From: Operating system: n/a PHP version: 5.3.6 Package: GD related Bug Type: Bug Bug description:imagepolygon, imagefilledpolygon num_points requirement
Description: ------------ The gd extension function imagepolygon() requires at least 3 points. While this restriction is documented for imagefilledpolygon(), it is not documented for imagepolygon(). Since both are implemented with the same function php_imagepolygon() and contain the same check, the documentation for imagepolygon() should be updated to match imagefilledpolygon() in requiring at least 3 points. However, this is not just a documentation problem. The implementation does not actually check for num_points >= 3 as the documentation for imagefilledpolygon says. It checks that the points array size is at least 6 (3 points, 2 values each). So you can plot a 2-point or even 1-point filled or unfilled polygon, if you use an array with 3 or more points in it but specify num_points=2 or 1. This is very strange, not working as documented, and surely not as intended. But there's more. As far as I can tell, libgd (bundled or stand-alone) doesn't actually have a 3-point minimum restriction to gdImagePolygon() or gdImageFilledPolygon(), although it does seem to be documented. See the sample code below, which plots 2-point filled and unfilled polygons by using the above trick. It also works with num_points=1. If true, the PHP check for 3 or more points is not needed at all. Test script: --------------- <?php # Plot illegal 2-point polygon and filled polygon using over-sized array. $g = imagecreate(300, 300); $bgnd = imagecolorallocate($g, 255, 255, 255); $fgnd = imagecolorallocate($g, 0, 0, 0); imagefilledpolygon($g, array(100,10, 100,100, 180,100), 2, $fgnd); imagepolygon($g, array(200,10, 200,100, 280,100), 2, $fgnd); imagepng($g); Expected result: ---------------- An error, since num_points=2 is not valid per documentation of ImageFilledPolygon. Actual result: -------------- A PNG image with 2 lines (2-point polygons). -- Edit bug report at http://bugs.php.net/bug.php?id=55005&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=55005&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=55005&r=trysnapshot53 Try a snapshot (trunk): http://bugs.php.net/fix.php?id=55005&r=trysnapshottrunk Fixed in SVN: http://bugs.php.net/fix.php?id=55005&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=55005&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=55005&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=55005&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=55005&r=needscript Try newer version: http://bugs.php.net/fix.php?id=55005&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=55005&r=support Expected behavior: http://bugs.php.net/fix.php?id=55005&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=55005&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=55005&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=55005&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=55005&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=55005&r=dst IIS Stability: http://bugs.php.net/fix.php?id=55005&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=55005&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=55005&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=55005&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=55005&r=mysqlcfg
