Previously I mentioned a tutorial on how to make smooth lines using Cocos2D inspired by the iPad Paper app.
Heres tutorial on capturing, and drawing smooth lines and curves from Jason Harwig using UIKit and OpenGL ES.
The tutorial goes through the process of capturing the signature accurately using UIPanGestureRecognizer, drawing quadratic bezier curves between the points to smooth out the signature, and varying width using velocity and tessellation for the Paper app style widening effect.
Here’s an image showing a smoothed signature created using the code:
You can find the tutorial over on the Near Infinity blog here.
The example source code demonstrating the techniques in action can be found on Github here.
A great example on how to create a smoothed out signature.