thx@philmoz: you are right, the pictures look very magenta atm, so I thought this must be some kind of alignment issue and your explanation confirmed that. Actually when testing the border problems I was a bit in a hurry, so I did not recognize the strange colors in the pictures, shot a whole evening and wondered later when going through them
Here are the updated border values with the eveness taken into account:
// borders
#define CAM_RAW_MARGIN_LEFT 96
#define CAM_RAW_MARGIN_RIGHT 8
#define CAM_RAW_MARGIN_TOP 18 // 17 --> 18 (even)
#define CAM_RAW_MARGIN_BOTTOM 0
// cropping
#define CAM_JPEG_WIDTH (CAM_RAW_ROWPIX - CAM_RAW_MARGIN_LEFT - CAM_RAW_MARGIN_RIGHT)
#define CAM_JPEG_HEIGHT (CAM_RAW_ROWS - CAM_RAW_MARGIN_TOP - CAM_RAW_MARGIN_BOTTOM)
#define CAM_ACTIVE_AREA_X1 (CAM_RAW_MARGIN_LEFT)
#define CAM_ACTIVE_AREA_Y1 (CAM_RAW_MARGIN_TOP)
#define CAM_ACTIVE_AREA_X2 (CAM_RAW_ROWPIX - CAM_RAW_MARGIN_RIGHT)
#define CAM_ACTIVE_AREA_Y2 (CAM_RAW_ROWS - CAM_RAW_MARGIN_BOTTOM)
I think the 4 extra values (CAM_RAW_MARGIN_X) make it more understandable and less error prone. I compiled the new values and the nafraf code r435 together with the current trunk r2908. Colors look as expected again and borders are cropped.
This version does not show any CHDK touch button in shooting mode with firmware 1.01a. Playback mode works as expected.
