feat(转换能力): 完善转换渲染，优化字体加载

assets/webui/ofdgo.js

@@ -3575,19 +3575,7 @@ async function loadDocumentLocalFonts(available, openSeq = state.openSeq) {
 }
 
 async function selectLocalFonts(fonts) {
-	const available = new Map();
+	const available = fontManager.localEntries(fonts);
-	for (const font of fonts) {
-		const names = [
-			fontManager.localName(font),
-			font.postscriptName && `${font.postscriptName}.ttf`,
-			font.family && `${[font.family, font.style].filter(Boolean).join(" ")}.ttf`,
-		];
-		for (const name of names) {
-			if (name && !available.has(name)) {
-				available.set(name, font);
-			}
-		}
-	}
 	const matched = await callWASM("ofdgoMatchFontFiles", [...available.keys()]);
 	return [...new Set(matched.map((name) => available.get(name)))];
 }
@@ -4502,11 +4490,15 @@ function updateBatchControls() {
 	batchElements.Cancel.disabled = batch.canceled;
 	batchElements.Close.textContent = batch.running ? "收起" : "关闭";
 	batchElements.Count.textContent = batch.items.length ? `${batch.items.length}个文件` : "";
-	const formats = batch.items.length ? batch.items.map(item => item.format || batchElements.Format.value) : [batchElements.Format.value];
+	batchElements.DPIRow.hidden = !(batch.items.length ? batch.items : [null]).some(batchUsesDPI);
-	batchElements.DPIRow.hidden = !formats.some(value => batch.formats.find(format => format.value === value)?.raster);
 	batchElements.Button.toggleAttribute("data-running", batch.running);
 }
 
+function batchUsesDPI(item) {
+	const format = item?.format || batchElements.Format.value;
+	return Boolean(batch.formats.find(value => value.value === format)?.raster || item && /\.pdf$/i.test(item.file.name));
+}
+
 function batchStatus(item, status, text) {
 	item.status = status;
 	item.text = text;
@@ -4558,12 +4550,24 @@ function startBatchWorker() {
 		};
 		worker.onerror = event => fail(new Error(event.message || "转换引擎异常"));
 		worker.onmessageerror = () => fail(new Error("转换数据传递失败"));
-		worker.onmessage = ({ data }) => {
+		worker.onmessage = async ({ data }) => {
 			if (data.type === "ready") { resolve(); return; }
 			if (data.type === "exit") { fail(new Error(data.error)); return; }
 			if (data.type === "progress") { batchElements.Status.textContent = data.text; return; }
 			const request = batch.requests.get(data.id);
 			if (!request) return;
+			if (data.type === "font") {
+				try {
+					const font = batch.localFonts.get(data.name);
+					if (!font) throw new Error("系统字体不可用");
+					if (!batch.fontData.has(font)) batch.fontData.set(font, fontManager.read(font));
+					const bytes = await batch.fontData.get(font);
+					worker.postMessage({ type: "font", request: data.request, bytes });
+				} catch (err) {
+					worker.postMessage({ type: "font", request: data.request, error: err.message });
+				}
+				return;
+			}
 			if (data.type === "output") { request.outputName = data.name; return; }
 			if (data.type === "conversion") { request.onProgress?.(data); return; }
 			batch.requests.delete(data.id);
@@ -4593,9 +4597,10 @@ async function runBatch() {
 	const dpi = Number(batchElements.DPI.value);
 	const archive = batchElements.Destination.value === "archive";
 	const backend = state.renderBackend;
+	const fontKey = [fontManager.permission, fontManager.records().map(font => [font.id, font.name, font.enabled, font.checksum])];
 	for (const item of batch.items) {
 		const format = batch.formats.find(format => format.value === (item.format || defaultFormat.value));
-		const key = JSON.stringify([format.value, pageRange(item), format.raster ? dpi : 0, archive, backend]);
+		const key = JSON.stringify([format.value, pageRange(item), batchUsesDPI(item) ? dpi : 0, archive, backend, fontKey]);
 		if (item.settingsKey !== key) {
 			item.status = "pending";
 			item.text = "待转";
@@ -4629,6 +4634,12 @@ async function runBatch() {
 			}
 		} else destination = await window.showDirectoryPicker({ mode: "readwrite" });
 		if (batch.canceled) return;
+		if (jobs.some(item => /\.pdf$/i.test(item.file.name) || !["ofd", "txt"].includes(item.format || defaultFormat.value))) {
+			await requestLocalFontsBeforeOpen();
+		}
+		if (batch.canceled) return;
+		batch.localFonts = fontManager.localEntries();
+		batch.fontData = new Map();
 		batchElements.Status.textContent = "正在准备引擎";
 		await startBatchWorker();
 		const fonts = await fontManager.files(fontManager.records());
@@ -4642,7 +4653,8 @@ async function runBatch() {
 			const outputName = () => (format.paged ? unique : `${unique}.${format.extension}`).toLowerCase();
 			for (let suffix = 2; archive && names.has(outputName()); suffix++) unique = `${base} (${suffix})`;
 			names.add(outputName());
-			const options = { format: format.value, pages: pageRange(item), dpi, backend, archive, base: unique, credentials: null };
+			const options = { format: format.value, pages: pageRange(item), dpi, backend, archive, base: unique, credentials: null,
+				fontNames: [...batch.localFonts.keys()] };
 			try {
 				for (;;) {
 					try {
@@ -4694,6 +4706,8 @@ async function runBatch() {
 		batch.worker = null;
 		batch.requests.clear();
 		batch.activeID = 0;
+		batch.fontData?.clear();
+		batch.localFonts?.clear();
 		if (storage && stagingName) {
 			try { await storage.removeEntry(stagingName, { recursive: true }); }
 			catch { batchElements.Status.textContent += " · 临时文件清理失败"; }

assets/webui/ofdgo_font.js

@@ -396,6 +396,20 @@ export class FontManager {
 		return `${name}.ttf`;
 	}
 
+	localEntries(fonts = this.catalog) {
+		const entries = new Map();
+		const disabled = new Set(this.localFonts.filter(font => !font.enabled).map(font => font.name));
+		for (const font of fonts) {
+			if (disabled.has(this.localName(font))) continue;
+			const names = [this.localName(font), font.postscriptName && `${font.postscriptName}.ttf`,
+				font.family && `${[font.family, font.style].filter(Boolean).join(" ")}.ttf`];
+			for (const name of names) {
+				if (name && !entries.has(name)) entries.set(name, font);
+			}
+		}
+		return entries;
+	}
+
 	canReadLocal() {
 		return typeof window.queryLocalFonts === "function";
 	}

assets/webui/ofdgo_wasm.js

@@ -2,7 +2,14 @@ importScripts("./wasm_exec.js");
 
 let pending = Promise.resolve();
 const operations = new Map();
+const fontRequests = new Map();
+let fontSequence = 0;
 self.onmessage = ({ data }) => {
+	if (data.type === "font") {
+		fontRequests.get(data.request)?.(data);
+		fontRequests.delete(data.request);
+		return;
+	}
 	if (data.type === "cancel") {
 		operations.get(data.id)?.abort();
 		return;
@@ -96,7 +103,20 @@ async function handleBatchMessage({ id, name, args }) {
 					finish(done);
 				},
 				(action, pageName, done) => boundary(action, pageName).then(() => finish(done), err => finish(done, err)),
-				done => finish(done), fonts);
+				done => finish(done), fonts, (name, done) => {
+					if (signal.aborted) { done(null, "", true); return; }
+					const request = ++fontSequence;
+					const cancel = () => {
+						fontRequests.delete(request);
+						done(null, "", true);
+					};
+					signal.addEventListener("abort", cancel, { once: true });
+					fontRequests.set(request, result => {
+						signal.removeEventListener("abort", cancel);
+						done(result.bytes, result.error || "", signal.aborted);
+					});
+					self.postMessage({ id, type: "font", request, name });
+				});
 		} else {
 			const [entries, handle] = args;
 			if (handle) output = await handle.createWritable();

