feat(前端界面): OFDGo WebUI支持单页输出

assets/webui/index.html

@@ -10,25 +10,34 @@
 	<div class="app">
 		<header class="toolbar app-bar">
 			<input id="ofdInput" class="file-input" type="file" accept=".ofd,application/ofd,application/zip">
-			<button id="ofdButton" class="button primary" type="button" data-short="打开">打开</button>
 			<input id="fontInput" class="file-input" type="file" accept=".ttf,.otf,.ttc,font/*" multiple>
-			<button id="togglePagesButton" class="icon-button" type="button" title="页面栏" aria-label="页面栏" aria-pressed="true">&#9776;</button>
-			<button id="toggleMetaButton" class="icon-button" type="button" title="信息栏" aria-label="信息栏" aria-pressed="true">&#9432;</button>
+			<div class="tool-group">
+				<button id="ofdButton" class="button primary" type="button" data-short="打开">打开</button>
+				<button id="togglePagesButton" class="icon-button" type="button" title="页面栏" aria-label="页面栏" aria-pressed="true">&#9776;</button>
+				<button id="toggleMetaButton" class="icon-button" type="button" title="信息栏" aria-label="信息栏" aria-pressed="true">&#9432;</button>
+			</div>
 			<div class="toolbar-space"></div>
-			<button id="prevButton" class="icon-button" type="button" title="上一页" disabled>&lsaquo;</button>
-			<label class="page-control">
-				<input id="pageInput" type="number" min="1" value="1" disabled>
-				<span>/</span>
-				<span id="pageTotal">0</span>
-			</label>
-			<button id="nextButton" class="icon-button" type="button" title="下一页" disabled>&rsaquo;</button>
-			<div class="divider"></div>
-			<button id="zoomOutButton" class="icon-button" type="button" title="缩小" disabled>-</button>
-			<span id="zoomLabel" class="zoom-label">100%</span>
-			<button id="zoomInButton" class="icon-button" type="button" title="放大" disabled>+</button>
-			<button id="fitButton" class="button" type="button" data-short="宽" disabled>适宽</button>
-			<button id="fitHeightButton" class="button" type="button" data-short="高" disabled>适高</button>
-			<button id="exportButton" class="button" type="button" data-short="PDF" title="导出 PDF" aria-label="导出 PDF" disabled>PDF</button>
+			<div class="tool-group">
+				<button id="prevButton" class="icon-button" type="button" title="上一页" disabled>&lsaquo;</button>
+				<label class="page-control">
+					<input id="pageInput" type="number" min="1" value="1" disabled>
+					<span>/</span>
+					<span id="pageTotal">0</span>
+				</label>
+				<button id="nextButton" class="icon-button" type="button" title="下一页" disabled>&rsaquo;</button>
+			</div>
+			<div class="tool-group">
+				<button id="zoomOutButton" class="icon-button" type="button" title="缩小" disabled>-</button>
+				<span id="zoomLabel" class="zoom-label">100%</span>
+				<button id="zoomInButton" class="icon-button" type="button" title="放大" disabled>+</button>
+				<button id="fitButton" class="button" type="button" data-short="宽" disabled>适宽</button>
+				<button id="fitHeightButton" class="button" type="button" data-short="高" disabled>适高</button>
+			</div>
+			<div class="tool-group">
+				<select id="pageExportFormat" class="format-select" title="单页格式" aria-label="单页格式" disabled></select>
+				<button id="exportPageButton" class="button" type="button" data-short="页" title="导出单页" aria-label="导出单页" disabled>单页</button>
+				<button id="exportButton" class="button" type="button" data-short="文档" title="导出文档 PDF" aria-label="导出文档 PDF" disabled>文档</button>
+			</div>
 		</header>
 
