When highlighting, Color QuickDraw replaces the background color with the highlight color when your application draws or copies images between graphics ports. This has the visual effect of using a highlighting pen to select the object. With basic QuickDraw, you can use InvertRect , InvertRgn , InvertArc , InvertRoundRect , or InvertPoly and any image-copying routine that uses the srcXor source mode to invert objects on the screen. In general, however, you should use highlighting with Color QuickDraw when selecting and deselecting objects such as text or graphics.
Inversion reverses the colors of all pixels within the rectangle's boundary.
Although this procedure operates on color pixels in color graphics ports, the results are predictable only with direct pixels or 1-bit pixel maps. Figure 15 Difference between highlighting and inverting The global variable HiliteRGB is read from parameter RAM when the machine starts. Basic graphics ports use the color stored in the HiliteRGB global variable as the highlight color. Color graphics ports default to the HiliteRGB global variable, but you can override this by using the HiliteColor procedure, described on HiliteColor . To turn highlighting on when using Color QuickDraw, you can clear the highlight bit just before calling InvertRect , InvertRgn , InvertArc , InvertRoundRect , InvertPoly , or any drawing or image-copying routine that uses the patXor or srcXor transfer mode.