feat(渲染能力): 修正页面与模板的图层叠放顺序

ofdgo_object.go

@@ -119,6 +119,7 @@ func decodeObjectContainer(d *xml.Decoder, start xml.StartElement, decode func(*
 func (l *Layer) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
 	*l = Layer{}
 	l.ID = attrValue(start, "ID")
+	l.Type = attrValue(start, "Type")
 	l.DrawParam = attrValue(start, "DrawParam")
 	return decodeObjectContainer(d, start, l.decodeObject)
 }

ofdgo_page.go

@@ -41,6 +41,7 @@ type Content struct {
 // Layer 图层
 type Layer struct {
 	ID                   string                 `xml:"ID,attr"`
+	Type                 string                 `xml:"Type,attr"`
 	DrawParam            string                 `xml:"DrawParam,attr"`
 	Objects              []GraphicObject        `xml:"-"`
 	TextObject           []TextObject           `xml:"TextObject"`

ofdgo_renderer.go

@@ -118,24 +118,19 @@ func (r *Renderer) renderPageToContext(ctx *canvas.Context, page *PageContent, d
 		ctx.SetFillColor(canvas.White)
 		ctx.DrawPath(0, 0, canvas.Rectangle(box.W, box.H))
 	}
-	if len(page.Template) > 0 && r.Reader.doc != nil {
+	for order := range 3 {
+		if r.Reader.doc != nil {
 			for _, tplRef := range page.Template {
-			if tplRef.ZOrder != "Foreground" {
+				kind := tplRef.ZOrder
+				if kind == "" {
+					kind = "Background"
+				}
+				if layerOrder(kind) == order {
 					r.renderTemplate(ctx, tplRef.TemplateID, pageH)
 				}
 			}
 		}
-	if page.Content.Layer != nil {
-		for _, layer := range page.Content.Layer {
-			r.renderLayer(ctx, layer, pageH, nil, nil)
-		}
-	}
-	if len(page.Template) > 0 && r.Reader.doc != nil {
-		for _, tplRef := range page.Template {
-			if tplRef.ZOrder == "Foreground" {
-				r.renderTemplate(ctx, tplRef.TemplateID, pageH)
-			}
-		}
+		r.renderLayers(ctx, page.Content.Layer, pageH, order)
 	}
 	if r.RenderAnnotations {
 		r.renderAnnotations(ctx, page.ID, pageH)

ofdgo_renderer_layer.go

@@ -53,8 +53,29 @@ func (r *Renderer) renderTemplate(ctx *canvas.Context, templateID string, pageH
 		}
 		r.templatePageCache[templateID] = tplContent
 	}
-	if tplContent.Content.Layer != nil {
-		for _, layer := range tplContent.Content.Layer {
+	for order := range 3 {
+		r.renderLayers(ctx, tplContent.Content.Layer, pageH, order)
+	}
+}
+
+// layerOrder 获取图层类型的绘制顺序
+// 入参: kind 图层类型
+// 返回: int 绘制顺序
+func layerOrder(kind string) int {
+	switch kind {
+	case "Background":
+		return 0
+	case "Foreground":
+		return 2
+	}
+	return 1
+}
+
+// renderLayers 按原顺序渲染指定类型的图层
+// 入参: ctx 画布上下文, layers 图层列表, pageH 页面高度, order 图层类型顺序
+func (r *Renderer) renderLayers(ctx *canvas.Context, layers []Layer, pageH float64, order int) {
+	for _, layer := range layers {
+		if layerOrder(layer.Type) == order {
 			r.renderLayer(ctx, layer, pageH, nil, nil)
 		}
 	}