feat(图像渲染): 强化图像渲染

ofdgo_renderer.go

@@ -554,6 +554,9 @@ func (r *Renderer) renderPath(ctx *canvas.Context, obj PathObject, pageH float64
 		}
 	}
 	p := r.buildPath(obj, pageH, ctm)
+	if rectPath := r.buildTinyFillRectPath(obj, pageH, ctm, bx, by); rectPath != nil {
+		p = rectPath
+	}
 	shouldFill := true
 	if obj.Fill != nil {
 		shouldFill = *obj.Fill
@@ -1155,6 +1158,49 @@ func (r *Renderer) buildPath(obj PathObject, pageH float64, ctm Matrix) *canvas.
 	return p
 }
 
+// buildTinyFillRectPath 构建微小填充矩形路径
+// 入参: obj 路径对象, pageH 页面高度, ctm 变换矩阵, bx 边界X坐标, by 边界Y坐标
+// 返回: *canvas.Path 路径对象
+func (r *Renderer) buildTinyFillRectPath(obj PathObject, pageH float64, ctm Matrix, bx, by float64) *canvas.Path {
+	if obj.Fill == nil || !*obj.Fill || obj.Stroke == nil || *obj.Stroke {
+		return nil
+	}
+	box, err := ParseBox(obj.Boundary)
+	if err != nil || box.W <= 0 || box.H <= 0 || box.W > 0.6 || box.H > 0.6 {
+		return nil
+	}
+	tokens := strings.Fields(obj.AbbreviatedData)
+	if len(tokens) != 11 || tokens[0] != "M" || tokens[3] != "L" || tokens[6] != "L" || tokens[9] != "L" || tokens[10] != "C" {
+		return nil
+	}
+	points := make([][2]float64, 0, 4)
+	for i := 1; i < 10; i += 3 {
+		x, errX := strconv.ParseFloat(tokens[i], 64)
+		y, errY := strconv.ParseFloat(tokens[i+1], 64)
+		if errX != nil || errY != nil {
+			return nil
+		}
+		tx, ty := ctm.Transform(x, y)
+		points = append(points, [2]float64{tx + bx, pageH - (ty + by)})
+	}
+	minX, maxX := points[0][0], points[0][0]
+	minY, maxY := points[0][1], points[0][1]
+	for _, point := range points[1:] {
+		minX = math.Min(minX, point[0])
+		maxX = math.Max(maxX, point[0])
+		minY = math.Min(minY, point[1])
+		maxY = math.Max(maxY, point[1])
+	}
+	expand := math.Min(box.W, box.H) * 0.08
+	p := &canvas.Path{}
+	p.MoveTo(minX-expand, minY-expand)
+	p.LineTo(maxX+expand, minY-expand)
+	p.LineTo(maxX+expand, maxY+expand)
+	p.LineTo(minX-expand, maxY+expand)
+	p.Close()
+	return p
+}
+
 // parseIndexRunes 解析索引字形
 // 入参: indexStr 索引字符串, fontID 字体ID
 // 返回: []rune 字形列表