November 2011
Intermediate to advanced
348 pages
7h 2m
English
Content preview from HTML5 Canvas Cookbook
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Getting image data
Now that we know how to draw images and videos, let's try accessing the image data to see what kind of properties we can play with.
Note
WARNING: This recipe must run on a web server due to security constraints with the getImageData() method.
Getting ready...
Before we get started working with image data, it's important that we cover canvas security and the RGBA color space.
So why is canvas security important with respect to accessing image data? Simply put, in order to access image data, we need to use the getImateData() method of the canvas context which will throw a SECURITY_ERR exception if we try accessing image data from an ...
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