diff --git a/assets/webui/index.html b/assets/webui/index.html
index ec8ebad..df95d50 100644
--- a/assets/webui/index.html
+++ b/assets/webui/index.html
@@ -57,7 +57,7 @@
 		<div id="editorTools" class="editor-toolbar" role="toolbar" aria-label="创作工具" hidden>
 			<div class="editor-group">
 				<button id="selectObjectButton" class="button" type="button" aria-pressed="true">选择</button>
-				<button id="editTextButton" class="button" type="button" aria-label="修改文字" disabled>修改</button>
+				<button id="editObjectButton" class="button" type="button" aria-label="修改对象" disabled>修改</button>
 				<button id="copyObjectButton" class="button" type="button" aria-label="复制对象" disabled>复制</button>
 				<button id="deleteObjectButton" class="button" type="button" disabled>删除</button>
 				<select id="objectOrder" class="order-select" aria-label="对象层级" disabled>
@@ -67,6 +67,15 @@
 					<option value="top">置顶</option>
 					<option value="bottom">置底</option>
 				</select>
+				<select id="objectAlign" class="order-select" aria-label="页面对齐" disabled>
+					<option value="" hidden>对齐</option>
+					<option value="left">左侧</option>
+					<option value="center">水平居中</option>
+					<option value="right">右侧</option>
+					<option value="top">顶部</option>
+					<option value="middle">垂直居中</option>
+					<option value="bottom">底部</option>
+				</select>
 				<span>对象</span>
 			</div>
 			<div class="editor-group">
@@ -149,7 +158,7 @@
 			<form id="insertForm">
 				<div id="insertTextRow" class="form-row">
 					<label for="insertText">内容</label>
-					<input id="insertText" type="text" required autofocus>
+					<textarea id="insertText" rows="3" required autofocus></textarea>
 				</div>
 				<div id="insertFontRow" class="form-row">
 					<label for="insertFont">字体</label>
diff --git a/assets/webui/ofdgo.css b/assets/webui/ofdgo.css
index 9982869..e7b64d3 100644
--- a/assets/webui/ofdgo.css
+++ b/assets/webui/ofdgo.css
@@ -42,6 +42,7 @@ body {
 
 button,
 input,
+textarea,
 select {
 	font: inherit;
 }
@@ -56,6 +57,7 @@ button {
 
 button:disabled,
 input:disabled,
+textarea:disabled,
 select:disabled {
 	cursor: not-allowed;
 	opacity: 0.48;
@@ -63,6 +65,7 @@ select:disabled {
 
 button:focus-visible,
 input:focus-visible,
+textarea:focus-visible,
 select:focus-visible,
 a:focus-visible {
 	outline: 2px solid var(--focus);
@@ -105,7 +108,7 @@ a:focus-visible {
 }
 
 .editor-group:has(#selectObjectButton) {
-	grid-template-columns: repeat(5, max-content);
+	grid-template-columns: repeat(6, max-content);
 }
 
 .editor-group:has(#insertTextButton) {
@@ -430,6 +433,7 @@ button:not(:disabled):hover {
 .form-row input[type="number"],
 .form-row input[type="file"],
 .form-row select,
+.form-row textarea,
 .text-size input {
 	width: 100%;
 	min-width: 0;
@@ -441,6 +445,14 @@ button:not(:disabled):hover {
 	color: #1f2428;
 }
 
+.form-row textarea {
+	height: auto;
+	min-height: var(--control-height);
+	padding: 6px;
+	line-height: 1.5;
+	resize: vertical;
+}
+
 .form-unit.text-size {
 	grid-template-columns: calc(2em + 22px) auto;
 	gap: 6px;
@@ -1120,6 +1132,28 @@ button.outline-link:hover {
 	pointer-events: none;
 }
 
+.edit-text {
+	position: absolute;
+	overflow: hidden;
+	z-index: 1;
+	margin: -2px;
+	padding: 1px;
+	border: 1px solid var(--accent);
+	border-radius: 0;
+	background: #fff;
+	outline: none;
+	resize: none;
+	font-kerning: none;
+	font-variant-ligatures: none;
+	letter-spacing: 0;
+	cursor: text;
+	touch-action: auto;
+}
+
+.edit-text:focus-visible {
+	outline: none;
+}
+
 .editing-select .edit-layer {
 	display: block;
 }
@@ -1831,11 +1865,13 @@ button.outline-link:hover {
 }
 
 @media (max-width: 360px) {
+	.editor-group:has(#selectObjectButton),
 	.editor-group:has(#addPageButton) {
 		grid-template-columns: repeat(3, max-content);
 	}
 
-	.editor-group:has(#addPageButton) > button {
+	.editor-group:has(#addPageButton) > button,
+	.editor-group:has(#selectObjectButton) > :not(span) {
 		grid-row: auto;
 	}
 }
diff --git a/assets/webui/ofdgo.js b/assets/webui/ofdgo.js
index b1b0986..20d6efd 100644
--- a/assets/webui/ofdgo.js
+++ b/assets/webui/ofdgo.js
@@ -36,7 +36,7 @@ const state = {
 	dirty: false,
 	editorInfo: null,
 	savedRevision: null,
-	textObject: null,
+	insertObject: null,
 	insertFonts: [],
 	textFonts: [],
 	ofdBytes: null,
@@ -87,9 +87,10 @@ const el = {
 	editorTools: document.querySelector("#editorTools"),
 	selectObjectButton: document.querySelector("#selectObjectButton"),
 	deleteObjectButton: document.querySelector("#deleteObjectButton"),
-	editTextButton: document.querySelector("#editTextButton"),
+	editObjectButton: document.querySelector("#editObjectButton"),
 	copyObjectButton: document.querySelector("#copyObjectButton"),
 	objectOrder: document.querySelector("#objectOrder"),
+	objectAlign: document.querySelector("#objectAlign"),
 	textFont: document.querySelector("#textFont"),
 	textSize: document.querySelector("#textSize"),
 	textColor: document.querySelector("#textColor"),
@@ -229,7 +230,16 @@ const canvasEditor = new CanvasEditor(el.viewerPanel, {
 	onTransform: (item, change) => changeDocument("ofdgoTransformObject", item,
 		change.x + item.x * (1 - change.scale), change.y + item.y * (1 - change.scale), change.scale),
 	onDelete: (item) => changeDocument("ofdgoDeleteObject", item),
-	onEdit: (item) => openInsertPanel(true, item),
+	onEdit: editCanvasObject,
+	onCommitText: (item, value) => changeDocument("ofdgoUpdateText", item, value, null, item.size, null),
+	onTextChange: () => {
+		const editing = canvasEditor.input;
+		setDirty(state.editing && (state.editorInfo?.revision !== state.savedRevision
+			|| Boolean(editing && editing.input.value !== editing.item.text)));
+		if (!editing) {
+			syncSelection();
+		}
+	},
 });
 
 el.selectObjectButton.addEventListener("click", () => {
@@ -247,9 +257,9 @@ el.deleteObjectButton.addEventListener("click", () => {
 		changeDocument("ofdgoDeleteObject", canvasEditor.selected);
 	}
 });
-el.editTextButton.addEventListener("click", () => {
-	if (canvasEditor.selected && !canvasEditor.selected.image) {
-		openInsertPanel(true, canvasEditor.selected);
+el.editObjectButton.addEventListener("click", () => {
+	if (canvasEditor.selected) {
+		openInsertPanel(!canvasEditor.selected.image, canvasEditor.selected);
 	}
 });
 el.textSize.addEventListener("change", () => changeTextStyle(false));
@@ -291,6 +301,13 @@ el.objectOrder.addEventListener("change", () => {
 	const targets = { up: item.order + 1, down: item.order - 1, top: item.count - 1, bottom: 0 };
 	return changeDocument("ofdgoMoveObject", item, targets[action]);
 });
+el.objectAlign.addEventListener("change", () => {
+	const alignment = el.objectAlign.value;
+	el.objectAlign.value = "";
+	if (canvasEditor.selected && alignment) {
+		return changeDocument("ofdgoAlignObject", canvasEditor.selected, alignment);
+	}
+});
 el.undoButton.addEventListener("click", () => changeDocument("ofdgoUndo"));
 el.redoButton.addEventListener("click", () => changeDocument("ofdgoRedo"));
 el.addPageButton.addEventListener("click", () => {
@@ -325,7 +342,7 @@ el.createForm.addEventListener("submit", createDocument);
 el.insertTextButton.addEventListener("click", () => openInsertPanel(true));
 el.insertImageButton.addEventListener("click", () => openInsertPanel(false));
 el.insertCancel.addEventListener("click", () => el.insertPanel.close());
-el.insertPanel.addEventListener("close", () => { state.textObject = null; });
+el.insertPanel.addEventListener("close", () => { state.insertObject = null; });
 el.insertForm.addEventListener("submit", insertObject);
 el.insertFontAdd.addEventListener("click", () => openFontFile(el.fontInput));
 el.saveButton.addEventListener("click", () => exportFile(true, null, "ofd"));
@@ -633,6 +650,33 @@ async function createDocument(event) {
 	}
 }
 
+async function editCanvasObject(item) {
+	if (item.image) {
+		return openInsertPanel(false, item);
+	}
+	if (!state.editing || document.body.hasAttribute("aria-busy") || canvasEditor.input) {
+		return;
+	}
+	const openSeq = state.openSeq;
+	setBusy(true);
+	try {
+		const data = await callWASM("ofdgoEditorFont", item.font);
+		const face = new FontFace(`ofdgo-edit-${item.font}`, data.bytes);
+		await face.load();
+		if (openSeq === state.openSeq && item.node.isConnected) {
+			canvasEditor.editText(item, face);
+		}
+	} catch (err) {
+		if (openSeq === state.openSeq) {
+			showError(err, false);
+		}
+	} finally {
+		if (openSeq === state.openSeq) {
+			setBusy(false);
+		}
+	}
+}
+
 async function openInsertPanel(text, item = null) {
 	if (!state.editing || document.body.hasAttribute("aria-busy")) {
 		return;
@@ -645,13 +689,13 @@ async function openInsertPanel(text, item = null) {
 		return;
 	}
 	el.insertForm.reset();
-	state.textObject = item;
-	if (item) {
+	state.insertObject = item;
+	if (item && text) {
 		state.insertFonts = [];
 		el.insertText.value = item.text;
 	}
-	el.insertPanel.setAttribute("aria-label", item ? "修改文字" : text ? "添加文字" : "添加图片");
-	el.insertSubmit.textContent = item ? "修改" : "添加";
+	el.insertPanel.setAttribute("aria-label", item ? text ? "修改文字" : "替换图片" : text ? "添加文字" : "添加图片");
+	el.insertSubmit.textContent = item ? text ? "修改" : "替换" : "添加";
 	for (const [row, input] of [[el.insertTextRow, el.insertText], [el.insertFontRow, el.insertFont]]) {
 		row.hidden = !text;
 		input.disabled = !text;
@@ -665,7 +709,7 @@ async function openInsertPanel(text, item = null) {
 
