GEOS SDK TechDocs
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6.3 The 16-Bit Limit on Visual Bounds
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6.5 Managing 32-Bit Geometry
In normal-sized visible trees,
MSG_VIS_DRAW
gets sent to all objects in the tree. This draws the entire visible tree, no matter what portions are visible on the screen. For large documents, this can quickly get unwieldy and inefficient.
A better solution is for the layer object of each particular layer to intercept
MSG_VIS_DRAW
and pass it on only to those objects in the affected portion of the document. For this to work, of course, the layer object must know something of the structure and composition of the visible branch below it. This is the primary reason the visible object library does not offer a standard visible layer class--in essence, it must be defined specifically for each application.
GEOS SDK TechDocs
|
| 6.3 The 16-Bit Limit on Visual Bounds
| 6.5 Managing 32-Bit Geometry