The problem is draw arc with two pints on 开发者_如何学Pythonbitmap with radius and clockwise direction.
From your one-sentence question, I'm gonna assume you're ok with drawing Bezier curves. If not, there is plenty of information about them out there.
Anyway, you cannot create a perfect circular arc with Bezier curves (or splines). What you can do is approximating a circle to a level where the eye won't be able to see the difference. This is usually done with 8 quadratic Bezier curve segments, each covering 1/8th of the circle. This is i.e. how Adobe Flash creates circles.
If you're after a plain parametrization using sin and cos, it's way easier:
for (float t = 0; t < 2 * Math.PI; t+=0.05) {
float x = radius * sin(t);
float y = radius * cos(t);
}
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