 function updateInsertFonts() {
 	const selected = state.insertFonts[Number(el.insertFont.value)];
-	state.insertFonts = editorFonts(state.textObject);
+	state.insertFonts = editorFonts(state.insertObject?.image ? null : state.insertObject);
 	setFontOptions(el.insertFont, state.insertFonts, selected);
 	el.insertSubmit.disabled = !el.insertTextRow.hidden && !state.insertFonts.length;
 	el.insertStatus.textContent = el.insertSubmit.disabled ? "尚未添加字体" : "";
@@ -707,7 +751,7 @@ async function insertObject(event) {
 	}
 	let openSeq = state.openSeq;
 	const text = !el.insertTextRow.hidden;
-	const item = state.textObject;
+	const item = state.insertObject;
 	const index = item?.index ?? state.pageIndex;
 	const page = state.doc.pages[index];
 	const x = Math.min(20, page.width / 10);
@@ -729,7 +773,8 @@ async function insertObject(event) {
 		}
 		const value = item && data === null && el.insertText.value === item.text ? null : el.insertText.value;
 		const doc = item
-			? await callWASM("ofdgoUpdateText", item.index, item.id, value, data, item.size, null)
+			? text ? await callWASM("ofdgoUpdateText", item.index, item.id, value, data, item.size, null)
+			: await callWASM("ofdgoReplaceImage", item.index, item.id, data)
 			: text ? await callWASM("ofdgoInsertText", index, el.insertText.value, data, x, y, 12 * 25.4 / 72, "#000000")
 			: await callWASM("ofdgoInsertImage", index, data, x, y, page.width - x * 2);
 		if (openSeq !== state.openSeq) {
@@ -822,15 +867,8 @@ async function changeDocument(name, item, ...args) {
 			const page = doc.pages[pageIndex];
 			const keepScroll = doc.pageIndex === undefined && page.id === previous.id && pageIndex === state.pageIndex
 				&& page.width === previous.width && page.height === previous.height;
-			await openDocument({ doc, openSeq, skipAutoFonts: true, pageIndex, fitMode: state.fitMode, scale: state.scale });
-			if (openSeq === state.openSeq) {
-				if (keepScroll) {
-					el.viewerPanel.scrollLeft = scrollLeft;
-					el.viewerPanel.scrollTop = scrollTop;
-				} else {
-					scrollToPage(pageIndex);
-				}
-			}
+			await openDocument({ doc, openSeq, skipAutoFonts: true, pageIndex, fitMode: state.fitMode, scale: state.scale,
+				keepPreview: true, previewScroll: keepScroll ? { scrollLeft, scrollTop } : null });
 		}
 		if (openSeq === state.openSeq) {
 			el.viewerPanel.focus({ preventScroll: true });
@@ -877,19 +915,7 @@ async function refreshEditorPage(doc, index, openSeq) {
 		throw err;
 	} finally {
 		if (openSeq === state.openSeq) {
-			const pages = [...state.pageCache.values()];
-			for (const [name, image] of state.svgImages) {
-				if (!pages.some((page) => page.imageNames.includes(name))) {
-					URL.revokeObjectURL(image.url);
-					state.svgImages.delete(name);
-				}
-			}
-			for (const [name, font] of state.svgFonts) {
-				if (!pages.some((page) => page.fonts.some((item) => item.name === name))) {
-					document.fonts.delete(font);
-					state.svgFonts.delete(name);
-				}
-			}
+			releasePageResources();
 			renderMeta();
 			updateControls();
 			loadDocumentDetails(openSeq);
@@ -902,6 +928,22 @@ async function refreshEditorPage(doc, index, openSeq) {
 	}
 }
 
+function releasePageResources() {
+	const pages = [...state.pageCache.values()];
+	for (const [name, image] of state.svgImages) {
+		if (!pages.some((page) => page.imageNames.includes(name))) {
+			URL.revokeObjectURL(image.url);
+			state.svgImages.delete(name);
+		}
+	}
+	for (const [name, font] of state.svgFonts) {
+		if (!pages.some((page) => page.fonts.some((item) => item.name === name))) {
+			document.fonts.delete(font);
+			state.svgFonts.delete(name);
+		}
+	}
+}
+
 async function openOFDFile() {
 	if (document.body.hasAttribute("aria-busy")) {
 		return;
@@ -1703,6 +1745,7 @@ async function openDocument(options = {}) {
 		return;
 	}
 	const openSeq = options.openSeq || (state.openSeq += 1);
+	const previewIDs = options.keepPreview ? [...state.visiblePages].map((index) => state.doc.pages[index].id) : [];
 	if (!state.ready || state.wasmExited) {
 		await ensureWASM();
 	}
@@ -1716,10 +1759,12 @@ async function openDocument(options = {}) {
 		updateFontSummary();
 		renderFontList();
 	}
-	setBusy(true, "正在打开文档", 20, STATUS.opening);
+	options.keepPreview ? setBusy(true) : setBusy(true, "正在打开文档", 20, STATUS.opening);
 	try {
-		setProgress("正在解析文档", 52);
-		await nextFrame();
+		if (!options.keepPreview) {
+			setProgress("正在解析文档", 52);
+			await nextFrame();
+		}
 		if (openSeq !== state.openSeq) {
 			return;
 		}
@@ -1762,13 +1807,30 @@ async function openDocument(options = {}) {
 		if (openSeq !== state.openSeq) {
 			return;
 		}
-		resetPageFlow();
+		if (options.keepPreview) {
+			resetPageLoading();
+			state.pageCache.clear();
+			const indices = new Set([pageIndex, ...doc.pages.filter((page) => previewIDs.includes(page.id)).map((page) => page.index)]);
+			for (const index of indices) {
+				await loadPageData(index, { openSeq, priority: 0, refresh: true });
+				if (openSeq !== state.openSeq) {
+					return;
+				}
+			}
+		}
+		resetPageFlow(options.keepPreview);
 		renderPageList();
 		if (options.resetScroll || el.outlineList.childElementCount === 0) {
 			renderOutlines();
 		}
 		renderMeta();
 		renderPageFlow();
+		if (options.keepPreview) {
+			for (const [index, page] of state.pageCache) {
+				mountPageSVG(index, page, openSeq);
+			}
+			releasePageResources();
+		}
 		if (options.resetScroll) {
 			el.viewerPanel.scrollLeft = 0;
 			el.viewerPanel.scrollTop = 0;
@@ -1778,8 +1840,20 @@ async function openDocument(options = {}) {
 			el.metaPanel.scrollTop = 0;
 		}
 		applyFit(false);
+		if (options.keepPreview) {
+			if (options.previewScroll) {
+				Object.assign(el.viewerPanel, options.previewScroll);
+			} else {
+				scrollToPage(pageIndex);
+			}
+			setStatus(pageStatus(pageIndex, pageCount));
+		}
 		await nextFrame();
-		const page = await renderPage(pageIndex, { keepBusy: true, scroll: false, openSeq });
+		if (openSeq !== state.openSeq) {
+			return;
+		}
+		const page = options.keepPreview ? state.pageCache.get(pageIndex)
+			: await renderPage(pageIndex, { keepBusy: true, scroll: false, openSeq });
 		if (page && options.resetScroll) {
 			el.viewerPanel.focus({ preventScroll: true });
 		}
@@ -2051,16 +2125,11 @@ function renderPageFlow() {
 	el.pageFrame.hidden = false;
 }
 