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/tdewolff/canvas v0.0.0-20260923214215-09804640d00c
 	github.com/tdewolff/font v0.0.0-20260913163313-54f98bb59ee6
 	github.com/xiaoqidun/jbig2 v1.1.1
-	github.com/xiaoqidun/pdfgo v0.0.0-20260926132451-00d165f66ad7
+	github.com/xiaoqidun/pdfgo v0.0.0-20260926152052-3a4cb2e9266a
 	golang.org/x/crypto v0.57.0
 	golang.org/x/image v0.46.0
 	golang.org/x/text v0.42.0

go.sum

@@ -62,8 +62,8 @@ github.com/tdewolff/test v1.0.12 h1:7F21DqIajswxuche0geHdrUZRCWE4oko4b7bcmkkrxk=
 github.com/tdewolff/test v1.0.12/go.mod h1:XPuWBzvdUzhCuxWO1ojpXsyzsA5bFoS3tO/Q3kFuTG8=
 github.com/xiaoqidun/jbig2 v1.1.1 h1:SjliS9ZO0e9HX5oYUfBuXrfFsXhWricrSz+XY4zORDI=
 github.com/xiaoqidun/jbig2 v1.1.1/go.mod h1:8QonVWtENmh2kc6l+leqeGl7psb79DWlHDkCpdChjfQ=
-github.com/xiaoqidun/pdfgo v0.0.0-20260926132451-00d165f66ad7 h1:yRhuqMZm146rOe1682qJJoBld8zwNYg3RwvdvWkbwzk=
+github.com/xiaoqidun/pdfgo v0.0.0-20260926152052-3a4cb2e9266a h1:BT4VQisXVY8OlUdZFE6WTOIktGk8fCQOfkWlSxvL+cc=
-github.com/xiaoqidun/pdfgo v0.0.0-20260926132451-00d165f66ad7/go.mod h1:4Pf0JO0BEf1uzRY+uZjlMjN/OPn3PYa0YMi6cqPPTLQ=
+github.com/xiaoqidun/pdfgo v0.0.0-20260926152052-3a4cb2e9266a/go.mod h1:4Pf0JO0BEf1uzRY+uZjlMjN/OPn3PYa0YMi6cqPPTLQ=
 github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZqKjWU=
 github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E=
 github.com/yuin/goldmark v1.8.5 h1:r6N5afV5qj/5S4UTch8agZHJ8UxNCMwX7WjkkJam2NA=

internal/webui/wasm.go

@@ -398,10 +398,10 @@ func convertPDFDocument(args []js.Value) (any, error) {
 }
 
 // convertFile 使用库转换独立文件，不读取或修改当前阅读和编辑会话
-// 入参: args 随机读取、文件大小、转换选项、写出、进度、文件边界、取消检查及字体
+// 入参: args 随机读取、文件大小、转换选项、写出、进度、文件边界、取消检查、字体及按需字体读取
 // 返回: any 转换报告, error 转换错误
 func convertFile(args []js.Value) (any, error) {
-	if len(args) != 8 {
+	if len(args) != 9 {
 		return nil, fmt.Errorf("missing conversion arguments")
 	}
 	settings := args[2]
@@ -422,9 +422,13 @@ func convertFile(args []js.Value) (any, error) {
 			return awaitExport(args[4], progress.Stage, progress.Completed, progress.Total)
 		},
 	}
-	if len(fonts) > 0 {
+	fontSources := []fs.FS{ofdgo.NewFontFS(fonts)}
-		options.RendererOptions = append(options.RendererOptions, ofdgo.WithFontFS(ofdgo.NewFontFS(fonts)))
+	if names := settings.Get("fontNames"); !names.IsUndefined() && names.Length() > 0 {
+		fontSources = append(fontSources, ofdgo.NewLazyFontFS(stringsFromJS(names), func(name string) ([]byte, error) {
+			return loadConversionFont(args[8], name)
+		}))
 	}
+	options.RendererOptions = append(options.RendererOptions, ofdgo.WithFontFS(fontSources...))
 	if value := settings.Get("credentials"); !value.IsNull() && !value.IsUndefined() {
 		credentials, err := credentialsFromJS(value)
 		if err != nil {
@@ -476,6 +480,30 @@ func convertFile(args []js.Value) (any, error) {
 	return report, nil
 }
 
+// loadConversionFont 按需读取浏览器已授权字体，不预读系统字体目录
+// 入参: load 浏览器读取函数, name 字体文件名
+// 返回: []byte 字体内容, error 读取错误或取消原因
+func loadConversionFont(load js.Value, name string) ([]byte, error) {
+	done := make(chan error, 1)
+	var data []byte
+	callback := js.FuncOf(func(this js.Value, args []js.Value) any {
+		var err error
+		if args[2].Bool() {
+			err = context.Canceled
+		} else if message := args[1].String(); message != "" {
+			err = fmt.Errorf("%s", message)
+		} else {
+			data, err = bytesFromJS(args[0])
+		}
+		done <- err
+		return nil
+	})
+	defer callback.Release()
+	load.Invoke(name, callback)
+	err := <-done
+	return data, err
+}
+
 // packFiles 将已经成功转换的文件逐个打包，不重复转换或读取整个文件
 // 入参: args 文件列表、分块读取、分块写出、进度及取消检查
 // 返回: any 输出格式, error 打包错误

ofdgo_editor_open.go

@@ -783,15 +783,17 @@ func (e *Editor) editorFont(id string) (FontMetrics, error) {
 		return nil, &EditError{Code: EditFontUnavailable, Err: fmt.Errorf("fonts: %w", ErrBackendUnavailable)}
 	}
 	var data []byte
-	createdExternal := false
+	var external *Font
 	for _, resource := range e.resources {
 		if resource.font != nil && resource.font.ID == id {
 			data = resource.data
-			createdExternal = resource.font.FontFile == ""
+			if resource.font.FontFile == "" {
+				external = resource.font
+			}
 			break
 		}
 	}
-	if data == nil && e.source != nil && !createdExternal {
+	if data == nil && e.source != nil && external == nil {
 		if e.fontRenderer == nil {
 			e.fontRenderer = e.newRenderer(e.source.reader)
 		}
@@ -801,12 +803,9 @@ func (e *Editor) editorFont(id string) (FontMetrics, error) {
 		}
 		data = resolved.Data
 	}
-	if data == nil && createdExternal {
+	if data == nil && external != nil {
-		reader, err := e.Reader()
+		reader := &Reader{doc: &Document{}, fontResourcesRead: true, fontCache: map[string]*Font{id: external}}
-		if err != nil {
+		resolved, err := e.newRenderer(reader).ResolveFont(id, true)
-			return nil, &EditError{Code: EditFontUnavailable, Err: err}
-		}
-		resolved, err := e.newRenderer(reader).ResolveFont(id, false)
 		if err != nil {
 			return nil, &EditError{Code: EditFontUnavailable, Err: err}
 		}

ofdgo_font_fs.go

@@ -21,6 +21,7 @@ import (
 	"path"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -30,9 +31,10 @@ type FontFile struct {
 	Data []byte
 }
 
-// FontFS 内存字体文件系统
+// FontFS 缓存字体数据及名称索引的只读文件系统
 type FontFS struct {
 	files      map[string][]byte
+	loaders    map[string]func() ([]byte, error)
 	names      []string
 	candidates []fontFileCandidate
 }
@@ -62,6 +64,32 @@ func NewFontFS(fonts []FontFile) *FontFS {
 	return fsys
 }
 
