Classes Class XbpPresSpace() :maxColorIndex()

Method XbpPresSpace():maxColorIndex() Foundation

Returns the number of colors that can be simultaneously defined in the color palette.

Syntax 
:maxColorIndex( [<lCompatible>] ) --> nMaxColors
Parameters
<lCompatible>
The parameter controls the behavior of this method. It defaults to .T. (true) which yields a return value compatible with earlier Xbase++ versions. If it is set to .F. (false), the return value depends on the color depth supported by the device context.
Return

This method returns a numeric value indicating the maximum number of colors that can be simultaneously defined in a presentation space's color palette. This value depends on the device context linked to the presentation space (it is device dependent).

When the device context supports a 16-bit or higher color depth and .F. (false) is passed for <lCompatible>, the return value is 0. If .T. (true) is passed, a numeric value greater than zero is returned regardless of the color depth.

Description

The :maxColorIndex() method is used to determine the maximum value that can be specified for the method :setColorIndex(). This value depends on the hardware (graphics card or printer) and is 255 when the device context supports 8-bit colors. This means that a maximum of 256 colors can be defined and used at the same time (values for :maxColorIndex() begin with 0).

Today's graphics cards generally support 24-bit colors, or true colors, which means that colors can be defined without a color palette. In this case, colors are defined using RGB-values (see GraMakeRGBColor() ). To test whether or not colors can be defined as RGB values, the method is used as follows: 

IF oPS:maxColorIndex( .F. ) == 0 
   <code using RGB color values> 
ELSE 
   <code using color indexes> 
ENDIF

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