feat(editor): 添加撤销重做功能

实现完整的撤销重做功能，包括：
1. 添加工具栏撤销/重做按钮及快捷键支持
2. 实现状态保存与恢复机制
3. 添加状态变化检测与历史记录管理
4. 更新相关UI交互以触发状态保存

js/script.js

@@ -60,6 +60,15 @@
     let maxOffsetX = 0;
     let isInteractingWithBgImage = false;
 
+    // 撤销重做相关变量
+    const undoStack = [];
+    const redoStack = [];
+    const MAX_HISTORY = 50;
+    let isUndoing = false;
+    let saveStateTimer = null;
+    let lastSavedState = null;
+    const SAVE_DELAY = 300; // 防抖延迟 300ms
+
     // 初始化
     init();
 
@@ -100,6 +109,23 @@
         // 保存按钮
         saveBtn.addEventListener('click', saveImage);
 
+        // 撤销重做按钮
+        const undoBtn = document.getElementById('undoBtn');
+        const redoBtn = document.getElementById('redoBtn');
+        
+        undoBtn.addEventListener('click', (e) => {
+            e.preventDefault();
+            e.stopPropagation();
+            undo();
+        });
+        redoBtn.addEventListener('click', (e) => {
+            e.preventDefault();
+            e.stopPropagation();
+            redo();
+        });
+        
+        updateUndoRedoButtons();
+
         // 初始化输入框
         initInput(input1);
         initInput(input2);
@@ -127,6 +153,9 @@
                 opacityValue.textContent = e.target.value + '%';
             }
         });
+        opacitySlider.addEventListener('change', () => {
+            saveState();
+        });
 
         // 旋转滑块
         rotateSlider.addEventListener('input', (e) => {
@@ -150,6 +179,9 @@
                 rotateValue.textContent = rotateDeg + '°';
             }
         });
+        rotateSlider.addEventListener('change', () => {
+            saveState();
+        });
 
         // 水平镜像按钮
         mirrorHBtn.addEventListener('click', () => {
@@ -171,6 +203,9 @@
                     }
                     
                     img.style.transform = newTransform;
+                    
+                    // 保存状态
+                    saveState();
                 }
             }
         });
@@ -181,6 +216,9 @@
             bgScaleValue.textContent = e.target.value + '%';
             updateBgImage();
         });
+        bgScaleSlider.addEventListener('change', () => {
+            saveState();
+        });
 
         // 背景图透明度滑块
         bgOpacitySlider.addEventListener('input', (e) => {
@@ -188,6 +226,9 @@
             bgOpacityValue.textContent = e.target.value + '%';
             bgImage.style.opacity = bgImageOpacity;
         });
+        bgOpacitySlider.addEventListener('change', () => {
+            saveState();
+        });
 
         // 点击空白区域取消选中
         document.addEventListener('click', (e) => {
@@ -273,9 +314,301 @@
         // 加载默认背景图
         loadDefaultBackground();
 
+        // 保存初始状态
+        setTimeout(() => {
+            saveState();
+        }, 500);
 
