This is an example script I wrote for myself to help me learn how to used the imagearc functions. Maybe if will also help others.
<?php
$image_width=360;$image_height=360;
$img = imagecreatetruecolor($image_width,$image_height); $color = imagecolorallocate($img,255,255,255);
imagefilledrectangle($img,0,0,$image_width,$image_height,$color);
$r=$image_width/2 - $image_width/32 ; $cx=$image_width/2;
$cy=$image_height/2;
$color = imagecolorallocate($img,0,0,0);
imagearc($img, $cx, $cy, $r*2, $r*2, 0, 360, $color); imagefilledarc($img, $cx, $cy, $r*1, $r*1, 0, 90, $color,IMG_ARC_CHORD); imagefilledarc($img, $cx, $cy, $r*1, $r*1, 180, 270, $color,IMG_ARC_PIE); $font_number=5; $string="Hello world!";
imagestring($img, $font_number, $cx-(imagefontwidth($font_number)*strlen($string))/2, $cy-120, $string, $color);
header("Content-type: image/png");
imagepng($img);$filename="imagearc";
imagepng($img,"./frames/$filename.png",9); imagedestroy($img);
?>