Cross Domain Canvas Images
You can do some really awesome stuff with images when you push their data into canvas. And of course, when you're done playing around with the image, you can export the canvas data to an IMG element and data URI. What we sometimes don't remember, however, is that the cross-origin rules apply to those images, so if you try to convert an image from another host to canvas, you'll get an error. You can use this snippet from HTML5 Boilerplate within the image host domain's .htaccess file to allow cross-origin data reading of images:
<IfModule mod_setenvif.c>
<IfModule mod_headers.c>
<FilesMatch "\.(cur|gif|ico|jpe?g|png|svgz?|webp)$">
SetEnvIf Origin ":" IS_CORS
Header set Access-Control-Allow-Origin "*" env=IS_CORS
</FilesMatch>
</IfModule>
</IfModule>
Allowing for CORS within .htaccess then allows you to pull image data when the image is on another domain. This is especially useful on CDNs! .htaccess is a life-saver sometimes!
![Creating Scrolling Parallax Effects with CSS]()
Introduction
For quite a long time now websites with the so called "parallax" effect have been really popular.
In case you have not heard of this effect, it basically includes different layers of images that are moving in different directions or with different speed. This leads to a...
![7 Essential JavaScript Functions]()
I remember the early days of JavaScript where you needed a simple function for just about everything because the browser vendors implemented features differently, and not just edge features, basic features, like addEventListener and attachEvent. Times have changed but there are still a few functions each developer should...
![9 More Mind-Blowing WebGL Demos]()
With Firefox OS, asm.js, and the push for browser performance improvements, canvas and WebGL technologies are opening a world of possibilities. I featured 9 Mind-Blowing Canvas Demos and then took it up a level with 9 Mind-Blowing WebGL Demos, but I want to outdo...
![Vertically Centering with Flexbox]()
Vertically centering sibling child contents is a task we've long needed on the web but has always seemed way more difficult than it should be. We initially used tables to accomplish the task, then moved on to CSS and JavaScript tricks because table layout was horribly...
I’m finding that I get CORS errors when I request from my own site and then convert them to base64 images using the “canvas technique” referred to here. Is that expected?