+		if err != nil {
+			return SVGResources{}, err
+		}
+		c.RenderTo(s)
+	}
+	if s.err != nil {
+		return SVGResources{}, s.err
+	}
+	s.SetCustomStyle(s.styles.String())
+	if err := s.Close(); err != nil {
+		return SVGResources{}, err
+	}
+	return SVGResources{Fonts: s.fonts, Images: s.images}, buffer.Flush()
+}
+
+// beginObject 标记直接对象及复合或注解成员，模板图元不单独标记
+// 入参: object 图形对象
+// 返回: bool 是否写入分组
+func (s *svgResourceRenderer) beginObject(object *GraphicObject) bool {
+	id := s.objects[object]
+	attribute := "data-ofd-object"
+	if id == "" {
+		if len(s.objectStack) == 0 || !s.objectStack[len(s.objectStack)-1].composite {
+			return false
+		}
+		parent := &s.objectStack[len(s.objectStack)-1]
+		id = fmt.Sprintf("%s/%d", parent.path, parent.next)
+		parent.next++
+		attribute = "data-ofd-child"
+	}
+	s.objectStack = append(s.objectStack, svgObjectGroup{path: id, composite: object.Type == "CompositeObject" || object.Type == "CompositeGraphicUnit"})
+	fmt.Fprintf(s.writer, `<g %s="%s">`, attribute, html.EscapeString(id))
+	return true
+}
+
+// endObject 结束对象分组
+func (s *svgResourceRenderer) endObject() {
+	s.objectStack = s.objectStack[:len(s.objectStack)-1]
+	fmt.Fprint(s.writer, `</g>`)
+}
+
+// beginAnnotation 标记完整注解外观，内部图元保持原有层级和绘制顺序
+// 入参: id 注解标识
+// 返回: bool 是否写入分组
+func (s *svgResourceRenderer) beginAnnotation(id string) bool {
+	if s.objects == nil {
+		return false
+	}
+	s.objectStack = append(s.objectStack, svgObjectGroup{path: "annotation:" + id, composite: true})
+	fmt.Fprintf(s.writer, `<g data-ofd-object="annotation:%s">`, html.EscapeString(id))
+	return true
+}
+
+// skipObjects 为不可见资源保留内部成员序号
+// 入参: count 直接成员数量
+func (s *svgResourceRenderer) skipObjects(count int) {
+	if len(s.objectStack) > 0 {
+		s.objectStack[len(s.objectStack)-1].next += count
+	}
+}
+
+// RenderImage 绘制图片，分离资源时保持原始编码、尺寸和变换
+// 入参: img 图片对象, m 变换矩阵
+func (s *svgResourceRenderer) RenderImage(img image.Image, m canvas.Matrix) {
+	if s.imageNames == nil {
+		s.SVG.RenderImage(img, m)
+		return
+	}
+	name, ok := s.imageNames[img]
+	if !ok {
+		resource := SVGImage{MIME: "image/png"}
+		if encoded, ok := img.(*canvasimage.Image); ok {
+			resource.MIME, resource.Data = encoded.Mimetype, encoded.Bytes
+		} else {
+			var buffer bytes.Buffer
+			if err := png.Encode(&buffer, img); err != nil {
+				s.err = err
+				return
+			}
+			resource.Data = buffer.Bytes()
+		}
+		name = fmt.Sprintf("ofdgo-image-%x", sha256.Sum256(resource.Data))
+		resource.Name = name
+		s.imageNames[img] = name
+		if !s.seen[name] {
+			s.seen[name] = true
+			s.images = append(s.images, resource)
+		}
+	}
+	_, height := s.Size()
+	size := img.Bounds().Size()
+	fmt.Fprintf(s.writer, `<image transform="%s" width="%d" height="%d" xlink:href="%s"/>`, m.Translate(0, float64(size.Y)).ToSVG(height), size.X, size.Y, name)
+}
+
+// RenderText 绘制文字并记录实际使用的字体资源
+// 入参: text 文字对象, m 变换矩阵
+func (s *svgResourceRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
+	if text.Empty() {
+		return
+	}
+	font := text.MostCommonFontFace().Font
+	resource, ok := s.renderer.svgFontCache[font]
+	if !ok {
+		data := font.SFNT.Write()
+		resource = SVGFont{
+			Name:   fmt.Sprintf("ofdgo-%x-%d", sha256.Sum256(data), font.Style()),
+			Weight: font.Style().CSS(),
+			Style:  "normal",
+			Data:   data,
+		}
+		if font.Style().Italic() {
+			resource.Style = "italic"
+		}
+		s.renderer.svgFontCache[font] = resource
+	}
+	if !s.seen[resource.Name] {
+		s.seen[resource.Name] = true
+		s.fonts = append(s.fonts, resource)
+		fmt.Fprintf(&s.styles, ".%s{font-family:%s!important}", resource.Name, resource.Name)
+	}
+	s.SetClass(resource.Name)
+	s.SVG.RenderText(text, m)
+	s.SetClass()
+}
@@ -48,6 +48,7 @@ type Editor struct {
 	fonts           map[string]*font.SFNT
 	fontFS          []fs.FS
 	fontRenderer    *Renderer
+	compiler        PageCompiler
 	images          map[string]image.Point
 	resourceID      map[editorResourceKey]string
 	maxID           int
@@ -68,6 +69,25 @@ func (e *Editor) SetFontFS(fsys ...fs.FS) {
 	e.fontRenderer = nil
 }

+// SetPageCompiler 设置编辑对象度量使用的页面编译器，不改变文档或撤销历史
+// 与Renderer使用相同实例可统一显示、搜索和选区，nil禁用度量，不隐式回退
+// 入参: compiler 页面编译器
+func (e *Editor) SetPageCompiler(compiler PageCompiler) {
+	e.compiler = compiler
+	if e.fontRenderer != nil {
+		e.fontRenderer.backends.Compiler = compiler
+	}
+}
+
+// newRenderer 使用编辑器字体来源和页面编译器创建资源度量器
+// 入参: reader 当前文档快照
+// 返回: *Renderer 度量器
+func (e *Editor) newRenderer(reader *Reader) *Renderer {
+	backends := defaultRenderBackends()
+	backends.Compiler = e.compiler
+	return NewRenderer(reader, WithFontFS(e.fontFS...), WithRenderBackends(backends))
+}
+
 // editorResource 文档内嵌资源
 type editorResource struct {
 	name       string
@@ -113,6 +133,7 @@ func NewEditor() *Editor {
 		fonts:      make(map[string]*font.SFNT),
 		images:     make(map[string]image.Point),
 		resourceID: make(map[editorResourceKey]string),
+		compiler:   CanvasBackend{},
 	}
 }

@@ -400,7 +400,7 @@ func (e *Editor) annotationScope(page int, path ObjectPath) (*Reader, *Renderer,
 		reader.Close()
 		return nil, nil, nil, nil, err
 	}
-	renderer := NewRenderer(reader, WithFontFS(e.fontFS...))
+	renderer := e.newRenderer(reader)
 	root.parent, root.visible = IdentityMatrix, true
 	scope := root
 	for depth := 0; ; depth++ {
@@ -249,7 +249,11 @@ func (e *Editor) ReplaceAnnotationText(page int, id, old, value string, style Te
 			visiting := make(map[string]bool)
 			var replace func([]*editorCompositeNode) error
 			replace = func(nodes []*editorCompositeNode) error {
-				for i, member := range edit.measureCompositeMembers(renderer, nodes) {
+				members, err := edit.measureCompositeMembers(renderer, nodes)
+				if err != nil {
+					return err
+				}
+				for i, member := range members {
 					if member.Object.Type == "TextObject" && member.Object.TextObject.Text() == old {
 						if err := edit.updateCompositeText(nodes[i], member, &value, style, nil, nil); err != nil {
 							return err
@@ -20,8 +20,6 @@ import (
 	"reflect"
 	"slices"
 	"strconv"
-
-	"github.com/tdewolff/canvas"
 )

 // editorObjectPosition 对象所属图层及层内索引
@@ -395,7 +393,7 @@ func editorDistribution(boxes []Box, indexes []editorObjectPosition, axis string
 	gap := (positions[last] + sizes[last] - positions[first] - total) / float64(len(order)-1)
 	for i, index := range order[:len(order)-1] {
 		step := sizes[index] + gap
-		if canvas.Equal(step, 0) {
+		if geometryEqual(step, 0) {
 			step = 0
 		}
 		if step < 0 || step == 0 && compareEditorPosition(indexes[index], indexes[order[i+1]]) > 0 {
@@ -406,7 +404,7 @@ func editorDistribution(boxes []Box, indexes []editorObjectPosition, axis string
 	for _, index := range order[1 : len(order)-1] {
 		position := next
 		next += sizes[index] + gap
-		if canvas.Equal(position, positions[index]) {
+		if geometryEqual(position, positions[index]) {
 			continue
 		}
 		dx, dy := position-positions[index], 0.0
@@ -633,10 +631,10 @@ func editorAlignment(box, target Box, alignment string) Matrix {
 	case "bottom":
 		matrix.f = target.Y + target.H - box.H - box.Y
 	}
-	if canvas.Equal(matrix.e, 0) {
+	if geometryEqual(matrix.e, 0) {
 		matrix.e = 0
 	}
-	if canvas.Equal(matrix.f, 0) {
+	if geometryEqual(matrix.f, 0) {
 		matrix.f = 0
 	}
 	return matrix
@@ -737,7 +735,7 @@ func (e *Editor) objectBounds(page int, objects []GraphicObject) ([]Box, error)
 	if _, err := reader.PageContentByIndex(page); err != nil {
 		return nil, err
 	}
-	renderer := NewRenderer(reader, WithFontFS(e.fontFS...))
+	renderer := e.newRenderer(reader)
 	boxes := make([]Box, len(objects))
 	for i, object := range objects {
 		layer, _, findErr := e.findObject(page, editorObjectID(object))
@@ -157,7 +157,7 @@ func (e *Editor) CompositeObjects(page int, path ObjectPath) ([]CompositeMember,
 		return nil, err
 	}
 	defer reader.Close()
-	return e.measureCompositeMembers(renderer, members), nil
+	return e.measureCompositeMembers(renderer, members)
 }

 // CompositeObject 读取指定内部成员，仅度量该成员并保留完整容器位置
@@ -200,7 +200,10 @@ func (e *Editor) CompositeObjectsAt(page int, path ObjectPath, indexes []int) ([
 		position.Count++
 		containers[node.span.parent] = position
 	}
-	members := e.measureCompositeMembers(renderer, selected)
+	members, err := e.measureCompositeMembers(renderer, selected)
+	if err != nil {
+		return nil, err
+	}
 	for i, index := range indexes {
 		members[i].Position = positions[index]
 		members[i].Position.Count = containers[nodes[index].span.parent].Count
@@ -328,7 +331,7 @@ func (e *Editor) compositeScope(page int, path ObjectPath) (*Reader, *Renderer,
 		reader.Close()
 		return nil, nil, nil, nil, err
 	}
-	renderer := NewRenderer(reader, WithFontFS(e.fontFS...))
+	renderer := e.newRenderer(reader)
 	root.parent, root.visible, root.defaults = IdentityMatrix, true, renderer.drawParamDefaults(layer.DrawParam, nil)
 	root.drawParams = []string{layer.DrawParam}
 	scope := root
@@ -501,8 +504,8 @@ func (e *Editor) compositeMembers(n *editorCompositeNode, reader *Reader, render

 // measureCompositeMembers 按父变换、裁剪和继承样式度量成员，透明对象保留选区，未着色路径按轮廓度量
 // 入参: renderer 渲染器, nodes 成员
-// 返回: []CompositeMember 独立快照及操作能力
-func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorCompositeNode) []CompositeMember {
+// 返回: []CompositeMember 独立快照及操作能力, error 度量错误
+func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorCompositeNode) ([]CompositeMember, error) {
 	result := make([]CompositeMember, len(nodes))
 	positions := make(map[*editorXML]ObjectPosition)
 	orderable := make(map[*editorXML]bool)
@@ -517,7 +520,7 @@ func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorComp
 		positions[parent] = position
 	}
 	for i, node := range nodes {
-		bounds := &boundsRenderer{collect: true}
+		var bounds ObjectMeasurement
 		object := node.object
 		object.TextObject.Alpha, object.PathObject.Alpha = nil, nil
 		object.ImageObject.Alpha, object.CompositeGraphicUnit.Alpha = nil, nil
@@ -525,10 +528,14 @@ func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorComp
 			object.PathObject.Stroke = nil
 		}
 		if node.visible {
-			renderer.renderObject(canvas.NewContext(bounds), &object, 0, node.defaults, &node.parent, node.boundaryInCTM, node.clip)
+			var err error
+			bounds, err = renderer.MeasureObject(object, MeasureOptions{Defaults: node.defaults, Parent: &node.parent, BoundaryInCTM: node.boundaryInCTM, Clip: geometryCanvasPath(node.clip), Contours: true})
+			if err != nil {
+				return nil, err
+			}
 		}
 		transform := node.transformable()
-		capability := ObjectCapabilities{Transform: transform, Arrange: transform && bounds.box.W > 0 && bounds.box.H > 0,
+		capability := ObjectCapabilities{Transform: transform, Arrange: transform && bounds.Bounds.W > 0 && bounds.Bounds.H > 0,
 			Delete: true, Copy: transform && editorXMLCopyable(node.node), Order: orderable[node.span.parent], ReplaceImage: node.object.Type == "ImageObject"}
 		capability.Ungroup = transform && capability.Order && e.compositeUngroupable(node.node) && (node.object.CompositeGraphicUnit.ResourceID != "" || len(node.object.CompositeGraphicUnit.Objects) != 0)
 		capability.Stretch = transform && e.objectStretchable(node.object, make(map[string]bool))
@@ -557,7 +564,7 @@ func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorComp
 				}
 			}
 		}
-		if transform && node.object.Type == "ImageObject" && bounds.box.W > 0 && bounds.box.H > 0 {
+		if transform && node.object.Type == "ImageObject" && bounds.Bounds.W > 0 && bounds.Bounds.H > 0 {
 			clips := node.object.ImageObject.Clips
 			_, capability.CropImage = node.matrix(clips == nil || clips.TransFlag == nil || *clips.TransFlag).Invert()
 			capability.FitImage = capability.CropImage && axisAlignedMatrix(NewMatrix(node.object.ImageObject.CTM))
@@ -566,11 +573,11 @@ func (e *Editor) measureCompositeMembers(renderer *Renderer, nodes []*editorComp
 		_, ctm := editorGeometry(node.object)
 		matrix := node.parent.Multiply(NewMatrix(ctm))
 		position := positions[node.span.parent]
-		result[i] = CompositeMember{Object: style, Bounds: bounds.box, Contours: bounds.contours, Matrix: node.matrix(true), StrokeScale: math.Sqrt(math.Abs(matrix.a*matrix.d - matrix.b*matrix.c)), Capabilities: capability, Position: position, Transform: transform, Cropped: node.states[editorObjectID(node.object)].crop != nil}
+		result[i] = CompositeMember{Object: style, Bounds: bounds.Bounds, Contours: bounds.Contours, Matrix: node.matrix(true), StrokeScale: math.Sqrt(math.Abs(matrix.a*matrix.d - matrix.b*matrix.c)), Capabilities: capability, Position: position, Transform: transform, Cropped: node.states[editorObjectID(node.object)].crop != nil}
 		position.Index++
 		positions[node.span.parent] = position
 	}
-	return result
+	return result, nil
 }

 // transformable 校验内部对象能否保留原文进行几何操作，不执行绘制测量
@@ -741,7 +748,11 @@ func (e *Editor) editCompositeObjects(page int, path ObjectPath, indexes []int,
 		if len(selected) == 0 {
 			return nil
 		}
-		return edit(renderer, selectedNodes, e.measureCompositeMembers(renderer, selectedNodes))
+		members, err := e.measureCompositeMembers(renderer, selectedNodes)
+		if err != nil {
+			return err
+		}
+		return edit(renderer, selectedNodes, members)
 	})
 }

@@ -82,7 +82,7 @@ func (e *Editor) pasteCompositeSelection(selection *CompositeSelection, paste fu
 		return err
 	}
 	defer reader.Close()
-	renderer := NewRenderer(reader, WithFontFS(e.fontFS...))
+	renderer := e.newRenderer(reader)
 	var objects []GraphicObject
 	for _, source := range selection.nodes {
 		copy, err := newEditorCompositeNode(source.data)
@@ -638,7 +638,7 @@ func (e *Editor) editorFont(id string) (*font.SFNT, error) {
 		definition := e.source.reader.fontCache[id]
 		if definition != nil && definition.FontFile == "" {
 			if e.fontRenderer == nil {
-				e.fontRenderer = NewRenderer(e.source.reader, WithFontFS(e.fontFS...))
+				e.fontRenderer = e.newRenderer(e.source.reader)
 			}
 			style := canvasFontStyle(definition)
 			for _, source := range e.fontRenderer.fontSources(id, definition, style) {
@@ -200,7 +200,7 @@ func (e *Editor) transformMatrix(object GraphicObject, matrix Matrix) (GraphicOb
 		return GraphicObject{}, err
 	}
 	defer reader.Close()
-	return e.transformBorderedImage(object, matrix, origin, NewRenderer(reader, WithFontFS(e.fontFS...)))
+	return e.transformBorderedImage(object, matrix, origin, e.newRenderer(reader))
 }

 // objectStretchable 允许图片及纯图片资源独立调整宽高，内联组合仍保持比例
@@ -32,6 +32,13 @@ type Point struct {
 	X, Y float64
 }

