ncl_rgbhls - Man Page

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

#include <ncarg/ncargC.h>

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

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.

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

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

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

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

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

Hardcopy: NCAR Graphics Fundamentals, UNIX Version

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