fast algorithm for drawing filled circles?

c algorithm graphics geometry
horseyguy picture horseyguy · Jul 29, 2009 · Viewed 79.3k times · Source

I am using Bresenham's circle algorithm for fast circle drawing. However, I also want to (at the request of the user) draw a filled circle.

Is there a fast and efficient way of doing this? Something along the same lines of Bresenham?

The language I am using is C.

Answer

AakashM picture AakashM · Jul 29, 2009

Having read the Wikipedia page on Bresenham's (also 'Midpoint') circle algorithm, it would appear that the easiest thing to do would be to modify its actions, such that instead of 

setPixel(x0 + x, y0 + y);
setPixel(x0 - x, y0 + y);

and similar, each time you instead do

lineFrom(x0 - x, y0 + y, x0 + x, y0 + y);

That is, for each pair of points (with the same y) that Bresenham would you have you plot, you instead connect with a line.

Related questions

Cheap way of calculating cubic bezier length

An analytical solution for cubic bezier length seems not to exist, but it does not mean that coding a cheap solution does not exist. By cheap I mean something like in the range of 50-100 ns (or less). Does someone …

Read More
Source code for Xiaolin Wu's line algorithm in C?

I'm looking for a nice and efficient implementation of Xiaolin Wu's anti-aliased line drawing algorithm in C, does anyone have this code they could share with me? Thanks

Read More
Printing prime numbers from 1 through 100

This c++ code prints out the following prime numbers: 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97. But I don't think that's the way my book wants it to be written. It mentions something about square root of a number. So I did try changing my 2nd loop …

Read More