+// geometryEqual 比较毫米坐标，使用固定绝对误差，不受绘图库全局精度影响
+// 入参: a、b 待比较的坐标
+// 返回: bool 是否在容差内相等
+func geometryEqual(a, b float64) bool {
+	return math.Abs(a-b) <= 1e-10
+}
+
 // ParseBox 解析Box字符串
 // 入参: s 字符串
 // 返回: Box 矩形对象, error 错误信息
@@ -63,6 +70,19 @@ type Matrix struct {
 // IdentityMatrix 单位矩阵
 var IdentityMatrix = Matrix{1, 0, 0, 1, 0, 0}

+// MatrixFromValues 从a、b、c、d、e、f构造矩阵，不经过文本格式化
+// 入参: values 矩阵分量
+// 返回: Matrix 变换矩阵
+func MatrixFromValues(values [6]float64) Matrix {
+	return Matrix{a: values[0], b: values[1], c: values[2], d: values[3], e: values[4], f: values[5]}
+}
+
+// Values 返回a、b、c、d、e、f的独立副本，保留原始浮点精度
+// 返回: [6]float64 矩阵分量
+func (m Matrix) Values() [6]float64 {
+	return [6]float64{m.a, m.b, m.c, m.d, m.e, m.f}
+}
+
 // NewMatrix 解析CTM字符串
 // 入参: s 字符串
 // 返回: Matrix 矩阵对象
@@ -0,0 +1,42 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+// GeometryPath 保存独立于绘图库的几何路径，不扁平化曲线或舍入坐标
+// 坐标以左上角为原点，单位为毫米，子路径从Move开始，Close回到当前子路径起点
+type GeometryPath []GeometrySegment
+
+// GeometryVerb 表示几何路径指令
+type GeometryVerb uint8
+
+const (
+	GeometryMove GeometryVerb = iota
+	GeometryLine
+	GeometryQuad
+	GeometryCubic
+	GeometryArc
+	GeometryClose
+)
+
+// GeometrySegment 保存路径端点、贝塞尔控制点或端点式椭圆弧参数
+// 弧线Rotation单位为度，Sweep为true表示顺时针，Large表示大弧
+type GeometrySegment struct {
+	Verb               GeometryVerb
+	End                Point
+	Control1, Control2 Point
+	RadiusX, RadiusY   float64
+	Rotation           float64
+	Large, Sweep       bool
+}
@@ -0,0 +1,101 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+
+	"github.com/gogpu/gg"
+)
+
+// GGBackend 不注册全局GPU设备或回退到其他绘图库的CPU后端
+type GGBackend struct{}
+
+// Name 返回后端标识
+// 返回: string 后端标识
+func (GGBackend) Name() string { return "gg" }
+
+// Render 绘制已编译页面，使用自有双圆渐变语义保持原有定位
+// 入参: page 只读页面
+// 返回: image.Image 图像, error 绘制错误
+func (GGBackend) Render(page *RasterPage) (image.Image, error) {
+	w, h, err := page.PixelSize()
+	if err != nil {
+		return nil, err
+	}
+	pixmap := gg.NewPixmap(w, h)
+	img := pixmap.ImageView()
+	raster := gg.NewSoftwareRenderer(w, h)
+	for i, cmd := range page.Commands {
+		m := page.PixelTransform(cmd.Transform, h)
+		if cmd.Image != nil {
+			drawRasterImage(img, cmd.Image, m)
+			continue
+		}
+		path := gg.NewPath()
+		for _, s := range cmd.Path {
+			end, c1, c2 := m.Apply(s.End), m.Apply(s.Control1), m.Apply(s.Control2)
+			switch s.Verb {
+			case RasterMove:
+				path.MoveTo(end.X, end.Y)
+			case RasterLine:
+				path.LineTo(end.X, end.Y)
+			case RasterQuad:
+				path.QuadraticTo(c1.X, c1.Y, end.X, end.Y)
+			case RasterCubic:
+				path.CubicTo(c1.X, c1.Y, c2.X, c2.Y, end.X, end.Y)
+			case RasterClose:
+				path.Close()
+			default:
+				return nil, fmt.Errorf("gg command %d: unsupported path verb %d", i, s.Verb)
+			}
+		}
+		paint := gg.NewPaint()
+		paint.SetFillBrush(gg.SolidBrush{Color: ggRGBA(cmd.Paint.Color)})
+		if g := cmd.Paint.Gradient; g != nil {
+			if g.Kind != RasterLinear && g.Kind != RasterRadial {
+				return nil, fmt.Errorf("gg command %d: unsupported gradient %d", i, g.Kind)
+			}
+			inverse, err := m.Inverse()
+			if err != nil {
+				return nil, fmt.Errorf("gg command %d: %w", i, err)
+			}
+			paint.SetFillBrush(gg.NewCustomBrush(func(x, y float64) gg.RGBA {
+				p := inverse.Apply(RasterPoint{X: x, Y: y})
+				return ggRGBA(g.At(p.X, p.Y))
+			}))
+		}
+		if cmd.EvenOdd {
+			paint.FillRule = gg.FillRuleEvenOdd
+		}
+		if err := raster.Fill(pixmap, path, paint); err != nil {
+			return nil, fmt.Errorf("gg command %d: %w", i, err)
+		}
+	}
+	return img, nil
+}
+
+// ggRGBA 将标准库预乘颜色转换为gg的非预乘颜色
+// 入参: c 预乘颜色
+// 返回: gg.RGBA 非预乘颜色
+func ggRGBA(c color.RGBA) gg.RGBA {
+	if c.A == 0 {
+		return gg.Transparent
+	}
+	a := float64(c.A)
+	return gg.RGBA{R: float64(c.R) / a, G: float64(c.G) / a, B: float64(c.B) / a, A: a / 255}
+}
@@ -0,0 +1,202 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"math"
+)
+
+// RasterPage 已解析的光栅绘制页面，单位为毫米，页面坐标原点在左上角
+// DPI决定像素尺寸和编译时的字形、描边精度，修改DPI后应重新编译
+// 页面及其引用资源在渲染期间只读，不用于重建或保存OFD
+type RasterPage struct {
+	Width, Height float64
+	DPI           float64
+	Commands      []RasterCommand
+}
+
+// RasterMatrix 按a、b、c、d、e、f排列的仿射矩阵，零值不是单位矩阵
+type RasterMatrix [6]float64
+
+// RasterPoint 路径或渐变坐标
+type RasterPoint struct{ X, Y float64 }
+
+// RasterVerb 路径指令
+type RasterVerb uint8
+
+const (
+	RasterMove RasterVerb = iota
+	RasterLine
+	RasterQuad
+	RasterCubic
+	RasterClose
+)
+
+// RasterSegment 路径片段，RasterMove和RasterLine使用End，RasterQuad使用Control1和End
+type RasterSegment struct {
+	Verb               RasterVerb
+	Control1, Control2 RasterPoint
+	End                RasterPoint
+}
+
+// RasterCommand 填充路径或绘制图像，Image非空时为图像指令
+// Transform将局部坐标映射到页面，图像局部坐标与image.Image的像素坐标一致
+// 字形和描边由页面编译器生成轮廓，裁剪与底纹在编译时解析
+type RasterCommand struct {
+	Path      []RasterSegment
+	Paint     RasterPaint
+	EvenOdd   bool
+	Transform RasterMatrix
+	Image     image.Image
+}
+
+// RasterPaint 预乘RGBA纯色或渐变，Gradient非空时忽略Color
+type RasterPaint struct {
+	Color    color.RGBA
+	Gradient *RasterGradient
+}
+
+// RasterGradientKind 渐变类型
+type RasterGradientKind uint8
+
+const (
+	RasterLinear RasterGradientKind = iota
+	RasterRadial
+)
+
+// RasterStop 按Offset升序排列的预乘RGBA颜色节点
+type RasterStop struct {
+	Offset float64
+	Color  color.RGBA
+}
+
+// RasterGradient 局部坐标下的线性或双圆径向渐变，区间外延续边界颜色
+type RasterGradient struct {
+	Kind       RasterGradientKind
+	Start, End RasterPoint
+	R0, R1     float64
+	Stops      []RasterStop
+}
+
+// PixelSize 检查页面尺寸并计算目标像素大小
+// 返回: int 宽度, int 高度, error 无效尺寸
+func (p *RasterPage) PixelSize() (int, int, error) {
+	if p == nil || !rasterPositive(p.Width) || !rasterPositive(p.Height) || !rasterPositive(p.DPI) {
+		return 0, 0, fmt.Errorf("invalid raster page size or DPI")
+	}
+	scale := p.DPI / 25.4
+	w, h := math.Floor(p.Width*scale+0.5), math.Floor(p.Height*scale+0.5)
+	if !rasterPositive(w) || !rasterPositive(h) || w*h > math.MaxInt32/4 {
+		return 0, 0, fmt.Errorf("invalid raster pixel dimensions: %g x %g", w, h)
+	}
+	return int(w), int(h), nil
+}
+
+// rasterPositive 判断正有限数
+// 入参: v 待检查数值
+// 返回: bool 是否为正有限数
+func rasterPositive(v float64) bool { return v > 0 && !math.IsInf(v, 0) && !math.IsNaN(v) }
+
+// Apply 将局部点映射到目标坐标
+// 入参: p 局部点
+// 返回: RasterPoint 目标点
+func (m RasterMatrix) Apply(p RasterPoint) RasterPoint {
+	return RasterPoint{m[0]*p.X + m[2]*p.Y + m[4], m[1]*p.X + m[3]*p.Y + m[5]}
+}
+
+// Inverse 求逆矩阵，退化或行列式非有限时返回错误
+// 返回: RasterMatrix 逆矩阵, error 无效矩阵
+func (m RasterMatrix) Inverse() (RasterMatrix, error) {
+	det := m[0]*m[3] - m[1]*m[2]
+	if det == 0 || math.IsNaN(det) || math.IsInf(det, 0) {
+		return RasterMatrix{}, fmt.Errorf("invalid raster transform")
+	}
+	return RasterMatrix{m[3] / det, -m[1] / det, -m[2] / det, m[0] / det,
+		(m[2]*m[5] - m[3]*m[4]) / det, (m[1]*m[4] - m[0]*m[5]) / det}, nil
+}
+
+// At 采样局部坐标下的渐变，使用预乘颜色插值
+// 入参: x 横坐标, y 纵坐标
+// 返回: color.RGBA 采样颜色
+func (g *RasterGradient) At(x, y float64) color.RGBA {
+	dx, dy := g.End.X-g.Start.X, g.End.Y-g.Start.Y
+	px, py := x-g.Start.X, y-g.Start.Y
+	t := 0.0
+	if g.Kind == RasterRadial {
+		dr := g.R1 - g.R0
+		a, b, c := dx*dx+dy*dy-dr*dr, -2*(px*dx+py*dy+g.R0*dr), px*px+py*py-g.R0*g.R0
+		t = rasterRadialPosition(a, b, c, g.R0, dr)
+	} else if length := dx*dx + dy*dy; length > 0 {
+		t = (px*dx + py*dy) / length
+	}
+	return g.colorAt(t)
+}
+
+// rasterRadialPosition 求双圆渐变中半径非负的有效参数
+// 入参: a 二次项系数, b 一次项系数, c 常数项, radius 起始半径, delta 半径增量
+// 返回: float64 渐变位置，范围为0至1
+func rasterRadialPosition(a, b, c, radius, delta float64) float64 {
+	x, y := math.NaN(), math.NaN()
+	if a == 0 {
+		if b != 0 {
+			x = -c / b
+		}
+	} else if d := b*b - 4*a*c; d >= 0 {
+		q := -0.5 * (b + math.Copysign(math.Sqrt(d), b))
+		if q == 0 {
+			x = -b / (2 * a)
+		} else {
+			x, y = q/a, c/q
+			if x > y {
+				x, y = y, x
+			}
+		}
+	}
+	for _, t := range []float64{y, x} {
+		if t >= 0 && t <= 1 && radius+delta*t >= 0 {
+			return t
+		}
+	}
+	for _, t := range []float64{x, y} {
+		if t > 0 && radius+delta*t >= 0 {
+			return 1
+		}
+	}
+	return 0
+}
+
+// colorAt 插值有序颜色节点
+// 入参: t 渐变位置
+// 返回: color.RGBA 预乘颜色
+func (g *RasterGradient) colorAt(t float64) color.RGBA {
+	if len(g.Stops) == 0 {
+		return color.RGBA{}
+	}
+	if t <= g.Stops[0].Offset {
+		return g.Stops[0].Color
+	}
+	for i := 1; i < len(g.Stops); i++ {
+		before, after := g.Stops[i-1], g.Stops[i]
+		if t < after.Offset {
+			u := uint32((t-before.Offset)/(after.Offset-before.Offset)*65535 + 0.5)
+			blend := func(a, b uint8) uint8 { return uint8(((65535-u)*uint32(a)*257 + u*uint32(b)*257) >> 24) }
+			return color.RGBA{blend(before.Color.R, after.Color.R), blend(before.Color.G, after.Color.G), blend(before.Color.B, after.Color.B), blend(before.Color.A, after.Color.A)}
+		}
+	}
+	return g.Stops[len(g.Stops)-1].Color
+}
@@ -0,0 +1,40 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"image"
+
+	"golang.org/x/image/draw"
+	"golang.org/x/image/math/f64"
+)
+
+// drawRasterImage 按页面变换采样图像，两后端共享相同的高质量图像插值
+// 入参: dst 目标图像, src 源图像, m 像素坐标变换
+func drawRasterImage(dst draw.Image, src image.Image, m RasterMatrix) {
+	draw.CatmullRom.Transform(dst, f64.Aff3{m[0], m[2], m[4], m[1], m[3], m[5]}, src, src.Bounds(), draw.Over, nil)
+}
+
+// PixelTransform 将页面毫米变换转换为像素变换，保留尺寸取整后的原点位置
+// 入参: m 局部到页面变换, height 目标像素高度
+// 返回: RasterMatrix 局部到像素变换
+func (p *RasterPage) PixelTransform(m RasterMatrix, height int) RasterMatrix {
+	scale := p.DPI / 25.4
+	for i := range m {
+		m[i] *= scale
+	}
+	m[5] += float64(height) - p.Height*scale
+	return m
+}
@@ -52,6 +52,7 @@ type Renderer struct {
 	decodeImages          bool
 	pageText              *PageText
 	textOnly              bool
+	backends              RenderBackends
 }

