Determines how the bit values for the source pixels are combined with the bit values for destination pixels to produce the final result. The sixteen values here correspond to the 16 different possible 2x2 truth tables. Only a couple of these values are usually useful; for colored images, only GDK_COPY, GDK_XOR and GDK_INVERT are generally useful. For bitmaps, GDK_AND and GDK_OR are also useful.
Value | Symbolic name | Description |
| 0 | Gdk::COPY | |
| 1 | Gdk::INVERT | |
| 2 | Gdk::XOR | |
| 3 | Gdk::CLEAR | |
| 4 | Gdk::AND | |
| 5 | Gdk::AND_REVERSE | |
| 6 | Gdk::AND_INVERT | |
| 7 | Gdk::NOOP | |
| 8 | Gdk::OR | |
| 9 | Gdk::EQUIV | |
| 10 | Gdk::OR_REVERSE | |
| 11 | Gdk::COPY_INVERT | |
| 12 | Gdk::OR_INVERT | |
| 13 | Gdk::NAND | |
| 14 | Gdk::NOR | |
| 15 | Gdk::SET |