From:             info at silisoftware dot com
Operating system: Windows XP Pro
PHP version:      4.3.5
PHP Bug Type:     GD related
Bug description:  ImageSetThickness + ImageArc = strange results

Description:
------------
Drawing an arc with an image thickness of other than 1 produces very
strange results. The thicker the line specified, the "hairier" it gets. At
5px it's uneven, 25px quite ragged, at 50px and above it gets very
non-round. The best way I can show the problem is with some sample
images:

http://www.silisoftware.com/temp/imagearc/



Not sure if it's a related issue, but I notice if I use the same code to
draw an arc from 1-360 degrees, it looks like a big hairy "+" instead of a
"o", but if I draw from 0-360 degrees it becomes a 1px circle, no matter
what I specify for ImageSetThickness.

Reproduce code:
---------------
$imagethickness = 100;



$gdimg_output = ImageCreateTrueColor(400, 400);

$color_bg = ImageColorAllocate($gdimg_output,   0, 0, 255);

$color_fg = ImageColorAllocate($gdimg_output, 255, 0,   0);

ImageSetThickness($gdimg_output, $imagethickness);

ImageFilledRectangle($gdimg_output, 0, 0, 400, 400, $color_bg);

ImageArc($gdimg_output, 200, 200, 200, 200, 90, 360, $color_fg);

ImagePNG($gdimg_output);



Expected result:
----------------
100px thick, 270-degree red arc on blue background

Actual result:
--------------
This: http://www.silisoftware.com/temp/imagearc/100.png



270-degree red arc on blue background, but thickness varies from 1px to
100px, it looks "hairy", with a tendency to elongate into a "+" rather
than a "o" (more pronounced the thicker the line is set to).

-- 
Edit bug report at http://bugs.php.net/?id=27756&edit=1
-- 
Try a CVS snapshot (php4):  http://bugs.php.net/fix.php?id=27756&r=trysnapshot4
Try a CVS snapshot (php5):  http://bugs.php.net/fix.php?id=27756&r=trysnapshot5
Fixed in CVS:               http://bugs.php.net/fix.php?id=27756&r=fixedcvs
Fixed in release:           http://bugs.php.net/fix.php?id=27756&r=alreadyfixed
Need backtrace:             http://bugs.php.net/fix.php?id=27756&r=needtrace
Need Reproduce Script:      http://bugs.php.net/fix.php?id=27756&r=needscript
Try newer version:          http://bugs.php.net/fix.php?id=27756&r=oldversion
Not developer issue:        http://bugs.php.net/fix.php?id=27756&r=support
Expected behavior:          http://bugs.php.net/fix.php?id=27756&r=notwrong
Not enough info:            http://bugs.php.net/fix.php?id=27756&r=notenoughinfo
Submitted twice:            http://bugs.php.net/fix.php?id=27756&r=submittedtwice
register_globals:           http://bugs.php.net/fix.php?id=27756&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=27756&r=php3
Daylight Savings:           http://bugs.php.net/fix.php?id=27756&r=dst
IIS Stability:              http://bugs.php.net/fix.php?id=27756&r=isapi
Install GNU Sed:            http://bugs.php.net/fix.php?id=27756&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=27756&r=float

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