 		<main class="workspace">

assets/webui/ofdgo.css

@@ -32,7 +32,8 @@ body {
 }
 
 button,
-input {
+input,
+select {
 	font: inherit;
 }
 
@@ -45,13 +46,15 @@ button {
 }
 
 button:disabled,
-input:disabled {
+input:disabled,
+select:disabled {
 	cursor: not-allowed;
 	opacity: 0.48;
 }
 
 button:focus-visible,
 input:focus-visible,
+select:focus-visible,
 a:focus-visible {
 	outline: 2px solid var(--focus);
 	outline-offset: 2px;
@@ -149,10 +152,29 @@ button:not(:disabled):hover {
 	flex: 1 1 auto;
 }
 
-.divider {
+.tool-group {
+	position: relative;
+	display: inline-flex;
+	align-items: center;
+	gap: 8px;
+	flex: 0 0 auto;
+	min-width: 0;
+}
+
+.tool-group + .tool-group {
+	margin-left: 2px;
+	padding-left: 18px;
+}
+
+.tool-group + .tool-group::before {
+	position: absolute;
+	top: 50%;
+	left: 5px;
 	width: 1px;
 	height: 22px;
 	background: var(--line);
+	content: "";
+	transform: translateY(-50%);
 }
 
 .page-control {
@@ -176,6 +198,16 @@ button:not(:disabled):hover {
 	background: transparent;
 }
 
+.format-select {
+	height: var(--control-height);
+	min-width: 64px;
+	padding: 0 7px;
+	border: 1px solid var(--line);
+	border-radius: 0;
+	background: #ffffff;
+	color: #1f2428;
+}
+
 .zoom-label {
 	min-width: 42px;
 	text-align: center;
@@ -842,11 +874,20 @@ body[aria-busy="true"] .viewer-panel {
 		row-gap: 0;
 	}
 
-	.divider {
+	.toolbar-space {
 		display: none;
 	}
 
-	.toolbar-space {
+	.tool-group {
+		gap: 6px;
+	}
+
+	.tool-group + .tool-group {
+		margin-left: 0;
+		padding-left: 0;
+	}
+
+	.tool-group + .tool-group::before {
 		display: none;
 	}
 
@@ -894,6 +935,11 @@ body[aria-busy="true"] .viewer-panel {
 		padding-inline: 8px;
 	}
 
+	.format-select {
+		min-width: 56px;
+		padding: 0 5px;
+	}
+
 	.footer-links {
 		justify-content: flex-end;
 	}

assets/webui/ofdgo.js

@@ -26,11 +26,14 @@ const STATUS = {
 	engine: "正在准备引擎",
 	recovering: "正在恢复引擎",
 	fonts: "正在匹配字体",
-	exporting: "正在导出 PDF",
+	exporting: "正在导出文档 PDF",
+	pageExporting: "正在导出单页",
 };
 const WASM_CALLBACKS = [
 	"ofdgoOpen",
 	"ofdgoRenderPage",
+	"ofdgoExportFormats",
+	"ofdgoExportPage",
 	"ofdgoExportPDF",
 	"ofdgoFontCandidates",
 ];
@@ -63,6 +66,7 @@ const state = {
 	thumbnailCache: new Map(),
 	thumbnailInFlight: new Set(),
 	thumbnailObserver: null,
+	exportFormats: [],
 	showPages: !COMPACT_LAYOUT.matches,
 	showMeta: !COMPACT_LAYOUT.matches,
 };
@@ -84,6 +88,8 @@ const el = {
 	zoomLabel: document.querySelector("#zoomLabel"),
 	fitButton: document.querySelector("#fitButton"),
 	fitHeightButton: document.querySelector("#fitHeightButton"),
+	pageExportFormat: document.querySelector("#pageExportFormat"),
+	exportPageButton: document.querySelector("#exportPageButton"),
 	exportButton: document.querySelector("#exportButton"),
 	emptyState: document.querySelector("#emptyState"),
 	progressPanel: document.querySelector("#progressPanel"),
@@ -119,6 +125,7 @@ el.zoomOutButton.addEventListener("click", () => setScale(state.scale - 0.1));
 el.zoomInButton.addEventListener("click", () => setScale(state.scale + 0.1));
 el.fitButton.addEventListener("click", fitWidth);
 el.fitHeightButton.addEventListener("click", fitHeight);
+el.exportPageButton.addEventListener("click", exportCurrentPage);
 el.exportButton.addEventListener("click", exportPDF);
 el.pageInput.addEventListener("change", () => {
 	const page = Number.parseInt(el.pageInput.value, 10);
@@ -180,6 +187,7 @@ async function boot() {
 	try {
 		await ensureWASM();
 		setProgress("引擎准备完成", 70);
+		loadExportFormats();
 		setEmpty("选择 OFD 文件");
 		updateFontSummary();
 		renderFontList();
@@ -195,6 +203,21 @@ async function boot() {
 	}
 }
 
