int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };

[simonik]

I have to change it¨to int row_offsets[] = { 0x00, 0x40, 0x10, 0x50 };

[larryfant]

I checked that constructor parameter cols is used for nothing. That should be used to calculate row_offsets instead of hard coded values. I'll check forks first has somebody implemented that already.

[kirk-loeten]

This solution ist flexible:
int row_offsets[] = { 0x00, 0x40, _cols, 0x40 + _cols };