1 files changed, 168 insertions, 0 deletions
diff --git a/src/animation/gtd-animation-utils.c b/src/animation/gtd-animation-utils.c
new file mode 100644
index 0000000..7ab2198
--- /dev/null
+++ b/src/animation/gtd-animation-utils.c
@@ -0,0 +1,168 @@
+/* gtd-animation-utils.c
+ *
+ * Copyright 2020 Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "gtd-animation-utils.h"
+
+
+typedef struct
+{
+  GType value_type;
+  GtdProgressFunc func;
+} ProgressData;
+
+G_LOCK_DEFINE_STATIC (progress_funcs);
+static GHashTable *progress_funcs = NULL;
+
+gboolean
+gtd_has_progress_function (GType gtype)
+{
+  const char *type_name = g_type_name (gtype);
+
+  if (progress_funcs == NULL)
+    return FALSE;
+
+  return g_hash_table_lookup (progress_funcs, type_name) != NULL;
+}
+
+gboolean
+gtd_run_progress_function (GType         gtype,
+                           const GValue *initial,
+                           const GValue *final,
+                           gdouble       progress,
+                           GValue       *retval)
+{
+  ProgressData *pdata;
+  gboolean res;
+
+  G_LOCK (progress_funcs);
+
+  if (G_UNLIKELY (!progress_funcs))
+    {
+      res = FALSE;
+      goto out;
+    }
+
+  pdata = g_hash_table_lookup (progress_funcs, g_type_name (gtype));
+  if (G_UNLIKELY (!pdata))
+    {
+      res = FALSE;
+      goto out;
+    }
+
+  res = pdata->func (initial, final, progress, retval);
+
+out:
+  G_UNLOCK (progress_funcs);
+
+  return res;
+}
+
+static void
+progress_data_destroy (gpointer data)
+{
+  g_free (data);
+}
+
+/**
+ * gtd_interval_register_progress_func: (skip)
+ * @value_type: a #GType
+ * @func: a #GtdProgressFunc, or %NULL to unset a previously
+ *   set progress function
+ *
+ * Sets the progress function for a given @value_type, like:
+ *
+ * |[
+ *   gtd_interval_register_progress_func (MY_TYPE_FOO,
+ *                                            my_foo_progress);
+ * ]|
+ *
+ * Whenever a #GtdInterval instance using the default
+ * #GtdInterval::compute_value implementation is set as an
+ * interval between two #GValue of type @value_type, it will call
+ * @func to establish the value depending on the given progress,
+ * for instance:
+ *
+ * |[
+ *   static gboolean
+ *   my_int_progress (const GValue *a,
+ *                    const GValue *b,
+ *                    gdouble       progress,
+ *                    GValue       *retval)
+ *   {
+ *     gint ia = g_value_get_int (a);
+ *     gint ib = g_value_get_int (b);
+ *     gint res = factor * (ib - ia) + ia;
+ *
+ *     g_value_set_int (retval, res);
+ *
+ *     return TRUE;
+ *   }
+ *
+ *   gtd_interval_register_progress_func (G_TYPE_INT, my_int_progress);
+ * ]|
+ *
+ * To unset a previously set progress function of a #GType, pass %NULL
+ * for @func.
+ *
+ * Since: 1.0
+ */
+void
+gtd_interval_register_progress_func (GType           value_type,
+                                     GtdProgressFunc func)
+{
+  ProgressData *progress_func;
+  const char *type_name;
+
+  g_return_if_fail (value_type != G_TYPE_INVALID);
+
+  type_name = g_type_name (value_type);
+
+  G_LOCK (progress_funcs);
+
+  if (G_UNLIKELY (!progress_funcs))
+    progress_funcs = g_hash_table_new_full (NULL, NULL, NULL, progress_data_destroy);
+
+  progress_func = g_hash_table_lookup (progress_funcs, type_name);
+
+  if (G_UNLIKELY (progress_func))
+    {
+      if (func == NULL)
+        {
+          g_hash_table_remove (progress_funcs, type_name);
+          g_free (progress_func);
+        }
+      else
+        {
+          progress_func->func = func;
+        }
+    }
+  else
+    {
+      progress_func = g_new0 (ProgressData, 1);
+      progress_func->value_type = value_type;
+      progress_func->func = func;
+
+      g_hash_table_replace (progress_funcs,
+                            (gpointer) type_name,
+                            progress_func);
+    }
+
+  G_UNLOCK (progress_funcs);
+}