-function resetPageFlow() {
-	for (const font of state.svgFonts.values()) {
-		document.fonts.delete(font);
+function resetPageFlow(keepCache = false) {
+	if (!keepCache) {
+		state.pageCache.clear();
+		releasePageResources();
 	}
-	state.svgFonts.clear();
-	for (const image of state.svgImages.values()) {
-		URL.revokeObjectURL(image.url);
-	}
-	state.svgImages.clear();
-	state.pageCache.clear();
 	state.selectedPages.clear();
 	state.documentSelection = null;
 	state.visiblePages.clear();
@@ -2124,8 +2193,9 @@ function flowPageObserver() {
 function unmountPage(index) {
 	const shell = pageShell(index);
 	const selection = document.getSelection();
-	const range = selection.rangeCount ? selection.getRangeAt(0) : null;
-	if (range && (!state.documentSelection || !isDocumentSelection(range)) && range.intersectsNode(shell)) {
+	const range = !selection.isCollapsed && selection.rangeCount ? selection.getRangeAt(0) : null;
+	if (canvasEditor.input?.item.index === index
+		|| range && (!state.documentSelection || !isDocumentSelection(range)) && range.intersectsNode(shell)) {
 		state.selectedPages.add(index);
 		return;
 	}
@@ -2365,7 +2435,12 @@ function createTextLayer(text) {
 		const line = document.createElement("span");
 		line.className = "text-run";
 		const chars = Array.from(run.text);
+		let end = 0;
 		for (const item of run.spans || []) {
+			const breaks = chars.slice(end, item.start).filter((char) => char === "\n").join("");
+			if (breaks) {
+				line.append(document.createTextNode(breaks));
+			}
 			const span = document.createElement("span");
 			span.textContent = chars.slice(item.start, item.end).join("");
 			let width = widths.get(span.textContent);
@@ -2376,6 +2451,11 @@ function createTextLayer(text) {
 			const [a, b, c, d, e, f] = item.matrix.map((value) => value * MM_TO_PX);
 			span.style.transform = `matrix(${a / width}, ${b / width}, ${c / 100}, ${d / 100}, ${e}, ${f})`;
 			line.append(span);
+			end = item.end;
+		}
+		const breaks = chars.slice(end).filter((char) => char === "\n").join("");
+		if (breaks) {
+			line.append(document.createTextNode(breaks));
 		}
 		layer.append(line);
 	}
@@ -3866,9 +3946,8 @@ function updateEditorTools() {
 
 function updateObjectControls(item, reset = false) {
 	const disabled = !item || !state.ready || state.exporting;
-	el.deleteObjectButton.disabled = el.copyObjectButton.disabled = disabled;
-	el.editTextButton.disabled = !item || item.image || !state.ready || state.exporting;
-	el.textFont.disabled = el.textSize.disabled = el.textColor.disabled = el.editTextButton.disabled;
+	el.deleteObjectButton.disabled = el.copyObjectButton.disabled = el.editObjectButton.disabled = el.objectAlign.disabled = disabled;
+	el.textFont.disabled = el.textSize.disabled = el.textColor.disabled = disabled || item.image;
 	updateTextFonts(item);
 	if (reset || el.textSize.disabled || document.activeElement !== el.textSize) {
 		el.textSize.value = item && !item.image ? textPoints(item.size) : "";
diff --git a/assets/webui/ofdgo_edit.js b/assets/webui/ofdgo_edit.js
index 2e926a3..f414c12 100644
--- a/assets/webui/ofdgo_edit.js
+++ b/assets/webui/ofdgo_edit.js
@@ -44,7 +44,7 @@ export class CanvasEditor {
 		viewer.addEventListener("keydown", (event) => this.keyDown(event));
 		viewer.addEventListener("dblclick", () => {
 			const item = this.selected;
-			if (this.enabled && item && !item.image && !this.options.busy()) {
+			if (this.enabled && item && !this.input && !this.options.busy()) {
 				this.options.onEdit(item);
 			}
 		});
@@ -107,12 +107,16 @@ export class CanvasEditor {
 	}
 
 	clear() {
+		this.closeText();
 		this.cancel();
 		this.selectLast = false;
 		this.select(null);
 	}
 