     }
 
+    // ==================== 撤销重做功能 ====================
+
+    // 保存当前状态（带防抖）
+    function saveState(immediate = false) {
+        if (isUndoing) return;
+
+        // 清除之前的定时器
+        if (saveStateTimer) {
+            clearTimeout(saveStateTimer);
+            saveStateTimer = null;
+        }
+
+        const doSave = () => {
+            const state = captureState();
+            
+            // 如果新状态与上一个状态相同，不保存
+            if (lastSavedState && statesEqual(state, lastSavedState)) {
+                return;
+            }
+            
+            undoStack.push(state);
+            lastSavedState = JSON.parse(JSON.stringify(state));
+            
+            // 限制历史记录数量
+            if (undoStack.length > MAX_HISTORY) {
+                undoStack.shift();
+            }
+            
+            // 清空重做栈
+            redoStack.length = 0;
+            
+            updateUndoRedoButtons();
+        };
+
+        if (immediate) {
+            doSave();
+        } else {
+            saveStateTimer = setTimeout(doSave, SAVE_DELAY);
+        }
+    }
+
+    // 捕获当前状态
+    function captureState() {
+        return {
+            // 背景图状态
+            bgImageSrc: bgImage.src,
+            bgImageScale: bgImageScale,
+            bgImageOpacity: bgImageOpacity,
+            imageOffsetX: imageOffsetX,
+            
+            // 层叠图状态
+            overlays: Array.from(overlayLayer.querySelectorAll('.overlay-image')).map(el => {
+                const img = el.querySelector('img');
+                return {
+                    src: img ? img.src : '',
+                    left: el.style.left,
+                    top: el.style.top,
+                    width: el.style.width,
+                    height: el.style.height,
+                    opacity: el.style.opacity,
+                    transform: el.style.transform,
+                    imgTransform: img ? img.style.transform : ''
+                };
+            }),
+            
+            // 文本输入框状态
+            textInputs: Array.from(document.querySelectorAll('.preview-input-layer .text-input')).map(el => ({
+                id: el.id,
+                content: el.innerText.replace('×', '').trim(),
+                left: el.style.left,
+                top: el.style.top,
+                color: el.style.color,
+                fontFamily: el.style.fontFamily,
+                fontSize: el.style.fontSize,
+                fontWeight: el.style.fontWeight,
+                fontStyle: el.style.fontStyle,
+                isLocked: el.dataset.locked === 'true'
+            }))
+        };
+    }
+
+    // 比较两个状态是否相同
+    function statesEqual(state1, state2) {
+        return JSON.stringify(state1) === JSON.stringify(state2);
+    }
+
+    // 撤销
+    function undo() {
+        if (undoStack.length <= 1) return;
+        
+        isUndoing = true;
+        
+        // 将当前状态移到重做栈
+        const currentState = undoStack.pop();
+        redoStack.push(currentState);
+        
+        // 恢复上一个状态
+        const prevState = undoStack[undoStack.length - 1];
+        restoreState(prevState);
+        
+        updateUndoRedoButtons();
+        
+        isUndoing = false;
+    }
+
+    // 重做
+    function redo() {
+        if (redoStack.length === 0) return;
+        
+        isUndoing = true;
+        
+        // 从重做栈恢复状态
+        const state = redoStack.pop();
+        undoStack.push(state);
+        
+        restoreState(state);
+        
+        updateUndoRedoButtons();
+        
+        isUndoing = false;
+    }
+
+    // 恢复状态
+    function restoreState(state) {
+        // 恢复背景图
+        if (state.bgImageSrc) {
+            if (state.bgImageSrc !== bgImage.src) {
+                // 创建新图片对象确保加载完成
+                const img = new Image();
+                img.onload = () => {
+                    currentImage = img;
+                    bgImage.src = state.bgImageSrc;
+                    bgImageScale = state.bgImageScale;
+                    bgImageOpacity = state.bgImageOpacity;
+                    imageOffsetX = state.imageOffsetX;
+                    
+                    bgScaleSlider.value = Math.round(bgImageScale * 100);
+                    bgScaleValue.textContent = Math.round(bgImageScale * 100) + '%';
+                    bgOpacitySlider.value = Math.round(bgImageOpacity * 100);
+                    bgOpacityValue.textContent = Math.round(bgImageOpacity * 100) + '%';
+                    
+                    updateBgImage();
+                    
+                    // 更新UI状态
+                    imageContainer.classList.remove('empty');
+                    emptyTip.classList.add('hidden');
+                };
+                img.src = state.bgImageSrc;
+            } else {
+                // 相同的图片，直接更新参数
+                bgImageScale = state.bgImageScale;
+                bgImageOpacity = state.bgImageOpacity;
+                imageOffsetX = state.imageOffsetX;
+                
+                bgScaleSlider.value = Math.round(bgImageScale * 100);
