colorutil.js

colorize: function(options) {
        var canvas = document.createElement('canvas');
        canvas.width = options.image.width;
        canvas.height = options.image.height;
        var context = canvas.getContext('2d');
        context.drawImage(options.image, 0, 0, options.image.width, options.image.height,
            0, 0, options.image.width, options.image.height);
        context.globalCompositeOperation = 'color';
        var colorCanvas = document.createElement('canvas');
        colorCanvas.width = options.image.width;
        colorCanvas.height = options.image.height;
        var colorContext = colorCanvas.getContext('2d');
        colorContext.fillStyle = options.color;
        colorContext.globalAlpha = options.alpha;
        colorContext.fillRect(0, 0, options.image.width, options.image.height);
        if(options.regions) { // Paint custom regions if specified
            for(var i = 0; i < options.regions.length; i++) {
                var reg = options.regions[i];
                colorContext.clearRect(reg.x, reg.y, reg.w, reg.h);
                colorContext.fillStyle = reg.color ? reg.color : options.color;
                colorContext.globalAlpha = reg.alpha ? reg.alpha : options.alpha;
                colorContext.fillRect(reg.x, reg.y, reg.w, reg.h);
            }
        }
        context.drawImage(colorCanvas,0,0);
        applyAlpha(options.image, canvas); // Restore original alpha channel
        return canvas;
    }