From 6b526bb1c05d120200de2d9a7d9059e37eeca784 Mon Sep 17 00:00:00 2001
From: Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
Date: Tue, 20 Feb 2018 05:03:00 +0900
Subject: [PATCH] Assert image page dimension in OptimizeLayerFrames (#990)

OptimizeLayerFrames initializes the background with some assumptions for
image page dimension.
---
 MagickCore/layer.c | 9 +++++----
 config/english.xml | 3 +++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/MagickCore/layer.c b/MagickCore/layer.c
index c74424311..2fb707f12 100644
--- a/MagickCore/layer.c
+++ b/MagickCore/layer.c
@@ -962,10 +962,11 @@ static Image *OptimizeLayerFrames(const Image *image,
   {
     if ((curr->columns != image->columns) || (curr->rows != image->rows))
       ThrowImageException(OptionError,"ImagesAreNotTheSameSize");
-    /*
-      FUTURE: also check that image is also fully coalesced (full page)
-      Though as long as they are the same size it should not matter.
-    */
+
+    if ((curr->page.x != 0) || (curr->page.y != 0) ||
+        (curr->page.width != image->page.width) ||
+        (curr->page.height != image->page.height))
+      ThrowImageException(OptionError,"ImagePagesAreNotCoalesced");
   }
   /*
     Allocate memory (times 2 if we allow the use of frame duplications)
diff --git a/config/english.xml b/config/english.xml
index 535691254..69e6ddb44 100644
--- a/config/english.xml
+++ b/config/english.xml
@@ -652,6 +652,9 @@
         <message name="ImagesAreNotTheSameSize">
           images are not the same size
         </message>
+        <message name="ImagePagesAreNotCoalesced">
+          image pages are not coalesced
+        </message>
         <message name="ImageSizeMustExceedBevelWidth">
           size must exceed bevel width
         </message>
-- 
2.40.0