添加背景页面切换缩略图时自动记住已经添加的背景颜色

src/views/tools/add_background/add_background.vue

@@ -669,7 +669,90 @@ const selectHistoryItem = async (index: number) => {
     await cacheResultImage(item.resultImage)
   }
   
-  await initializeCanvas()
+  // Initialize canvas and apply saved background color
+  await initializeCanvasWithBackground(item.backgroundColor)
+}
+
+const initializeCanvasWithBackground = async (bgColor: string) => {
+  if (!canvasRef.value || !uploadedImageUrl.value) {
+    processing.value = false
+    return
+  }
+  
+  try {
+    await nextTick()
+    
+    // Clean up old canvas
+    if (fabricCanvas) {
+      fabricCanvas.dispose()
+      fabricCanvas = null
+    }
+    
+    // Create new fabric canvas
+    fabricCanvas = new Canvas(canvasRef.value, {
+      selection: false
+    })
+    
+    // Load image using fabric v7 API
+    const img = await FabricImage.fromURL(uploadedImageUrl.value, {
+      crossOrigin: 'anonymous'
+    })
+    
+    if (!img || !fabricCanvas) {
+      processing.value = false
+      return
+    }
+    
+    const previewSection = canvasRef.value?.closest('.preview-section') as HTMLElement
+    if (!previewSection) {
+      processing.value = false
+      return
+    }
+    
+    const previewRect = previewSection.getBoundingClientRect()
+    const padding = 100
+    const maxAvailableWidth = Math.max(400, previewRect.width - padding)
+    const maxAvailableHeight = Math.max(400, previewRect.height - 300)
+    
+    const imgWidth = img.width || 1
+    const imgHeight = img.height || 1
+    
+    const scale = Math.min(
+      maxAvailableWidth / imgWidth,
+      maxAvailableHeight / imgHeight,
+      1
+    )
+    
+    img.scale(scale)
+    
+    const canvasWidth = img.getScaledWidth()
+    const canvasHeight = img.getScaledHeight()
+    
+    // Use setDimensions for fabric v7
+    fabricCanvas.setDimensions({ width: canvasWidth, height: canvasHeight })
+    
+    img.set({
+      left: 0,
+      top: 0,
+      selectable: false,
+      evented: false
+    })
+    
+    // Apply saved background color if provided
+    if (bgColor) {
+      fabricCanvas.backgroundColor = bgColor
+    }
+    
+    fabricCanvas.add(img)
+    fabricCanvas.centerObject(img)
+    fabricCanvas.renderAll()
+    
+    processing.value = false
+  } catch (error) {
+    console.error('Canvas initialization error:', error)
+    message.error(t('Failed to load image'))
+    processing.value = false
+  }
 }
 
 const getHistoryThumbnailUrl = (item: HistoryItem): string => {