Apple MA434Z/A User Manual - Page 766

Inverting Transformations The Move2D and CornerPin nodes have an inverseTransform parameter. This aptly named parameter inverts the effect of the transformation, numerically. For example, a pan of 100 with inverseTransform activated becomes a pan of -100. The parameters themselves are not changed, just their effects on the composition. In the case of Move2D, you can use inverseTransform to turn imported tracking data into stabilization data. In the case of CornerPin, you can set the four corners to map to four arbitrary points. The classic example of this is to pin an image onto the front of a television screen. Using the inverseTransform parameter, you could extract the original image that appears angled on the television screen, and remap it into a flat image. This technique is helpful for generating texture maps from photos for 3D renders. Onscreen Controls Most of the transform nodes have onscreen controls that let you interactively manipulate your images directly in the Viewer. These controls appear whenever that node's parameters are loaded. Note: Many of these controls are also shared by other nodes with similar functionality. If an image moves offscreen-that is, beyond the boundaries of the Viewer-its transform controls remain visible in the Viewer area. When an image undergoes an extreme transformation and moves "offscreen," the best way to locate it is to zoom out in the Viewer until you see its transform controls. 766 Chapter 26 Transformations, Motion Blur, and AutoAlign