 	start(event) {
+		if (this.input) {
+			return;
+		}
 		if (!this.enabled || this.options.busy() || event.button !== 0 || this.drag) {
 			return;
 		}
@@ -173,11 +177,11 @@ export class CanvasEditor {
 	}
 
 	keyDown(event) {
-		if (!this.enabled || !this.selected || this.options.busy() || event.ctrlKey || event.metaKey || event.altKey || event.isComposing) {
+		if (this.input || !this.enabled || !this.selected || this.options.busy() || event.ctrlKey || event.metaKey || event.altKey || event.isComposing) {
 			return;
 		}
 		const directions = { ArrowLeft: [-1, 0], ArrowRight: [1, 0], ArrowUp: [0, -1], ArrowDown: [0, 1] };
-		const edit = (event.key === "Enter" || event.key === "F2") && !this.selected.image;
+		const edit = event.key === "Enter" || event.key === "F2";
 		if (event.key !== "Escape" && event.key !== "Delete" && !edit && !directions[event.key]) {
 			return;
 		}
@@ -200,4 +204,84 @@ export class CanvasEditor {
 			}
 		}
 	}
+
+	editText(item, face) {
+		this.cancel();
+		this.closeText();
+		this.select(item);
+		document.fonts.add(face);
+		const input = document.createElement("textarea");
+		input.className = "edit-text";
+		input.setAttribute("aria-label", "编辑文字");
+		input.wrap = "off";
+		input.spellcheck = false;
+		input.value = item.text;
+		Object.assign(input.style, {
+			left: `${item.x * PX_PER_MM}px`, top: `${item.y * PX_PER_MM}px`,
+			width: `${Math.max(item.width, Math.min(50, item.page.width - item.x)) * PX_PER_MM + 4}px`,
+			minHeight: `${item.height * PX_PER_MM + 4}px`,
+			fontFamily: `"${face.family}"`, fontSize: `${item.size * PX_PER_MM}px`,
+			lineHeight: item.lineHeight ? `${item.lineHeight * PX_PER_MM}px` : "normal", color: item.color,
+		});
+		this.input = { input, item, face };
+		item.surface.append(input);
+		const resize = () => {
+			input.style.height = "0px";
+			input.style.height = `${input.scrollHeight + 2}px`;
+		};
+		input.addEventListener("input", () => {
+			resize();
+			this.options.onTextChange();
+		});
+		input.addEventListener("blur", () => this.commitText());
+		input.addEventListener("keydown", (event) => {
+			event.stopPropagation();
+			if (event.isComposing || input.readOnly) {
+				return;
+			}
+			if (event.key === "Escape") {
+				event.preventDefault();
+				this.closeText();
+				this.viewer.focus({ preventScroll: true });
+			} else if (event.key === "Enter" && (event.ctrlKey || event.metaKey)) {
+				event.preventDefault();
+				this.commitText();
+			}
+		});
+		resize();
+		input.focus({ preventScroll: true });
+		input.select();
+	}
+
+	async commitText() {
+		const editing = this.input;
+		if (!editing || editing.input.readOnly) {
+			return;
+		}
+		if (editing.input.value === editing.item.text) {
+			this.closeText();
+			return;
+		}
+		editing.input.readOnly = true;
+		const saved = await this.options.onCommitText(editing.item, editing.input.value);
+		if (this.input !== editing) {
+			return;
+		}
+		if (saved) {
+			this.closeText();
+		} else {
+			editing.input.readOnly = false;
+			editing.input.focus({ preventScroll: true });
+		}
+	}
+
+	closeText() {
+		const editing = this.input;
+		this.input = null;
+		if (editing) {
+			editing.input.remove();
+			document.fonts.delete(editing.face);
+			this.options.onTextChange();
+		}
+	}
 }
diff --git a/internal/webui/wasm.go b/internal/webui/wasm.go
index aed52bc..8de5656 100644
--- a/internal/webui/wasm.go
+++ b/internal/webui/wasm.go
@@ -26,6 +26,7 @@ import (
 	"image"
 	"io"
 	"math"
+	"strconv"
 	"syscall/js"
 
 	"github.com/xiaoqidun/ofdgo"
@@ -101,6 +102,9 @@ func RunWASM() {
 	registerCallback("ofdgoInsertText", insertText)
 	registerCallback("ofdgoUpdateText", updateText)
 	registerCallback("ofdgoInsertImage", insertImage)
+	registerCallback("ofdgoReplaceImage", replaceImage)
+	registerCallback("ofdgoEditorFont", editorFont)
+	registerCallback("ofdgoAlignObject", alignObject)
 	registerCallback("ofdgoTransformObject", transformObject)
 	registerCallback("ofdgoCopyObject", copyObject)
 	registerCallback("ofdgoMoveObject", moveObject)
@@ -612,6 +616,11 @@ func editorObjects(index int, text *ofdgo.PageText) ([]any, error) {
 				item := map[string]any{"id": id, "image": object.Type == "ImageObject", "x": box.X, "y": box.Y, "width": box.W, "height": box.H, "order": order, "count": len(layer.Objects)}
 				if object.Type == "TextObject" {
 					item["text"], item["font"], item["fontName"], item["size"] = textValues[id], object.TextObject.Font, fontNames[object.TextObject.Font], object.TextObject.Size
+					if codes := object.TextObject.TextCode; len(codes) > 1 {
+						first, _ := strconv.ParseFloat(codes[0].Y, 64)
+						second, _ := strconv.ParseFloat(codes[1].Y, 64)
+						item["lineHeight"] = second - first
+					}
 					var r, g, b float64
 					if fill := object.TextObject.FillColor; fill != nil {
 						if _, err := fmt.Sscan(fill.Value, &r, &g, &b); err != nil {
@@ -627,6 +636,67 @@ func editorObjects(index int, text *ofdgo.PageText) ([]any, error) {
 	return objects, nil
 }
 
