How to draw a color wheel in objective-c

Question

I am trying to draw a color wheel for an iPhone, but I can\'t get the gradient to rotate around a point. I am trying to use gradients but objective-c provides a linear grad

Answer 1

I did something like this by creating a large RGBA bitmap, coloring each pixel depending on its location converted to polar coordinates, then converting the bitmap to an image and drawing the image scaled down. The scaling down was to help antialias pixelation near the center.