mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 15:06:46 +08:00
215 lines
7.1 KiB
Go
215 lines
7.1 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ofdgo
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import (
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"maps"
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"slices"
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)
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// editorChange 页面或对象操作及其修订标识
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type editorChange struct {
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undo func(*Editor)
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redo func(*Editor)
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before uint64
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after uint64
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}
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// Transaction 将多项修改作为一次原子操作提交，失败时保留原文档及历史
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// 回调仅操作传入的编辑器，不可保留该实例供后续使用
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// 入参: edit 批量修改回调
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// 返回: error 修改错误
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func (e *Editor) Transaction(edit func(*Editor) error) error {
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before := *e
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before.Info = cloneEditorData(e.Info)
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next := e.transactionSnapshot()
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next.history, next.historyIndex, next.historyLimit = nil, 0, 0
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*e = next
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if err := edit(e); err != nil {
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*e = before
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return err
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}
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changed := e.revision != before.revision
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e.history, e.historyIndex, e.historyLimit = before.history, before.historyIndex, before.historyLimit
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e.backends, e.fontDirs, e.fontFS = before.backends, before.fontDirs, before.fontFS
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e.fontRenderer, e.fontMetrics = before.fontRenderer, before.fontMetrics
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if changed {
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e.serial, e.revision = before.serial, before.revision
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if change := e.recordChange(); change != nil {
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after := e.transactionSnapshot()
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before.history, after.history = nil, nil
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change.undo = func(e *Editor) { e.restoreTransaction(before) }
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change.redo = func(e *Editor) { e.restoreTransaction(after) }
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}
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}
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return nil
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}
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// SetHistoryLimit 设置撤销和重做记录的总上限，默认关闭，非正数关闭并释放记录
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// 缩减上限时优先保留最近的撤销记录，不影响当前文档及修订标识
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// 记录页面、对象及SetInfo操作，不包含Info的直接修改及字体、图片注册，资源继续共享
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// 入参: limit 最大记录数
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func (e *Editor) SetHistoryLimit(limit int) {
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e.historyLimit = max(0, limit)
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if e.historyLimit == 0 {
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e.history = nil
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e.historyIndex = 0
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return
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}
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if len(e.history) > e.historyLimit {
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start := max(0, e.historyIndex-e.historyLimit)
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end := min(len(e.history), start+e.historyLimit)
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e.history = slices.Clone(e.history[start:end])
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e.historyIndex -= start
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}
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}
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// CanUndo 判断是否有可撤销的操作
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// 返回: bool 是否可以撤销
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func (e *Editor) CanUndo() bool {
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return e.historyIndex > 0
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}
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// CanRedo 判断是否有可重做的操作
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// 返回: bool 是否可以重做
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func (e *Editor) CanRedo() bool {
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return e.historyIndex < len(e.history)
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}
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// Undo 撤销最近一次操作，保留资源和已分配的标识
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// 返回: bool 是否执行了撤销
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func (e *Editor) Undo() bool {
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if !e.CanUndo() {
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return false
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}
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e.historyIndex--
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change := e.history[e.historyIndex]
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change.undo(e)
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e.revision = change.before
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return true
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}
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// Redo 重做最近一次撤销的操作，新的有效修改会清除重做记录
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// 返回: bool 是否执行了重做
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func (e *Editor) Redo() bool {
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if !e.CanRedo() {
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return false
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}
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change := e.history[e.historyIndex]
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change.redo(e)
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e.historyIndex++
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e.revision = change.after
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return true
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}
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// Revision 获取当前修订标识，撤销或重做时恢复对应标识
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// Info的直接修改和资源注册不计入修订，标识仅在当前Editor实例内有效
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// 返回: uint64 修订标识
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func (e *Editor) Revision() uint64 {
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return e.revision
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}
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// transactionSnapshot 复制可变容器，保留只读XML、图元及二进制资源的共享
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// 返回: Editor 独立事务状态
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func (e *Editor) transactionSnapshot() Editor {
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next := *e
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next.Info = cloneEditorData(e.Info)
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next.pages = make([]PageContent, len(e.pages))
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for i, page := range e.pages {
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next.pages[i] = copyEditorPage(page)
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}
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next.resources = slices.Clone(e.resources)
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next.fonts, next.images, next.resourceID = maps.Clone(e.fonts), maps.Clone(e.images), maps.Clone(e.resourceID)
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next.origins = maps.Clone(e.origins)
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next.removedPages = maps.Clone(e.removedPages)
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next.fontMetrics = maps.Clone(e.fontMetrics)
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if e.source != nil {
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source := *e.source
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source.pages, source.origins = maps.Clone(source.pages), maps.Clone(source.origins)
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next.source = &source
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}
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return next
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}
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// restoreTransaction 恢复文档状态并保留历史容器、共享资源和递增标识
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// 入参: state 文档状态
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func (e *Editor) restoreTransaction(state Editor) {
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state = state.transactionSnapshot()
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if len(e.resources) > len(state.resources) {
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state.resources = append(state.resources, e.resources[len(state.resources):]...)
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}
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maps.Copy(state.fonts, e.fonts)
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maps.Copy(state.images, e.images)
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maps.Copy(state.resourceID, e.resourceID)
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state.history, state.historyIndex, state.historyLimit = e.history, e.historyIndex, e.historyLimit
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state.serial, state.maxID = max(e.serial, state.serial), max(e.maxID, state.maxID)
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state.backends, state.fontDirs, state.fontFS = e.backends, e.fontDirs, e.fontFS
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state.fontRenderer, state.fontMetrics = e.fontRenderer, e.fontMetrics
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*e = state
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}
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// recordChange 分配修订标识并为已完成的有效修改预留记录
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// 返回: *editorChange 记录，未启用历史时为nil
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func (e *Editor) recordChange() *editorChange {
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e.serial++
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change := editorChange{before: e.revision, after: e.serial}
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e.revision = e.serial
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if e.historyLimit == 0 {
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return nil
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}
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clear(e.history[e.historyIndex:])
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e.history = e.history[:e.historyIndex]
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if len(e.history) == e.historyLimit {
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copy(e.history, e.history[1:])
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e.history = e.history[:len(e.history)-1]
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}
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e.history = append(e.history, change)
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e.historyIndex = len(e.history)
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return &e.history[e.historyIndex-1]
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}
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// recordPageAddition 记录新增或复制的页面
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// 入参: index 页面索引
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func (e *Editor) recordPageAddition(index int) {
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if change := e.recordChange(); change != nil {
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page := copyEditorPage(e.pages[index])
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change.undo = func(e *Editor) { e.pages = slices.Delete(e.pages, index, index+1) }
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change.redo = func(e *Editor) { e.pages = slices.Insert(e.pages, index, copyEditorPage(page)) }
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}
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}
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// copyEditorPage 复制页面容器，共享经校验且按替换方式更新的对象数据
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// 入参: page 页面
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// 返回: PageContent 独立页面容器
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func copyEditorPage(page PageContent) PageContent {
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page.Content.Layer = slices.Clone(page.Content.Layer)
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for i := range page.Content.Layer {
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page.Content.Layer[i].Objects = slices.Clone(page.Content.Layer[i].Objects)
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}
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return page
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}
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// moveEditorItem 按目标索引移动页面或对象
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// 入参: items 页面或对象序列, from 原索引, to 目标索引
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func moveEditorItem[T any](items []T, from, to int) {
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item := items[from]
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if from < to {
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copy(items[from:to], items[from+1:to+1])
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} else {
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copy(items[to+1:from+1], items[to:from])
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}
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items[to] = item
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}
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