From 6c3068b81368e4bad4c69e27920dbd4fe71de3d8 Mon Sep 17 00:00:00 2001
From: xiaoqidun <xiaoqidun@gmail.com>
Date: Sun, 11 Oct 2026 11:48:34 +0800
Subject: [PATCH] =?UTF-8?q?feat(=E5=9B=BE=E5=83=8F=E5=8E=8B=E7=BC=A9):=20?=
 =?UTF-8?q?=E4=BF=AE=E5=A4=8D=E6=9B=BF=E6=8D=A2=E5=9B=BE=E5=83=8F=E5=8E=8B?=
 =?UTF-8?q?=E7=BC=A9=E4=B8=8E=E8=92=99=E7=89=88=E4=BF=9D=E6=8A=A4?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ofdgo_compression.go        | 10 ++++++++--
 ofdgo_compression_images.go | 15 ++++++++++-----
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/ofdgo_compression.go b/ofdgo_compression.go
index e6b0297..fe7296d 100644
--- a/ofdgo_compression.go
+++ b/ofdgo_compression.go
@@ -174,7 +174,7 @@ func (e *Editor) outputSnapshot(ctx context.Context, options WriteOptions) (*Edi
 	return &snapshot, nil
 }
 
-// compressionImageSafety 保护蒙版资源，识别不能可靠降采样的图案及隐藏内容
+// compressionImageSafety 保护蒙版及其原图和替换图像，识别不能可靠降采样的图案及隐藏内容
 // 入参: ctx 取消上下文, images 图片资源
 // 返回: map[string]bool 只能无损处理的资源路径, bool 是否可分析尺寸, error 读取或取消错误
 func (r *Reader) compressionImageSafety(ctx context.Context, images []ImageInfo) (map[string]bool, bool, error) {
@@ -251,7 +251,7 @@ func (r *Reader) compressionImageSafety(ctx context.Context, images []ImageInfo)
 					if element.Name.Local == "Pattern" {
 						geometry = false
 					}
-					resource, masked := "", false
+					resource, substitution, masked := "", "", false
 					for _, attr := range element.Attr {
 						if attr.Name.Space != "" {
 							continue
@@ -262,6 +262,9 @@ func (r *Reader) compressionImageSafety(ctx context.Context, images []ImageInfo)
 						if attr.Name.Local == "ResourceID" {
 							resource = editorResourceID(attr.Value)
 						}
+						if attr.Name.Local == "Substitution" {
+							substitution = editorResourceID(attr.Value)
+						}
 						if attr.Name.Local == "ImageMask" {
 							masks[editorResourceID(attr.Value)] = true
 							masked = true
@@ -269,6 +272,9 @@ func (r *Reader) compressionImageSafety(ctx context.Context, images []ImageInfo)
 					}
 					if masked {
 						masks[resource] = true
+						if substitution != "" {
+							masks[substitution] = true
+						}
 					}
 				case xml.EndElement:
 					stack = stack[:len(stack)-1]
diff --git a/ofdgo_compression_images.go b/ofdgo_compression_images.go
index c561b8c..873585a 100644
--- a/ofdgo_compression_images.go
+++ b/ofdgo_compression_images.go
@@ -157,7 +157,7 @@ func (r *Reader) compressionImageSizes(ctx context.Context, images []ImageInfo,
 	return result, ctx.Err()
 }
 
-// DrawObject 收集图片的完整显示尺寸，不使用裁剪后的局部面积
+// DrawObject 汇总原图和替换图像的完整显示尺寸，不使用裁剪后的局部面积
 // 入参: object 图形对象, state 继承状态
 // 返回: error 取消或几何错误
 func (v *compressionImages) DrawObject(object *GraphicObject, state RenderState) error {
@@ -168,8 +168,8 @@ func (v *compressionImages) DrawObject(object *GraphicObject, state RenderState)
 		return nil
 	}
 	img := object.ImageObject
-	id := editorResourceID(img.ResourceID)
-	if id == "" {
+	ids := [2]string{editorResourceID(img.ResourceID), editorResourceID(img.Substitution)}
+	if ids[0] == "" || img.Substitution != "" && ids[1] == "" {
 		return fmt.Errorf("invalid image resource")
 	}
 	box, err := ParseBox(img.Boundary)
@@ -185,8 +185,13 @@ func (v *compressionImages) DrawObject(object *GraphicObject, state RenderState)
 	if size.X == 0 || size.Y == 0 {
 		return fmt.Errorf("invalid image placement")
 	}
-	old := v.sizes[id]
-	v.sizes[id] = image.Pt(max(old.X, size.X), max(old.Y, size.Y))
+	for _, id := range ids {
+		if id == "" {
+			continue
+		}
+		old := v.sizes[id]
+		v.sizes[id] = image.Pt(max(old.X, size.X), max(old.Y, size.Y))
+	}
 	return nil
 }