I have some code which is drawing a buffered image to the screen to allow smooth scrolling around a large map. This method uses fillRect to clear part of the image in the backbuffer whilst motion occurs, before overwriting that chunk with level graphics. This all works fine under emulation and some handsets but goes wrong on an early 7650, with the graphics not being cleared (seemingly by fillRect) before being overwritten. The backbuffer is larger than the screen (about 280*250) and I was wondering if anybody knew about any bugs regarding filllRect and offscreen, out of bounds drawing, are there any limitations to it or reported firmware problems.
Are you doing any clipping back there, or getting the size of the rect dynamically? There is a bug with the getHeight() method in FullCanvas (and it cascades into the Graphics.getClipHeight() of the Graphics object you get in paint()), where it returns 144 instead of 208 (like it was a normal Canvas). This often causes for stuff not appearing in the bottom of the screen.