[gegl] convert-space: handle CMYK and fix bug in property name

[Øyvind "pippin" Kolås <ok src gnome org>]

commit a5ce14e9f5199654cb5e53ae585496719b76fd98
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Nov 30 05:05:31 2020 +0100

    convert-space: handle CMYK and fix bug in property name
    
    We cannot have a property named "name" since this is a property that
    exists on GeglNode. In addition a logic bug made the name always
    take precedence, forcing "sRGB" to be the converted to space.
    
    We now also create "YA float", "RGBA float" or "CMYKA float" depending
    on the type of color model associated with the space instead of
    forcing RGBA, thus gegl:convert-space is sufficient to go between
    RGB and CMYK.

 operations/core/convert-space.c | 57 ++++++++++++++++++++++++-----------------
 1 file changed, 33 insertions(+), 24 deletions(-)
---
diff --git a/operations/core/convert-space.c b/operations/core/convert-space.c
index 18a3b9ce9..21e617504 100644
--- a/operations/core/convert-space.c
+++ b/operations/core/convert-space.c
@@ -13,7 +13,7 @@
  * You should have received a copy of the GNU Lesser General Public
  * License along with GEGL; if not, see <https://www.gnu.org/licenses/>.
  *
- * Copyright 2006 Øyvind Kolås <pippin gimp org>
+ * Copyright 2020 Øyvind Kolås <pippin gimp org>
  */
 
 #include "config.h"
@@ -22,7 +22,7 @@
 
 #ifdef GEGL_PROPERTIES
 
-property_string (name, _("Name"), "sRGB")
+property_string (space_name, _("Space name"), "sRGB")
    description (_("One of: sRGB, Adobish, Rec2020, ProPhoto, Apple, ACEScg, ACES2065-1"))
 property_format (pointer, _("Pointer"), NULL)
    description (_("pointer to a const * Babl space"))
@@ -44,14 +44,10 @@ gegl_convert_space_prepare (GeglOperation *operation)
   const Babl *aux_format = gegl_operation_get_source_format (operation,
                                                             "aux");
   GeglProperties *o = GEGL_PROPERTIES (operation);
-  const Babl *space = babl_space (o->name);
+  const Babl *space = babl_space (o->space_name);
   if (o->pointer)
     space = o->pointer;
-  if (aux_format)
-  {
-    space = babl_format_get_space (aux_format);
-  }
-  if (!space && o->path)
+  if (o->path && o->path[0])
   {
     gchar *icc_data = NULL;
     gsize icc_length;
@@ -60,43 +56,56 @@ gegl_convert_space_prepare (GeglOperation *operation)
     {
       const char *error = NULL;
       const Babl *s = babl_space_from_icc (icc_data, (gint)icc_length,
-                                 BABL_ICC_INTENT_RELATIVE_COLORIMETRIC, &error);
+                                 BABL_ICC_INTENT_RELATIVE_COLORIMETRIC,
+                                 &error);
       if (s) space = s;
       g_free (icc_data);
     }
   }
 
-  gegl_operation_set_format (operation, "output",
-                             babl_format_with_space ("RGBA float", space));
+  if (aux_format)
+  {
+    space = babl_format_get_space (aux_format);
+  }
+
+  const Babl *format;
+  if (babl_space_is_cmyk (space))
+  {
+    format = babl_format_with_space ("CMYKA float", space);
+  }
+  else if (babl_space_is_gray (space))
+  {
+    format = babl_format_with_space ("YA float", space);
+  }
+  else
+  {
+    format = babl_format_with_space ("RGBA float", space);
+  }
+  gegl_operation_set_format (operation, "output", format);
 }
 
 static gboolean
 gegl_convert_space_process (GeglOperation        *operation,
-                            GeglOperationContext *context,
-                            const gchar          *output_prop,
+                            GeglBuffer           *input,
+                            GeglBuffer           *aux,
+                            GeglBuffer           *output,
                             const GeglRectangle  *result,
                             gint                  level)
 {
-  GeglBuffer *input;
-
-  input = GEGL_BUFFER (gegl_operation_context_get_object (context, "input"));
-  if (!input)
-    {
-      return FALSE;
-    }
-
-  gegl_operation_context_take_object (context, "output",
-                                      g_object_ref ((GObject *) input));
+  gegl_buffer_copy (input, result, GEGL_ABYSS_NONE, output, result);
   return TRUE;
 }
 
+
 static void
 gegl_op_class_init (GeglOpClass *klass)
 {
   GeglOperationClass *operation_class;
+  GeglOperationComposerClass *operation_composer_class;
 
   operation_class = GEGL_OPERATION_CLASS (klass);
-  operation_class->process = gegl_convert_space_process;
+  operation_composer_class = GEGL_OPERATION_COMPOSER_CLASS (klass);
+  operation_composer_class->process = gegl_convert_space_process;
   operation_class->prepare = gegl_convert_space_prepare;
 
   gegl_operation_class_set_keys (operation_class,