1 files changed, 154 insertions, 0 deletions
diff --git a/src/animate-timer.vala b/src/animate-timer.vala
new file mode 100644
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+/* -*- Mode: Vala; indent-tabs-mode: nil; tab-width: 4 -*-
+ *
+ * Copyright (C) 2011,2012 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * 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/>.
+ *
+ * Authors: Robert Ancell <robert.ancell@canonical.com>
+ *          Michael Terry <michael.terry@canonical.com>
+ */
+
+private class AnimateTimer : Object
+{
+    /* x and y are 0.0 to 1.0 */
+    public delegate double EasingFunc (double x);
+
+    /* The following are the same intervals that Unity uses */
+    public static const int INSTANT = 150; /* Good for animations that don't convey any information */
+    public static const int FAST =    250; /* Good for animations that convey duplicated information */
+    public static const int NORMAL =  500;
+    public static const int SLOW =   1000; /* Good for animations that convey information that is only presented in the animation */
+
+    /* speed is in milliseconds */
+    public unowned EasingFunc easing_func { get; private set; }
+    public int speed { get; set; }
+    public bool is_running { get { return timeout != 0; } }
+    public double progress { get; private set; }
+
+    /* progress is from 0.0 to 1.0 */
+    public signal void animate (double progress);
+
+    /* AnimateTimer requires two things: an easing function and a speed.
+
+       The speed is just the duration of the animation in milliseconds.
+
+       The easing function describes how fast the animation occurs at different
+       parts of the duration.
+
+       See http://hosted.zeh.com.br/tweener/docs/en-us/misc/transitions.html
+       for examples of various easing functions.
+
+       A few are provided with this class, notably ease_in_out and
+       ease_out_quint.
+    */
+    /* speed is in milliseconds */
+    public AnimateTimer (EasingFunc func, int speed)
+    {
+        Object (speed: speed);
+        this.easing_func = func;
+    }
+
+    ~AnimateTimer ()
+    {
+        stop ();
+    }
+
+    /* temp_speed is in milliseconds */
+    public void reset (int temp_speed = -1)
+    {
+        stop ();
+
+        timeout = Timeout.add (16, animate_cb);
+        progress = 0;
+        start_time = 0;
+        extra_time = 0;
+        extra_progress = 0;
+
+        if (temp_speed == -1)
+            temp_speed = speed;
+
+        length = temp_speed * TimeSpan.MILLISECOND;
+    }
+
+    public void stop ()
+    {
+        if (timeout != 0)
+            Source.remove (timeout);
+        timeout = 0;
+    }
+
+    private uint timeout = 0;
+    private TimeSpan start_time = 0;
+    private TimeSpan length = 0;
+    private TimeSpan extra_time = 0;
+    private double extra_progress = 0.0;
+
+    private bool animate_cb ()
+    {
+        if (start_time == 0)
+            start_time = GLib.get_monotonic_time ();
+
+        var time_progress = normalize_time (GLib.get_monotonic_time ());
+        progress = calculate_progress (time_progress);
+        animate (progress);
+
+        if (time_progress >= 1.0)
+        {
+            timeout = 0;
+            return false;
+        }
+        else
+            return true;
+    }
+
+    /* Returns 0.0 to 1.0 where 1.0 is at or past end_time */
+    private double normalize_time (TimeSpan now)
+    {
+        if (length == 0)
+            return 1.0f;
+
+        return (((double)(now - start_time)) / length).clamp (0.0, 1.0);
+    }
+
+    /* Returns 0.0 to 1.0 where 1.0 is done.
+       time is not normalized yet! */
+    private double calculate_progress (double time_progress)
+    {
+        var y = easing_func (time_progress);
+        return y.clamp (0.0, 1.0);
+    }
+
+    public static double ease_in_out (double x)
+    {
+        return (1 - Math.cos (Math.PI * x)) / 2;
+    }
+
+    /*public static double ease_in_quad (double x)
+    {
+        return Math.pow (x, 2);
+    }*/
+    /*public static double ease_out_quad (double x)
+    {
+        return -1 * Math.pow (x - 1, 2) + 1;
+    }*/
+
+    /*public static double ease_in_quint (double x)
+    {
+        return Math.pow (x, 5);
+    }*/
+    public static double ease_out_quint (double x)
+    {
+        return Math.pow (x - 1, 5) + 1;
+    }
+}
+