 // RendererOption 渲染器配置选项
@@ -64,6 +65,13 @@ func (r *Renderer) SetFontFS(fsys ...fs.FS) {
 	r.resetFontCache()
 }

+// FontSources 返回外部字体配置副本，供自定义编译器和导出后端读取
+// 内嵌字体通过Reader.FontData读取，系统字体由各实现自行匹配
+// 返回: []string 字体目录, []fs.FS 字体文件系统
+func (r *Renderer) FontSources() ([]string, []fs.FS) {
+	return append([]string(nil), r.fontDirs...), append([]fs.FS(nil), r.fontFS...)
+}
+
 // resetFontCache 重置字体匹配、加载和字形缓存
 func (r *Renderer) resetFontCache() {
 	r.fontMap = make(map[string]*canvas.FontFamily)
@@ -78,13 +86,11 @@ func (r *Renderer) resetFontCache() {
 	r.textGlyphPathCache = make(map[textGlyphPathCacheKey]textGlyphPathCacheValue)
 }

-// RenderPage 渲染特定页面内容
+// RenderPage 编译页面为与绘图库无关的只读绘制数据
 // 入参: page 页面内容
-// 返回: *canvas.Canvas 画布实例, error 错误信息
-func (r *Renderer) RenderPage(page *PageContent) (*canvas.Canvas, error) {
-	renderer := *r
-	renderer.decodeImages = true
-	return renderer.renderPage(page)
+// 返回: *RasterPage 绘制页面, error 错误信息
+func (r *Renderer) RenderPage(page *PageContent) (*RasterPage, error) {
+	return r.CompilePage(page)
 }

 // renderPage 渲染特定页面内容
@@ -125,10 +131,10 @@ func (r *Renderer) GetPageBox(page *PageContent) (Box, error) {
 	return ParseBox(boxStr)
 }

-// RenderPageToContext 渲染页面到指定上下文
+// renderCanvasContext 渲染页面到默认解释器上下文
 // 入参: ctx 画布上下文, page 页面内容
 // 返回: error 错误信息
-func (r *Renderer) RenderPageToContext(ctx *canvas.Context, page *PageContent) error {
+func (r *Renderer) renderCanvasContext(ctx *canvas.Context, page *PageContent) error {
 	renderer := *r
 	renderer.decodeImages = true
 	return renderer.renderPageToContext(ctx, page, true)
@@ -240,8 +246,8 @@ func (r *Renderer) PageLinks(page *PageContent) ([]PageLink, error) {

 // RenderPageByIndex 按索引渲染页面
 // 入参: index 页面索引，从0开始
-// 返回: *canvas.Canvas 画布实例, error 错误信息
-func (r *Renderer) RenderPageByIndex(index int) (*canvas.Canvas, error) {
+// 返回: *RasterPage 绘制页面, error 错误信息
+func (r *Renderer) RenderPageByIndex(index int) (*RasterPage, error) {
 	page, err := r.Reader.PageContentByIndex(index)
 	if err != nil {
 		return nil, err
@@ -14,12 +14,7 @@

 package ofdgo

-import (
-	"fmt"
-	"image"
-
-	"github.com/tdewolff/canvas"
-)
+import "fmt"

 // ObjectBounds 获取文字、路径、图片或复合对象在页面坐标中的轴对齐范围，不修改对象
 // 文字采用字形范围，路径包含描边与裁剪，图片采用裁剪后的几何范围，不解码像素或排除透明像素
@@ -28,7 +23,8 @@ import (
 // 入参: object 图形对象, drawParam 图层绘制参数标识，无继承时为空
 // 返回: Box 毫米坐标范围, error 错误信息
 func (r *Renderer) ObjectBounds(object GraphicObject, drawParam string) (Box, error) {
-	return r.measureObject(object, drawParam, &boundsRenderer{})
+	result, err := r.MeasureObject(object, MeasureOptions{Defaults: r.drawParamDefaults(drawParam, nil)})
+	return result.Bounds, err
 }

