From 565b7f6db41037c935b2cbf54241bc13f56b4e65 Mon Sep 17 00:00:00 2001
From: xiaoqidun <xiaoqidun@gmail.com>
Date: Sat, 12 Sep 2026 12:25:18 +0800
Subject: [PATCH] =?UTF-8?q?feat(=E6=80=A7=E8=83=BD=E4=BC=98=E5=8C=96):=20?=
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---
 internal/webui/webui.go |  9 +++------
 ofdgo.go                | 12 +-----------
 ofdgo_renderer.go       | 20 ++++++++++++++++++++
 ofdgo_renderer_image.go | 12 ++++++++++++
 4 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/internal/webui/webui.go b/internal/webui/webui.go
index 048690c..07b6fe0 100644
--- a/internal/webui/webui.go
+++ b/internal/webui/webui.go
@@ -237,18 +237,15 @@ func (s *Session) Close() error {
 // 入参: fonts 字体文件列表
 // 返回: error 错误信息
 func (s *Session) SetFonts(fonts []FontFile) error {
-	opts := []ofdgo.RendererOption{
-		ofdgo.WithDPI(s.Renderer.DPI),
-		ofdgo.WithAnnotations(s.Renderer.RenderAnnotations),
-	}
 	if len(fonts) > 0 {
 		fontFS := ofdgo.NewFontFS(fonts)
 		if fontFS.Len() == 0 {
 			return fmt.Errorf("invalid font file")
 		}
-		opts = append(opts, ofdgo.WithFontFS(fontFS))
+		s.Renderer.SetFontFS(fontFS)
+	} else {
+		s.Renderer.SetFontFS()
 	}
-	s.Renderer = ofdgo.NewRenderer(s.Reader, opts...)
 	return nil
 }
 
diff --git a/ofdgo.go b/ofdgo.go
index 74d2712..eec37e0 100644
--- a/ofdgo.go
+++ b/ofdgo.go
@@ -20,8 +20,6 @@ import (
 	"image"
 	"io"
 	"io/fs"
-
-	"github.com/tdewolff/canvas"
 )
 
 // Open 打开OFD文件
@@ -71,18 +69,10 @@ func NewRenderer(reader *Reader, opts ...RendererOption) *Renderer {
 		RenderAnnotations:     true,
 		DrawParams:            reader.drawParamCache,
 		CompositeGraphicUnits: reader.compositeGraphicUnitCache,
-		FontMap:               make(map[string]*canvas.FontFamily),
-		FontGIDMap:            make(map[string]map[uint16]rune),
-		FontCIDMap:            make(map[string]map[uint16]rune),
-		fontCache:             make(map[fontCacheKey]*canvas.FontFamily),
-		fontSourceCache:       make(map[string][]fontSource),
-		fontSourceUsed:        make(map[string]fontSource),
-		fontDirCandidates:     make(map[string][]fontFileCandidate),
-		fontFSCandidates:      make(map[int][]fontFileCandidate),
-		textGlyphPathCache:    make(map[textGlyphPathCacheKey]textGlyphPathCacheValue),
 		templatePageCache:     make(map[string]*PageContent),
 		imageCache:            make(map[string]image.Image),
 	}
+	r.resetFontCache()
 	for _, opt := range opts {
 		opt(r)
 	}
diff --git a/ofdgo_renderer.go b/ofdgo_renderer.go
index 7d5c1c5..6ed9cb2 100644
--- a/ofdgo_renderer.go
+++ b/ofdgo_renderer.go
@@ -50,6 +50,26 @@ type Renderer struct {
 // RendererOption 渲染器配置选项
 type RendererOption func(*Renderer)
 
+// SetFontFS 替换外部字体文件系统并重置字体缓存
+// 入参: fsys 字体文件系统
+func (r *Renderer) SetFontFS(fsys ...fs.FS) {
+	r.fontFS = append([]fs.FS(nil), fsys...)
+	r.resetFontCache()
+}
+
+// resetFontCache 重置字体匹配、加载和字形缓存
+func (r *Renderer) resetFontCache() {
+	r.FontMap = make(map[string]*canvas.FontFamily)
+	r.FontGIDMap = make(map[string]map[uint16]rune)
+	r.FontCIDMap = make(map[string]map[uint16]rune)
+	r.fontCache = make(map[fontCacheKey]*canvas.FontFamily)
+	r.fontSourceCache = make(map[string][]fontSource)
+	r.fontSourceUsed = make(map[string]fontSource)
+	r.fontDirCandidates = make(map[string][]fontFileCandidate)
+	r.fontFSCandidates = make(map[int][]fontFileCandidate)
+	r.textGlyphPathCache = make(map[textGlyphPathCacheKey]textGlyphPathCacheValue)
+}
+
 // RenderPage 渲染特定页面内容
 // 入参: page 页面内容
 // 返回: *canvas.Canvas 画布实例, error 错误信息
diff --git a/ofdgo_renderer_image.go b/ofdgo_renderer_image.go
index aaf4763..1f5ebef 100644
--- a/ofdgo_renderer_image.go
+++ b/ofdgo_renderer_image.go
@@ -140,6 +140,18 @@ func imageWithMask(img, mask image.Image) image.Image {
 		maskBounds = bounds
 	}
 	out := image.NewNRGBA(bounds)
+	if src, ok := source.(*image.NRGBA); ok {
+		for y := 0; y < bounds.Dy(); y++ {
+			offset := src.PixOffset(bounds.Min.X, bounds.Min.Y+y)
+			row := out.Pix[y*out.Stride : (y+1)*out.Stride]
+			copy(row, src.Pix[offset:offset+len(row)])
+			for x := 3; x < len(row); x += 4 {
+				a := imageGrayAt(opacity, maskBounds.Min.X+x/4, maskBounds.Min.Y+y).Y
+				row[x] = uint8(int(row[x]) * int(a) / 255)
+			}
+		}
+		return out
+	}
 	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
 		for x := bounds.Min.X; x < bounds.Max.X; x++ {
 			mx := maskBounds.Min.X + x - bounds.Min.X