ncl_rgbyiq - Man Page

CALL RGBYIQ (R, G, B, Y, I, Q)

#include <ncarg/ncargC.h>

void c_rgbyiq (float r, float g, float b, float *y,
float *i, float *q)

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.

Y

(REAL, output, range [0.,1.])  This is the color component of a television signal that is shown on black-and-white televisions; Y minimizes the effect of two colors appearing different to the human eye but mapping to similar monochrome intensities.

I

(REAL, output, range [-.6,.6])  attains its maximum when the input triple is (1.,0.,0.); I attains its minimum when the input triple is (0.,1.,1.).

Q

(REAL, output, range [-.52,.52])  attains its maximum when the input triple is (1.,0.,1.); Q attains its minimum when the input triple is (0.,1.,0.).

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

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

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

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

Hardcopy: NCAR Graphics Fundamentals, UNIX Version

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