+// NewLazyFontFS 创建按需读取的字体文件系统，按文件名匹配，不预读字体内容
+// 每个文件的读取结果仅缓存一次；目录条目大小为0，打开后可获取实际大小
+// 入参: names 包含字体名称和样式的文件名, load 按原文件名读取独立字体的非nil函数
+// 返回: *FontFS 字体文件系统
+func NewLazyFontFS(names []string, load func(string) ([]byte, error)) *FontFS {
+	fsys := &FontFS{files: make(map[string][]byte), loaders: make(map[string]func() ([]byte, error))}
+	for _, original := range names {
+		name := cleanFontName(original)
+		if name == "." || !isFontFileName(name) {
+			continue
+		}
+		if _, exists := fsys.files[name]; exists {
+			continue
+		}
+		fsys.names = append(fsys.names, name)
+		fsys.files[name] = nil
+		fsys.loaders[name] = sync.OnceValues(func() ([]byte, error) {
+			data, err := load(original)
+			return bytes.Clone(data), err
+		})
+	}
+	sort.Strings(fsys.names)
+	fsys.candidates = fontFileCandidates(fsys.names, path.Base)
+	return fsys
+}
+
 // Len 获取字体文件数量
 // 返回: int 字体文件数量
 func (fsys *FontFS) Len() int {
@@ -85,6 +113,13 @@ func (fsys *FontFS) Open(name string) (fs.File, error) {
 	if !ok {
 		return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrNotExist}
 	}
+	if load := fsys.loaders[strings.ToLower(name)]; load != nil {
+		var err error
+		data, err = load()
+		if err != nil {
+			return nil, &fs.PathError{Op: "open", Path: name, Err: err}
+		}
+	}
 	return &fontMemFile{
 		Reader: bytes.NewReader(data),
 		info: fontFileInfo{
@@ -281,7 +316,9 @@ type fontFileCandidate struct {
 	face       int
 	base       string
 	lowerBase  string
+	filename   string
 	normalized string
+	names      []string
 	fold       string
 }
 
@@ -293,11 +330,13 @@ func fontFileCandidates(names []string, base func(string) string) []fontFileCand
 	for _, name := range names {
 		if isFontFileName(name) {
 			baseName := base(name)
+			normalized := fontNormalizeName(strings.TrimSuffix(baseName, path.Ext(baseName)))
 			files = append(files, fontFileCandidate{
 				name:       name,
 				base:       baseName,
 				lowerBase:  strings.ToLower(baseName),
-				normalized: fontNormalizeName(baseName),
+				filename:   normalized,
+				normalized: normalized,
 				fold:       strings.ToLower(name),
 			})
 		}
@@ -370,7 +409,7 @@ func (m fontPatternMatcher) rankCandidate(file fontFileCandidate) int {
 		}
 		return fontMatchNone
 	}
-	name := file.normalized
+	name := m.candidateName(file)
 	if name == m.stem {
 		return fontMatchExact
 	}
@@ -401,6 +440,26 @@ func (m fontPatternMatcher) rankCandidate(file fontFileCandidate) int {
 	return fontMatchNone
 }
 
+// candidateName 保留同族内部名称的区分，只有无关联时使用调用方文件别名
+// 入参: file 字体文件候选
+// 返回: string 用于统一匹配名称与样式的规范名称
+func (m fontPatternMatcher) candidateName(file fontFileCandidate) string {
+	if len(file.names) == 0 || file.base == "" || m.stem == "" {
+		return file.normalized
+	}
+	for _, name := range file.names {
+		if strings.HasPrefix(name, m.stem) {
+			return file.normalized
+		}
+		for _, alias := range m.aliases {
+			if strings.HasPrefix(name, alias) {
+				return file.normalized
+			}
+		}
+	}
+	return file.filename
+}
+
 // styleSuffixNormalized 获取规范字体名称的样式后缀
 // 入参: name 规范字体名称
 // 返回: string 样式后缀
@@ -441,7 +500,7 @@ func appendFontFileMatch(matches *[]fontFileMatch, seen map[fontFileKey]int, mat
 	if rank == fontMatchNone {
 		return
 	}
-	suffix := matcher.styleSuffixNormalized(file.normalized)
+	suffix := matcher.styleSuffixNormalized(matcher.candidateName(file))
 	if rank == fontMatchFuzzy {
 		suffix = matcher.styleSuffixNormalized(fontNormalizeName(file.base))
 	}

ofdgo_font_name.go

@@ -33,7 +33,7 @@ type fontNameRecord struct {
 	Offset   uint16
 }
 
-// appendFontFileNames 使用字体内部名称匹配，缺失时保留文件名
+// appendFontFileNames 建立各字体的内部名称与文件别名匹配候选
 // 入参: candidates 字体候选, index 文件候选索引, faces 各字体内部名称
 // 返回: []fontFileCandidate 字体候选列表
 func appendFontFileNames(candidates []fontFileCandidate, index int, faces [][]string) []fontFileCandidate {
@@ -41,8 +41,12 @@ func appendFontFileNames(candidates []fontFileCandidate, index int, faces [][]st
 	replaced := false
 	for face, names := range faces {
 		file.face = face
-		for _, name := range names {
+		file.names = make([]string, len(names))
-			file.normalized = fontNormalizeName(name)
+		for i, name := range names {
+			file.names[i] = fontNormalizeName(name)
+		}
+		for _, name := range file.names {
+			file.normalized = name
 			if !replaced {
 				candidates[index] = file
 				replaced = true

ofdgo_font_source.go

@@ -210,12 +210,12 @@ func (r *Renderer) fontSources(fontID string, font *Font) []fontSource {
 	seen := make(map[fontSourceKey]bool)
 	for _, dir := range r.fontDirs {
 		for _, match := range r.matchFontFiles(dir, names, bold, italic) {
-			sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFile, name: match.name, face: match.face, exact: true, priority: min(match.priority, 0)})
+			sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFile, name: match.name, face: match.face, exact: match.rank == fontMatchExact, priority: min(match.priority, 0)})
 		}
 	}
 	for index := range r.fontFS {
 		for _, match := range r.matchFontFS(index, names, bold, italic) {
-			sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFS, index: index, name: match.name, face: match.face, exact: true, priority: min(match.priority, 0)})
+			sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFS, index: index, name: match.name, face: match.face, exact: match.rank == fontMatchExact, priority: min(match.priority, 0)})
 		}
 	}
 	sortFontSources(sources)
@@ -223,7 +223,7 @@ func (r *Renderer) fontSources(fontID string, font *Font) []fontSource {
 	if canLoadSystemFonts() {
 		for _, dir := range systemFontDirs() {
 			for _, match := range r.matchFontFiles(dir, names, bold, italic) {
-				sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFile, name: match.name, face: match.face, exact: true, priority: min(match.priority, 0)})
+				sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFile, name: match.name, face: match.face, exact: match.rank == fontMatchExact, priority: min(match.priority, 0)})
 			}
 		}
 		for _, name := range fontSystemNames(names...) {

ofdgo_paint.go

@@ -16,6 +16,7 @@ package ofdgo
 
 import (
 	"image/color"
+	"math"
 	"strconv"
 	"strings"
 )
@@ -31,6 +32,29 @@ func (r *Renderer) ResolveColor(value string, index *int, space string, alpha *i
 // 入参: value 颜色值, index 调色板索引, space 颜色空间标识, alpha 透明度
 // 返回: color.Color 颜色对象
 func (r *Renderer) parseColorWithAlpha(value string, index *int, space string, alpha *int) color.Color {
+	kind, values := r.colorComponents(value, index, space)
+	var components [4]uint8
+	for i, value := range values {
+		components[i] = uint8(math.Round(value * 255))
+	}
+	red, green, blue := components[0], components[1], components[2]
+	switch kind {
+	case "GRAY":
+		green, blue = red, red
+	case "CMYK":
+		red, green, blue = color.CMYKToRGB(components[0], components[1], components[2], components[3])
+	}
+	a := 255
+	if alpha != nil {
+		a = clampColor(*alpha)
+	}
+	return color.RGBA{R: uint8(int(red) * a / 255), G: uint8(int(green) * a / 255), B: uint8(int(blue) * a / 255), A: uint8(a)}
+}
+
+// colorComponents 读取颜色空间及归一化分量，保留源位深供渐变插值
+// 入参: value 颜色值, index 调色板索引, space 颜色空间标识
+// 返回: string 颜色模型, [4]float64 单位分量
+func (r *Renderer) colorComponents(value string, index *int, space string) (string, [4]float64) {
 	if space == "" && r.Reader.doc != nil {
 		space = strconv.Itoa(r.Reader.doc.CommonData.DefaultCS)
 	}
@@ -53,30 +77,19 @@ func (r *Renderer) parseColorWithAlpha(value string, index *int, space string, a
 		count = 4
 	}
 	parts := strings.Fields(value)
-	var components [4]uint8
+	var components [4]float64
 	limit := 1<<bits - 1
 	if len(parts) >= count {
 		for i, part := range parts[:count] {
 			v, err := parseColorComponent(part)
 			if err != nil || v < 0 || limit < v {
-				components = [4]uint8{}
+				components = [4]float64{}
 				break
 			}
-			components[i] = uint8((v*255 + limit/2) / limit)
+			components[i] = float64(v) / float64(limit)
 		}
 	}
-	red, green, blue := components[0], components[1], components[2]
+	return kind, components
-	switch kind {
-	case "GRAY":
-		green, blue = red, red
-	case "CMYK":
-		red, green, blue = color.CMYKToRGB(components[0], components[1], components[2], components[3])
-	}
-	a := 255
-	if alpha != nil {
-		a = clampColor(*alpha)
-	}
-	return color.RGBA{R: uint8(int(red) * a / 255), G: uint8(int(green) * a / 255), B: uint8(int(blue) * a / 255), A: uint8(a)}
 }
 
