feat(后端架构): 完善后端解耦

ofdgo_geom_path.go

@@ -14,6 +14,11 @@
 
 package ofdgo
 
+import (
+	"fmt"
+	"strings"
+)
+
 // GeometryPath 保存独立于绘图库的几何路径，不扁平化曲线或舍入坐标
 // 坐标以左上角为原点，单位为毫米，子路径从Move开始，Close回到当前子路径起点
 type GeometryPath []GeometrySegment
@@ -40,3 +45,69 @@ type GeometrySegment struct {
 	Rotation           float64
 	Large, Sweep       bool
 }
+
+// SVG 将几何路径编码为SVG路径，不改变曲线或坐标精度
+// 返回: string SVG路径, error 不支持的路径指令
+func (p GeometryPath) SVG() (string, error) {
+	return p.encode(true)
+}
+
+// OFD 将几何路径编码为OFD紧缩路径
+// 返回: string 紧缩路径, error 不支持的路径指令
+func (p GeometryPath) OFD() (string, error) {
+	return p.encode(false)
+}
+
+// encode 按目标格式写入路径，圆弧标志采用两种格式均支持的0和1
+// 入参: svg 是否使用SVG指令
+// 返回: string 路径数据, error 不支持的路径指令
+func (p GeometryPath) encode(svg bool) (string, error) {
+	var value strings.Builder
+	for _, segment := range p {
+		x, y := ofdNumber(segment.End.X), ofdNumber(segment.End.Y)
+		switch segment.Verb {
+		case GeometryMove:
+			fmt.Fprintf(&value, "M %s %s ", x, y)
+		case GeometryLine:
+			fmt.Fprintf(&value, "L %s %s ", x, y)
+		case GeometryQuad:
+			fmt.Fprintf(&value, "Q %s %s %s %s ", ofdNumber(segment.Control1.X), ofdNumber(segment.Control1.Y), x, y)
+		case GeometryCubic:
+			command := "B"
+			if svg {
+				command = "C"
+			}
+			fmt.Fprintf(&value, "%s %s %s %s %s %s %s ", command, ofdNumber(segment.Control1.X), ofdNumber(segment.Control1.Y), ofdNumber(segment.Control2.X), ofdNumber(segment.Control2.Y), x, y)
+		case GeometryArc:
+			large, sweep := 0, 0
+			if segment.Large {
+				large = 1
+			}
+			if segment.Sweep {
+				sweep = 1
+			}
+			fmt.Fprintf(&value, "A %s %s %s %d %d %s %s ", ofdNumber(segment.RadiusX), ofdNumber(segment.RadiusY), ofdNumber(segment.Rotation), large, sweep, x, y)
+		case GeometryClose:
+			if svg {
+				value.WriteString("Z ")
+			} else {
+				value.WriteString("C ")
+			}
+		default:
+			return "", fmt.Errorf("unsupported geometry command %d", segment.Verb)
+		}
+	}
+	return strings.TrimSpace(value.String()), nil
+}
+
+// geometryClipPath 将页面路径转换为标准填充裁剪对象
+// 入参: path 页面毫米路径
+// 返回: PathObject 裁剪路径, error 无效指令错误
+func geometryClipPath(path GeometryPath) (PathObject, error) {
+	data, err := path.OFD()
+	if err != nil {
+		return PathObject{}, err
+	}
+	fill, stroke := true, false
+	return PathObject{Boundary: "0 0 1 1", Fill: &fill, Stroke: &stroke, AbbreviatedData: data}, nil
+}