image_color_conversion.c

spiht的压缩解压缩c编写的

#include "spiht.h"
#include "spihtdecode.h"

void QccIMGImageRGBtoYUV(double *y, double *u, double *v,
                         int r, int g, int b)
{
  *y =  0.3*r + 0.59*g + 0.11*b;
  *u =  0.7*r - 0.59*g - 0.11*b;
  *v = -0.3*r - 0.59*g + 0.89*b;
}

void QccIMGImageYUVtoRGB(int *r, int *g, int *b,
                         double y, double u, double v)
{
  /*  Plus 0.5 to round to nearest int  */
  *r = QccIMGClipPixelValue(y + u) + 0.5;
  *g = QccIMGClipPixelValue((0.59*y - 0.3*u - 0.11*v)/0.59) + 0.5;
  *b = QccIMGClipPixelValue(y + v) + 0.5;
}