 // parseColorComponent 解析颜色分量
@@ -232,6 +245,55 @@ func (r *Renderer) GradientStops(segments []ShdSegment, alpha *int) []ColorStop
 	return gradient
 }
 
+// renderGradientStops 在CMYK分量空间插值，将RGB分段误差控制在半个8位灰阶内
+// 入参: segments 原始颜色分段, alpha 对象透明度
+// 返回: []ColorStop 仅供绘制的颜色节点，不改变原始分段
+func (r *Renderer) renderGradientStops(segments []ShdSegment, alpha *int) []ColorStop {
+	stops := r.GradientStops(segments, alpha)
+	if len(stops) < 2 {
+		return stops
+	}
+	var result []ColorStop
+	for i, stop := range stops {
+		if i > 0 && stops[i-1].Offset < stop.Offset {
+			a, b := segments[i-1].Color, segments[i].Color
+			leftKind, left := r.colorComponents(a.Value, a.Index, a.ColorSpace)
+			rightKind, right := r.colorComponents(b.Value, b.Index, b.ColorSpace)
+			if leftKind == "CMYK" && rightKind == "CMYK" {
+				a0, a1 := float64(stops[i-1].Color.A)/255, float64(stop.Color.A)/255
+				dk, da := right[3]-left[3], a1-a0
+				bound := 0.0
+				for c := 0; c < 3; c++ {
+					dc := right[c] - left[c]
+					bound = math.Max(bound, 2*math.Abs(dc*dk)+2*math.Abs(da)*(math.Abs(dc)+math.Abs(dk)))
+				}
+				steps := int(math.Ceil(math.Sqrt(bound * 255 / 4)))
+				if steps > 1 && result == nil {
+					result = append(make([]ColorStop, 0, len(stops)+steps-1), stops[:i]...)
+				}
+				for j := 1; j < steps; j++ {
+					t := float64(j) / float64(steps)
+					var values [4]float64
+					for c := range values {
+						values[c] = left[c]*(1-t) + right[c]*t
+					}
+					opacity := a0*(1-t) + a1*t
+					black := (1 - values[3]) * opacity * 255
+					color := color.RGBA{R: uint8(math.Round((1 - values[0]) * black)), G: uint8(math.Round((1 - values[1]) * black)), B: uint8(math.Round((1 - values[2]) * black)), A: uint8(math.Round(opacity * 255))}
+					result = append(result, ColorStop{Offset: stops[i-1].Offset*(1-t) + stop.Offset*t, Color: color})
+				}
+			}
+		}
+		if result != nil {
+			result = append(result, stop)
+		}
+	}
+	if result == nil {
+		return stops
+	}
+	return result
+}
+
 // gradientPositions 按显式锚点补全渐变分段位置，保留原顺序
 // 入参: segments 渐变分段
 // 返回: []float64 分段位置

ofdgo_paint_model.go

@@ -68,7 +68,7 @@ func (r *Renderer) ResolvePaint(fill *FillColor) Paint {
 	paint := Paint{Kind: PaintSolid, Color: colorToRGBA(base)}
 	if node := fill.AxialShd; node != nil {
 		start, end := parseFloats(node.StartPoint), parseFloats(node.EndPoint)
-		stops := r.GradientStops(node.Segment, fill.Alpha)
+		stops := r.renderGradientStops(node.Segment, fill.Alpha)
 		if len(start) >= 2 && len(end) >= 2 && len(stops) != 0 && (!geometryEqual(start[0], end[0]) || !geometryEqual(start[1], end[1])) {
 			paint.Kind = PaintLinear
 			paint.Gradient = &Shading{Start: Point{X: start[0], Y: start[1]}, End: Point{X: end[0], Y: end[1]}, Stops: stops, Extend: node.Extend, MapType: node.MapType, MapUnit: node.MapUnit}
@@ -77,7 +77,7 @@ func (r *Renderer) ResolvePaint(fill *FillColor) Paint {
 	}
 	if node := fill.RadialShd; node != nil && node.EndRadius > 0 {
 		start, end := parseFloats(node.StartPoint), parseFloats(node.EndPoint)
-		stops := r.GradientStops(node.Segment, fill.Alpha)
+		stops := r.renderGradientStops(node.Segment, fill.Alpha)
 		if len(start) >= 2 && len(end) >= 2 && len(stops) != 0 {
 			paint.Kind = PaintRadial
 			paint.Gradient = &Shading{Start: Point{X: start[0], Y: start[1]}, End: Point{X: end[0], Y: end[1]}, StartRadius: node.StartRadius, EndRadius: node.EndRadius, Stops: stops, Extend: node.Extend, MapType: node.MapType, MapUnit: node.MapUnit, Eccentricity: node.Eccentricity, Angle: node.Angle}