+function loadExportFormats() {
+	const formats = callWASM("ofdgoExportFormats") || [];
+	state.exportFormats = formats;
+	el.pageExportFormat.replaceChildren();
+	for (const format of formats) {
+		const option = document.createElement("option");
+		option.value = format.value;
+		option.textContent = format.label;
+		el.pageExportFormat.append(option);
+	}
+	if (formats.length) {
+		el.pageExportFormat.value = formats[0].value;
+	}
+}
+
 async function ensureWASM() {
 	if (state.ready && !state.wasmExited) {
 		return;
@@ -858,14 +881,14 @@ async function exportPDF() {
 		return;
 	}
 	const openSeq = state.openSeq;
-	el.exportButton.disabled = true;
-	setBusy(true, "正在准备 PDF", 18, STATUS.exporting);
+	setExportControlsDisabled(true);
+	setBusy(true, "正在准备文档 PDF", 18, STATUS.exporting);
 	try {
 		await waitForPaint();
 		if (openSeq !== state.openSeq) {
 			return;
 		}
-		setProgress("正在生成 PDF", 45);
+		setProgress("正在生成文档 PDF", 45);
 		await waitForPaint();
 		if (openSeq !== state.openSeq) {
 			return;
@@ -874,18 +897,53 @@ async function exportPDF() {
 		if (openSeq !== state.openSeq) {
 			return;
 		}
-		setProgress("正在保存 PDF", 86);
+		setProgress("正在保存文档 PDF", 86);
 		const bytes = base64ToBytes(result.base64);
-		const blob = new Blob([bytes], { type: "application/pdf" });
-		const link = document.createElement("a");
-		const url = URL.createObjectURL(blob);
-		link.href = url;
-		link.download = pdfFileName();
-		document.body.append(link);
-		link.click();
-		link.remove();
-		window.setTimeout(() => URL.revokeObjectURL(url), 1000);
-		setStatus(`PDF 已导出 ${formatBytes(result.size || bytes.length)}`);
+		downloadBytes(bytes, "application/pdf", pdfFileName());
+		setStatus(`文档 PDF 已导出 ${formatBytes(result.size || bytes.length)}`);
+	} catch (err) {
+		if (openSeq === state.openSeq) {
+			showError(err, false);
+		}
+	} finally {
+		if (openSeq === state.openSeq) {
+			setBusy(false);
+			updateControls();
+		}
+	}
+}
+
+async function exportCurrentPage() {
+	if (!state.doc) {
+		return;
+	}
+	const format = el.pageExportFormat.value;
+	if (!format) {
+		return;
+	}
+	const info = exportFormatInfo(format);
+	const label = info?.label || String(format || "").toUpperCase();
+	const openSeq = state.openSeq;
+	setExportControlsDisabled(true);
+	setBusy(true, `正在准备 ${label}`, 18, STATUS.pageExporting);
+	try {
+		await waitForPaint();
+		if (openSeq !== state.openSeq) {
+			return;
+		}
+		setProgress(`正在生成 ${label}`, 45);
+		await waitForPaint();
+		if (openSeq !== state.openSeq) {
+			return;
+		}
+		const result = callWASM("ofdgoExportPage", state.pageIndex, format);
+		if (openSeq !== state.openSeq) {
+			return;
+		}
+		setProgress(`正在保存 ${result.label || label}`, 86);
+		const bytes = base64ToBytes(result.base64);
+		downloadBytes(bytes, result.mime || info?.mime || "application/octet-stream", pageFileName(result.extension || info?.extension || format));
+		setStatus(`${result.label || label} 已导出 ${formatBytes(result.size || bytes.length, result.label || label)}`);
 	} catch (err) {
 		if (openSeq === state.openSeq) {
 			showError(err, false);
@@ -1536,9 +1594,17 @@ function updateControls() {
 	el.fitHeightButton.disabled = !hasDoc;
 	el.fitButton.toggleAttribute("aria-pressed", hasDoc && state.fitMode === "width");
 	el.fitHeightButton.toggleAttribute("aria-pressed", hasDoc && state.fitMode === "height");
+	el.pageExportFormat.disabled = !hasDoc || !state.exportFormats.length;
+	el.exportPageButton.disabled = !hasDoc || !state.exportFormats.length;
 	el.exportButton.disabled = !hasDoc;
 }
 