+// editorFont 读取创作对象的完整内嵌字体，供画布输入使用
+// 入参: args 字体资源标识
+// 返回: any 字体数据, error 错误信息
+func editorFont(args []js.Value) (any, error) {
+	if currentEditor == nil {
+		return nil, fmt.Errorf("no document is being created")
+	}
+	fonts, err := currentSession.Reader.Fonts()
+	if err != nil {
+		return nil, err
+	}
+	for _, font := range fonts {
+		if font.ID == args[0].String() {
+			data, err := currentSession.Reader.ResData(font.FontFile)
+			if err != nil {
+				return nil, err
+			}
+			return successResult(map[string]any{"bytes": bytesToJS(data)}), nil
+		}
+	}
+	return nil, fmt.Errorf("font resource %q not found", args[0].String())
+}
+
+// replaceImage 替换图片资源并更新预览
+// 入参: args 页码、对象标识和图片数据
+// 返回: any 文档信息, error 错误信息
+func replaceImage(args []js.Value) (any, error) {
+	if currentEditor == nil {
+		return nil, fmt.Errorf("no document is being created")
+	}
+	data, err := bytesFromJS(args[2])
+	if err != nil {
+		return nil, err
+	}
+	revision := currentEditor.Revision()
+	if err := currentEditor.ReplaceImage(args[0].Int(), args[1].String(), data); err != nil {
+		return nil, err
+	}
+	if currentEditor.Revision() == revision {
+		return editorSummary(), nil
+	}
+	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
+}
+
+// alignObject 将对象对齐页面并更新预览
+// 入参: args 页码、对象标识和对齐方式
+// 返回: any 文档信息, error 错误信息
+func alignObject(args []js.Value) (any, error) {
+	if currentEditor == nil {
+		return nil, fmt.Errorf("no document is being created")
+	}
+	revision := currentEditor.Revision()
+	if err := currentEditor.AlignObject(args[0].Int(), args[1].String(), args[2].String()); err != nil {
+		return nil, err
+	}
+	if currentEditor.Revision() == revision {
+		return editorSummary(), nil
+	}
+	return previewEditor(currentEditor, currentSession.Renderer.RenderAnnotations)
+}
+
 // transformObject 等比缩放后平移对象
 // 入参: args 页码、对象标识、位移和缩放比例
 // 返回: any 文档信息, error 错误信息
@@ -810,7 +880,7 @@ func updateText(args []js.Value) (any, error) {
 			}
 		}
 		object.TextObject.Size = args[4].Float()
-		if err := currentEditor.LayoutText(&object.TextObject, args[2].String()); err != nil {
+		if err := currentEditor.LayoutText(&object.TextObject, args[2].String(), 0); err != nil {
 			return nil, err
 		}
 	}
@@ -877,7 +947,7 @@ func insertText(args []js.Value) (any, error) {
 		Boundary: fmt.Sprintf("%g %g %g %g", box.X, box.Y, box.W, box.H),
 		Font:     fontID, Size: args[5].Float(),
 	}}
-	if err := currentEditor.LayoutText(&object.TextObject, args[1].String()); err != nil {
+	if err := currentEditor.LayoutText(&object.TextObject, args[1].String(), 0); err != nil {
 		return nil, err
 	}
 	if err := setTextColor(&object.TextObject, args[6].String()); err != nil {
diff --git a/ofdgo_editor.go b/ofdgo_editor.go
index 948c5db..131c8cb 100644
--- a/ofdgo_editor.go
+++ b/ofdgo_editor.go
@@ -613,7 +613,7 @@ func cloneEditorObject(object GraphicObject) (GraphicObject, error) {
 	return object, nil
 }
 
-// AddText 添加单行文字，使用嵌入字体的字宽定位，不进行段落排版和复杂文字塑形
+// AddText 添加文字，按显式换行和嵌入字体度量定位，不自动折行或进行复杂文字塑形
 // 入参: page 页面索引, box 文字边界, value 原文, fontID 字体资源标识, size 字号
 // 返回: string 对象标识, error 错误信息
 func (e *Editor) AddText(page int, box Box, value, fontID string, size float64) (string, error) {
@@ -621,13 +621,13 @@ func (e *Editor) AddText(page int, box Box, value, fontID string, size float64)
 		Boundary: fmt.Sprintf("%s %s %s %s", ofdNumber(box.X), ofdNumber(box.Y), ofdNumber(box.W), ofdNumber(box.H)),
 		Font:     fontID, Size: size,
 	}}
-	if err := e.LayoutText(&object.TextObject, value); err != nil {
+	if err := e.LayoutText(&object.TextObject, value, 0); err != nil {
 		return "", err
 	}
 	return e.AddObject(page, object)
 }
 
-// UpdateText 按AddText规则重排横向单行文字，保留对象标识、顺序、边界及绘制属性
+// UpdateText 按AddText规则重排横向文字，保留对象标识、顺序、边界及绘制属性
 // 自定义文字定位使用UpdateObject，不进行段落排版和复杂文字塑形
 // 入参: page 页面索引, id 文字对象标识, value 原文, fontID 字体资源标识, size 字号
 // 返回: error 错误信息
@@ -641,7 +641,7 @@ func (e *Editor) UpdateText(page int, id, value, fontID string, size float64) er
 		return fmt.Errorf("object %q is not text", id)
 	}
 	object.TextObject.Font, object.TextObject.Size = fontID, size
-	if err := e.LayoutText(&object.TextObject, value); err != nil {
+	if err := e.LayoutText(&object.TextObject, value, 0); err != nil {
 		return err
 	}
 	object, err = e.prepareObject(id, object)
@@ -704,6 +704,83 @@ func (e *Editor) TransformObject(page int, id string, dx, dy, scale float64) err
 	return e.UpdateObject(page, id, object)
 }
 
