2022-07-06 09:16:25 +00:00
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# 1. CanvasItem之draw和update
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2022-07-06 10:02:11 +00:00
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- Canvas是画布的意思，所以CanvasItem代表了就是可以被绘制节点，可以设置可视化界面和材质的颜色
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- 所有的2D节点和GUI节点都继承于CanvasItem节点
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- CanvasItem是按树的树的广度优先遍历顺序绘制的
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- draw指定了要绘制的东西
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- 当要draw绘制的改变了，需要调用update
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- hide和show，隐藏和现实节点
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- CanvasItem可以绘制直线，正方形，长方形，圆，图片
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