Description:
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the imagearc and imagefilledarc functions don't seem to support images using truecolor and alphablending.
In the following example I don't need alphablending, but I require it to use other images as background.

Reproduce code:
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<?php
//outputs strange image
$img = imagecreatetruecolor(100, 100);

//works fine using palette image instead
//$img = imagecreate(100, 100);

imagesavealpha($img, true);
imagealphablending($img, true);
$transparent = imagecolorallocatealpha($img, 255, 255, 255, 80);

//make the background transparent
imagefill($img, 0, 0, $transparent);

$color = imagecolorallocatealpha($img, 0, 255, 0, 100);
imagefilledarc($img, 49, 49, 100, 100, 0 , 359, $color, IMG_ARC_PIE);
header('content-type: image/png');
imagepng($img);
?>

Expected result:
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Same result as using the paletteimage version.

Actual result:
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Strange looking arcs and filled arcs.