From a1eeca490f26e9fa74a5d4dcc35fd3e2f43681a0 Mon Sep 17 00:00:00 2001
From: Jehan <jehan@girinstud.io>
Date: Wed, 14 Aug 2019 14:56:28 +0200
Subject: [PATCH] libgimp: support all GimpItem subclasses as argument and
 return values.

---
 libgimp/gimpgpparams-body.c | 82 +++++++++++++++++++++++++++++--------
 libgimp/gimpgpparams.c      |  2 +
 2 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/libgimp/gimpgpparams-body.c b/libgimp/gimpgpparams-body.c
index 3134da66a0..4ec7ab4bc9 100644
--- a/libgimp/gimpgpparams-body.c
+++ b/libgimp/gimpgpparams-body.c
@@ -173,26 +173,26 @@ _gimp_param_spec_to_gp_param_def (GParamSpec *pspec,
        * included from app/ which won't know of the types.
        */
       if (g_strcmp0 (g_type_name (pspec->value_type), "GimpImage") == 0)
-        {
-          param_def->type_name = "GimpParamImageID";
-          param_def->param_def_type = GP_PARAM_DEF_TYPE_ID;
-          param_def->meta.m_id.none_ok = TRUE;
-        }
+        param_def->type_name = "GimpParamImageID";
+      if (g_strcmp0 (g_type_name (pspec->value_type), "GimpDisplay") == 0)
+        param_def->type_name = "GimpParamDisplayID";
       else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpItem") == 0)
-        {
-          param_def->type_name = "GimpParamItemID";
-          param_def->param_def_type = GP_PARAM_DEF_TYPE_ID;
-          param_def->meta.m_id.none_ok = TRUE;
-        }
+        param_def->type_name = "GimpParamItemID";
       else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpDrawable") == 0)
-        {
-          param_def->type_name = "GimpParamDrawableID";
-          param_def->param_def_type = GP_PARAM_DEF_TYPE_ID;
-          param_def->meta.m_id.none_ok = TRUE;
-        }
+        param_def->type_name = "GimpParamDrawableID";
       else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpLayer") == 0)
+        param_def->type_name = "GimpParamLayerID";
+      else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpChannel") == 0)
+        param_def->type_name = "GimpParamChannelID";
+      else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpLayerMask") == 0)
+        param_def->type_name = "GimpParamLayerMaskID";
+      else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpSelection") == 0)
+        param_def->type_name = "GimpParamSelectionID";
+      else if (g_strcmp0 (g_type_name (pspec->value_type), "GimpVectors") == 0)
+        param_def->type_name = "GimpParamVectorsID";
+
+      if (G_PARAM_SPEC_TYPE_NAME (pspec)  != param_def->type_name)
         {
-          param_def->type_name = "GimpParamLayerID";
           param_def->param_def_type = GP_PARAM_DEF_TYPE_ID;
           param_def->meta.m_id.none_ok = TRUE;
         }
@@ -610,6 +610,56 @@ _gimp_value_to_gp_param (const GValue *value,
       _gimp_param_spec_to_gp_param_def (g_value_get_param (value),
                                         &param->data.d_param_def);
     }
+  else if (G_VALUE_HOLDS_OBJECT (value))
+    {
+#ifdef  __LIBGIMP_GPPARAMS__
+      GObject     *object    = g_value_get_object (value);
+      const gchar *type_name = NULL;
+
+      if (full_copy)
+        g_clear_pointer (&param->type_name, g_free);
+
+      if (GIMP_IS_IMAGE (object))
+        {
+          type_name = "GimpImageID";
+          param->param_type = GP_PARAM_TYPE_INT;
+          param->data.d_int = gimp_image_get_id (GIMP_IMAGE (object));
+        }
+      if (GIMP_IS_DISPLAY (object))
+        {
+          type_name = "GimpDisplayID";
+          param->param_type = GP_PARAM_TYPE_INT;
+          param->data.d_int = gimp_display_get_id (GIMP_DISPLAY (object));
+        }
+      else if (GIMP_IS_ITEM (object))
+        {
+          param->param_type = GP_PARAM_TYPE_INT;
+          param->data.d_int = gimp_item_get_id (GIMP_ITEM (object));
+
+          if (GIMP_IS_LAYER (object))
+            type_name = "GimpLayerID";
+          else if (GIMP_IS_LAYER_MASK (object))
+            type_name = "GimpLayerMaskID";
+          else if (GIMP_IS_SELECTION (object))
+            type_name = "GimpSelectionID";
+          else if (GIMP_IS_VECTORS (object))
+            type_name = "GimpVectorsID";
+          else if (GIMP_IS_CHANNEL (object))
+            type_name = "GimpChannelID";
+          else if (GIMP_IS_DRAWABLE (object))
+            type_name = "GimpDrawableID";
+          else
+            type_name = "GimpItemID";
+        }
+      if (type_name)
+        {
+          if (full_copy)
+            param->type_name = g_strdup (type_name);
+          else
+            param->type_name = (gchar *) type_name;
+        }
+#endif  /* __LIBGIMP_GPPARAMS__ */
+    }
 
   if (param->param_type == -1)
     g_printerr ("%s: GValue contains unsupported type '%s'\n",
diff --git a/libgimp/gimpgpparams.c b/libgimp/gimpgpparams.c
index a7bfd1daaf..b78a060482 100644
--- a/libgimp/gimpgpparams.c
+++ b/libgimp/gimpgpparams.c
@@ -37,7 +37,9 @@
 /*  include the implementation, they are shared between app/ and
  *  libgimp/ but need different headers.
  */
+#define  __LIBGIMP_GPPARAMS__
 #include "gimpgpparams-body.c"
+#undef  __LIBGIMP_GPPARAMS__
 
 GParamSpec *
 _gimp_gp_param_def_to_param_spec (gpointer          gimp,