.Net and GDI+ how-to draw an inner bevel on rounded rectangle

There are two things to take into account when drawing bevels:

1. the "lighting effect" behaves one way on the upper left half of the object, and the other way on the lower right half (brightening the UL, darkening the LR).

2. you need multiple, nested, similar paths, that are inset from each other by a single pixel all around (because, typically, bevels are drawn 2 pixels wide).

To address #1 you need to (a) figure out your darker and lighter colors, and (b) split the graphics path in to a pair of UL & LR parts. You will also need (for #2) the exact pixel height and width of the path.

To address #2, you need to use GDI+'s transform to scale the path by exactly 2 pixels in height and width, and to offset the scaled path by exactly 1 pixel - so that the new path fits exactly inside the original.

Now you have four "half paths", with a pair that fits inside the other pair, that you can render light/normal/dark/super-dark. I would use Windows' magnifier to see the color arrangement of beveled controls to get an idea of what colors to use where.

You're probably going to have to tweak your paths so that they join correctly at the 'cut' ends between the UL and LR parts; given that you have rounded corners, you may also find that you need to do something extra at the cut corners to make an acceptable gradient from light to dark (with square cornered boxes this is never an issue). You may may need to make special corner segments to handle this.