Color Key Format

[C++]

A color key is described in a DDCOLORKEY structure. If the color key is a single color, both members of this structure should be assigned the same value. Otherwise the color key is a range of colors.

Color keys are specified using the pixel format of a surface. If a surface is in a palettized format, the color key is given as an index or a range of indices. If the surface is in a non-palattized display mode, the color keys are specified in the raw pixel format. For instance, to set a bright purple color key in 16-bit 5:6:5 mode, you would use a value of 0xf81F (All 5 red bits are set, and all 5 blue bits are set).

Some examples of valid color keys follow:

8-bit palettized mode

// Palette entry 26 is the color key. 
dwColorSpaceLowValue = 26; 
dwColorSpaceHighValue = 26;

16-bit color mode

// Color is bright purple
dwColorSpaceLowValue = 0xf81F; 
dwColorSpaceHighValue = 0xf81F;

Support for a range of colors rather than a single color is hardware-dependent. Check the dwCKeyCaps member of the DDCAPS structure for the hardware. The HEL does not support color ranges.

[Visual Basic]

A color key is described in a DDCOLORKEY type. If the color key is a single color, both members of this structure should be assigned the same value. Otherwise the color key is a range of colors.

Some examples of valid color keys follow:

8-bit palettized mode

// Palette entry 26 is the color key. 
low = 26 
high = 26

24-bit true-color mode

// Color red in hex is the color key. 
low = &H000000FF 
high = &H000000FF

Support for a range of colors rather than a single color is hardware-dependent. Check the lCKeyCaps member of the DDCAPS type for the hardware. The HEL does not support color ranges.