ofdgo_pdf.go

@@ -164,14 +164,7 @@ func ImportPDF(ctx context.Context, source io.ReaderAt, size int64, options PDFI
 		importer.maskClips = make(map[*pdfgo.SoftMask]pdfgo.Path)
 		importer.compositeCache = nil
 		importer.clipTexts = make(map[*pdfgo.TextClip]TextObject)
-		visitor := pdfgo.Visitor{Path: importer.path, Text: importer.text, Image: importer.image, Warning: importer.warning}
+		if err := importer.compositePage(nil, func(visitor pdfgo.Visitor) error { return reader.WalkPage(ctx, page, visitor) }); err != nil {
-		visitor.Group = func(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error {
-			if mark.Page && mark.ColorSpace != nil && mark.ColorSpace.Model == "DeviceCMYK" && !mark.ColorSpace.Calibrated() {
-				return importer.compositePage(mark.ColorSpace, walk)
-			}
-			return importer.group(mark, walk, visitor)
-		}
-		if err := reader.WalkPage(ctx, page, visitor); err != nil {
 			return fmt.Errorf("import PDF page %d: %w", index+1, err)
 		}
 		if err := importer.flushPath(); err != nil {
@@ -466,9 +459,6 @@ func (p *pdfImporter) appendPath(mark pdfgo.PathMark) error {
 		if !ok {
 			return fmt.Errorf("invalid PDF stroke matrix")
 		}
-		if mark.Style.Fill.Radial != nil || mark.Style.Stroke.Radial != nil {
-			return &pdfgo.UnsupportedError{Feature: "radial gradient with anisotropic path stroke"}
-		}
 		drawing.matrix, origin, scale = inverse, Box{}, 1
 		m := p.matrix.Mul(mark.StrokeMatrix)
 		marginScale = math.Max(math.Hypot(m[0], m[2]), math.Hypot(m[1], m[3]))
@@ -531,6 +521,9 @@ func (p *pdfImporter) appendPath(mark pdfgo.PathMark) error {
 // 入参: paint PDF画刷, box 对象边界
 // 返回: *FillColor OFD颜色或渐变, error 图案转换错误
 func (p *pdfImporter) paintColor(paint pdfgo.Paint, box Box) (*FillColor, error) {
+	if paint.Mesh != nil {
+		return nil, &pdfgo.UnsupportedError{Feature: "bicubic mesh conversion"}
+	}
 	color := p.color(paint)
 	if paint.Tiling != nil {
 		pattern, err := p.tilingPattern(paint.Tiling, paint)
@@ -542,8 +535,20 @@ func (p *pdfImporter) paintColor(paint pdfgo.Paint, box Box) (*FillColor, error)
 	}
 	if paint.Radial != nil {
 		gradient := paint.Radial
-		start, end := p.matrix.Apply(gradient.Start), p.matrix.Apply(gradient.End)
+		matrix := p.matrix
-		scale := math.Hypot(p.matrix[0], p.matrix[1])
+		if gradient.Matrix != (pdfgo.Matrix{}) {
+			matrix = matrix.Mul(gradient.Matrix)
+		}
+		start, end := matrix.Apply(gradient.Start), matrix.Apply(gradient.End)
+		xx, yy, xy := matrix[0]*matrix[0]+matrix[2]*matrix[2], matrix[1]*matrix[1]+matrix[3]*matrix[3], matrix[0]*matrix[1]+matrix[2]*matrix[3]
+		major := (xx + yy + math.Hypot(xx-yy, 2*xy)) / 2
+		determinant := matrix[0]*matrix[3] - matrix[1]*matrix[2]
+		if major <= 0 || determinant == 0 {
+			return nil, fmt.Errorf("invalid PDF radial gradient matrix")
+		}
+		scale := math.Sqrt(major)
+		eccentricity := math.Sqrt(math.Max(0, 1-determinant*determinant/(major*major)))
+		angle := math.Atan2(2*xy, xx-yy) * 90 / math.Pi
 		extend := 0
 		if gradient.Extend[0] {
 			extend |= 1
@@ -551,9 +556,9 @@ func (p *pdfImporter) paintColor(paint pdfgo.Paint, box Box) (*FillColor, error)
 		if gradient.Extend[1] {
 			extend |= 2
 		}
-		shading := &RadialShd{StartPoint: pdfNumbers(start.X-box.X, start.Y-box.Y), EndPoint: pdfNumbers(end.X-box.X, end.Y-box.Y), StartRadius: gradient.StartRadius * scale, EndRadius: gradient.EndRadius * scale, Extend: strconv.Itoa(extend)}
+		shading := &RadialShd{StartPoint: pdfNumbers(start.X-box.X, start.Y-box.Y), EndPoint: pdfNumbers(end.X-box.X, end.Y-box.Y), StartRadius: gradient.StartRadius * scale, EndRadius: gradient.EndRadius * scale, Eccentricity: eccentricity, Angle: angle, Extend: strconv.Itoa(extend)}
 		var err error
-		shading.Segment, err = pdfGradientSegments(gradient.Stops, gradient.Space)
+		shading.Segment, err = p.gradientSegments(gradient.Stops, gradient.Space)
 		if err != nil {
 			return nil, err
 		}
@@ -587,7 +592,7 @@ func (p *pdfImporter) paintColor(paint pdfgo.Paint, box Box) (*FillColor, error)
 	}
 	shading := &AxialShd{StartPoint: pdfNumbers(start.X-box.X, start.Y-box.Y), EndPoint: pdfNumbers(end.X-box.X, end.Y-box.Y), Extend: strconv.Itoa(extend)}
 	var err error
-	shading.Segment, err = pdfGradientSegments(gradient.Stops, gradient.Space)
+	shading.Segment, err = p.gradientSegments(gradient.Stops, gradient.Space)
 	if err != nil {
 		return nil, err
 	}

ofdgo_pdf_composite.go

@@ -37,6 +37,7 @@ type pdfCompositePixel struct {
 	values [4]float64
 	alpha  float64
 	effect float64
+	shape  float64
 }
 
 // pdfCompositor 在指定局部区域中按源颜色空间合成PDF图元
@@ -47,6 +48,7 @@ type pdfCompositor struct {
 	inverse       pdfgo.Matrix
 	cache         *pdfCompositeCache
 	masks         map[*pdfgo.SoftMask][]float64
+	meshes        map[pdfMeshKey][]pdfMeshPixel
 }
 
 // pdfCompositeKey 区分图元的填充与描边几何
@@ -68,13 +70,14 @@ type pdfCompositeCache struct {
 	geometry map[pdfCompositeKey]pdfCompositeGeometry
 	images   map[*pdfgo.Image]*pdfgo.ImageComponents
 	masks    map[*pdfgo.SoftMask][]pdfCompositeNode
+	meshes   map[*pdfgo.MeshGradient][]pdfMeshTriangle
 }
 
 // compositingCache 按需创建单页合成缓存，页面切换时由导入器释放
 // 返回: *pdfCompositeCache 当前页面缓存
 func (p *pdfImporter) compositingCache() *pdfCompositeCache {
 	if p.compositeCache == nil {
-		p.compositeCache = &pdfCompositeCache{geometry: map[pdfCompositeKey]pdfCompositeGeometry{}, images: map[*pdfgo.Image]*pdfgo.ImageComponents{}, masks: map[*pdfgo.SoftMask][]pdfCompositeNode{}}
+		p.compositeCache = &pdfCompositeCache{geometry: map[pdfCompositeKey]pdfCompositeGeometry{}, images: map[*pdfgo.Image]*pdfgo.ImageComponents{}, masks: map[*pdfgo.SoftMask][]pdfCompositeNode{}, meshes: map[*pdfgo.MeshGradient][]pdfMeshTriangle{}}
 	}
 	return p.compositeCache
 }
@@ -162,8 +165,17 @@ func (p *pdfImporter) compositePage(space *pdfgo.ColorSpace, walk func(pdfgo.Vis
 	if err != nil {
 		return err
 	}
+	if len(nodes) == 1 && nodes[0].group != nil && nodes[0].group.Page {
+		space = nodes[0].group.ColorSpace
+		if !nodes[0].group.Knockout {
+			nodes = nodes[0].children
+		}
+	}
+	if space == nil {
+		space = &pdfgo.ColorSpace{Model: "DeviceRGB"}
+	}
 	for i, node := range nodes {
-		if node.opaque(space) {
+		if node.opaque(space) || space.SRGBEquivalent() && node.direct() {
 			if err := node.emit(p.visitor()); err != nil {
 				return fmt.Errorf("convert graphic %d: %w", i+1, err)
 			}
@@ -188,7 +200,7 @@ func (p *pdfImporter) compositePage(space *pdfgo.ColorSpace, walk func(pdfgo.Vis
 func (n pdfCompositeNode) opaque(space *pdfgo.ColorSpace) bool {
 	if n.group != nil {
 		g := n.group
-		if g.Alpha != 1 || g.SoftMask != nil || !pdfNormalBlend(g.BlendMode) || g.ColorSpace != nil && !g.ColorSpace.Equal(space) {
+		if g.Knockout || g.Alpha != 1 || g.SoftMask != nil || !pdfNormalBlend(g.BlendMode) || g.ColorSpace != nil && !g.ColorSpace.Equal(space) {
 			return false
 		}
 		for _, child := range n.children {
@@ -214,6 +226,24 @@ func (n pdfCompositeNode) opaque(space *pdfgo.ColorSpace) bool {
 	return true
 }
 
