Move OpenGL code from GisOpenGL to objects

[grits] / src / objects / gis-callback.c

diff --git a/src/objects/gis-callback.c b/src/objects/gis-callback.c
index 05fa7467b5769abe92f5a5bc3651c3aedd3801a7..89dada46427be40eadbc3bef7e8e3297e02215bb 100644 (file)
--- a/src/objects/gis-callback.c
+++ b/src/objects/gis-callback.c
@@ -15,9 +15,46 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * SECTION:gis-callback
+ * @short_description: Custom callback objects
+ *
+ * #GisCallback objects are used for custom drawing functions. A common example
+ * of this would be to render something which does not easily fit into a normal
+ * object. For instance, a Heads-Up-Display overlay.
+ *
+ * Callbacks are an alternate to extending GisObject with a new class and
+ * should be used when only once instance of the object will be needed.
+ */
+
 #include <config.h>
 #include "gis-callback.h"
 
+/**
+ * gis_callback_new:
+ * @callback:  the function to call to draw the object
+ * @user_data: user data to pass to the drawing function
+ *
+ * Create a #GisCallback object with an associated function and user data.
+ *
+ * Returns: the new #GisCallback
+ */
+GisCallback *gis_callback_new(GisCallbackFunc draw_cb, gpointer user_data)
+{
+       GisCallback *cb = g_object_new(GIS_TYPE_CALLBACK, NULL);
+       cb->draw      = draw_cb;
+       cb->user_data = user_data;
+       return cb;
+}
+
+/* Proxy class methods to per-object methods */
+static void proxy_draw(GisObject *_cb, GisOpenGL *opengl)
+{
+       GisCallback *cb = GIS_CALLBACK(_cb);
+       if (cb->draw)
+               cb->draw(cb, opengl, cb->user_data);
+}
+
 /* GisCallback */
 G_DEFINE_TYPE(GisCallback, gis_callback, GIS_TYPE_OBJECT);
 static void gis_callback_init(GisCallback *cb)
@@ -26,12 +63,6 @@ static void gis_callback_init(GisCallback *cb)
 
 static void gis_callback_class_init(GisCallbackClass *klass)
 {
-}
-
-GisCallback *gis_callback_new(GisCallbackFunc callback, gpointer user_data)
-{
-       GisCallback *cb = g_object_new(GIS_TYPE_CALLBACK, NULL);
-       cb->callback  = callback;
-       cb->user_data = user_data;
-       return cb;
+       GisObjectClass *object_class = GIS_OBJECT_CLASS(klass);
+       object_class->draw = proxy_draw;
 }