ArcGIS Engine中最短路径，C封装的，在VB.net中调用.rar-ArcGIS Engine in the shortest path, C package, in VB.net call. Rar

SkPageFlipper manages alternating inval dirty regions for a rectangular area.Sk Page Flipper .

empty this now, so we can correctly record any inval calls that might be made during the draw call. -empty this now, so we can correctly record any inval calls that might be made during the draw call.

compute the inval region now, before we see if there are any pixels.