Legacy Document

Inside Macintosh: Imaging With QuickDraw /

Chapter 3 - QuickDraw Drawing / QuickDraw Drawing Reference

Routines / Drawing With the Eight-Color System

BackColor

To change a basic graphics port's background color, use the BackColor procedure.

PROCEDURE BackColor (color: LongInt); 

color

One of eight color values. You can use the constants described for the ForeColor procedure in the previous section.

DESCRIPTION

The BackColor procedure sets the background color for the current graphics port to the color that you specify in the color parameter. When you draw with the patCopy and srcCopy transfer modes, for example, white pixels are drawn in the color you specify with BackColor.

SPECIAL CONSIDERATIONS

The BackColor procedure may move or purge memory blocks in the application heap. Your application should not call this procedure at interrupt time.

SEE ALSO

All nonwhite colors appear as black on black-and-white screens. Before you use BackColor, you can use the DeviceLoop procedure, which is described in the chapter "Graphics Devices," to determine the color characteristics of the current screen.

In System 7, you may instead use the Color QuickDraw procedure RGBBackColor, which is described in the chapter "Color QuickDraw."