[nautilus] selection-canvas-item: use GdkFrameClock for rubberband animation

[Cosimo Cecchi <cosimoc src gnome org>]

commit 1f18e1f8cebe8d491b76f039d21717010688b7c3
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Tue Sep 16 21:56:05 2014 -0700

    selection-canvas-item: use GdkFrameClock for rubberband animation
    
    Make it a bit smoother.

 .../nautilus-selection-canvas-item.c               |   57 +++++++++++--------
 1 files changed, 33 insertions(+), 24 deletions(-)
---
diff --git a/libnautilus-private/nautilus-selection-canvas-item.c 
b/libnautilus-private/nautilus-selection-canvas-item.c
index 52c12a6..b1ebea6 100644
--- a/libnautilus-private/nautilus-selection-canvas-item.c
+++ b/libnautilus-private/nautilus-selection-canvas-item.c
@@ -68,10 +68,10 @@ struct _NautilusSelectionCanvasItemDetails {
        double fade_out_fill_alpha;
        double fade_out_outline_alpha;
 
-       double fade_out_fill_delta;
-       double fade_out_outline_delta;  
+       gint64 fade_out_start_time;
+       gint64 fade_out_end_time;
 
-       guint fade_out_handler_id;
+       guint fade_out_tick_id;
 };
 
 G_DEFINE_TYPE (NautilusSelectionCanvasItem, nautilus_selection_canvas_item, EEL_TYPE_CANVAS_ITEM);
@@ -114,7 +114,7 @@ nautilus_selection_canvas_item_draw (EelCanvasItem *item,
 
                actual_fill = self->priv->fill_color;
 
-               if (self->priv->fade_out_handler_id != 0) {
+               if (self->priv->fade_out_tick_id != 0) {
                        actual_fill.alpha = self->priv->fade_out_fill_alpha;
                }
 
@@ -131,7 +131,7 @@ nautilus_selection_canvas_item_draw (EelCanvasItem *item,
 
                actual_outline = self->priv->outline_color;
 
-               if (self->priv->fade_out_handler_id != 0) {
+               if (self->priv->fade_out_tick_id != 0) {
                        actual_outline.alpha = self->priv->fade_out_outline_alpha;
                }
 
@@ -434,43 +434,52 @@ nautilus_selection_canvas_item_bounds (EelCanvasItem *item,
        *y2 = self->priv->y2 + hwidth;
 }
 
-#define FADE_OUT_STEPS 5
-#define FADE_OUT_SPEED 30
-
 static gboolean
-fade_and_request_redraw (gpointer user_data)
+fade_and_request_redraw (GtkWidget *canvas,
+                        GdkFrameClock *frame_clock,
+                        gpointer user_data)
 {
        NautilusSelectionCanvasItem *self = user_data;
+       gint64 frame_time;
+       gdouble percentage;
 
-       if (self->priv->fade_out_fill_alpha <= 0 ||
-           self->priv->fade_out_outline_alpha <= 0) {
-               self->priv->fade_out_handler_id = 0;
+       frame_time = gdk_frame_clock_get_frame_time (frame_clock);
+       if (frame_time >= self->priv->fade_out_end_time) {
+               self->priv->fade_out_tick_id = 0;
                eel_canvas_item_destroy (EEL_CANVAS_ITEM (self));
 
-               return FALSE;
+               return G_SOURCE_REMOVE;
        }
 
-       self->priv->fade_out_fill_alpha -= self->priv->fade_out_fill_delta;
-       self->priv->fade_out_outline_alpha -= self->priv->fade_out_outline_delta;
+       percentage = 1.0 - (gdouble) (frame_time - self->priv->fade_out_start_time) /
+               (gdouble) (self->priv->fade_out_end_time - self->priv->fade_out_start_time);
+
+       self->priv->fade_out_fill_alpha = self->priv->fill_color.alpha * percentage;
+       self->priv->fade_out_outline_alpha = self->priv->outline_color.alpha * percentage;
 
        eel_canvas_item_request_redraw (EEL_CANVAS_ITEM (self));
 
-       return TRUE;
+       return G_SOURCE_CONTINUE;
 }
 
 void
 nautilus_selection_canvas_item_fade_out (NautilusSelectionCanvasItem *self,
                                         guint transition_time)
 {
+       EelCanvasItem *item = EEL_CANVAS_ITEM (self);
+       GtkWidget *widget;
+       GdkFrameClock *clock;
+
        self->priv->fade_out_fill_alpha = self->priv->fill_color.alpha;
        self->priv->fade_out_outline_alpha = self->priv->outline_color.alpha;
 
-       self->priv->fade_out_fill_delta = self->priv->fade_out_fill_alpha / FADE_OUT_STEPS;
-       self->priv->fade_out_outline_delta = self->priv->fade_out_outline_alpha / FADE_OUT_STEPS;
+       widget = GTK_WIDGET (item->canvas);
+       clock = gtk_widget_get_frame_clock (widget);
+       self->priv->fade_out_start_time = gdk_frame_clock_get_frame_time (clock);
+       self->priv->fade_out_end_time = self->priv->fade_out_start_time + 1000 * transition_time;
 
-       self->priv->fade_out_handler_id =
-               g_timeout_add ((guint) (transition_time / FADE_OUT_STEPS),
-                              fade_and_request_redraw, self);
+       self->priv->fade_out_tick_id =
+               gtk_widget_add_tick_callback (GTK_WIDGET (item->canvas), fade_and_request_redraw, self, NULL);
 }
 
 static void
@@ -478,9 +487,9 @@ nautilus_selection_canvas_item_dispose (GObject *obj)
 {
        NautilusSelectionCanvasItem *self = NAUTILUS_SELECTION_CANVAS_ITEM (obj);
 
-       if (self->priv->fade_out_handler_id != 0) {
-               g_source_remove (self->priv->fade_out_handler_id);
-               self->priv->fade_out_handler_id = 0;
+       if (self->priv->fade_out_tick_id != 0) {
+               gtk_widget_remove_tick_callback (GTK_WIDGET (EEL_CANVAS_ITEM (self)->canvas), 
self->priv->fade_out_tick_id);
+               self->priv->fade_out_tick_id = 0;
        }
 
        G_OBJECT_CLASS (nautilus_selection_canvas_item_parent_class)->dispose (obj);