An improved setPixel function for drawing on a canvas (allows color to be specified using HTML hex codes)

Improved setPixel

Object.prototype.setPixel = function(point, rgba) {
    if(!this.hasOwnProperty('data')) {
        throw'This method only works with ImageData objects created with createImageData';
    }
    var imageData = this;
    
    if(typeof rgba == 'string') {
        var useDefault = true; //If anything is wrong with the hex code, fall back to a default color
        var matches;
        
        //We were passed a string so let's see if it's a valid hex code
        if(rgba.length == 7) {
            //Full length hex code (eg #AABBCC)
            matches = rgba.toLowerCase().match(/#([abcdef0-9]{2})([abcdef0-9]{2})([abcdef0-9]{2})/);
        }else if(rgba.length == 4) {
            //Short hex code (eg #ABC)
            matches = [
                '',
                rgba[1]+rgba[1],
                rgba[2]+rgba[2],
                rgba[3]+rgba[3]
                ];
        }
                
        if(matches.length == 4) {
            rgba = [];
            for(var i=1;i<=3;i++) {
                rgba.push(parseInt(matches[i],16));
            }
            rgba.push(255); //Add the alpha
            useDefault = false;
        }
        
        if(useDefault) {
            rgba = [255,255,255,255];              
        }
    }
    
    if(rgba.length <= 3 ) { rgba.push(255); } //Add alpha if not provided
    i = (point.x + point.y * imageData.width) * 4;
    
    console.log('Drawing at ' + point.x + ',' + point.y);
    
    imageData.data[i  ] = rgba[0]; //r
    imageData.data[i+1] = rgba[1]; //g
    imageData.data[i+2] = rgba[2]; //b
    imageData.data[i+3] = rgba[3]; //a
};