feat(渲染编辑): 补全替换图解析渲染与保存

ofdgo_editor.go

@@ -847,6 +847,11 @@ func (v *editorValidation) prepareObject(id string, object GraphicObject) (Graph
 		if _, err := e.editorImage(obj.ResourceID); err != nil {
 			return GraphicObject{}, err
 		}
+		if obj.Substitution != "" {
+			if _, err := e.editorImage(obj.Substitution); err != nil {
+				return GraphicObject{}, err
+			}
+		}
 		if obj.ImageMask != "" {
 			if _, err := e.editorImage(obj.ImageMask); err != nil {
 				return GraphicObject{}, err

ofdgo_editor_color.go

@@ -462,6 +462,7 @@ func collectObjectReferences(object GraphicObject, used map[string]bool) {
 		actions = object.PathObject.Actions
 	case "ImageObject":
 		used[object.ImageObject.ResourceID], used[object.ImageObject.ImageMask] = true, true
+		used[object.ImageObject.Substitution] = true
 		if object.ImageObject.Border != nil {
 			collectPaintReferences((*FillColor)(object.ImageObject.Border.BorderColor), used)
 		}

ofdgo_editor_xml.go

@@ -307,7 +307,7 @@ func editorXMLSupported(node *editorXML) bool {
 			children += " Clips"
 		}
 	case "ImageObject":
-		allowed, children = "ID Boundary CTM ResourceID ImageMask Visible Alpha", "Clips"
+		allowed, children = "ID Boundary CTM ResourceID Substitution ImageMask Visible Alpha", "Clips"
 	case "TextCode":
 		allowed = "X Y DeltaX DeltaY"
 	case "FillColor", "StrokeColor":
@@ -344,7 +344,7 @@ func editorXMLTransformable(node *editorXML) bool {
 	case "PathObject":
 		attrs = "ID Boundary CTM DrawParam LineWidth MiterLimit Join Cap Rule DashPattern DashOffset Visible Stroke Fill Alpha"
 	case "ImageObject":
-		attrs = "ID Boundary CTM ResourceID ImageMask Visible Alpha"
+		attrs = "ID Boundary CTM ResourceID Substitution ImageMask Visible Alpha"
 	case "CompositeObject", "CompositeGraphicUnit":
 		attrs = "ID Boundary CTM ResourceID DrawParam Visible Alpha"
 	default:

ofdgo_image_resource.go

@@ -94,6 +94,38 @@ func (r *Renderer) ImageResource(id string) (image.Image, error) {
 	return r.cachedImageResource(path)
 }
 
+// imageObjectResource 读取主图，无法读取或解码时使用对象声明的替换图
+// 入参: object 图像对象
+// 返回: image.Image 图片资源, error 读取或解码错误
+func (r *Renderer) imageObjectResource(object ImageObject) (image.Image, error) {
+	read := func(id string) (image.Image, error) {
+		img, err := r.ImageResource(id)
+		if err == nil && (r.decodeImages || object.Substitution != "") {
+			pixels, decodeErr := imagePixelData(img)
+			err = decodeErr
+			if r.decodeImages {
+				img = pixels
+			}
+		}
+		return img, err
+	}
+	img, err := read(object.ResourceID)
+	if err == nil || object.Substitution == "" || object.Substitution == object.ResourceID {
+		return img, err
+	}
+	if r.pageContext != nil && r.pageContext.Err() != nil {
+		return nil, r.pageContext.Err()
+	}
+	if r.OutputContext != nil && r.OutputContext.Err() != nil {
+		return nil, r.OutputContext.Err()
+	}
+	img, substituteErr := read(object.Substitution)
+	if substituteErr != nil {
+		return nil, fmt.Errorf("image resource %q: %w; substitution %q: %w", object.ResourceID, err, object.Substitution, substituteErr)
+	}
+	return img, nil
+}
+
 // newEncodedImage 接管编码数据并读取头信息
 // 入参: data 原始编码
 // 返回: *EncodedImage 惰性图片, error 头信息或格式错误

ofdgo_page.go

@@ -240,16 +240,17 @@ type ShdColor struct {
 
 // ImageObject 图片对象
 type ImageObject struct {
-	ID         string       `xml:"ID,attr"`
-	Boundary   string       `xml:"Boundary,attr"`
-	ResourceID string       `xml:"ResourceID,attr"`
-	ImageMask  string       `xml:"ImageMask,attr"`
-	CTM        string       `xml:"CTM,attr"`
-	Alpha      *int         `xml:"Alpha,attr"`
-	Visible    *bool        `xml:"Visible,attr"`
-	Border     *ImageBorder `xml:"Border"`
-	Clips      *Clips       `xml:"Clips"`
-	Actions    []Action     `xml:"Actions>Action"`
+	ID           string       `xml:"ID,attr"`
+	Boundary     string       `xml:"Boundary,attr"`
+	ResourceID   string       `xml:"ResourceID,attr"`
+	Substitution string       `xml:"Substitution,attr"`
+	ImageMask    string       `xml:"ImageMask,attr"`
+	CTM          string       `xml:"CTM,attr"`
+	Alpha        *int         `xml:"Alpha,attr"`
+	Visible      *bool        `xml:"Visible,attr"`
+	Border       *ImageBorder `xml:"Border"`
+	Clips        *Clips       `xml:"Clips"`
+	Actions      []Action     `xml:"Actions>Action"`
 }
 
 // ImageBorder 图像边框

ofdgo_render_compile_image.go

@@ -59,7 +59,7 @@ func (c *semanticCompiler) imageObject(object ImageObject, state RenderState) er
 			return err
 		}
 	} else {
-		img, err := c.renderer.ImageResource(object.ResourceID)
+		img, err := c.renderer.imageObjectResource(object)
 		if err != nil {
 			return err
 		}

ofdgo_renderer_image_canvas.go

@@ -38,12 +38,7 @@ func (r *Renderer) renderImage(ctx *canvas.Context, obj ImageObject, pageH float
 	if obj.Visible != nil && !*obj.Visible || obj.Alpha != nil && *obj.Alpha == 0 {
 		return
 	}
-	resPath, ok := resourceValue(r.Reader.ResMap, obj.ResourceID)
-	if !ok {
-		r.renderError = fmt.Errorf("image resource %q not found", obj.ResourceID)
-		return
-	}
-	img, err := r.decodeImageResource(resPath)
+	img, err := r.imageObjectResource(obj)
 	if err != nil {
 		r.renderError = err
 		return

ofdgo_writer.go

@@ -849,6 +849,7 @@ func (x *ofdXML) object(object GraphicObject, root bool) {
 		attrs.add("CTM", obj.CTM)
 		attrs.add("ResourceID", obj.ResourceID)
 		attrs.add("ImageMask", obj.ImageMask)
+		attrs.add("Substitution", obj.Substitution)
 		attrs.flag("Visible", obj.Visible)
 		attrs.alpha(obj.Alpha)
 		actions = obj.Actions