HTML5 Canvas image contrast

Question

I\'ve been writing an image processing program which applies effects through HTML5 canvas pixel processing. I\'ve achieved Thresholding, Vintaging, and ColorGradient pixel m

Answer 1

This javascript implementation complies with the SVG/CSS3 definition of "contrast" (and the following code will render your canvas image identically):

/*contrast filter function*/
//See definition at https://drafts.fxtf.org/filters/#contrastEquivalent
//pixels come from your getImageData() function call on your canvas image
contrast = function(pixels, value){
    var d = pixels.data;
    var intercept = 255*(-value/2 + 0.5);
    for(var i=0;i 255) d[i] = 255;
        if(d[i+1] > 255) d[i+1] = 255;
        if(d[i+2] > 255) d[i+2] = 255;
        if(d[i] < 0) d[i] = 0;
        if(d[i+1] < 0) d[i+1] = 0;
        if(d[i+2] < 0) d[i+2] = 0;
    }
    return pixels;
}