+                bgScaleValue.textContent = Math.round(bgImageScale * 100) + '%';
+                bgOpacitySlider.value = Math.round(bgImageOpacity * 100);
+                bgOpacityValue.textContent = Math.round(bgImageOpacity * 100) + '%';
+                
+                updateBgImage();
+            }
+        } else {
+            // 没有背景图，清空
+            bgImage.src = '';
+            currentImage = null;
+            imageContainer.classList.add('empty');
+            emptyTip.classList.remove('hidden');
+        }
+        
+        // 恢复层叠图
+        overlayLayer.innerHTML = '';
+        state.overlays.forEach(overlayData => {
+            const div = document.createElement('div');
+            div.className = 'overlay-image';
+            div.style.left = overlayData.left;
+            div.style.top = overlayData.top;
+            div.style.width = overlayData.width;
+            div.style.height = overlayData.height;
+            div.style.opacity = overlayData.opacity;
+            div.style.transform = overlayData.transform;
+            
+            const img = document.createElement('img');
+            img.src = overlayData.src;
+            img.style.transform = overlayData.imgTransform;
+            img.draggable = false;
+            
+            div.appendChild(img);
+            overlayLayer.appendChild(div);
+            
+            // 重新初始化拖拽
+            initOverlayDrag(div);
+        });
+        
+        // 恢复文本输入框
+        const inputLayer = document.getElementById('previewInputLayer');
+        
+        // 先隐藏所有预设输入框
+        [input1, input2, input3].forEach(inputEl => {
+            if (inputEl) {
+                inputEl.classList.add('hidden');
+            }
+        });
+        
+        // 清除动态添加的输入框（保留预设的三个）
+        const allInputs = inputLayer.querySelectorAll('.text-input');
+        allInputs.forEach(input => {
+            if (input.id !== 'input1' && input.id !== 'input2' && input.id !== 'input3') {
+                input.remove();
+            }
+        });
+        
+        state.textInputs.forEach(inputData => {
+            let input = document.getElementById(inputData.id);
+            if (!input) {
+                // 创建新的输入框
+                input = document.createElement('div');
+                input.id = inputData.id;
+                input.className = 'text-input';
+                input.contentEditable = false;
+                input.dataset.placeholder = '请输入';
+                inputLayer.appendChild(input);
+                initInput(input);
+            }
+            
+            // 显示输入框
+            input.classList.remove('hidden');
+            
+            // 清除现有内容（保留删除按钮）
+            const deleteBtn = input.querySelector('.text-delete-btn');
+            input.innerHTML = '';
+            
+            // 设置文本内容
+            input.appendChild(document.createTextNode(inputData.content));
+            
+            // 重新添加删除按钮
+            if (deleteBtn) {
+                input.appendChild(deleteBtn);
+            } else {
+                const newDeleteBtn = document.createElement('button');
+                newDeleteBtn.className = 'text-delete-btn';
+                newDeleteBtn.innerHTML = '×';
+                newDeleteBtn.addEventListener('click', (e) => {
+                    e.stopPropagation();
+                    input.remove();
+                    saveState();
+                });
+                input.appendChild(newDeleteBtn);
+            }
+            
+            // 应用样式
+            input.style.left = inputData.left;
+            input.style.top = inputData.top;
+            input.style.color = inputData.color || '#000000';
+            input.style.fontFamily = inputData.fontFamily || '';
+            input.style.fontSize = inputData.fontSize || '';
+            input.style.fontWeight = inputData.fontWeight || 'bold';
+            input.style.fontStyle = inputData.fontStyle || 'normal';
+            input.dataset.locked = inputData.isLocked ? 'true' : '';
+            
+            // 更新锁定样式
+            if (inputData.isLocked) {
+                input.classList.add('locked');
+            } else {
+                input.classList.remove('locked');
+            }
+            
+            // 检查是否需要显示 placeholder
+            if (!inputData.content.trim()) {
+                input.classList.add('show-placeholder');
+            } else {
+                input.classList.remove('show-placeholder');
+            }
+        });
+    }
+
+    // 更新撤销重做按钮状态
+    function updateUndoRedoButtons() {
+        const undoBtn = document.getElementById('undoBtn');
+        const redoBtn = document.getElementById('redoBtn');
+        
+        if (undoBtn) {
+            undoBtn.disabled = undoStack.length <= 1;
+        }
+        if (redoBtn) {
+            redoBtn.disabled = redoStack.length === 0;
+        }
+    }
+
     // 加载默认背景图
     function loadDefaultBackground() {
         const defaultBgUrl = './images/default-bg.jpg';
@@ -334,6 +667,9 @@
                 
