Re: No support for ImageMagick 7 in emacs-26

[Paul Eggert <eggert@cs.ucla.edu>]

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On 11/25/18 11:38 PM, Ulrich Mueller wrote:
>>> (In fact, Gentoo has a consolidated patch for 26.1:
>>> https://gitweb.gentoo.org/proj/emacs-patches.git/tree/emacs/26.1/02_all_imagemagick-7.patch)
> Effectively, the only code change in the consolidated patch is the
> following in image.c:
>
> -      MagickRealType color_scale = 65535.0 / QuantumRange;
> +      double quantum_range = QuantumRange;
> +      MagickRealType color_scale = 65535.0 / quantum_range;

We don't need to apply this to the emacs-26 branch, as it does not 
affect behavior and is used only to pacify a GCC warning. I suppose 
Gentoo enables warnings somehow, and doesn't want that warning. But in 
general we no longer worry about --enable-gcc-warnings diagnostics in 
the emacs-26 branch.

Anyway, the business part of the Gentoo patch is everything else in that 
patch.

On 11/26/18 9:38 AM, Eli Zaretskii wrote:
 > The other one is that inclusion of a header file
 > was moved to a different place for some reason.  (Yes, I'm being
 > paranoid

This is OK since exactly the same include files are included, in exactly 
the same order, when HAVE_IMAGEMAGICK7 is not defined.

So how about the attached patch for the emacs-26 branch?


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From 9648f9e622471b36111847c0ed352303c8c09504 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 26 Nov 2018 17:37:16 -0800
Subject: [PATCH] Support ImageMagick version 7

Backport from master.
* configure.ac (HAVE_IMAGEMAGICK7): New macro.
(HAVE_IMAGEMAGICK): Also define if using ImageMagick 7 or later.
* src/image.c [HAVE_IMAGEMAGICK7]: Include
<MagickWand/MagickWand.h> and <MagickCore/version.h> instead of
<wand/MagickWand.h> and <magick/version.h>.
(PixelSetMagickColor, MagickPixelPacket) [HAVE_IMAGEMAGICK7]:
New compatibility definitions.
---
 configure.ac | 15 +++++++++------
 src/image.c  | 13 +++++++++++--
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index dc6d776d45..a4d0feaad5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2521,11 +2521,14 @@ AC_DEFUN
 HAVE_IMAGEMAGICK=no
 if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes" || test "${HAVE_W32}" = "yes"; then
   if test "${with_imagemagick}" != "no"; then
-    ## 6.3.5 is the earliest version known to work; see Bug#17339.
-    ## 6.8.2 makes Emacs crash; see Bug#13867.
-    ## 7 and later have not been ported to; See Bug#25967.
-    IMAGEMAGICK_MODULE="Wand >= 6.3.5 Wand != 6.8.2 Wand < 7"
-    EMACS_CHECK_MODULES([IMAGEMAGICK], [$IMAGEMAGICK_MODULE])
+    EMACS_CHECK_MODULES([IMAGEMAGICK], [MagickWand >= 7])
+    if test $HAVE_IMAGEMAGICK = yes; then
+       AC_DEFINE([HAVE_IMAGEMAGICK7], 1, [Define to 1 if using ImageMagick7.])
+    else
+       ## 6.3.5 is the earliest version known to work; see Bug#17339.
+       ## 6.8.2 makes Emacs crash; see Bug#13867.
+       EMACS_CHECK_MODULES([IMAGEMAGICK], [Wand >= 6.3.5 Wand != 6.8.2])
+    fi
 
     if test $HAVE_IMAGEMAGICK = yes; then
       OLD_CFLAGS=$CFLAGS
@@ -5404,7 +5407,7 @@ AC_DEFUN
   Does Emacs use -lrsvg-2?                                ${HAVE_RSVG}
   Does Emacs use cairo?                                   ${HAVE_CAIRO}
   Does Emacs use -llcms2?                                 ${HAVE_LCMS2}
-  Does Emacs use imagemagick (version 6)?                 ${HAVE_IMAGEMAGICK}
+  Does Emacs use imagemagick?                             ${HAVE_IMAGEMAGICK}
   Does Emacs support sound?                               ${HAVE_SOUND}
   Does Emacs use -lgpm?                                   ${HAVE_GPM}
   Does Emacs use -ldbus?                                  ${HAVE_DBUS}
diff --git a/src/image.c b/src/image.c
index a6b2d9060b..cc99f33d5f 100644
--- a/src/image.c
+++ b/src/image.c
@@ -8272,11 +8272,20 @@ imagemagick_image_p (Lisp_Object object)
 /* The GIF library also defines DrawRectangle, but its never used in Emacs.
    Therefore rename the function so it doesn't collide with ImageMagick.  */
 #define DrawRectangle DrawRectangleGif
-#include <wand/MagickWand.h>
+
+#ifdef HAVE_IMAGEMAGICK7
+# include <MagickWand/MagickWand.h>
+# include <MagickCore/version.h>
+/* ImageMagick 7 compatibility definitions.  */
+# define PixelSetMagickColor PixelSetPixelColor
+typedef PixelInfo MagickPixelPacket;
+#else
+# include <wand/MagickWand.h>
+# include <magick/version.h>
+#endif
 
 /* ImageMagick 6.5.3 through 6.6.5 hid PixelGetMagickColor for some reason.
    Emacs seems to work fine with the hidden version, so unhide it.  */
-#include <magick/version.h>
 #if 0x653 <= MagickLibVersion && MagickLibVersion <= 0x665
 extern WandExport void PixelGetMagickColor (const PixelWand *,
 					    MagickPixelPacket *);
-- 
2.19.1