From 93565e3f82ab36565270a0ed176283c8e395eb63 Mon Sep 17 00:00:00 2001
From: Tim Starling <tstarling@users.mediawiki.org>
Date: Tue, 24 Aug 2010 08:48:46 +0000
Subject: [PATCH] Fixes for new ImageMagick: * (bug 24824) Support ImageMagick
 6.5.6-2+ JPEG decoder size hint, to reduce memory usage when such an
 ImageMagick is used for scaling. * Removed -size option since it doesn't act
 as a JPEG decoder size hint with recent ImageMagicks, and it may cause
 undesired behaviour in the future since it's documented to do something
 different now. * Disable multithreaded behaviour in recent ImageMagick, to
 avoid a deadlock when a resource limit such as $wgMaxShellMemory is hit. *
 Fixed some comments.

Replaces WMF live hack.
---
 RELEASE-NOTES             |  4 ++++
 includes/media/Bitmap.php | 19 ++++++++++---------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index bc5c4c7b4e..15cc91f497 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -303,6 +303,10 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
   a repository due to missing 'name' attribute from the API list=allimages
 * (bug 24898) MediaWiki uses /tmp even if a vHost-specific tempdir is set, also
   make wfTempDir() return a sane value for Windows on worst-case
+* (bug 24824) Support ImageMagick 6.5.6-2+ JPEG decoder size hint, to reduce 
+  memory usage when such an ImageMagick is used for scaling.
+* Disable multithreaded behaviour in recent ImageMagick, to avoid a deadlock 
+  when a resource limit such as $wgMaxShellMemory is hit.
 
 === API changes in 1.17 ===
 * (bug 22738) Allow filtering by action type on query=logevent.
diff --git a/includes/media/Bitmap.php b/includes/media/Bitmap.php
index 3bb585240a..3f39fab762 100644
--- a/includes/media/Bitmap.php
+++ b/includes/media/Bitmap.php
@@ -120,12 +120,15 @@ class BitmapHandler extends ImageHandler {
 			$scene = false;
 			$animation_pre = '';
 			$animation_post = '';
+			$decoderHint = '';
 			if ( $mimeType == 'image/jpeg' ) {
 				$quality = "-quality 80"; // 80%
 				# Sharpening, see bug 6193
 				if ( ( $physicalWidth + $physicalHeight ) / ( $srcWidth + $srcHeight ) < $wgSharpenReductionThreshold ) {
 					$sharpen = "-sharpen " . wfEscapeShellArg( $wgSharpenParameter );
 				}
+				// JPEG decoder hint to reduce memory, available since IM 6.5.6-2
+				$decoderHint = "-define jpeg:size={$physicalWidth}x{$physicalHeight}";
 			} elseif ( $mimeType == 'image/png' ) {
 				$quality = "-quality 95"; // zlib 9, adaptive filtering
 			} elseif( $mimeType == 'image/gif' ) {
@@ -150,20 +153,18 @@ class BitmapHandler extends ImageHandler {
 				$tempEnv = '';
 			}
 
-			# Specify white background color, will be used for transparent images
-			# in Internet Explorer/Windows instead of default black.
-
-			# Note, we specify "-size {$physicalWidth}" and NOT "-size {$physicalWidth}x{$physicalHeight}".
-			# It seems that ImageMagick has a bug wherein it produces thumbnails of
-			# the wrong size in the second case.
-
 			$cmd  = 
 				$tempEnv .
+				// Use one thread only, to avoid deadlock bugs on OOM
+				'OMP_NUM_THREADS=1 ' .
 				wfEscapeShellArg( $wgImageMagickConvertCommand ) .
-				" {$quality} -background white -size {$physicalWidth} ".
+				// Specify white background color, will be used for transparent images
+				// in Internet Explorer/Windows instead of default black.
+				" {$quality} -background white".
+				" {$decoderHint} " .
 				wfEscapeShellArg( $this->escapeMagickInput( $srcPath, $scene ) ) .
 				" {$animation_pre}" .
-				// For the -resize option a "!" is needed to force exact size,
+				// For the -thumbnail option a "!" is needed to force exact size,
 				// or ImageMagick may decide your ratio is wrong and slice off
 				// a pixel.
 				" -thumbnail " . wfEscapeShellArg( "{$physicalWidth}x{$physicalHeight}!" ) .
-- 
2.20.1