The BGR macro is used to swap red and blue in a color.
COLORREF BGR(COLORREF color);
Needs swap colors in red and blue.
Returns the color after swapping red and blue.
Colors are represented in memory as 0xbbggrr (bb-blue, gg-green, rr-red), but the color in the memory is 0xrrggbb. Note that the red and blue of the two are the opposite. When directly manipulating the memory, the red and blue parts of the color can be exchanged through the BGR macro.