ncl_rgbhls man page

RGBHLS — Converts a color specification given in the Red, Green, Blue (RGB) color space to color values in the Hue, Lightness, Saturation (HLS) color space.

Synopsis

CALL RGBHLS (R, G, B, H, L, S)

C-Binding Synopsis

#include <ncarg/ncargC.h>

void c_rgbhls (float r, float g, float b, float *h,
float *l, float *s)

Description

R
(REAL, input, range [0.,1.]) represents the red intensity component of the input point in RGB color space.
G
(REAL, input, range [0.,1.]) represents the green intensity component of the input point in RGB color space.
B
(REAL, input, range [0.,1.]) represents the blue intensity component of the input point in RGB color space.
H
(REAL, output, range [0.,360.) ) represents the hue of the input point in HLS color space. A value of (0.,0.,B) in the input space will result in a hue of 0. in the output space.
L
(REAL, output, range [0.,100.]) represents the lightness value of the input point in HLS color space. Lightness is a measure of the quantity of light - a lightness of 0. is black, and a lightness of 100. gives white. The pure hues occur at lightness value 50.
S
(REAL, output, range [0.,100.]) represents the saturation value of the input point in HLS color space. Saturation is a measure of how much white light is mixed with the color. Saturation values of 0. represent grays (with a gray value equal to the lightness value L). Saturation values of 100. are fully saturated colors. The hue is undefined when S=0. The fully saturated pure hues occur when S=100. and L=50. The saturation value should be thought of as a percentage.

Examples

Use the ncargex command to see the following relevant examples: tcolcv, fcce02.

C-Binding Description

The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

Access

To use RGBHLS or c_rgbhls, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.

Messages

See the colconv man page for a description of all Colconv error messages and/or informational messages.

See Also

Online: colconv, hlsrgb, hsvrgb, rgbhsv, rgbyiq, yiqrgb, ncarg_cbind.

Hardcopy: NCAR Graphics Fundamentals, UNIX Version

Info

March 1993 UNIX NCAR GRAPHICS