feat(后端架构): 完善后端解耦

ofdgo_drawparam.go

@@ -0,0 +1,123 @@
+// 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
+
+const defaultPathLineWidth = 0.353
+const defaultMiterLimit = 3.528
+
+// mergeGraphicObjectAlpha 合并图形对象透明度
+// 入参: obj 图形对象, alpha 父级透明度
+// 返回: GraphicObject 合并后的图形对象
+func mergeGraphicObjectAlpha(obj GraphicObject, alpha *int) GraphicObject {
+	if alpha == nil {
+		return obj
+	}
+	switch obj.Type {
+	case "TextObject":
+		obj.TextObject.Alpha = mergeAlpha(obj.TextObject.Alpha, alpha)
+	case "PathObject":
+		obj.PathObject.Alpha = mergeAlpha(obj.PathObject.Alpha, alpha)
+	case "ImageObject":
+		obj.ImageObject.Alpha = mergeAlpha(obj.ImageObject.Alpha, alpha)
+	case "CompositeGraphicUnit", "CompositeObject":
+		obj.CompositeGraphicUnit.Alpha = mergeAlpha(obj.CompositeGraphicUnit.Alpha, alpha)
+	}
+	return obj
+}
+
+// drawParamDefaults 合并绘制参数默认样式
+// 入参: id 绘制参数ID, defaults 默认绘制参数
+// 返回: *DrawParam 合并后的绘制参数
+func (r *Renderer) drawParamDefaults(id string, defaults *DrawParam) *DrawParam {
+	if id == "" {
+		return defaults
+	}
+	dp := r.getDrawParam(id, nil)
+	if dp == nil {
+		return defaults
+	}
+	if defaults == nil {
+		return dp
+	}
+	return mergeDrawParam(*defaults, dp)
+}
+
+// mergeDrawParam 合并绘制参数属性
+// 入参: base 基础绘制参数, dp 覆盖绘制参数
+// 返回: *DrawParam 合并后的绘制参数
+func mergeDrawParam(base DrawParam, dp *DrawParam) *DrawParam {
+	if dp.LineWidth > 0 {
+		base.LineWidth = dp.LineWidth
+	}
+	if dp.Join != "" {
+		base.Join = dp.Join
+	}
+	if dp.Cap != "" {
+		base.Cap = dp.Cap
+	}
+	if dp.DashPattern != "" || dp.dashPatternSet {
+		base.DashPattern = dp.DashPattern
+		base.dashPatternSet = dp.dashPatternSet
+	}
+	if dp.DashOffset != nil {
+		base.DashOffset = dp.DashOffset
+	}
+	if dp.MiterLimit > 0 {
+		base.MiterLimit = dp.MiterLimit
+	}
+	if dp.FillColor != nil {
+		base.FillColor = dp.FillColor
+	}
+	if dp.StrokeColor != nil {
+		base.StrokeColor = dp.StrokeColor
+	}
+	if dp.Font != "" {
+		base.Font = dp.Font
+	}
+	if dp.Size > 0 {
+		base.Size = dp.Size
+	}
+	if dp.Weight > 0 {
+		base.Weight = dp.Weight
+	}
+	if dp.Italic {
+		base.Italic = dp.Italic
+	}
+	return &base
+}
+
+// getDrawParam 获取绘制参数逻辑
+// 入参: id 参数ID, visited 访问记录
+// 返回: *DrawParam 绘制参数
+func (r *Renderer) getDrawParam(id string, visited map[string]bool) *DrawParam {
+	if visited == nil {
+		visited = make(map[string]bool)
+	}
+	if visited[id] {
+		return nil
+	}
+	visited[id] = true
+	if dp, ok := r.DrawParams[id]; ok {
+		if dp.Relative != "" {
+			base := r.getDrawParam(dp.Relative, visited)
+			if base == nil {
+				return dp
+			}
+			return mergeDrawParam(*base, dp)
+		}
+		return dp
+	}
+	return nil
+}