A quadtree does the same thing for two-dimensional space. It takes a rectangular region and divides it into four equal quadrants: northwest, northeast, southwest, southeast. If a quadrant has too many points in it, it subdivides again and again. Each subdivision creates smaller and smaller cells where points are densely packed.
增量同步：持续追加实时变更数据
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- Allow user to specify the anchor positions (horizontal and vertical) for the icon relative to the canvas (default: center and center)