 // ObjectContour 页面坐标中的填充轮廓，Path为SVG路径，EvenOdd表示奇偶填充
@@ -57,7 +53,7 @@ func (r *Renderer) AnnotationGeometry(annotation Annotation) (Box, []ObjectConto
 				continue
 			}
 			if path == "" {
-				path = canvas.Rectangle(region.W, region.H).Translate(region.X, region.Y).ToSVG()
+				path = fmt.Sprintf("M%g %gH%gV%gH%gZ", region.X, region.Y, region.X+region.W, region.Y+region.H, region.X)
 			}
 			box = unionTextBox(box, region)
 			contours = append(contours, ObjectContour{Path: path})
@@ -82,161 +78,16 @@ func (r *Renderer) ObjectGeometry(object GraphicObject, drawParam string) (Box,
 	if object.Type != "PathObject" && object.Type != "ImageObject" && object.Type != "CompositeObject" && object.Type != "CompositeGraphicUnit" {
 		return Box{}, nil, fmt.Errorf("contours require a path, image or composite object")
 	}
-	bounds := &boundsRenderer{collect: true}
-	box, err := r.measureObject(object, drawParam, bounds)
-	return box, bounds.contours, err
+	result, err := r.MeasureObject(object, MeasureOptions{Defaults: r.drawParamDefaults(drawParam, nil), Contours: true})
+	return result.Bounds, result.Contours, err
 }

-// measureObject 复用渲染逻辑收集对象范围与可选轮廓
-// 入参: object 对象, drawParam 图层绘制参数标识, bounds 度量目标
-// 返回: Box 毫米范围, error 错误信息
-func (r *Renderer) measureObject(object GraphicObject, drawParam string, bounds *boundsRenderer) (Box, error) {
-	if object.Type != "TextObject" && object.Type != "PathObject" && object.Type != "ImageObject" && object.Type != "CompositeObject" && object.Type != "CompositeGraphicUnit" {
-		return Box{}, fmt.Errorf("unsupported object type %q", object.Type)
+// MeasureObject 使用当前页面编译器度量对象，保持绘制与选区的字体和几何语义一致
+// 入参: object 图形对象, options 度量上下文
+// 返回: ObjectMeasurement 度量结果, error 错误信息
+func (r *Renderer) MeasureObject(object GraphicObject, options MeasureOptions) (ObjectMeasurement, error) {
+	if r.backends.Compiler == nil {
+		return ObjectMeasurement{}, fmt.Errorf("%w: object measurement", ErrBackendUnavailable)
 	}
-	boundary, ctm := editorGeometry(object)
-	if _, err := creationBox(boundary); err != nil {
-		return Box{}, err
-	}
-	if ctm != "" {
-		if _, err := creationNumbers(ctm, 6); err != nil {
-			return Box{}, err
-		}
-	}
-	renderer := *r
-	renderer.pageText = nil
-	renderer.textOnly = false
-	defaults := renderer.drawParamDefaults(drawParam, nil)
-	ctx := canvas.NewContext(bounds)
-	switch object.Type {
-	case "TextObject":
-		renderer.pageText = &PageText{}
-		renderer.textOnly = true
-		renderer.renderText(ctx, object.TextObject, 0, defaults, nil, false, nil)
-		var box Box
-		for _, run := range renderer.pageText.Runs {
-			for _, glyph := range run.Boxes {
-				box = unionTextBox(box, glyph)
-			}
-		}
-		return box, nil
-	case "PathObject":
-		obj := object.PathObject
-		defaults = renderer.drawParamDefaults(obj.DrawParam, defaults)
-		obj.DrawParam = ""
-		if defaults != nil {
-			style := *defaults
-			style.FillColor = boundsColor(style.FillColor)
-			style.StrokeColor = (*StrokeColor)(boundsColor((*FillColor)(style.StrokeColor)))
-			defaults = &style
-		}
-		obj.FillColor = boundsColor(obj.FillColor)
-		obj.StrokeColor = (*StrokeColor)(boundsColor((*FillColor)(obj.StrokeColor)))
-		renderer.renderPath(ctx, obj, 0, defaults, nil, false, nil)
-	case "ImageObject":
-		renderer.measureImage(ctx, object.ImageObject, 0, nil, false, nil)
-	case "CompositeObject", "CompositeGraphicUnit":
-		renderer.renderCompositeGraphicUnit(ctx, object.CompositeGraphicUnit, 0, defaults, nil, false, nil)
-	}
-	return bounds.box, nil
+	return r.backends.Compiler.MeasureObject(r, object, options)
 }
-
-// measureImage 复用图片变换与裁剪语义度量范围，不读取像素数据
-// 入参: ctx 度量画布, obj 图片, pageH 页面高度, parentCTM 父变换, boundaryInCTM 边界是否参与变换, parentClip 父裁剪
-func (r *Renderer) measureImage(ctx *canvas.Context, obj ImageObject, pageH float64, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) {
-	if obj.Visible != nil && !*obj.Visible || obj.Alpha != nil && *obj.Alpha == 0 {
-		return
-	}
-	box, _ := ParseBox(obj.Boundary)
-	ctm := NewMatrix(obj.CTM)
-	if obj.CTM == "" {
-		ctm = Matrix{a: box.W, d: box.H}
-	}
-	m := TranslationMatrix(box.X, box.Y).Multiply(ctm)
-	if parentCTM != nil {
-		if boundaryInCTM {
-			m = parentCTM.Multiply(m)
-		} else {
-			m = TranslationMatrix(box.X, box.Y).Multiply(*parentCTM).Multiply(ctm)
-		}
-	}
-	p := canvas.Rectangle(1, 1).Transform(canvas.Matrix{{m.a, m.c, m.e}, {-m.b, -m.d, pageH - m.f}})
-	clip := intersectClipPath(parentClip, r.buildObjectClipPath(obj.Clips, pageH, box.X, box.Y, ctm, parentCTM, boundaryInCTM))
-	ctx.Renderer.(*boundsRenderer).add(applyClipPath(p, clip))
-	if obj.Border != nil {
-		border := *obj.Border
-		border.BorderColor = (*StrokeColor)(boundsColor((*FillColor)(border.BorderColor)))
-		obj.Border = &border
-		r.renderImageBorder(ctx, obj, box, pageH, parentCTM, boundaryInCTM, clip)
-	}
-}
-
-// boundsColor 以底纹的基础颜色和透明度度量轮廓，不修改原画刷
-// 入参: color 填充或描边颜色
-// 返回: *FillColor 用于度量的颜色
-func boundsColor(color *FillColor) *FillColor {
-	if color == nil || color.Pattern == nil {
-		return color
-	}
-	return &FillColor{Value: color.Value, Index: color.Index, ColorSpace: color.ColorSpace, Alpha: color.Alpha}
-}
-
-// boundsRenderer 收集绘制范围，不分配页面像素或合并独立图形轮廓
-type boundsRenderer struct {
-	box      Box
-	collect  bool
-	contours []ObjectContour
-}
-
-// Size 返回不限定边界的度量画布尺寸
-// 返回: float64 宽度, float64 高度
-func (r *boundsRenderer) Size() (float64, float64) {
-	return 0, 0
-}
-
-// add 合并路径的精确曲线范围并转换为向下的纵轴
-// 入参: path 绘制路径
-func (r *boundsRenderer) add(path *canvas.Path) {
-	r.addContour(path, false)
-}
-
-// addContour 合并范围并按需保留独立填充区域
-// 入参: path 绘制路径, evenOdd 是否使用奇偶规则
-func (r *boundsRenderer) addContour(path *canvas.Path, evenOdd bool) {
-	if path.Empty() {
-		return
-	}
-	rect := path.Bounds()
-	r.box = unionTextBox(r.box, Box{X: rect.X0, Y: -rect.Y1, W: rect.W(), H: rect.H()})
-	if r.collect {
-		outline := &canvas.Path{}
-		for _, subpath := range path.Split() {
-			subpath = subpath.Copy()
-			subpath.Close()
-			outline = outline.Append(subpath)
-		}
-		r.contours = append(r.contours, ObjectContour{Path: outline.Transform(canvas.Matrix{{1, 0, 0}, {0, -1, 0}}).ToSVG(), EvenOdd: evenOdd})
-	}
-}
-
-// RenderPath 收集填充与描边范围，保持线帽、连接和虚线语义
-// 入参: path 路径, style 绘制样式, m 变换矩阵
-func (r *boundsRenderer) RenderPath(path *canvas.Path, style canvas.Style, m canvas.Matrix) {
-	if style.HasFill() {
-		r.addContour(path.Copy().Transform(m), style.FillRule == canvas.EvenOdd)
-	}
-	if style.HasStroke() {
-		p := path.Dash(style.DashOffset, style.Dashes...).Stroke(style.StrokeWidth, style.StrokeCapper, style.StrokeJoiner, canvas.Tolerance)
-		r.add(p.Transform(m))
-	}
-}
-
-// RenderText 收集绘制文字范围
-// 入参: text 文字, m 变换矩阵
-func (r *boundsRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
-	text.RenderTo(r, m, 0)
-}
-
-// RenderImage 度量不展开底纹图片
-// 入参: img 图片, m 变换矩阵
-func (r *boundsRenderer) RenderImage(img image.Image, m canvas.Matrix) {}
@@ -16,8 +16,6 @@ package ofdgo

 import (
 	"archive/zip"
-	"bufio"
-	"bytes"
 	"fmt"
 	"image"
 	"image/jpeg"
@@ -26,13 +24,7 @@ import (
 	"strconv"
 	"strings"

