## Presentation Device Driver Reference for OS/2

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### GreDrawBits Parameter - lRop

lRop (LONG) - input Raster operation code.

The low-order byte represents a mix value in the range, hex 00 - hex FF. Raster operation code values and the mix-bit table are defined in the Presentation Manager Programming Reference. The handling routine uses lRop to determine the operations to perform on pattern, source, and target to get the required mix.

In addition to the raster operation values defined at the API, the presentation driver must support ROP_GRAY (hex 000080CA). This value is used to shade the text for menu items that are not currently selectable. When ROP_GRAY is set, the handling routine overpaints the foreground pattern using the current pattern and the background pattern color ( background pels for the pattern are not changed). For the PATSYM_HALFTONE pattern, this overpaints the background pattern color onto alternate pels, leaving those in between unchanged.