                 // 显示预设的文本输入框
                 showPresetTextInputs();
+                
+                // 保存状态（立即）
+                saveState(true);
             };
             img.src = e.target.result;
         };
@@ -381,6 +717,9 @@
         initInput(textEl);
 
         selectInput(textEl);
+        
+        // 保存状态（立即）
+        saveState(true);
     }
 
     // 加载层叠图
@@ -436,6 +775,8 @@
         deleteBtn.addEventListener('click', (e) => {
             e.stopPropagation();
             overlayEl.remove();
+            // 保存状态（立即）
+            saveState(true);
         });
         overlayEl.appendChild(deleteBtn);
 
@@ -452,6 +793,9 @@
 
         // 选中新添加的层叠图
         selectOverlay(overlayEl);
+        
+        // 保存状态（立即）
+        saveState(true);
     }
 
     // 初始化层叠图交互
@@ -534,6 +878,9 @@
             document.removeEventListener('mouseup', handleDragEnd);
             document.removeEventListener('touchmove', handleDragMove);
             document.removeEventListener('touchend', handleDragEnd);
+            
+            // 保存状态
+            saveState();
         }
 
         // 缩放控制（四角）
@@ -633,6 +980,9 @@
                 document.removeEventListener('mouseup', endResize);
                 document.removeEventListener('touchmove', handleResize);
                 document.removeEventListener('touchend', endResize);
+                
+                // 保存状态
+                saveState();
             }
         });
     }
@@ -935,6 +1285,10 @@
         }
 
         function handleImageEnd() {
+            if (isDraggingImage) {
+                // 保存状态
+                saveState();
+            }
             isDraggingImage = false;
             isInteractingWithBgImage = false;
         }
@@ -1098,6 +1452,9 @@
                 isDragging = false;
                 element.classList.remove('dragging');
                 hideGuides();
+                
+                // 保存状态
+                saveState();
             }
 
             // 阻止事件冒泡
@@ -1240,6 +1597,9 @@
         editingInput = null;
         // 隐藏编辑器工具栏
         editorToolbar.classList.remove('active');
+        
+        // 保存状态
+        saveState();
     }
 
     // 更新工具栏状态
@@ -1735,6 +2095,7 @@
                 }
                 boldBtn.classList.toggle('active');
             }
+            saveState();
         });
 
         // 斜体按钮
@@ -1753,6 +2114,7 @@
                 }
                 italicBtn.classList.toggle('active');
             }
+            saveState();
         });
 
         // 锁定按钮
@@ -1767,6 +2129,7 @@
                 targetInput.classList.add('locked');
             }
             lockBtn.classList.toggle('active', !isLocked);
+            saveState();
         });
 
         // 颜色选择器
@@ -1780,12 +2143,16 @@
                 targetInput.style.color = colorPicker.value;
             }
         });
+        colorPicker.addEventListener('change', () => {
+            saveState();
+        });
 
         // 字体选择器
         fontPicker.addEventListener('change', () => {
             const targetInput = editingInput || selectedInput;
             if (!targetInput) return;
             targetInput.style.fontFamily = fontPicker.value;
+            saveState();
         });
 
         // 字号选择器 - 密码锁式滚轮
@@ -1814,6 +2181,7 @@
             if (targetInput) {
                 const currentSize = parseInt(window.getComputedStyle(targetInput).fontSize) || fontSizeValue;
                 updateFontSize(currentSize + 1, true);
+                saveState();
             }
         });
 
@@ -1822,6 +2190,7 @@
             if (targetInput) {
                 const currentSize = parseInt(window.getComputedStyle(targetInput).fontSize) || fontSizeValue;
                 updateFontSize(currentSize - 1, true);
+                saveState();
             }
         });
 
@@ -1832,6 +2201,7 @@
                 const currentSize = parseInt(window.getComputedStyle(targetInput).fontSize) || fontSizeValue;
                 const delta = e.deltaY > 0 ? -1 : 1;
                 updateFontSize(currentSize + delta, true);
+                saveState();
             }
         }, { passive: false });
     }
@@ -1839,6 +2209,23 @@
     // 初始化键盘微调功能（方向键 1px 移动）
     function initKeyboardNudge() {
         document.addEventListener('keydown', (e) => {
+            // 撤销重做快捷键
+            if ((e.ctrlKey || e.metaKey) && e.key === 'z') {
+                e.preventDefault();
+                if (e.shiftKey) {
+                    redo();
+                } else {
+                    undo();
+                }
+                return;
+            }
+            
+            if ((e.ctrlKey || e.metaKey) && e.key === 'y') {
+                e.preventDefault();
+                redo();
+                return;
+            }
+            
             // 如果正在编辑文本，不处理方向键
             if (editingInput) return;