From 6a379d983544b3e1b241860854646ca039724151 Mon Sep 17 00:00:00 2001
From: Ari Roponen <ari.roponen@gmail.com>
Date: Fri, 27 Apr 2018 15:14:36 +0300
Subject: [PATCH 2/2] Add partial image support for cairo builds

* src/image.c (lookup_rgb_color): Add cairo support.
(jpeg_load_body): Fix preprocessor symbol.  Move colors definition
into non-cairo part.
(imagemagick_load_image) [USE_CAIRO]: Add partial support for
cairo.
---
 src/image.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/image.c b/src/image.c
index 37416c1616..4c3f6c5ab0 100644
--- a/src/image.c
+++ b/src/image.c
@@ -4629,6 +4629,8 @@ lookup_rgb_color (struct frame *f, int r, int g, int b)
   return PALETTERGB (r >> 8, g >> 8, b >> 8);
 #elif defined HAVE_NS
   return RGB_TO_ULONG (r >> 8, g >> 8, b >> 8);
+#elif defined USE_CAIRO
+  return (0xffu << 24) | (r << 16) | (g << 8) | b;
 #else
   xsignal1 (Qfile_error,
 	    build_string ("This Emacs mishandles this image file type"));
@@ -6702,10 +6704,10 @@ jpeg_load_body (struct frame *f, struct image *img,
   FILE *volatile fp = NULL;
   JSAMPARRAY buffer;
   int row_stride, x, y;
-  unsigned long *colors;
   int width, height;
   int i, ir, ig, ib;
 #ifndef USE_CAIRO
+  unsigned long *colors;
   XImagePtr ximg = NULL;
 #endif
 
@@ -6823,7 +6825,7 @@ jpeg_load_body (struct frame *f, struct image *img,
     else
       ir = 0, ig = 0, ib = 0;
 
-#ifndef CAIRO
+#ifndef USE_CAIRO
     /* Use the color table mechanism because it handles colors that
        cannot be allocated nicely.  Such colors will be replaced with
        a default color, and we don't have to care about which colors
@@ -8551,6 +8553,9 @@ imagemagick_load_image (struct frame *f, struct image *img,
   double rotation;
   char hint_buffer[MaxTextExtent];
   char *filename_hint = NULL;
+#ifdef USE_CAIRO
+  void *data;
+#endif
 
   /* Initialize the ImageMagick environment.  */
   static bool imagemagick_initialized;
@@ -8751,6 +8756,19 @@ imagemagick_load_image (struct frame *f, struct image *img,
   /* We can now get a valid pixel buffer from the imagemagick file, if all
      went ok.  */
 
+#ifdef USE_CAIRO
+  data = xmalloc (width * height * 4);
+#ifdef HAVE_MAGICKEXPORTIMAGEPIXELS
+  MagickExportImagePixels (image_wand, 0, 0, width, height,
+			   "BGRA", CharPixel, data);
+#else
+  /* FIXME: Implement this. For now, make it white. */
+  memset(data, 0xff, width * height * 4);
+#endif
+  create_cairo_image_surface (img, data, width, height);
+  goto done;
+#endif /* USE_CAIRO */
+
   init_color_table ();
 
 #if defined (HAVE_MAGICKEXPORTIMAGEPIXELS) && ! defined (HAVE_NS)
@@ -8861,6 +8879,9 @@ imagemagick_load_image (struct frame *f, struct image *img,
   /* Put ximg into the image.  */
   image_put_x_image (f, img, ximg, 0);
 
+#ifdef USE_CAIRO
+ done:
+#endif
   /* Final cleanup. image_wand should be the only resource left. */
   DestroyMagickWand (image_wand);
   if (bg_wand) DestroyPixelWand (bg_wand);
-- 
2.17.0