Description:
------------
This bug looks fixed in the GD library, but for some reason the GD included in PHP still has this.

What happens is when drawing a line with anti aliasing enabled, the resulting line is 1 pixel shorter than it should be.

Fix (using snapshot: php5.2-200708270430.tar.gz):
--- gd.c       2007-08-26 23:44:04.000000000 -0500
+++ gd.c        2007-08-26 23:44:28.000000000 -0500
@@ -1351,7 +1351,7 @@
                x = x1 << 16;
                y = y1 << 16;
                inc = (dy * 65536) / dx;
-               while ((x >> 16) < x2) {
+               while ((x >> 16) <= x2) {
                        gdImageSetAAPixelColor(im, x >> 16, y >> 16, col, (y >> 8) & 0xFF);
                        if ((y >> 16) + 1 < im->sy) {
                                gdImageSetAAPixelColor(im, x >> 16, (y >> 16) + 1,col, (~y >> 8) & 0xFF);
@@ -1373,7 +1373,7 @@
                x = x1 << 16;
                y = y1 << 16;
                inc = (dx * 65536) / dy;
-               while ((y>>16) < y2) {
+               while ((y>>16) <= y2) {
                        gdImageSetAAPixelColor(im, x >> 16, y >> 16, col, (x >> 8) & 0xFF);
                        if ((x >> 16) + 1 < im->sx) {
                                gdImageSetAAPixelColor(im, (x >> 16) + 1, (y >> 16),col, (~x >> 8) & 0xFF);


Reproduce code:
---------------
<?php
$im=imagecreatetruecolor(30,30);

$c1=ImageColorAllocate($im,255,255,255);
$c2=ImageColorAllocate($im,  0,  0,  0);
imagefill( $im,0,0, $c1 );

imageline($im,5,5, 25,5, $c2);
imageantialias($im,true);
imageline($im,5,25, 25,25, $c2);

header("Content-type: image/png");
imagepng($im);
imagedestroy($im);

?>


Expected result:
----------------
Two lines of equal length

Actual result:
--------------
Top line is longer than bottom line by 1 pixel.