-	"github.com/tdewolff/canvas"
-	"github.com/tdewolff/canvas/renderers/pdf"
-	"github.com/tdewolff/canvas/renderers/ps"
-	"github.com/tdewolff/canvas/renderers/rasterizer"
-	"github.com/tdewolff/canvas/renderers/svg"
 	"golang.org/x/image/draw"
-	"golang.org/x/image/math/f64"
 )

 // RenderTo 按格式渲染单页，JPEG使用95画质
@@ -178,56 +170,18 @@ func (r *Renderer) exportProgress(completed, total int) error {
 	return nil
 }

-// rasterRenderer 保留页面物理尺寸的光栅渲染器
-type rasterRenderer struct {
-	*rasterizer.Rasterizer
-	width, height float64
-	dpmm          float64
-	linear        bool
-}
-
-// Size 返回页面物理尺寸
-// 返回: float64 宽度, float64 高度
-func (r *rasterRenderer) Size() (float64, float64) {
-	return r.width, r.height
-}
-
-// RenderImage 使用底层图片完成平移和缩放
-// 入参: img 图片对象, m 图片变换矩阵
-func (r *rasterRenderer) RenderImage(img image.Image, m canvas.Matrix) {
-	if !r.linear || m[0][1] != 0 || m[1][0] != 0 {
-		r.Rasterizer.RenderImage(img, m)
-		return
-	}
-	origin := m.Dot(canvas.Point{Y: float64(img.Bounds().Dy())}).Mul(r.dpmm)
-	m = m.Scale(r.dpmm, r.dpmm)
-	transform := f64.Aff3{m[0][0], -m[0][1], origin.X, -m[1][0], m[1][1], float64(r.Bounds().Dy()) - origin.Y}
-	draw.CatmullRom.Transform(r.Image, transform, img, img.Bounds(), draw.Over, nil)
-}
-
 // RenderToImage 渲染为光栅图
 // 入参: page 页面内容
 // 返回: image.Image 图像对象, error 错误信息
 func (r *Renderer) RenderToImage(page *PageContent) (image.Image, error) {
-	box, err := r.GetPageBox(page)
+	if r.backends.Raster == nil {
+		return nil, fmt.Errorf("raster: %w", ErrBackendUnavailable)
+	}
+	scene, err := r.CompilePage(page)
 	if err != nil {
 		return nil, err
 	}
-	dpmm := r.DPI / 25.4
-	colorSpace := canvas.DefaultColorSpace
-	_, linear := colorSpace.(canvas.LinearColorSpace)
-	raster := &rasterRenderer{
-		Rasterizer: rasterizer.New(box.W, box.H, canvas.DPMM(dpmm), colorSpace),
-		width:      box.W,
-		height:     box.H,
-		dpmm:       dpmm,
-		linear:     linear,
-	}
-	if err := r.RenderPageToContext(canvas.NewContext(raster), page); err != nil {
-		return nil, err
-	}
-	raster.Close()
-	return raster.Image, nil
+	return r.backends.Raster.Render(scene)
 }

 // RenderToPNG 渲染为PNG，像素尺寸由DPI决定
@@ -281,31 +235,8 @@ func fillWhiteBackground(img image.Image) image.Image {
 // 入参: page 页面内容, writer 输出流
 // 返回: error 错误信息
 func (r *Renderer) RenderToSVG(page *PageContent, writer io.Writer) error {
-	c, err := r.renderPage(page)
-	if err != nil {
-		return err
-	}
-	buffer := bufio.NewWriter(writer)
-	renderer := svg.New(buffer, c.W, c.H, nil)
-	c.RenderTo(renderer)
-	if err := renderer.Close(); err != nil {
-		return err
-	}
-	return buffer.Flush()
-}
-
-// replacePDFProducer 替换PDF的Producer属性
-// 入参: data PDF字节数据
-// 返回: []byte 替换后的PDF字节数据
-func replacePDFProducer(data []byte) []byte {
-	old := []byte("/Producer(tdewolff/canvas)")
-	idx := bytes.LastIndex(data, old)
-	if idx < 0 {
-		return data
-	}
-	dst := []byte("/Producer(xiaoqidun/ofdgo)")
-	copy(data[idx:idx+len(old)], dst)
-	return data
+	_, err := r.renderSVG(page, writer, SVGEmbedded)
+	return err
 }

 // RenderToPDF 渲染为PDF
@@ -316,7 +247,7 @@ func (r *Renderer) RenderToPDF(page *PageContent, writer io.Writer) error {
 	if err != nil {
 		return err
 	}
-	pages := []pdfPage{{Content: page, Box: box}}
+	pages := []RenderDocumentPage{{Content: page, Box: box}}
 	return r.renderPDFPages(pages, writer, nil)
 }

@@ -324,19 +255,10 @@ func (r *Renderer) RenderToPDF(page *PageContent, writer io.Writer) error {
 // 入参: page 页面内容, writer 输出流
 // 返回: error 错误信息
 func (r *Renderer) RenderToEPS(page *PageContent, writer io.Writer) error {
-	c, err := r.renderPage(page)
-	if err != nil {
-		return err
+	if r.backends.EPS == nil {
+		return fmt.Errorf("eps: %w", ErrBackendUnavailable)
 	}
-	options := ps.DefaultOptions
-	options.Format = ps.EncapsulatedPostScript
-	buffer := bufio.NewWriter(writer)
-	renderer := ps.New(buffer, c.W, c.H, &options)
-	c.RenderTo(renderer)
-	if err := renderer.Close(); err != nil {
-		return err
-	}
-	return buffer.Flush()
+	return r.backends.EPS.RenderEPS(r, page, writer)
 }

 // RenderToMultiPagePDF 将文档页面导出为多页PDF
@@ -354,7 +276,7 @@ func (r *Renderer) RenderToMultiPagePDF(writer io.Writer, indices ...int) error
 	if err := r.exportProgress(0, len(indices)); err != nil {
 		return err
 	}
-	pages := make([]pdfPage, len(indices))
+	pages := make([]RenderDocumentPage, len(indices))
 	for i, index := range indices {
 		page, err := r.Reader.PageContent(doc.Pages.Page[index])
 		if err != nil {
@@ -364,7 +286,7 @@ func (r *Renderer) RenderToMultiPagePDF(writer io.Writer, indices ...int) error
 		if err != nil {
 			return fmt.Errorf("failed to read page %d area: %w", index+1, err)
 		}
-		pages[i] = pdfPage{Content: page, Box: box}
+		pages[i] = RenderDocumentPage{Content: page, Box: box}
 	}
 	return r.renderPDFPages(pages, writer, r.OnExportProgress)
 }
@@ -379,59 +301,23 @@ func (r *Renderer) RenderPagesToPDF(contents []*PageContent, writer io.Writer) e
 	if err := r.exportProgress(0, len(contents)); err != nil {
 		return err
 	}
-	pages := make([]pdfPage, len(contents))
+	pages := make([]RenderDocumentPage, len(contents))
 	for i, page := range contents {
 		box, err := r.GetPageBox(page)
 		if err != nil {
 			return fmt.Errorf("failed to read page %d area: %w", i+1, err)
 		}
-		pages[i] = pdfPage{Content: page, Box: box}
+		pages[i] = RenderDocumentPage{Content: page, Box: box}
 	}
 	return r.renderPDFPages(pages, writer, r.OnExportProgress)
 }

