Apple MA434Z/A User Manual - Page 407

Nodes that modify image resolution also take advantage of the Shake Infinite Workspace. For example, if you apply a Crop node to a 20,000 x 20,000-pixel image, Shake calculates only the area of the image specified in the node. This is true even if you employ other nodes prior to the Crop. The Infinite Workspace allows Shake to limit the processing power needed by your script, because only the contents of the Crop window are calculated. This makes Shake ideally suited for high-resolution functions such as scrolling a large background image under lower-resolution foreground elements. When working with the Infinite Workspace, bear in mind the following: • You do not need to crop a small image before it is composited with a larger image when you are panning the image. Simply read in your image, apply the pan, and composite it over or under the larger image. • The Blur node gives you the option to blur pixels outside of the frame using the spread parameter. When set to 0, only pixels inside the frame are considered. When set to 1, outside pixels are calculated into the blur as well. When you read in an image and then blur the image, set the spread to 0. Otherwise, black ringing occurs around the edge because Shake adds the empty black region beyond the image border into its blur calculation. If you read in the image, scale it up, and then blur, you should set spread to 1, since there are now non-black pixels outside of the frame. Clipped Images If an image is clipped, it is usually because a Crop node has been applied, or because you have applied a Blur with a spread set to 0, which is including black outside the image area. Set spread to 1 in the Blur node's parameters. spread = 1 spread = 0 • If you transform an object, apply a color correction, then transform the object back to its original state, the entire image retains the result of the color correction, not just the portion that was in the frame when you applied the color correction. Chapter 15 Image Processing Basics 407