Changes the bit pattern used as the background pattern by the current graphics port.

void BackPat (
    const Pattern *pat
);

Parameter descriptions

pat

A bit pattern, as defined by a Pattern structure.

DISCUSSION

The BackPat function sets the bit pattern defined in the Pattern structure, which you specify in the pat parameter, to be the background pattern. (The standard bit patterns white, black, gray, ltGray, and dkGray are predefined; the initial background pattern for the graphics port is white.) This pattern is stored in the bkPat field of a GrafPort structure.

The BackPat function also sets a bit pattern for the background color in a color graphics port. The BackPat function creates a handle, of type PixPatHandle, for the bit pattern and stores this handle in the bkPixPat field of the CGrafPort structure. As in basic graphics ports, Color QuickDraw draws patterns in color graphics ports at the time of drawing, not at the time you use PenPat to set the pattern.

To define your own patterns, you typically create pattern, ëPAT’, or pattern list, ëPAT#’, resources.

SPECIAL CONSIDERATIONS

The BackPat function may move or purge memory blocks in the application heap; do not call this function at interrupt time.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.1 or later.

© 2000 Apple Computer, Inc. (Last Updated 6/30/2000)