Courteous Colors

Courteous colors may seem so polite as to be useless, but they can serve as

convenient placeholders. If your application uses a small number of colors,

you can place them in a palette, ordered according to your preference and

designated as courteous.

Suppose you have an open window named myColorWindow that has a palette

resource consisting of a set of eight colors: white, black, red, orange, yellow,

green, blue, and violet, in that order, each with a usage category specified as

courteous, as shown in the Figure below.

A courteous palette

The following example paints the rectangle myRect in yellow (palette entry

4, where white is 0).

SetPort (myColorWindow);

PaintRect (&myRect);

This is exactly analogous to the following sequence of Color QuickDraw

routines, where yellowRGB is of type ColorSpec:

yellowRGB.red = 0xFFFF;

yellowRGB.green = 0xFFFF;

yellowRGB.blue = 0x0000;

SetPort (myColorWindow);

RGBForeColor (&yellowRGB);

PaintRect (&myRect);

Colors with specified usage categories that cannot be satisfied by the

Palette Manager default to courteous colors. This occurs, for example,

when drawing to a direct device or one with a fixed CLUT.