From b71fa7cdf1cc04730382f1b7685fa887da6d25e9 Mon Sep 17 00:00:00 2001
From: Ingo Meyer <i.meyer@fz-juelich.de>
Date: Tue, 13 May 2025 16:24:54 +0200
Subject: [PATCH] Check directly if `compare` belongs to ImageMagick or
 GraphicsMagick

ImageMagick and GraphicsMagick can be installed in parallel, so don't
really on checking for `gm` existence to decide if `compare` calls
GraphicsMagick or ImageMagick code.
---
 diff-image | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/diff-image b/diff-image
index 0f6a316..902b126 100755
--- a/diff-image
+++ b/diff-image
@@ -208,7 +208,7 @@ fi
 density_flag=
 do_compare()
 {
-  if which gm > /dev/null
+  if compare --version | head -1 | grep -q "GraphicsMagick"
   then
     echo "NOTICE: GraphicsMagick does not support 'compare -fuzz', so omitting it"
     compare $density_flag $color_flag $backgroundcolor_flag -file png:- "$f1" "$f2" | \