Writing a paint program à la MS Paint - how to interpolate between mouse move events?

Question

I want to write a paint program in the style of MS Paint.

For painting things on screen when the user moves the mouse, I have to wait for mouse move events and draw

Answer 1

You can make them really smooth using splines: http://freespace.virgin.net/hugo.elias/graphics/x_bezier.htm

But you'll have to delay the drawing of each line segment until one frame later, so that you have the start and end points, plus the next and previous points available for the calculation.