COLOR_CONVERT Procedure

Converts colors to and from the RGB color system, and either the HLS or HSV systems.

COLOR_CONVERT, i₀, i₁, i₂, o₀, o₁, o₂, keyword

i₀, i₁, i₂ The input color triple(s). May be either scalars or arrays of the same length.

o₀, o₁, o₂ The variables to receive the result. Their structure is copied from the input parameters.

One of the following keywords is required:

CMY_RGB Convert from CMY (cyan, magenta, yellow) to RGB (red, green, blue).

HLS_RGB Convert from HLS (hue, lightness, saturation) to RGB .

HSV_RGB Convert from HSV (hue, saturation, value) to RGB.

RGB_CMY Convert from RGB to CMY.

RGB_HLS Convert from RGB to HLS.

RGB_HSV Convert from RGB to HSV.

RGB and CMY values are bytes in the range of 0 to 255.

Hue is a floating-point number measured in degrees, from 0.0 to 360.0; a hue of 0.0 degrees is the color red, green is 120.0 degrees, and blue is 240.0 degrees.

Saturation, lightness, and value are floating-point numbers in the range of 0.0 to 1.0.

Note that when RGB values are the same during an RGB to HSV conversion, the saturation is set to 0.0 and the hue is undefined.

COLOR_CONVERT, 255, 255, 0, h, s, v, /RGB_HSV

; Converts the RGB color triple (0,255,255), which is the color
; yellow at full intensity and saturation, to the HSV system. 

PRINT, h, s, v

60.00000       1.00000       1.00000

; The resulting hue in the variable h is 60 degrees. The saturation
; and value (s and v) are set to 1.0.

COLOR_EDIT, HLS, HSV, HSV_TO_RGB, LOADCT,MODIFYCT, PALETTE, PSEUDO, RGB_TO_HSV, STRETCH, TVLCT, WgCeditTool

For more background information about color systems, see the PV-WAVE User's Guide.

For a discussion of the various color systems, see Computer Graphics: Principles and Practice, by Foley, Van Dam, Feiner, and Hughes, Second Edition, Addison Wesley Publishing Company, Reading, MA, 1990, pp. 585-596.