how to pinch, swirl, stretch, uiimage using coregraphics?

Answer 1

CoreGraphics doesn't pinch or swirl. The most you can do in CoreGraphics is scale horizontally and vertically.

CoreImage on the Mac can handle these effects but CoreImage is not available on the iPhone.

To create effects like the one shown, you would need to get the raw pixel data (use CGImageGetDecode on the CGImage) and apply the effect manually.

More likely, this app applies the image to an OpenGL surface and distorts the surface.

Neither approach would be easy and I have no further information on how you'd do it.