+function setExportControlsDisabled(disabled) {
+	el.exportButton.disabled = disabled;
+	el.exportPageButton.disabled = disabled;
+	el.pageExportFormat.disabled = disabled;
+}
+
 function callWASM(name, ...args) {
 	const fn = globalThis[name];
 	if (typeof fn !== "function") {
@@ -1624,15 +1690,39 @@ function base64ToBytes(base64) {
 	return bytes;
 }
 
-function pdfFileName() {
-	const base = (state.fileName || state.doc?.title || "ofdgo").replace(/\.[^.]+$/, "");
-	const safe = base.replace(/[\\/:*?"<>|]+/g, "_").trim() || "ofdgo";
-	return `${safe}.pdf`;
+function downloadBytes(bytes, mime, name) {
+	const blob = new Blob([bytes], { type: mime });
+	const link = document.createElement("a");
+	const url = URL.createObjectURL(blob);
+	link.href = url;
+	link.download = name;
+	document.body.append(link);
+	link.click();
+	link.remove();
+	window.setTimeout(() => URL.revokeObjectURL(url), 1000);
 }
 
-function formatBytes(size) {
+function baseFileName() {
+	const base = (state.fileName || state.doc?.title || "ofdgo").replace(/\.[^.]+$/, "");
+	return base.replace(/[\\/:*?"<>|]+/g, "_").trim() || "ofdgo";
+}
+
+function pdfFileName() {
+	return `${baseFileName()}.pdf`;
+}
+
+function pageFileName(extension) {
+	const page = String(state.pageIndex + 1).padStart(String(state.doc?.pageCount || 1).length, "0");
+	return `${baseFileName()}_p${page}.${extension || "bin"}`;
+}
+
+function exportFormatInfo(value) {
+	return state.exportFormats.find((format) => format.value === value) || null;
+}
+
+function formatBytes(size, fallback = "PDF") {
 	if (!Number.isFinite(size) || size <= 0) {
-		return "PDF";
+		return fallback;
 	}
 	if (size < 1024 * 1024) {
 		return `${Math.round(size / 1024)} KB`;

internal/webui/wasm.go

@@ -42,6 +42,8 @@ type apiResult struct {
 func RunWASM() {
 	registerCallback("ofdgoOpen", openDocument)
 	registerCallback("ofdgoRenderPage", renderPage)
+	registerCallback("ofdgoExportFormats", exportFormats)
+	registerCallback("ofdgoExportPage", exportPage)
 	registerCallback("ofdgoExportPDF", exportPDF)
 	registerCallback("ofdgoFontCandidates", fontCandidates)
 	select {}
@@ -113,7 +115,38 @@ func renderPage(args []js.Value) (any, error) {
 	return currentSession.RenderPageSVG(args[0].Int())
 }
 
