Skip to content

Instantly share code, notes, and snippets.

@rambuvn
Created July 23, 2012 10:00
Show Gist options
  • Save rambuvn/3162918 to your computer and use it in GitHub Desktop.
Save rambuvn/3162918 to your computer and use it in GitHub Desktop.
Grayscale effect for html5 but still not check cross browsers
// On window load. This waits until images have loaded which is essential
jQuery(window).load(function(){
// Fade in images so there isn't a color "pop" document load and then on window load
jQuery(".wedding-page .album-cover img").fadeIn(500);
// clone image
jQuery('.wedding-page .album-cover img').each(function(){
var el = jQuery(this);
el.css({"position":"absolute"}).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({"position":"absolute","z-index":"998","opacity":"0"}).insertBefore(el).queue(function(){
var el = jQuery(this);
el.parent().css({"width":this.width,"height":this.height});
el.dequeue();
});
this.src = grayscale(this.src);
});
// Fade image
jQuery('.wedding-page .album-cover img').mouseover(function(){
jQuery(this).parent().find('img:first').stop().animate({opacity:1}, 1000);
})
jQuery('.img_grayscale').mouseout(function(){
jQuery(this).stop().animate({opacity:0}, 500);
});
});
// Grayscale w canvas method
function grayscale(src){
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
var imgObj = new Image();
imgObj.src = src;
canvas.width = imgObj.width;
canvas.height = imgObj.height;
ctx.drawImage(imgObj, 0, 0);
var imgPixels = ctx.getImageData(0, 0, canvas.width, canvas.height);
for(var y = 0; y < imgPixels.height; y++){
for(var x = 0; x < imgPixels.width; x++){
var i = (y * 4) * imgPixels.width + x * 4;
var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
imgPixels.data[i] = avg;
imgPixels.data[i + 1] = avg;
imgPixels.data[i + 2] = avg;
}
}
ctx.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
return canvas.toDataURL();
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment