History of rgb2ycbcr

== Syntax ==

:int rgb2ycbcr(int r, int g, int b, int z)

== Arguments ==

:r

::Red value

:g

::Green value

:b

::Blue value

:z

::Determines which value is returned. z=0 for Y, z=1 for Cb, z=2 for Cr

== Return ==

:Returns the Y, Cb or Cr value from 0 to 255 depending on the value of z

== Description ==

:Lets you convert RGB values to YCbCr values.

== Example ==

<code>

%ffp

ctl(0):"Y (Luminancy)",Range=(-255,255),val=0

ctl(1):"Cb (Chroma Blue)",Range=(-255,255),val=0

ctl(2):"Cr (Chroma Red)",Range=(-255,255),val=0

ForEveryTile:{

int r,g,b,i,cb,cr;

for (y= y_start; y < y_end; y++){

if(updateProgress(y,y_end)) abort();

for (x = x_start; x < x_end; x++){

r = src(x,y,0);

g = src(x,y,1);

b = src(x,y,2);

i = rgb2ycbcr (r,g,b,0);

cb = rgb2ycbcr (r,g,b,1);

cr =rgb2ycbcr (r,g,b,2);

//Do the adjustment

i = i + ctl(0);

cb = cb + ctl(1);

cr = cr + ctl(2);

pset( x, y, 0, ycbcr2rgb (i,cb,cr,0) );

pset( x, y, 1, ycbcr2rgb (i,cb,cr,1) );

pset( x, y, 2, ycbcr2rgb (i,cb,cr,2) );

}}

return true;

</code>

== Also see ==

:ycbcr2rgb

== Comments ==

:Everyone can add his comments about his experiences with this function here. Tips for using it are welcome, too.