-// renderPDFPages 渲染页面并复用调用方的字节缓冲
+// renderPDFPages 将已解析页面交给指定PDF后端
 // 入参: pages 页面列表, writer 输出流, progress 页面处理进度
 // 返回: error 错误信息
-func (r *Renderer) renderPDFPages(pages []pdfPage, writer io.Writer, progress func(int, int) error) error {
-	navigation := newPDFNavigation(r, r.Reader.doc, pages)
-	buf, direct := writer.(*bytes.Buffer)
-	if !direct {
-		buf = &bytes.Buffer{}
+func (r *Renderer) renderPDFPages(pages []RenderDocumentPage, writer io.Writer, progress func(int, int) error) error {
+	if r.backends.PDF == nil {
+		return fmt.Errorf("pdf: %w", ErrBackendUnavailable)
 	}
-	start := buf.Len()
-	p := pdf.New(buf, pages[0].Box.W, pages[0].Box.H, nil)
-	renderer := &pdfRenderer{PDF: p, glyphPaths: make(map[*canvas.Path]*canvas.Path)}
-	var info DocInfo
-	if docInfo, err := r.Reader.DocInfo(); err == nil {
-		info = *docInfo
-	}
-	p.SetInfo(info.Title, info.Subject, "", info.Author, "xiaoqidun/ofdgo")
-	for i, page := range pages {
-		if i > 0 {
-			p.NewPage(page.Box.W, page.Box.H)
-		}
-		navigation.apply(p, i)
-		if err := r.renderPageToContext(canvas.NewContext(renderer), page.Content, true); err != nil {
-			buf.Truncate(start)
-			return fmt.Errorf("failed to render page %d: %w", i+1, err)
-		}
-		pages[i].Content = nil
-		if progress != nil {
-			if err := progress(i+1, len(pages)); err != nil {
-				buf.Truncate(start)
-				return err
-			}
-		}
-	}
-	if err := p.Close(); err != nil {
-		buf.Truncate(start)
-		return err
-	}
-	data := replacePDFProducer(buf.Bytes()[start:])
-	if direct {
-		return nil
-	}
-	_, err := writer.Write(data)
-	return err
+	return r.backends.PDF.RenderPDF(r, pages, writer, progress)
 }
@@ -0,0 +1,57 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"fmt"
+	"io"
+)
+
+// PreviewOptions 指定页面显示方式，光栅预览不提供SVG对象分组
+type PreviewOptions struct {
+	Raster  bool
+	Objects bool
+}
+
+// RenderPreview 生成统一SVG容器及独立资源，原生程序与WebUI使用相同绘制入口
+// 入参: page 页面内容, writer 输出流, options 显示方式
+// 返回: SVGResources 需由调用方映射地址的资源, error 错误信息
+func (r *Renderer) RenderPreview(page *PageContent, writer io.Writer, options PreviewOptions) (SVGResources, error) {
+	if !options.Raster {
+		if options.Objects {
+			return r.RenderToSVGWithObjects(page, writer)
+		}
+		return r.RenderToSVGWithResources(page, writer)
+	}
+	if options.Objects {
+		return SVGResources{}, fmt.Errorf("raster preview does not provide SVG object groups")
+	}
+	box, err := r.GetPageBox(page)
+	if err != nil {
+		return SVGResources{}, err
+	}
+	var pixels bytes.Buffer
+	if err := r.RenderToPNG(page, &pixels); err != nil {
+		return SVGResources{}, err
+	}
+	name := fmt.Sprintf("ofdgo-image-%x", sha256.Sum256(pixels.Bytes()))
+	_, err = fmt.Fprintf(writer, `<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="%gmm" height="%gmm" viewBox="0 0 %g %g"><image width="%g" height="%g" preserveAspectRatio="none" xlink:href="%s"/></svg>`, box.W, box.H, box.W, box.H, box.W, box.H, name)
+	if err != nil {
+		return SVGResources{}, err
+	}
+	return SVGResources{Images: []SVGImage{{Name: name, MIME: "image/png", Data: pixels.Bytes()}}}, nil
+}
@@ -15,19 +15,8 @@
 package ofdgo

 import (
-	"bufio"
-	"bytes"
-	"crypto/sha256"
 	"fmt"
-	"html"
-	"image"
-	"image/png"
 	"io"
-	"strings"
-
-	"github.com/tdewolff/canvas"
-	canvasimage "github.com/tdewolff/canvas/image"
-	"github.com/tdewolff/canvas/renderers/svg"
 )

 // SVGFont SVG引用的字体资源，Name为CSS字体族标识，Data为只读字体数据
@@ -51,33 +40,11 @@ type SVGResources struct {
 	Images []SVGImage
 }

-// svgResourceRenderer 分离外部资源的SVG渲染器
-type svgResourceRenderer struct {
-	*svg.SVG
-	renderer    *Renderer
-	writer      io.Writer
-	fonts       []SVGFont
-	images      []SVGImage
-	imageNames  map[image.Image]string
-	seen        map[string]bool
-	styles      strings.Builder
-	err         error
-	objects     map[*GraphicObject]string
-	objectStack []svgObjectGroup
-}
-
-// svgObjectGroup 记录编辑分组的稳定路径，不把底纹内部绘制当作成员
-type svgObjectGroup struct {
-	path      string
-	next      int
-	composite bool
-}
-
 // RenderToSVGWithFonts 渲染为SVG并返回页面引用的字体资源，不在SVG中嵌入字体
 // 入参: page 页面内容, writer 输出流
 // 返回: []SVGFont 字体资源，可按Name复用并按Weight、Style注册，error 错误信息
 func (r *Renderer) RenderToSVGWithFonts(page *PageContent, writer io.Writer) ([]SVGFont, error) {
-	resources, err := r.renderSVGResources(page, writer, false, false)
+	resources, err := r.renderSVG(page, writer, SVGExternalFonts)
 	return resources.Fonts, err
 }

@@ -85,170 +52,22 @@ func (r *Renderer) RenderToSVGWithFonts(page *PageContent, writer io.Writer) ([]
 // 入参: page 页面内容, writer 输出流
 // 返回: SVGResources 可跨页面复用的资源, error 错误信息
 func (r *Renderer) RenderToSVGWithResources(page *PageContent, writer io.Writer) (SVGResources, error) {
-	return r.renderSVGResources(page, writer, true, false)
+	return r.renderSVG(page, writer, SVGExternalResources)
 }

 // RenderToSVGWithObjects 渲染SVG并为页面对象和注解添加data-ofd-object分组，注解标识使用annotation:前缀
 // 入参: page 页面内容, writer 输出流
 // 返回: SVGResources 字体和图片资源, error 错误信息
 func (r *Renderer) RenderToSVGWithObjects(page *PageContent, writer io.Writer) (SVGResources, error) {
-	return r.renderSVGResources(page, writer, true, true)
+	return r.renderSVG(page, writer, SVGObjects)
 }

