Fixed bug #61221 - imagegammacorrect function loses alpha channel

cmb69 · cmb69 · commit 7469c7e7d0ce · 2015-06-17T02:15:59.000+02:00
When applying imagegammacorrect() the alpha channel is now fully retained, instead of being completely lost.
diff --git a/ext/gd/gd.c b/ext/gd/gd.c
@@ -3045,10 +3045,11 @@ PHP_FUNCTION(imagegammacorrect)
 			for (x = 0; x < gdImageSX(im); x++)	{
 				c = gdImageGetPixel(im, x, y);
 				gdImageSetPixel(im, x, y,
-					gdTrueColor(
+					gdTrueColorAlpha(
 						(int) ((pow((pow((gdTrueColorGetRed(c)   / 255.0), input)), 1.0 / output) * 255) + .5),
 						(int) ((pow((pow((gdTrueColorGetGreen(c) / 255.0), input)), 1.0 / output) * 255) + .5),
-						(int) ((pow((pow((gdTrueColorGetBlue(c)  / 255.0), input)), 1.0 / output) * 255) + .5)
+						(int) ((pow((pow((gdTrueColorGetBlue(c)  / 255.0), input)), 1.0 / output) * 255) + .5),
+						gdTrueColorGetAlpha(c)
 					)
 				);
 			}
diff --git a/ext/gd/tests/bug61221.phpt b/ext/gd/tests/bug61221.phpt
@@ -0,0 +1,23 @@
+--TEST--
+Bug #61221 - imagegammacorrect function loses alpha channel
+--SKIPIF--
+<?php
+if (!extension_loaded('gd')) die('skip gd extension not available');
+?>
+--FILE--
+<?php
+$imagew = 50;
+$imageh = 50;
+$img = imagecreatetruecolor($imagew, $imageh);
+$blacktransparent = imagecolorallocatealpha($img, 0, 0, 0, 127);
+$redsolid = imagecolorallocate($img, 255, 0, 0);
+imagefill($img, 0, 0, $blacktransparent);
+imageline($img, $imagew / 2, 0, $imagew / 2, $imageh - 1, $redsolid);
+imageline($img, 0, $imageh / 2, $imagew - 1, $imageh / 2, $redsolid);
+imagegammacorrect($img, 1, 1);
+$color = imagecolorat($img, 0, 0);
+var_dump($color === $blacktransparent);
+imagedestroy($img);
+?>
+--EXPECT--
+bool(true)

Original file line number	Diff line number	Diff line change
`@@ -3045,10 +3045,11 @@ PHP_FUNCTION(imagegammacorrect)`
`3045`	`3045`	`for (x = 0; x < gdImageSX(im); x++) {`
`3046`	`3046`	`c = gdImageGetPixel(im, x, y);`
`3047`	`3047`	`gdImageSetPixel(im, x, y,`
`3048`		`- gdTrueColor(`
	`3048`	`+ gdTrueColorAlpha(`
`3049`	`3049`	`(int) ((pow((pow((gdTrueColorGetRed(c) / 255.0), input)), 1.0 / output) * 255) + .5),`
`3050`	`3050`	`(int) ((pow((pow((gdTrueColorGetGreen(c) / 255.0), input)), 1.0 / output) * 255) + .5),`
`3051`		`- (int) ((pow((pow((gdTrueColorGetBlue(c) / 255.0), input)), 1.0 / output) * 255) + .5)`
	`3051`	`+ (int) ((pow((pow((gdTrueColorGetBlue(c) / 255.0), input)), 1.0 / output) * 255) + .5),`
	`3052`	`+ gdTrueColorGetAlpha(c)`
`3052`	`3053`	`)`
`3053`	`3054`	`);`
`3054`	`3055`	`}`