[libgxps] gxps-images: Add support for JPEG images with GRAYSCALE color space

[Carlos Garcia Campos <carlosgc src gnome org>]

commit d94f36d4d2256aafa0ad7f032538b68eb18e1605
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Sun Feb 15 18:07:07 2015 +0100

    gxps-images: Add support for JPEG images with GRAYSCALE color space
    
    https://bugzilla.gnome.org/show_bug.cgi?id=744120

 libgxps/gxps-images.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/libgxps/gxps-images.c b/libgxps/gxps-images.c
index 28e26b2..8629b2b 100644
--- a/libgxps/gxps-images.c
+++ b/libgxps/gxps-images.c
@@ -263,6 +263,12 @@ gxps_images_create_from_jpeg (GXPSArchive *zip,
                                        p[2] = line[0];
                                        p[3] = 0xff;
                                        break;
+                                case JCS_GRAYSCALE:
+                                        p[0] = line[0];
+                                        p[1] = line[0];
+                                        p[2] = line[0];
+                                        p[3] = 0xff;
+                                        break;
                                default:
                                        GXPS_DEBUG (g_message ("Unsupported jpeg color space %s",
                                                                _jpeg_color_space_name 
(cinfo.out_color_space)));
@@ -272,10 +278,6 @@ gxps_images_create_from_jpeg (GXPSArchive *zip,
                                        g_object_unref (stream);
                                        return NULL;
                                }
-                               p[0] = line[2];
-                               p[1] = line[1];
-                               p[2] = line[0];
-                               p[3] = 0xff;
                                line += cinfo.out_color_components;
                                p += 4;
                        }