-// exportPDF 导出OFD为PDF
+// exportFormats 获取导出格式
+// 入参: args 浏览器参数
+// 返回: any 导出格式, error 错误信息
+func exportFormats(args []js.Value) (any, error) {
+	return ExportFormats(), nil
+}
+
+// exportPage 导出OFD单页
+// 入参: args 浏览器参数
+// 返回: any 导出结果, error 错误信息
+func exportPage(args []js.Value) (any, error) {
+	if currentSession == nil {
+		return nil, fmt.Errorf("ofd document is not opened")
+	}
+	if len(args) < 2 {
+		return nil, fmt.Errorf("missing export page arguments")
+	}
+	data, format, err := currentSession.ExportPage(args[0].Int(), args[1].String())
+	if err != nil {
+		return nil, err
+	}
+	return map[string]any{
+		"base64":    base64.StdEncoding.EncodeToString(data),
+		"size":      len(data),
+		"format":    format.Value,
+		"label":     format.Label,
+		"extension": format.Extension,
+		"mime":      format.MIME,
+	}, nil
+}
+
+// exportPDF 导出OFD文档为PDF
 // 入参: args 浏览器参数
 // 返回: any PDF结果, error 错误信息
 func exportPDF(args []js.Value) (any, error) {
@@ -124,7 +157,10 @@ func exportPDF(args []js.Value) (any, error) {
 	if err != nil {
 		return nil, err
 	}
-	return map[string]any{"base64": base64.StdEncoding.EncodeToString(data), "size": len(data)}, nil
+	return map[string]any{
+		"base64": base64.StdEncoding.EncodeToString(data),
+		"size":   len(data),
+	}, nil
 }
 
 // fontCandidates 获取字体候选名称

internal/webui/webui.go

@@ -17,6 +17,12 @@ package webui
 import (
 	"bytes"
 	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/jpeg"
+	"image/png"
+	"strings"
 
 	"github.com/xiaoqidun/ofdgo"
 )
@@ -72,6 +78,47 @@ type PageSVG struct {
 	SVG    string  `json:"svg"`
 }
 
+// ExportFormat 导出格式
+type ExportFormat struct {
+	Value     string `json:"value"`
+	Label     string `json:"label"`
+	Extension string `json:"extension"`
+	MIME      string `json:"mime"`
+}
+
+// supportedExportFormats 导出格式列表
+var supportedExportFormats = []ExportFormat{
+	{Value: "svg", Label: "SVG", Extension: "svg", MIME: "image/svg+xml"},
+	{Value: "pdf", Label: "PDF", Extension: "pdf", MIME: "application/pdf"},
+	{Value: "eps", Label: "EPS", Extension: "eps", MIME: "application/postscript"},
+	{Value: "png", Label: "PNG", Extension: "png", MIME: "image/png"},
+	{Value: "jpg", Label: "JPEG", Extension: "jpg", MIME: "image/jpeg"},
+}
+
+// ExportFormats 获取导出格式
+// 返回: []ExportFormat 导出格式列表
+func ExportFormats() []ExportFormat {
+	formats := make([]ExportFormat, len(supportedExportFormats))
+	copy(formats, supportedExportFormats)
+	return formats
+}
+
+// exportFormat 获取导出格式
+// 入参: value 格式值
+// 返回: ExportFormat 导出格式, bool 是否支持
+func exportFormat(value string) (ExportFormat, bool) {
+	value = strings.ToLower(strings.TrimSpace(value))
+	if value == "jpeg" {
+		value = "jpg"
+	}
+	for _, format := range supportedExportFormats {
+		if format.Value == value {
+			return format, true
+		}
+	}
+	return ExportFormat{}, false
+}
+
 // Open 打开浏览器内存中的OFD文档
 // 入参: data OFD文件数据, opts 打开选项
 // 返回: *Session 文档会话, error 错误信息
@@ -146,14 +193,7 @@ 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) {
-	if s == nil || s.Reader == nil || s.Renderer == nil || s.doc == nil {
-		return PageSVG{}, fmt.Errorf("ofd document is not opened")
-	}
-	if index < 0 || index >= len(s.doc.Pages.Page) {
-		return PageSVG{}, fmt.Errorf("page index %d out of range", index)
-	}
-	pageRef := s.doc.Pages.Page[index]
-	page, err := s.Reader.PageContent(pageRef)
+	pageRef, page, err := s.pageContent(index)
 	if err != nil {
 		return PageSVG{}, err
 	}
@@ -168,7 +208,46 @@ func (s *Session) RenderPageSVG(index int) (PageSVG, error) {
 	return PageSVG{Index: index, Number: index + 1, ID: pageRef.ID, Width: box.W, Height: box.H, SVG: buf.String()}, nil
 }
 