-// renderSVGResources 渲染SVG并收集外部资源
-// 入参: page 页面内容, writer 输出流, images 是否分离图片, objects 是否标识页面直接对象
-// 返回: SVGResources 外部资源, error 错误信息
-func (r *Renderer) renderSVGResources(page *PageContent, writer io.Writer, images, objects bool) (SVGResources, error) {
-	box, err := r.GetPageBox(page)
-	if err != nil {
-		return SVGResources{}, err
+// renderSVG 将SVG输出及对象分组交给指定后端
+// 入参: page 页面内容, writer 输出流, mode 资源封装方式
+// 返回: SVGResources 字体和图片资源, error 输出错误
+func (r *Renderer) renderSVG(page *PageContent, writer io.Writer, mode SVGMode) (SVGResources, error) {
+	if r.backends.SVG == nil {
+		return SVGResources{}, fmt.Errorf("svg: %w", ErrBackendUnavailable)
 	}
-	options := svg.DefaultOptions
-	options.EmbedFonts = false
-	buffer := bufio.NewWriter(writer)
-	s := &svgResourceRenderer{
-		SVG:      svg.New(buffer, box.W, box.H, &options),
-		renderer: r,
-		writer:   buffer,
-		seen:     make(map[string]bool),
-	}
-	if images {
-		s.imageNames = make(map[image.Image]string)
-	}
-	if objects {
-		s.objects = make(map[*GraphicObject]string)
-		for i := range page.Content.Layer {
-			for j := range page.Content.Layer[i].Objects {
-				object := &page.Content.Layer[i].Objects[j]
-				s.objects[object] = editorObjectID(*object)
-			}
-		}
-		if err := r.renderPageToContext(canvas.NewContext(s), page, true); err != nil {
-			return SVGResources{}, err
-		}
-	} else {
-		c, err := r.renderPage(page)
-		if err != nil {
-			return SVGResources{}, err
-		}
-		c.RenderTo(s)
-	}
-	if s.err != nil {
-		return SVGResources{}, s.err
-	}
-	s.SetCustomStyle(s.styles.String())
-	if err := s.Close(); err != nil {
-		return SVGResources{}, err
-	}
-	return SVGResources{Fonts: s.fonts, Images: s.images}, buffer.Flush()
-}
-
-// beginObject 标记直接对象及复合或注解成员，模板图元不单独标记
-// 入参: object 图形对象
-// 返回: bool 是否写入分组
-func (s *svgResourceRenderer) beginObject(object *GraphicObject) bool {
-	id := s.objects[object]
-	attribute := "data-ofd-object"
-	if id == "" {
-		if len(s.objectStack) == 0 || !s.objectStack[len(s.objectStack)-1].composite {
-			return false
-		}
-		parent := &s.objectStack[len(s.objectStack)-1]
-		id = fmt.Sprintf("%s/%d", parent.path, parent.next)
-		parent.next++
-		attribute = "data-ofd-child"
-	}
-	s.objectStack = append(s.objectStack, svgObjectGroup{path: id, composite: object.Type == "CompositeObject" || object.Type == "CompositeGraphicUnit"})
-	fmt.Fprintf(s.writer, `<g %s="%s">`, attribute, html.EscapeString(id))
-	return true
-}
-
-// endObject 结束对象分组
-func (s *svgResourceRenderer) endObject() {
-	s.objectStack = s.objectStack[:len(s.objectStack)-1]
-	fmt.Fprint(s.writer, `</g>`)
-}
-
-// beginAnnotation 标记完整注解外观，内部图元保持原有层级和绘制顺序
-// 入参: id 注解标识
-// 返回: bool 是否写入分组
-func (s *svgResourceRenderer) beginAnnotation(id string) bool {
-	if s.objects == nil {
-		return false
-	}
-	s.objectStack = append(s.objectStack, svgObjectGroup{path: "annotation:" + id, composite: true})
-	fmt.Fprintf(s.writer, `<g data-ofd-object="annotation:%s">`, html.EscapeString(id))
-	return true
-}
-
-// skipObjects 为不可见资源保留内部成员序号
-// 入参: count 直接成员数量
-func (s *svgResourceRenderer) skipObjects(count int) {
-	if len(s.objectStack) > 0 {
-		s.objectStack[len(s.objectStack)-1].next += count
-	}
-}
-
-// RenderImage 绘制图片，分离资源时保持原始编码、尺寸和变换
-// 入参: img 图片对象, m 变换矩阵
-func (s *svgResourceRenderer) RenderImage(img image.Image, m canvas.Matrix) {
-	if s.imageNames == nil {
-		s.SVG.RenderImage(img, m)
-		return
-	}
-	name, ok := s.imageNames[img]
-	if !ok {
-		resource := SVGImage{MIME: "image/png"}
-		if encoded, ok := img.(*canvasimage.Image); ok {
-			resource.MIME, resource.Data = encoded.Mimetype, encoded.Bytes
-		} else {
-			var buffer bytes.Buffer
-			if err := png.Encode(&buffer, img); err != nil {
-				s.err = err
-				return
-			}
-			resource.Data = buffer.Bytes()
-		}
-		name = fmt.Sprintf("ofdgo-image-%x", sha256.Sum256(resource.Data))
-		resource.Name = name
-		s.imageNames[img] = name
-		if !s.seen[name] {
-			s.seen[name] = true
-			s.images = append(s.images, resource)
-		}
-	}
-	_, height := s.Size()
-	size := img.Bounds().Size()
-	fmt.Fprintf(s.writer, `<image transform="%s" width="%d" height="%d" xlink:href="%s"/>`, m.Translate(0, float64(size.Y)).ToSVG(height), size.X, size.Y, name)
-}
-
-// RenderText 绘制文字并记录实际使用的字体资源
-// 入参: text 文字对象, m 变换矩阵
-func (s *svgResourceRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
-	if text.Empty() {
-		return
-	}
-	font := text.MostCommonFontFace().Font
-	resource, ok := s.renderer.svgFontCache[font]
-	if !ok {
-		data := font.SFNT.Write()
-		resource = SVGFont{
-			Name:   fmt.Sprintf("ofdgo-%x-%d", sha256.Sum256(data), font.Style()),
-			Weight: font.Style().CSS(),
-			Style:  "normal",
-			Data:   data,
-		}
-		if font.Style().Italic() {
-			resource.Style = "italic"
-		}
-		s.renderer.svgFontCache[font] = resource
-	}
-	if !s.seen[resource.Name] {
-		s.seen[resource.Name] = true
-		s.fonts = append(s.fonts, resource)
-		fmt.Fprintf(&s.styles, ".%s{font-family:%s!important}", resource.Name, resource.Name)
-	}
-	s.SetClass(resource.Name)
-	s.SVG.RenderText(text, m)
-	s.SetClass()
+	return r.backends.SVG.RenderSVG(r, page, writer, mode)
 }
@@ -21,8 +21,6 @@ import (
 	"strings"
 	"unicode"
 	"unicode/utf8"
-
-	"github.com/tdewolff/canvas"
 )

 // textPageTokens 保留文字及其复合图元和裁剪，跳过独立路径与图片
@@ -92,22 +90,14 @@ type TextMatch struct {
 	Boxes  []Box  `json:"boxes"`
 }

-// PageText 提取页面及启用注释的原文，复用当前字体配置和渲染位置计算
+// PageText 提取页面及启用注释的原文，复用当前编译器的字体和几何语义
 // 入参: page 页面内容
 // 返回: *PageText 页面文字, error 错误信息
 func (r *Renderer) PageText(page *PageContent) (*PageText, error) {
-	box, err := r.GetPageBox(page)
-	if err != nil {
-		return nil, err
+	if r.backends.Compiler == nil {
+		return nil, fmt.Errorf("%w: page text", ErrBackendUnavailable)
 	}
-	renderer := *r
-	renderer.OnPageText = nil
-	renderer.pageText = &PageText{}
-	renderer.textOnly = true
-	if err := renderer.renderPageToContext(canvas.NewContext(canvas.New(box.W, box.H)), page, false); err != nil {
-		return nil, err
-	}
-	return renderer.pageText, nil
+	return r.backends.Compiler.PageText(r, page)
 }

 // PageTextByIndex 按页面索引提取文字，避免解析独立路径和图片图元
@@ -230,17 +220,6 @@ func textGlyphSpans(runes []rune, transforms map[int]textGlyphTransform, offset
 	return spans
 }

-// textPathBox 将字形轮廓转换为页面区域
-// 入参: path 字形轮廓, pageH 页面高度
-// 返回: Box 字符区域
-func textPathBox(path *canvas.Path, pageH float64) Box {
-	if path.Empty() {
-		return Box{}
-	}
-	bounds := path.Bounds()
-	return Box{X: bounds.X0, Y: pageH - bounds.Y1, W: bounds.X1 - bounds.X0, H: bounds.Y1 - bounds.Y0}
-}
-
 // unionTextBox 合并同一字符的字形区域
 // 入参: a 已有区域, b 新区域
 // 返回: Box 合并区域
@@ -254,36 +233,3 @@ func unionTextBox(a, b Box) Box {
 	x, y := math.Min(a.X, b.X), math.Min(a.Y, b.Y)
 	return Box{X: x, Y: y, W: math.Max(a.X+a.W, b.X+b.W) - x, H: math.Max(a.Y+a.H, b.Y+b.H) - y}
 }
-
-// addSpan 收集字形选择区域，同一原文区间的多个字形合并为一项
-// 入参: start 起始字符, end 结束字符, bounds 字形布局区域, m 字形变换, clip 裁剪路径, pageH 页面高度
-func (run *TextRun) addSpan(start, end int, bounds canvas.Rect, m canvas.Matrix, clip *canvas.Path, pageH float64) {
-	if m.Det() == 0 {
-		return
-	}
-	if clip != nil {
-		path := canvas.Rectangle(bounds.W(), bounds.H()).Translate(bounds.X0, bounds.Y0).Transform(m)
-		path = applyClipPath(path, clip)
-		if path.Empty() {
-			return
-		}
-		bounds = path.Transform(m.Inv()).Bounds()
-	}
-	if bounds.W() < 0 || bounds.H() <= 0 {
-		return
-	}
-	m = canvas.Matrix{{1, 0, 0}, {0, -1, pageH}}.Mul(m).Translate(bounds.X0, bounds.Y1).Scale(bounds.W(), -bounds.H())
-	span := TextSpan{Start: start, End: end}
-	if n := len(run.Spans); n > 0 && run.Spans[n-1].Start == start && run.Spans[n-1].End == end {
-		span = run.Spans[n-1]
-		v := span.Matrix
-		previous := canvas.Matrix{{v[0], v[2], v[4]}, {v[1], v[3], v[5]}}
-		if previous.Det() != 0 {
-			bounds = canvas.Rect{X1: 1, Y1: 1}.Add(canvas.Rect{X1: 1, Y1: 1}.Transform(previous.Inv().Mul(m)))
-			m = previous.Translate(bounds.X0, bounds.Y0).Scale(bounds.W(), bounds.H())
-		}
-		run.Spans = run.Spans[:n-1]
-	}
-	span.Matrix = [6]float64{m[0][0], m[1][0], m[0][1], m[1][1], m[0][2], m[1][2]}
-	run.Spans = append(run.Spans, span)
-}
@@ -55,9 +55,9 @@ const (
 )

 // NewShape 创建使用标准紧缩路径的图形，默认黑色描边、不填充
-// 可调整返回对象的颜色、线宽等属性后通过 Editor.AddObject 写入
+// 可调整返回对象的颜色、线宽等属性后通过Editor.AddObject写入
 // 水平、垂直直线使用正尺寸边界，路径端点不变
-// 入参: kind 图形类型, box 图形范围；直线从 (X,Y) 到 (X+W,Y+H)，W、H 可为负或零
+// 入参: kind 图形类型, box 图形范围；直线从(X,Y)到(X+W,Y+H)，W、H可为负或零
 // 返回: PathObject 路径对象, error 错误信息
 func NewShape(kind ShapeKind, box Box) (PathObject, error) {
 	if !finite(box.X) || !finite(box.Y) || !finite(box.W) || !finite(box.H) || !finite(box.X+box.W) || !finite(box.Y+box.H) {