+// direct 检查sRGB图元能否使用标准OFD透明度而无需背景合成
+// 返回: bool 是否可直接转换
+func (n pdfCompositeNode) direct() bool {
+	if g := n.group; g != nil {
+		if g.Knockout || !pdfNormalBlend(g.BlendMode) || g.ColorSpace != nil && !g.ColorSpace.SRGBEquivalent() {
+			return false
+		}
+		for _, child := range n.children {
+			if !child.direct() {
+				return false
+			}
+		}
+		return true
+	}
+	s, fill, stroke := n.style()
+	return pdfNormalBlend(s.BlendMode) && !(fill && s.FillOverprint && pdfOverprintNeedsSeparation(s.Fill) || stroke && s.StrokeOverprint && pdfOverprintNeedsSeparation(s.Stroke))
+}
+
 // style 获取图元实际使用的图形状态
 // 返回: pdfgo.Style 图形状态, bool 是否填充, bool 是否描边
 func (n pdfCompositeNode) style() (pdfgo.Style, bool, bool) {

ofdgo_pdf_composite_draw.go

@@ -60,6 +60,7 @@ func (c *pdfCompositor) drawMark(node pdfCompositeNode, pixels []pdfCompositePix
 			result = append([]pdfCompositePixel(nil), pixels...)
 			for i := range result {
 				result[i].effect = 0
+				result[i].shape = 0
 			}
 		}
 	}
@@ -99,7 +100,14 @@ func (c *pdfCompositor) drawPaint(node pdfCompositeNode, outline bool, paint pdf
 	style, _, _ := node.style()
 	compatible := overprint && style.OverprintMode == 1 && node.image == nil && space.Model == "DeviceCMYK" && !space.Calibrated() && (paint.CMYK != nil || paint.Space != nil && paint.Space.Model == "DeviceCMYK" && !paint.Space.Calibrated())
 	step := 25.4 / c.importer.rasterDPI
-	uniform := node.image == nil && paint.Axial == nil && paint.Radial == nil && paint.Tiling == nil
+	uniform := node.image == nil && paint.Axial == nil && paint.Radial == nil && paint.Tiling == nil && paint.Mesh == nil
+	var mesh []pdfMeshPixel
+	if paint.Mesh != nil {
+		mesh, err = c.mesh(paint.Mesh, space)
+		if err != nil {
+			return err
+		}
+	}
 	var uniformValues [4]float64
 	uniformReady := false
 	for y := 0; y < c.height; y++ {
@@ -117,7 +125,10 @@ func (c *pdfCompositor) drawPaint(node pdfCompositeNode, outline bool, paint pdf
 				opacity *= mask[index]
 			}
 			var values [4]float64
-			if uniform {
+			if mesh != nil {
+				values = mesh[index].values
+				shape *= mesh[index].shape
+			} else if uniform {
 				if !uniformReady {
 					uniformValues, _, err = pdfCompositeColor(paint, pdfgo.Point{}, space, style.RenderingIntent)
 					uniformReady = true
@@ -140,10 +151,10 @@ func (c *pdfCompositor) drawPaint(node pdfCompositeNode, outline bool, paint pdf
 			if err != nil {
 				return err
 			}
-			if initial != nil {
 			if style.AlphaIsShape {
 				shape, opacity = shape*opacity, 1
 			}
+			if initial != nil {
 				pixel := initial[index]
 				if err := pdfCompositePaintOver(&pixel, values, opacity, space, mode, compatible); err != nil {
 					return err
@@ -152,6 +163,7 @@ func (c *pdfCompositor) drawPaint(node pdfCompositeNode, outline bool, paint pdf
 			} else if err := pdfCompositePaintOver(&pixels[index], values, shape*opacity, space, mode, compatible); err != nil {
 				return err
 			}
+			pixels[index].shape += shape * (1 - pixels[index].shape)
 		}
 	}
 	return nil
@@ -190,21 +202,71 @@ func (c *pdfCompositor) drawGroup(node pdfCompositeNode, pixels []pdfCompositePi
 		}
 	}
 	result := append([]pdfCompositePixel(nil), initial...)
+	if g.Knockout {
+		if err := c.drawKnockout(node.children, initial, result, space); err != nil {
+			return err
+		}
+	} else {
 		if err := c.draw(node.children, result, space); err != nil {
 			return err
 		}
+	}
 	mask, err := c.mask(g.SoftMask, parent)
 	if err != nil {
 		return err
 	}
+	if g.AlphaIsShape {
+		for i := range result {
+			result[i].shape *= g.Alpha
+			if mask != nil {
+				result[i].shape *= mask[i]
+			}
+		}
+	}
 	return pdfCompositeGroup(pixels, initial, result, space, parent, g.Alpha, mask, g.BlendMode)
 }
 
+// drawKnockout 将每个对象与组初始背景合成，再按对象形状替换先前对象
+// 入参: nodes 组图元, initial 初始背景, pixels 组输出, space 混合空间
+// 返回: error 图元或合成错误
+func (c *pdfCompositor) drawKnockout(nodes []pdfCompositeNode, initial, pixels []pdfCompositePixel, space *pdfgo.ColorSpace) error {
+	candidate := make([]pdfCompositePixel, len(initial))
+	for _, node := range nodes {
+		copy(candidate, initial)
+		if err := c.draw([]pdfCompositeNode{node}, candidate, space); err != nil {
+			return err
+		}
+		for i, source := range candidate {
+			pdfCompositeKnockout(&pixels[i], initial[i], source)
+		}
+	}
+	return nil
+}
+
+// pdfCompositeKnockout 移除未覆盖区域的初始背景贡献，保留形状与不透明度差异
+// 入参: target 累计组结果, initial 初始背景, source 单个对象合成结果
+func pdfCompositeKnockout(target *pdfCompositePixel, initial, source pdfCompositePixel) {
+	f := source.shape
+	if f == 0 {
+		return
+	}
+	alpha := target.alpha*(1-f) + source.alpha - initial.alpha*(1-f)
+	if alpha > 0 {
+		for j := range target.values {
+			target.values[j] = math.Max(0, math.Min(1, (target.values[j]*target.alpha*(1-f)+source.values[j]*source.alpha-initial.values[j]*initial.alpha*(1-f))/alpha))
+		}
+	}
+	target.alpha = math.Max(0, math.Min(1, alpha))
+	target.effect = target.effect*(1-f) + source.effect
+	target.shape += f * (1 - target.shape)
+}
+
 // pdfCompositeGroup 移除组初始背景贡献后，将组结果合成到父空间
 // 入参: pixels 父组输出, initial 初始背景, result 组结果, space 组空间, parent 父空间, opacity 组不透明度, mask 蒙版, mode 混合模式
 // 返回: error 颜色或混合错误
 func pdfCompositeGroup(pixels, initial, result []pdfCompositePixel, space, parent *pdfgo.ColorSpace, opacity float64, mask []float64, mode pdfgo.Name) error {
 	for i, pixel := range result {
+		pixels[i].shape += pixel.shape * (1 - pixels[i].shape)
 		if pixel.effect == 0 {
 			continue
 		}

ofdgo_pdf_group.go

@@ -39,6 +39,9 @@ type pdfPaintRegion struct {
 // 入参: mark 组边界状态, walk 组内容访问函数, visitor 页面访问器
 // 返回: error 不支持的组内容或转换错误
 func (p *pdfImporter) group(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error, visitor pdfgo.Visitor) error {
+	if mark.Knockout {
+		return &pdfgo.UnsupportedError{Feature: "knockout group outside page compositing"}
+	}
 	if mark.BlendMode != "" && mark.BlendMode != "Normal" && mark.BlendMode != "Compatible" {
 		return &pdfgo.UnsupportedError{Feature: "group blend mode " + string(mark.BlendMode)}
 	}
@@ -152,7 +155,7 @@ func (p *pdfImporter) groupPaths(mark pdfgo.GroupMark, walk func(pdfgo.Visitor)
 			if stroke {
 				color, overprint = path.Style.Stroke, path.Style.StrokeOverprint
 			}
-			if color.Tiling != nil || color.Axial != nil || color.Radial != nil || overprint && pdfOverprintNeedsSeparation(color) {
+			if color.Tiling != nil || color.Axial != nil || color.Radial != nil || color.Mesh != nil || overprint && pdfOverprintNeedsSeparation(color) {
 				return fmt.Errorf("%w: patterned or overprinted group content", errPDFGroupRaster)
 			}
 			if color.Alpha == 0 {

