[gimp] pygimp: fixes creation of GroupLayer objects

[João Sebastião de Oliveira Bueno Calligaris <jsbueno src gnome org>]

commit d180b9eb98dcca3853412200d18950e49223c77f
Author: João S. O. Bueno <gwidion gmail com>
Date:   Wed Mar 5 12:36:11 2014 -0300

    pygimp: fixes creation of GroupLayer objects
    
    Calling gimp.GrouLayer(...) directly was broken -
    (one could retrieve a layer group from the image
    or use the pdb call to get it working)
    
    Spotted by Markus Orreilly at
    http://stackoverflow.com/questions/12608210/

 plug-ins/pygimp/pygimp-drawable.c |   60 +++++++++++++++++++++++++++++++++----
 1 files changed, 54 insertions(+), 6 deletions(-)
---
diff --git a/plug-ins/pygimp/pygimp-drawable.c b/plug-ins/pygimp/pygimp-drawable.c
index a4b0b25..05f2d1e 100644
--- a/plug-ins/pygimp/pygimp-drawable.c
+++ b/plug-ins/pygimp/pygimp-drawable.c
@@ -1922,6 +1922,19 @@ pygimp_layer_new(gint32 ID)
 /* End of code for Layer objects */
 /* -------------------------------------------------------- */
 
+/* Since this help will primaly be seen from within
+ * GIMP's Python console, we should make it fit in that
+ * window's default size.
+ */
+
+#define GROUPLAYER_DOC ""                                \
+"gimp.GroupLayer(img, name="", opacity=100.0,   "        \
+"mode=gimp.NORMAL_MODE)\n"                               \
+"\n"                                                     \
+" Creates a new GroupLayer object that has to be \n"     \
+"subsequently added to an image. Use Image.add_layer \n" \
+"or pdb.gimp_image_insert_layer calls to do that. \n"    \
+
 static PyMethodDef grouplay_methods[] = {
     {NULL,              NULL}           /* sentinel */
 };
@@ -1963,11 +1976,46 @@ grouplay_repr(PyGimpLayer *self)
     return s;
 }
 
+static int
+grouplay_init(PyGimpLayer *self, PyObject *args, PyObject *kwargs)
+{
+    PyGimpImage *img;
+    char *name = "Layer Group";
+    GimpImageType type = GIMP_RGB_IMAGE;
+    double opacity = 100.0;
+    GimpLayerModeEffects mode = GIMP_NORMAL_MODE;
+
+
+    if (!PyArg_ParseTuple(args, "O!|sdi:gimp.Layer.__init__",
+                          &PyGimpImage_Type, &img, &name,
+                          &opacity, &mode))
+        return -1;
+
+    self->ID = gimp_layer_group_new(img->ID);
+
+    self->drawable = NULL;
+
+    if (self->ID < 0) {
+        PyErr_Format(pygimp_error,
+                     "could not create layer group '%s' of type %d on "
+                     "image (ID %d)",
+                     name, type, img->ID);
+        return -1;
+    }
+
+    gimp_layer_set_opacity(self->ID, opacity);
+    gimp_layer_set_mode(self->ID, mode);
+
+    gimp_item_set_name(self->ID, name);
+
+    return 0;
+}
+
 PyTypeObject PyGimpGroupLayer_Type = {
     PyObject_HEAD_INIT(NULL)
     0,                                  /* ob_size */
     "gimp.GroupLayer",                  /* tp_name */
-    sizeof(PyGimpGroupLayer),                /* tp_basicsize */
+    sizeof(PyGimpGroupLayer),           /* tp_basicsize */
     0,                                  /* tp_itemsize */
     /* methods */
     (destructor)drw_dealloc,            /* tp_dealloc */
@@ -1975,7 +2023,7 @@ PyTypeObject PyGimpGroupLayer_Type = {
     (getattrfunc)0,                     /* tp_getattr */
     (setattrfunc)0,                     /* tp_setattr */
     (cmpfunc)drw_cmp,                   /* tp_compare */
-    (reprfunc)grouplay_repr,                 /* tp_repr */
+    (reprfunc)grouplay_repr,            /* tp_repr */
     0,                                  /* tp_as_number */
     0,                                  /* tp_as_sequence */
     0,                                  /* tp_as_mapping */
@@ -1986,7 +2034,7 @@ PyTypeObject PyGimpGroupLayer_Type = {
     (setattrofunc)0,                    /* tp_setattro */
     0,                                  /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT,                 /* tp_flags */
-    NULL, /* Documentation string */
+    GROUPLAYER_DOC, /* Documentation string */
     (traverseproc)0,                    /* tp_traverse */
     (inquiry)0,                         /* tp_clear */
     (richcmpfunc)0,                     /* tp_richcompare */
@@ -1995,13 +2043,13 @@ PyTypeObject PyGimpGroupLayer_Type = {
     (iternextfunc)0,                    /* tp_iternext */
     grouplay_methods,                   /* tp_methods */
     0,                                  /* tp_members */
-    grouplay_getsets,                        /* tp_getset */
+    grouplay_getsets,                   /* tp_getset */
     &PyGimpLayer_Type,                  /* tp_base */
     (PyObject *)0,                      /* tp_dict */
     0,                                  /* tp_descr_get */
     0,                                  /* tp_descr_set */
     0,                                  /* tp_dictoffset */
-    (initproc)lay_init,                 /* tp_init */
+    (initproc)grouplay_init,            /* tp_init */
     (allocfunc)0,                       /* tp_alloc */
     (newfunc)0,                         /* tp_new */
 };
@@ -2015,7 +2063,7 @@ pygimp_group_layer_new(gint32 ID)
         Py_INCREF(Py_None);
         return Py_None;
     }
-    
+
     if (!gimp_item_is_group(ID)) {
         return pygimp_layer_new(ID);
     }