[gthumb] png: read the embedded color profile

[Paolo Bacchilega <paobac src gnome org>]

commit 8b70b1f0feb7e6bad03f79a96942b423e6cf8b7a
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Nov 29 09:43:07 2020 +0100

    png: read the embedded color profile

 extensions/cairo_io/cairo-image-surface-png.c | 38 ++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)
---
diff --git a/extensions/cairo_io/cairo-image-surface-png.c b/extensions/cairo_io/cairo-image-surface-png.c
index e0ba3c53..16f19f0d 100644
--- a/extensions/cairo_io/cairo-image-surface-png.c
+++ b/extensions/cairo_io/cairo-image-surface-png.c
@@ -21,6 +21,9 @@
 
 #include <config.h>
 #include <png.h>
+#if HAVE_LCMS2
+#include <lcms2.h>
+#endif
 #include <gthumb.h>
 #include "cairo-image-surface-png.h"
 
@@ -268,8 +271,41 @@ _cairo_image_surface_create_from_png (GInputStream  *istream,
                                metadata->thumbnail.image_height = atoi (text_ptr[i].text);
                }
        }
-
        g_free (row_pointers);
+
+#if HAVE_LCMS2
+       {
+               GthICCProfile *profile = NULL;
+               int            intent;
+               png_charp      name;
+               int            compression_type;
+               png_bytep      icc_data;
+               png_uint_32    icc_data_size;
+
+               if (png_get_sRGB (cairo_png_data->png_ptr,
+                                 cairo_png_data->png_info_ptr,
+                                 &intent) == PNG_INFO_sRGB)
+               {
+                       profile = gth_icc_profile_new_srgb ();
+               }
+               else if (png_get_iCCP (cairo_png_data->png_ptr,
+                                      cairo_png_data->png_info_ptr,
+                                      &name,
+                                      &compression_type,
+                                      &icc_data,
+                                      &icc_data_size) == PNG_INFO_iCCP)
+               {
+                       if ((icc_data_size > 0) && (icc_data != NULL))
+                               profile = gth_icc_profile_new (GTH_ICC_PROFILE_ID_UNKNOWN, 
cmsOpenProfileFromMem (icc_data, icc_data_size));
+               }
+
+               if (profile != NULL) {
+                       gth_image_set_icc_profile (image, profile);
+                       g_object_unref (profile);
+               }
+       }
+#endif
+
        _cairo_png_data_destroy (cairo_png_data);
 
        return image;