PHP: creating a smooth edged circle, image or font?

Question

I'm making a PHP image script that will create circles at a given radius.

I used:

<?php
imagefilledellipse ( $image, $cx, $cy, $w, $h, $color );
?>

but hate the rough edges it produces. So I was thinking of making or using a circle font that I will output using:

<?php
 imagettftext ( $image, $size, $angle, $x, $y, $color, 'fontfile.ttf', $text );
?>

So that the font will produce a circle that has a smooth edge. My problem is making the "font size" match the "radius size".

Any ideas? Or maybe a PHP class that will produce a smooth edge on a circle would be great!

Thank you.

Answer 1

Cairo does antialiasing well.

Answer 2

Clever idea, I like that!

But maybe this PHP class already does the trick: Antialiased filled Arcs/Ellipses for PHP (GD)

In many cases websites need dynamically created images: pie charts, rounded corners, menu buttons, etc. This list is endless. PHP, or more precisely the GD library, provides filled elliptical arcs and ellipses, but they are not antialiased. Therefore I have written a PHP function to render filled antialiased elliptical arcs or filled antialiased ellipses (as well as circles..) with PHP easily. Drawing these filled arcs is now a one-liner.

Answer 3

This article has what you are looking for: http://www.personal.3d-box.com/php/filledellipseaa.php

Alternately, you can make your own by translating Xiaolin Wu's fast AA circle algorithm from C: http://landkey.net/d/L/J/RF/index.php