QBitmap color inversion

[wysota]

In general we (humans) consider white to be the natural colour of paper and black to be the "ink" (opaque colour). QBitmap stores bits. Value 0 represents "empty" and value 1 represents "opaque". Black corresponds to 0 (#000000), white corresponds to 1 (#FFFFFF) so if the engine receives an "inverted" picture, it inverts it back so that you can see your "white is paper" despite the bit values really used by QBitmap. In other words the conversion tells the bitmap that although it sees black, it should show white and the other way round.