Raster-operation codes define how the graphics device interface (GDI) combines the bits from the selected pen with the bits in the destination bitmap.
This overview lists and describes the binary and ternary raster operations used by GDI. A binary raster operation involves two operands: a pen and a destination bitmap. A ternary raster operation involves three operands: a source bitmap, a brush, and a destination bitmap. Both binary and ternary raster operations use Boolean operators.