We have an application that uses CATiledLayer to render a large and complex vector drawing to the display. The scrolling and zooming peformance is quite good. We are having an issue when the image is zoomed in and the user is editing the vector items. They are able to select an item and modify it by moving the item or adjusting the item control points. We only update the visible area of the screen. Using Instruments. I can tell that our rendering code is properly clipping and in only called when the backing layers are updated. Memory overhead is low and our drawing routine is fast. The issue is in the screen update; we can see tearing as the CATiledLayer updates the tiles.
Does anyone know of a way to synchronize the drawing of all the tiles that are onscreen so they are blitted at the same time? If not, has anyone come up with any techniques to deal with type of issue?
Thanks in advance for any advice or input!