rotation/scaling speeds

[m|ke]

[mm40]

Those are some pretty big differences on the scaling which makes me think there is a difference in algorithms used between what you are doing and gapi/edge are doing, are you doing subpixel accuracy?

[m|ke]

[m|ke]

[mm40]

Actually it could depend on the screen rotation of the device, since gapidraw stores their images in screen aligned memory, perhaps the alignment is such that it is missing the cache on every read, where yours is hitting it, just a guess.