How to convert CMYK to RGB programmatically.

Question

Hi,
I have a CMYK colorspace in indesign, i want to convert that as RGB color space, I got some codes, but I am getting incorrect data.
Some of the codes which I tried are given below
        double cyan = 35.0;
        double magenta = 29.0;
        double yellow = 0.0;
        double black = 16.0;
        cyan = Math.min(255, cyan + black); //black is from K
        magenta = Math.min(255, magenta + black);
        yellow = Math.min(255, yellow + black);
        l_res[0] = 255 - cyan;
        l_res[1] = 255 - magenta;
        l_res[2] = 255 - yellow;
@Override
    public float[] toRGB(float[] p_colorvalue) {
        float[] l_res = {0,0,0};
        if (p_colorvalue.length >= 4)
            float l_black = (float)1.0 - p_colorvalue[3];
            l_res[0] = l_black * ((float)1.0 - p_colorvalue[0]);
            l_res[1] = l_black * ((float)1.0 - p_colorvalue[1]);
            l_res[2] = l_black * ((float)1.0 - p_colorvalue[2]);
        return (l_res);
The values are C=35, M = 29, Y = 0, K = 16 in CMYK color space and the correct RGB values are R = 142, G = 148, B = 186.
In adobe indesign, using swatches we can change the mode to CMYK or to RGB.
But I want to do that programmatically, Can I get any algorithm to convert CMYK to RGB which will give the correct RGB values.
And one more question, if the alpha value for RGB is 1 then what will be the alpha value for CMYK?
Can anyone help me to solve these issues... Thanks in advance.

Answer 1

All you have to do is loop thru the swatches and change the space to RGB. Below is an AppleScript, but it shouldn't be too difficult to come up with the equivalent JavaScript. Your document's assigned RGB space will determine what RGB space the CMYK converts to, so if you are looking for sRGB, then Edit>Assign Profiles...>Assign Profile: sRGB
tell application "Adobe InDesign CS3"
tell document 1
repeat with a from 1 to count of every swatch
try
set space of color a to RGB
end try
end repeat
display dialog "All swatches have been converted to RGB color"
end tell
end tell