+// ReplaceImage 替换图片资源，保留对象位置、尺寸、变换和绘制顺序
+// 入参: page 页面索引, id 图片对象标识, data PNG或JPEG数据
+// 返回: error 错误信息
+func (e *Editor) ReplaceImage(page int, id string, data []byte) error {
+	object, err := e.Object(page, id)
+	if err != nil {
+		return err
+	}
+	if object.Type != "ImageObject" {
+		return fmt.Errorf("object %q is not an image", id)
+	}
+	object.ImageObject.ResourceID, err = e.AddImage(data)
+	if err != nil {
+		return err
+	}
+	return e.UpdateObject(page, id, object)
+}
+
+// AlignObject 将对象对齐页面，文字采用实际字形范围，路径和图片采用对象边界
+// 入参: page 页面索引, id 对象标识, alignment 为left、center、right、top、middle或bottom
+// 返回: error 错误信息
+func (e *Editor) AlignObject(page int, id, alignment string) error {
+	if !slices.Contains([]string{"left", "center", "right", "top", "middle", "bottom"}, alignment) {
+		return fmt.Errorf("invalid alignment %q", alignment)
+	}
+	object, err := e.Object(page, id)
+	if err != nil {
+		return err
+	}
+	content := &e.pages[page]
+	pageBox, _ := ParseBox(content.Area.PhysicalBox)
+	var box Box
+	switch object.Type {
+	case "TextObject":
+		reader, err := e.Reader()
+		if err != nil {
+			return err
+		}
+		defer reader.Close()
+		renderer := NewRenderer(reader)
+		text, err := renderer.PageText(content)
+		if err != nil {
+			return err
+		}
+		for _, run := range text.Runs {
+			if run.ID == id {
+				for _, bounds := range run.Boxes {
+					box = unionTextBox(box, bounds)
+				}
+			}
+		}
+	case "PathObject":
+		box, _ = ParseBox(object.PathObject.Boundary)
+	case "ImageObject":
+		box, _ = ParseBox(object.ImageObject.Boundary)
+	}
+	if box.W <= 0 || box.H <= 0 {
+		return fmt.Errorf("object %q has no visible bounds", id)
+	}
+	dx, dy := 0.0, 0.0
+	switch alignment {
+	case "left":
+		dx = -box.X
+	case "center":
+		dx = (pageBox.W-box.W)/2 - box.X
+	case "right":
+		dx = pageBox.W - box.W - box.X
+	case "top":
+		dy = -box.Y
+	case "middle":
+		dy = (pageBox.H-box.H)/2 - box.Y
+	case "bottom":
+		dy = pageBox.H - box.H - box.Y
+	}
+	return e.TransformObject(page, id, dx, dy, 1)
+}
+
 // scaleTextNumbers 缩放已校验的文字定位数值，保留g重复编码
 // 入参: value 定位数值, scale 缩放比例
 // 返回: string 缩放后的数值
@@ -719,11 +796,11 @@ func scaleTextNumbers(value string, scale float64) string {
 	return strings.Join(fields, " ")
 }
 
-// LayoutText 按嵌入字体度量重排横向单行文字，设置基线和字距，保留绘制属性
-// 不进行段落排版和复杂文字塑形，不修改文档，通过AddObject或UpdateObject提交
-// 入参: obj 文字对象, value 原文
+// LayoutText 按显式换行和嵌入字体度量重排横向文字，保留绘制属性
+// 不自动折行或进行复杂文字塑形，不修改文档，通过AddObject或UpdateObject提交
+// 入参: obj 文字对象, value 原文, lineHeight 基线间距，0使用字体度量，单位为毫米
 // 返回: error 错误信息
-func (e *Editor) LayoutText(obj *TextObject, value string) error {
+func (e *Editor) LayoutText(obj *TextObject, value string, lineHeight float64) error {
 	if obj.ReadDirection != 0 || obj.CharDirection != 0 {
 		return fmt.Errorf("automatic text layout requires horizontal text")
 	}
@@ -734,26 +811,47 @@ func (e *Editor) LayoutText(obj *TextObject, value string) error {
 	if !finite(obj.Size) || obj.Size <= 0 || !finite(obj.HScale) || obj.HScale < 0 {
 		return fmt.Errorf("invalid text dimensions")
 	}
-	if !utf8.ValidString(value) || strings.ContainsAny(value, "\r\n\t") || value == "" {
-		return fmt.Errorf("text must be a nonempty UTF-8 line")
+	value = strings.ReplaceAll(strings.ReplaceAll(value, "\r\n", "\n"), "\r", "\n")
+	if !utf8.ValidString(value) || strings.Contains(value, "\t") || strings.Trim(value, "\n") == "" {
+		return fmt.Errorf("text must contain UTF-8 characters without tabs")
+	}
+	if !finite(lineHeight) || lineHeight < 0 {
+		return fmt.Errorf("line height must be finite and nonnegative")
 	}
 	hScale := obj.HScale
 	if hScale == 0 {
 		hScale = 1
 	}
-	runes := []rune(value)
-	deltas := make([]string, 0, len(runes)-1)
-	for i, char := range runes {
-		glyph := sfnt.GlyphIndex(char)
-		if glyph == 0 {
-			return fmt.Errorf("font does not contain U+%04X", char)
-		}
-		if i+1 < len(runes) {
-			deltas = append(deltas, ofdNumber(float64(sfnt.GlyphAdvance(glyph))*obj.Size/float64(sfnt.UnitsPerEm())*hScale))
-		}
+	ascender, descender, gap := sfnt.VerticalMetrics()
+	unit := obj.Size / float64(sfnt.UnitsPerEm())
+	if lineHeight == 0 {
+		lineHeight = math.Max(obj.Size, float64(int(ascender)-int(descender)+int(gap))*unit)
 	}
-	ascender, _, _ := sfnt.VerticalMetrics()
-	obj.TextCode = []TextCode{{X: "0", Y: ofdNumber(float64(ascender) * obj.Size / float64(sfnt.UnitsPerEm())), DeltaX: strings.Join(deltas, " "), Value: escapeOFDText(value)}}
+	lines := strings.Split(value, "\n")
+	codes := make([]TextCode, len(lines))
+	for line, value := range lines {
+		runes := []rune(value)
+		deltas := make([]string, 0, max(0, len(runes)-1))
+		for i, char := range runes {
+			glyph := sfnt.GlyphIndex(char)
+			if glyph == 0 {
+				return fmt.Errorf("font does not contain U+%04X", char)
+			}
+			if i+1 < len(runes) {
+				advance := float64(sfnt.GlyphAdvance(glyph)) * unit * hScale
+				if !finite(advance) {
+					return fmt.Errorf("text advance exceeds finite range")
+				}
+				deltas = append(deltas, ofdNumber(advance))
+			}
+		}
+		y := float64(ascender)*unit + float64(line)*lineHeight
+		if !finite(y) {
+			return fmt.Errorf("text baseline exceeds finite range")
+		}
+		codes[line] = TextCode{X: "0", Y: ofdNumber(y), DeltaX: strings.Join(deltas, " "), Value: escapeOFDText(value)}
+	}
+	obj.TextCode = codes
 	return nil
 }
 