-// ExportPDF 导出整个文档为PDF
+// ExportPage 导出单页
+// 入参: index 页面索引, value 导出格式
+// 返回: []byte 文件数据, ExportFormat 导出格式, error 错误信息
+func (s *Session) ExportPage(index int, value string) ([]byte, ExportFormat, error) {
+	format, ok := exportFormat(value)
+	if !ok {
+		return nil, ExportFormat{}, fmt.Errorf("unsupported export format %s", value)
+	}
+	_, page, err := s.pageContent(index)
+	if err != nil {
+		return nil, ExportFormat{}, err
+	}
+	var buf bytes.Buffer
+	switch format.Value {
+	case "svg":
+		err = s.Renderer.RenderToSVG(page, &buf)
+	case "pdf":
+		err = s.Renderer.RenderToPDF(page, &buf)
+	case "eps":
+		err = s.Renderer.RenderToEPS(page, &buf)
+	case "png":
+		img, renderErr := s.Renderer.RenderToImage(page)
+		if renderErr != nil {
+			return nil, ExportFormat{}, renderErr
+		}
+		err = png.Encode(&buf, img)
+	case "jpg":
+		img, renderErr := s.Renderer.RenderToImage(page)
+		if renderErr != nil {
+			return nil, ExportFormat{}, renderErr
+		}
+		err = jpeg.Encode(&buf, imageWithWhiteBackground(img), &jpeg.Options{Quality: 95})
+	}
+	if err != nil {
+		return nil, ExportFormat{}, err
+	}
+	return buf.Bytes(), format, nil
+}
+
+// ExportPDF 导出文档为PDF
 // 返回: []byte PDF文件数据, error 错误信息
 func (s *Session) ExportPDF() ([]byte, error) {
 	if s == nil || s.Reader == nil || s.Renderer == nil || s.doc == nil {
@@ -180,3 +259,32 @@ func (s *Session) ExportPDF() ([]byte, error) {
 	}
 	return buf.Bytes(), nil
 }
+
+// imageWithWhiteBackground 填充图片白色背景
+// 入参: img 图片对象
+// 返回: image.Image 图片对象
+func imageWithWhiteBackground(img image.Image) image.Image {
+	bounds := img.Bounds()
+	dst := image.NewRGBA(bounds)
+	draw.Draw(dst, bounds, &image.Uniform{C: color.White}, image.Point{}, draw.Src)
+	draw.Draw(dst, bounds, img, bounds.Min, draw.Over)
+	return dst
+}
+
+// pageContent 获取页面内容
+// 入参: index 页面索引
+// 返回: ofdgo.Page 页面引用, *ofdgo.PageContent 页面内容, error 错误信息
+func (s *Session) pageContent(index int) (ofdgo.Page, *ofdgo.PageContent, error) {
+	if s == nil || s.Reader == nil || s.Renderer == nil || s.doc == nil {
+		return ofdgo.Page{}, nil, fmt.Errorf("ofd document is not opened")
+	}
+	if index < 0 || index >= len(s.doc.Pages.Page) {
+		return ofdgo.Page{}, nil, fmt.Errorf("page index %d out of range", index)
+	}
+	pageRef := s.doc.Pages.Page[index]
+	page, err := s.Reader.PageContent(pageRef)
+	if err != nil {
+		return ofdgo.Page{}, nil, err
+	}
+	return pageRef, page, nil
+}