feat: 接入新动作 update_canvas

app/actions/update_canvas.py

@@ -0,0 +1,30 @@
+"""在大屏副本上更新画布属性，检查修改后的 Canvas 是否有效"""
+
+from copy import deepcopy
+
+from app.actions.base import BaseActionHandler
+from app.schemas.actions import UpdateCanvasAction
+from app.schemas.screen import Canvas, Screen
+
+
+class UpdateCanvasHandler(BaseActionHandler[UpdateCanvasAction]):
+    def apply(self, screen: Screen, action: UpdateCanvasAction) -> Screen:
+        properties = screen.canvas.model_dump()
+        # 顶层字段整体替换，嵌套对象不做深度合并
+        properties.update(deepcopy(action.properties))
+        canvas = Canvas.model_validate(properties)
+        result = screen.model_copy(deep=True)
+        result.canvas = canvas
+        return result
+
+
+if __name__ == "__main__":
+    screen = Screen.model_validate(
+        {"canvas": {"width": 1920, "height": 1080}, "nodes": []}
+    )
+    action = UpdateCanvasAction(
+        properties={"backgroundColor": "#000000", "width": 1600}
+    )
+    result = UpdateCanvasHandler().apply(screen, action)
+    print(result.model_dump_json(indent=2))
+    print("原始画布:", screen.canvas.model_dump())