ofdgo_pdf_mesh.go

@@ -0,0 +1,216 @@
+// 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"
+	"math"
+
+	"github.com/xiaoqidun/pdfgo"
+)
+
+// pdfMeshVertex 保存局部毫米坐标及原曲面参数
+type pdfMeshVertex struct {
+	point pdfgo.Point
+	u, v  float64
+}
+
+// pdfMeshTriangle 保存按输出精度细分的曲面网格
+type pdfMeshTriangle struct {
+	vertices [3]pdfMeshVertex
+	patch    int
+}
+
+// pdfMeshKey 区分网格及其输出混合空间
+type pdfMeshKey struct {
+	mesh  *pdfgo.MeshGradient
+	space *pdfgo.ColorSpace
+}
+
+// pdfMeshPixel 保存抗锯齿覆盖率与源空间合成分量
+type pdfMeshPixel struct {
+	values [4]float64
+	shape  float64
+}
+
+// pdfMeshSample 保存采样点参数，patch为一基编号，零表示未覆盖
+type pdfMeshSample struct {
+	u, v  float64
+	patch int
+}
+
+// meshTriangles 按曲面二阶导数界细分，将几何误差控制在输出像素的十六分之一内
+// 入参: mesh 原始曲面
+// 返回: []pdfMeshTriangle 细分结果, error 取消或坐标错误
+func (p *pdfImporter) meshTriangles(mesh *pdfgo.MeshGradient) ([]pdfMeshTriangle, error) {
+	matrix := p.matrix.Mul(mesh.Matrix)
+	var triangles []pdfMeshTriangle
+	for index, patch := range mesh.Patches {
+		for i := range patch.Points {
+			for j := range patch.Points[i] {
+				patch.Points[i][j] = matrix.Apply(patch.Points[i][j])
+			}
+		}
+		var duu, dvv, duv float64
+		for i := 0; i < 4; i++ {
+			for j := 0; j < 4; j++ {
+				a := patch.Points[i][j]
+				if i < 2 {
+					b, c := patch.Points[i+1][j], patch.Points[i+2][j]
+					duu = math.Max(duu, 6*math.Hypot(c.X-2*b.X+a.X, c.Y-2*b.Y+a.Y))
+				}
+				if j < 2 {
+					b, c := patch.Points[i][j+1], patch.Points[i][j+2]
+					dvv = math.Max(dvv, 6*math.Hypot(c.X-2*b.X+a.X, c.Y-2*b.Y+a.Y))
+				}
+				if i < 3 && j < 3 {
+					b, c, d := patch.Points[i+1][j], patch.Points[i][j+1], patch.Points[i+1][j+1]
+					duv = math.Max(duv, 9*math.Hypot(d.X-b.X-c.X+a.X, d.Y-b.Y-c.Y+a.Y))
+				}
+			}
+		}
+		steps := math.Max(1, math.Ceil(math.Sqrt(8*(duu+dvv+2*duv)*p.rasterDPI/25.4)))
+		if !finite(steps) || steps >= math.Sqrt(float64(int(^uint(0)>>1)/2)) {
+			return nil, fmt.Errorf("mesh subdivision exceeds platform integer range")
+		}
+		n := int(steps)
+		row := make([]pdfMeshVertex, n+1)
+		for i := range row {
+			u := float64(i) / steps
+			row[i] = pdfMeshVertex{patch.PointAt(u, 0), u, 0}
+		}
+		for j := 1; j <= n; j++ {
+			if err := p.ctx.Err(); err != nil {
+				return nil, err
+			}
+			v := float64(j) / steps
+			left := pdfMeshVertex{patch.PointAt(0, v), 0, v}
+			for i := 1; i <= n; i++ {
+				u := float64(i) / steps
+				right := pdfMeshVertex{patch.PointAt(u, v), u, v}
+				a, b := row[i-1], row[i]
+				triangles = append(triangles, pdfMeshTriangle{[3]pdfMeshVertex{a, b, left}, index}, pdfMeshTriangle{[3]pdfMeshVertex{b, right, left}, index})
+				row[i-1], left = left, right
+			}
+			row[n] = left
+		}
+	}
+	return triangles, nil
+}
+
+// mesh 对当前图块执行四倍超采样，曲面重叠按后补片及较大v、u取值
+// 入参: mesh 原曲面, space 输出混合空间
+// 返回: []pdfMeshPixel 颜色及覆盖, error 几何或颜色错误
+func (c *pdfCompositor) mesh(mesh *pdfgo.MeshGradient, space *pdfgo.ColorSpace) ([]pdfMeshPixel, error) {
+	key := pdfMeshKey{mesh, space}
+	if pixels, ok := c.meshes[key]; ok {
+		return pixels, nil
+	}
+	triangles, ok := c.cache.meshes[mesh]
+	if !ok {
+		var err error
+		triangles, err = c.importer.meshTriangles(mesh)
+		if err != nil {
+			return nil, err
+		}
+		if c.cache.meshes == nil {
+			c.cache.meshes = map[*pdfgo.MeshGradient][]pdfMeshTriangle{}
+		}
+		c.cache.meshes[mesh] = triangles
+	}
+	const samples = 4
+	w, h := c.width*samples, c.height*samples
+	grid := make([]pdfMeshSample, w*h)
+	scale := c.importer.rasterDPI / 25.4 * samples
+	for _, triangle := range triangles {
+		if err := c.importer.ctx.Err(); err != nil {
+			return nil, err
+		}
+		vertices := triangle.vertices
+		for i := range vertices {
+			vertices[i].point.X = (vertices[i].point.X - c.box.X) * scale
+			vertices[i].point.Y = (vertices[i].point.Y - c.box.Y) * scale
+		}
+		a, b, d := vertices[0].point, vertices[1].point, vertices[2].point
+		denominator := (b.Y-d.Y)*(a.X-d.X) + (d.X-b.X)*(a.Y-d.Y)
+		if denominator == 0 {
+			continue
+		}
+		minX, maxX := math.Min(a.X, math.Min(b.X, d.X)), math.Max(a.X, math.Max(b.X, d.X))
+		minY, maxY := math.Min(a.Y, math.Min(b.Y, d.Y)), math.Max(a.Y, math.Max(b.Y, d.Y))
+		if maxX < 0 || maxY < 0 || minX >= float64(w) || minY >= float64(h) {
+			continue
+		}
+		endX := int(math.Min(float64(w), math.Ceil(maxX)))
+		endY := int(math.Min(float64(h), math.Ceil(maxY)))
+		for y := int(math.Max(0, math.Floor(minY))); y < endY; y++ {
+			for x := int(math.Max(0, math.Floor(minX))); x < endX; x++ {
+				px, py := float64(x)+.5, float64(y)+.5
+				l0 := ((b.Y-d.Y)*(px-d.X) + (d.X-b.X)*(py-d.Y)) / denominator
+				l1 := ((d.Y-a.Y)*(px-d.X) + (a.X-d.X)*(py-d.Y)) / denominator
+				l2 := 1 - l0 - l1
+				if l0 < -1e-10 || l1 < -1e-10 || l2 < -1e-10 {
+					continue
+				}
+				u := math.Max(0, math.Min(1, l0*vertices[0].u+l1*vertices[1].u+l2*vertices[2].u))
+				v := math.Max(0, math.Min(1, l0*vertices[0].v+l1*vertices[1].v+l2*vertices[2].v))
+				current := &grid[y*w+x]
+				if triangle.patch+1 > current.patch || triangle.patch+1 == current.patch && (v > current.v || v == current.v && u > current.u) {
+					*current = pdfMeshSample{u, v, triangle.patch + 1}
+				}
+			}
+		}
+	}
+	pixels := make([]pdfMeshPixel, c.width*c.height)
+	for y := 0; y < h; y++ {
+		if err := c.importer.ctx.Err(); err != nil {
+			return nil, err
+		}
+		for x := 0; x < w; x++ {
+			sample := grid[y*w+x]
+			if sample.patch == 0 {
+				continue
+			}
+			values, err := mesh.ValuesAt(sample.patch-1, sample.u, sample.v)
+			if err != nil {
+				return nil, err
+			}
+			values, err = space.Convert(values[:mesh.Space.Components()], mesh.Space, mesh.Intent)
+			if err != nil {
+				return nil, err
+			}
+			pixel := &pixels[(y/samples)*c.width+x/samples]
+			for i, value := range values {
+				pixel.values[i] += value
+			}
+			pixel.shape++
+		}
+	}
+	for i := range pixels {
+		pixel := &pixels[i]
+		if pixel.shape == 0 {
+			continue
+		}
+		for j := range pixel.values {
+			pixel.values[j] /= pixel.shape
+		}
+		pixel.shape /= samples * samples
+	}
+	if c.meshes == nil {
+		c.meshes = map[pdfMeshKey][]pdfMeshPixel{}
+	}
+	c.meshes[key] = pixels
+	return pixels, nil
+}

ofdgo_pdf_shading.go

@@ -16,72 +16,61 @@ package ofdgo
 
 import (
 	"math"
-	"slices"
 