@@ -801,9 +899,6 @@ func (e *Editor) prepareText(obj *TextObject) error {
 		}
 		code.X, code.Y = x, y
 		runes := textCodeRunes(code.Value)
-		if len(runes) == 0 {
-			return fmt.Errorf("text code is empty")
-		}
 		for _, char := range runes {
 			if e.fonts[obj.Font].GlyphIndex(char) == 0 {
 				return fmt.Errorf("font does not contain U+%04X", char)
@@ -821,6 +916,9 @@ func (e *Editor) prepareText(obj *TextObject) error {
 		}
 		code.Value = escapeOFDText(string(runes))
 	}
+	if strings.Trim(obj.Text(), "\n") == "" {
+		return fmt.Errorf("text codes are empty")
+	}
 	return nil
 }
 
diff --git a/ofdgo_renderer_text.go b/ofdgo_renderer_text.go
index ae8b01e..f8e2ba0 100644
--- a/ofdgo_renderer_text.go
+++ b/ofdgo_renderer_text.go
@@ -198,7 +198,10 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 	}
 	codePos := 0
 	textPos := 0
-	for _, tc := range obj.TextCode {
+	for index, tc := range obj.TextCode {
+		if textRun != nil && obj.textCodeLineBreak(index) {
+			textPos++
+		}
 		var runes []rune
 		var glyphs []textGlyph
 		if tc.Index != "" {
diff --git a/ofdgo_search.go b/ofdgo_search.go
index 80a0569..c0da930 100644
--- a/ofdgo_search.go
+++ b/ofdgo_search.go
@@ -204,15 +204,8 @@ func foldText(text string) string {
 // 入参: obj 文本对象
 // 返回: *TextRun 文本及待填充的字符区域
 func (p *PageText) addRun(obj TextObject) *TextRun {
-	var text strings.Builder
-	for _, code := range obj.TextCode {
-		if code.Index == "" {
-			text.WriteString(string(textCodeRunes(code.Value)))
-		} else {
-			text.WriteRune('\uFFFC')
-		}
-	}
-	p.Runs = append(p.Runs, TextRun{ID: obj.ID, Text: text.String(), Boxes: make([]Box, utf8.RuneCountInString(text.String()))})
+	text := obj.Text()
+	p.Runs = append(p.Runs, TextRun{ID: obj.ID, Text: text, Boxes: make([]Box, utf8.RuneCountInString(text))})
 	return &p.Runs[len(p.Runs)-1]
 }
 
diff --git a/ofdgo_text.go b/ofdgo_text.go
index af941ea..845057c 100644
--- a/ofdgo_text.go
+++ b/ofdgo_text.go
@@ -25,6 +25,38 @@ import (
 	"github.com/tdewolff/font"
 )
 
+// Text 获取文字原文，同一行起点处的基线变化以换行分隔，字形索引以占位字符表示
+// 返回: string 原文
+func (obj TextObject) Text() string {
+	var text strings.Builder
+	for i, code := range obj.TextCode {
+		if obj.textCodeLineBreak(i) {
+			text.WriteByte('\n')
+		}
+		if code.Index == "" {
+			text.WriteString(string(textCodeRunes(code.Value)))
+		} else {
+			text.WriteRune('\uFFFC')
+		}
+	}
+	return text.String()
+}
+
+// textCodeLineBreak 判断横向文本是否回到行首并更换基线
+// 入参: index 文本编码索引
+// 返回: bool 是否换行
+func (obj TextObject) textCodeLineBreak(index int) bool {
+	if index == 0 || obj.ReadDirection != 0 || obj.CharDirection != 0 {
+		return false
+	}
+	code, previous := obj.TextCode[index], obj.TextCode[index-1]
+	x, ex := strconv.ParseFloat(code.X, 64)
+	start, es := strconv.ParseFloat(obj.TextCode[0].X, 64)
+	y, ey := strconv.ParseFloat(code.Y, 64)
+	prev, ep := strconv.ParseFloat(previous.Y, 64)
+	return ex == nil && es == nil && ey == nil && ep == nil && x == start && y != prev
+}
+
 // textGlyph 绘制字形
 type textGlyph struct {
 	Text    string