feat(编辑能力): 完善复合对象编辑，修复撤销后的粘贴路径和裁剪状态

ofdgo_editor_composite_image.go

@@ -0,0 +1,107 @@
+// 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
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+)
+
+// matrix 获取对象局部坐标到页面的变换，兼容旧式内联边界
+// 入参: transform 是否包含对象CTM
+// 返回: Matrix 坐标变换
+func (n *editorCompositeNode) matrix(transform bool) Matrix {
+	boundary, ctm := editorGeometry(n.object)
+	box, _ := ParseBox(boundary)
+	m := IdentityMatrix
+	if transform {
+		m = NewMatrix(ctm)
+		if n.object.Type == "ImageObject" && ctm == "" {
+			m = Matrix{a: box.W, d: box.H}
+		}
+	}
+	if n.boundaryInCTM {
+		return n.parent.Multiply(TranslationMatrix(box.X, box.Y)).Multiply(m)
+	}
+	if !transform {
+		return TranslationMatrix(box.X, box.Y)
+	}
+	return TranslationMatrix(box.X, box.Y).Multiply(n.parent).Multiply(m)
+}
+
+// CropCompositeImage 将内部图片与页面矩形取交集，保留原裁剪、蒙版、变换和边框
+// 只收窄可见区域，撤销恢复上次裁剪，不重采样图片
+// 入参: page 页面索引, path 父复合路径, index 图片序号, box 页面毫米范围
+// 返回: error 错误信息
+func (e *Editor) CropCompositeImage(page int, path ObjectPath, index int, box Box) error {
+	if _, err := creationBox(editorBoxString(box)); err != nil {
+		return err
+	}
+	return e.editCompositeObjects(page, path, []int{index}, func(_ *Renderer, nodes []*editorCompositeNode, members []CompositeMember) error {
+		node, member := nodes[0], members[0]
+		if !member.Capabilities.CropImage {
+			return fmt.Errorf("composite image cannot be cropped")
+		}
+		before := member.Bounds
+		if box.X <= before.X && box.Y <= before.Y && box.X+box.W >= before.X+before.W && box.Y+box.H >= before.Y+before.H {
+			return nil
+		}
+		if box.X+box.W <= before.X || box.Y+box.H <= before.Y || box.X >= before.X+before.W || box.Y >= before.Y+before.H {
+			return fmt.Errorf("crop does not intersect the image")
+		}
+		clips := node.object.ImageObject.Clips
+		inverse, _ := node.matrix(clips == nil || clips.TransFlag == nil || *clips.TransFlag).Invert()
+		shape, err := NewShape(ShapeRectangle, box)
+		if err != nil {
+			return err
+		}
+		fill, stroke := true, false
+		shape.Fill, shape.Stroke = &fill, &stroke
+		data, err := encodeOFDXML(func(x *ofdXML) {
+			x.clips(&Clips{Clip: []Clip{{Area: []ClipArea{{CTM: inverse.String(), Path: []PathObject{shape}}}}}})
+		})
+		if err != nil {
+			return err
+		}
+		data = bytes.TrimPrefix(data, []byte(xml.Header))
+		root, err := parseEditorXML(data)
+		if err != nil {
+			return err
+		}
+		var patch editorXMLPatch
+		if original := node.node.child("Clips"); original != nil {
+			clip, err := editorXMLStandalone(data[root.children[0].start:root.children[0].end], root.children[0])
+			if err != nil {
+				return err
+			}
+			content := append(bytes.Clone(node.data[original.open:original.close]), clip...)
+			patch = editorXMLContent(node.data, original, content)
+		} else {
+			data, err = editorXMLStandalone(data, root)
+			if err != nil {
+				return err
+			}
+			content := append(data, node.data[node.node.open:node.node.close]...)
+			patch = editorXMLContent(node.data, node.node, content)
+		}
+		updated, err := newEditorCompositeNode(editorPatchXML(node.data, []editorXMLPatch{patch}))
+		if err != nil {
+			return err
+		}
+		node.data, node.node, node.object, node.changed = updated.data, updated.node, updated.object, true
+		return nil
+	})
+}