 	"github.com/xiaoqidun/pdfgo"
 )
 
-// pdfGradientSegments 将线性源颜色及设备四色的截断点表达为OFD分段
+// gradientSegments 保留线性源颜色的设备分量，校准颜色经源空间转换
 // 入参: stops 源颜色分段, space 源颜色空间
-// 返回: []ShdSegment 等价RGB分段, error 不可线性表达的变换
+// 返回: []ShdSegment OFD颜色分段, error 不可线性表达的变换
-func pdfGradientSegments(stops []pdfgo.GradientStop, space *pdfgo.ColorSpace) ([]ShdSegment, error) {
+func (p *pdfImporter) gradientSegments(stops []pdfgo.GradientStop, space *pdfgo.ColorSpace) ([]ShdSegment, error) {
-	if len(stops) == 0 {
+	if err := pdfGradientStopsError(stops, space); err != nil {
-		return nil, &pdfgo.UnsupportedError{Feature: "nonlinear gradient conversion"}
-	}
-	calibrated := space != nil && space.Calibrated() && !space.SRGBEquivalent()
-	cmyk := space != nil && space.Model == "DeviceCMYK" && !space.Calibrated()
-	segments := make([]ShdSegment, 0, len(stops))
-	appendStop := func(position float64, rgb [3]float64) {
-		segments = append(segments, ShdSegment{Position: position, Color: ShdColor{Value: pdfNumbers(math.Round(rgb[0]*255), math.Round(rgb[1]*255), math.Round(rgb[2]*255))}})
-	}
-	for i, b := range stops {
-		if i > 0 {
-			a := stops[i-1]
-			if a.Position != b.Position && a.Values != b.Values {
-				if calibrated {
-					return nil, &pdfgo.UnsupportedError{Feature: "nonlinear ICC gradient conversion"}
-				}
-				if cmyk {
-					var crossings []float64
-					for c := 0; c < 3; c++ {
-						start, end := a.Values[c]+a.Values[3], b.Values[c]+b.Values[3]
-						if start != end {
-							if t := (1 - start) / (end - start); t > 0 && t < 1 {
-								crossings = append(crossings, t)
-							}
-						}
-					}
-					slices.Sort(crossings)
-					for _, t := range slices.Compact(crossings) {
-						var values [4]float64
-						for c := range values {
-							values[c] = a.Values[c]*(1-t) + b.Values[c]*t
-						}
-						rgb, err := space.RGB(values[:], "RelativeColorimetric")
-						if err != nil {
 		return nil, err
 	}
-						appendStop(a.Position+(b.Position-a.Position)*t, rgb)
+	cmyk := space != nil && space.Model == "DeviceCMYK" && !space.Calibrated()
+	segments := make([]ShdSegment, len(stops))
+	for i, stop := range stops {
+		paint := pdfgo.Paint{RGB: stop.RGB, Alpha: 1}
+		if cmyk {
+			paint.CMYK = &stop.Values
 		}
-				}
+		color := p.color(paint)
-			}
+		segments[i] = ShdSegment{Position: stop.Position, Color: ShdColor{Value: color.Value, ColorSpace: color.ColorSpace}}
-		}
-		appendStop(b.Position, b.RGB)
 	}
 	return segments, nil
 }
 
+// pdfGradientStopsError 检查源颜色分段是否可由OFD基本颜色表达
+// 入参: stops 源颜色分段, space 源颜色空间
+// 返回: error 不可线性表达的变换
+func pdfGradientStopsError(stops []pdfgo.GradientStop, space *pdfgo.ColorSpace) error {
+	if len(stops) == 0 {
+		return &pdfgo.UnsupportedError{Feature: "nonlinear gradient conversion"}
+	}
+	calibrated := space != nil && space.Calibrated() && !space.SRGBEquivalent()
+	if calibrated {
+		for i := 1; i < len(stops); i++ {
+			a, b := stops[i-1], stops[i]
+			if a.Position != b.Position && a.Values != b.Values {
+				return &pdfgo.UnsupportedError{Feature: "nonlinear ICC gradient conversion"}
+			}
+		}
+	}
+	return nil
+}
+
 // pdfGradientError 检查渐变能否精确映射为OFD线性分段
 // 入参: paint 画刷
 // 返回: error 不可等价表达的渐变
 func pdfGradientError(paint pdfgo.Paint) error {
+	if paint.Mesh != nil {
+		return &pdfgo.UnsupportedError{Feature: "bicubic mesh conversion"}
+	}
 	if paint.Axial != nil {
-		_, err := pdfGradientSegments(paint.Axial.Stops, paint.Axial.Space)
+		return pdfGradientStopsError(paint.Axial.Stops, paint.Axial.Space)
-		return err
 	}
 	if paint.Radial != nil {
-		_, err := pdfGradientSegments(paint.Radial.Stops, paint.Radial.Space)
+		return pdfGradientStopsError(paint.Radial.Stops, paint.Radial.Space)
-		return err
 	}
 	return nil
 }
@@ -90,7 +79,30 @@ func pdfGradientError(paint pdfgo.Paint) error {
 // 入参: mark 路径绘制信息
 // 返回: error 几何或着色错误
 func (p *pdfImporter) gradientPath(mark pdfgo.PathMark) error {
-	return p.compositeRegion(nil, pdfCompositeNode{path: &mark}, &pdfgo.ColorSpace{Model: "DeviceRGB"}, false)
+	cmyk := true
+	for i, paint := range []pdfgo.Paint{mark.Style.Fill, mark.Style.Stroke} {
+		if i == 0 && !mark.Fill || i == 1 && !mark.Stroke {
+			continue
+		}
+		space := paint.Space
+		switch {
+		case paint.Axial != nil:
+			space = paint.Axial.Space
+		case paint.Radial != nil:
+			space = paint.Radial.Space
+		case paint.Mesh != nil:
+			space = paint.Mesh.Space
+		}
+		if paint.CMYK == nil && (space == nil || space.Model != "DeviceCMYK" || space.Calibrated()) {
+			cmyk = false
+			break
+		}
+	}
+	space := &pdfgo.ColorSpace{Model: "DeviceRGB"}
+	if cmyk {
+		space.Model = "DeviceCMYK"
+	}
+	return p.compositeRegion(nil, pdfCompositeNode{path: &mark}, space, false)
 }
 
 // pdfShadingPosition 计算渐变参数，未延伸区域及不存在非负圆半径的位置不着色
@@ -103,6 +115,13 @@ func pdfShadingPosition(paint pdfgo.Paint, point pdfgo.Point) (float64, bool) {
 		return t, finite(t) && (t >= 0 || g.Extend[0]) && (t <= 1 || g.Extend[1])
 	}
 	g := paint.Radial
+	if g.Matrix != (pdfgo.Matrix{}) {
+		inverse, ok := g.Matrix.Inverse()
+		if !ok {
+			return 0, false
+		}
+		point = inverse.Apply(point)
+	}
 	dx, dy, dr := g.End.X-g.Start.X, g.End.Y-g.Start.Y, g.EndRadius-g.StartRadius
 	px, py := point.X-g.Start.X, point.Y-g.Start.Y
 	a, b, c := dx*dx+dy*dy-dr*dr, -2*(px*dx+py*dy+g.StartRadius*dr), px*px+py*py-g.StartRadius*g.StartRadius