I'm interested in what happens when you "Free Transform" an image in photoshop. It allows you to skew the image into a perspective, resize, rotate, and so on. How does the programming behind that work?
For a less technical description: The pixel values in the transformed image are generated as a function of the pixel values in the input image. Once you have the transformation function figured out, the rest is basic algebra.
If you want to get an idea of what these functions look like, flip to the "Examples in 2D graphics" section in the above Wikipedia link. There's examples there for rotation, resizing, shearing, and others.
For a less technical description: The pixel values in the transformed image are generated as a function of the pixel values in the input image. Once you have the transformation function figured out, the rest is basic algebra.
If you want to get an idea of what these functions look like, flip to the "Examples in 2D graphics" section in the above Wikipedia link. There's examples there for rotation, resizing, shearing, and others.