I have a problem on N82 with LCD screen refresh rate (also checked on 5500, and almost same situation occurs). In my app I'm moving a bitmap from left to right with speed 30fps (one frame 33 ms, but I also tried slower). To visualize my problem I created small bitmaps similar to that I'm using in my app:
On this image I'm moving small bitmap with background color TRgb( 128, 64, 0 ); and line color TRgb( 128, 0, 0 ); 3 times by 1 pixel in left direction. To move bitmap I'm using double buffering with offscreen bitmap and Direct Screen Access API and the same problem is when using anti tearing API (Direct Screen Bitmap).
On first column I created bitmaps that reflects what I'm seeing on phone screen and on the second column how this should look like.
FRAME 1 is a steady state
FRAME 2 is bitmap moved left by 1 pixel
FRAME 3 is bitmap moved left by 1 pixel
FRAME 4 is bitmap moved left by 1 pixel
FRAME 5,6,7 is a steady state
On screen we can see some kind of streak or trace left by previous frame.
I think differences between screen and memory is caused by low refresh rate of LCD. Using other colors for background and lines reduces this effect, but not solve problem.
Is there any algorithm or method to avoid this situation?