[gtk+] switch: Change handle_x to handle_pos

[Benjamin Otte <otte src gnome org>]

commit e1081bc4719c9e8cfef0d931d29838316412fa41
Author: Benjamin Otte <otte redhat com>
Date:   Mon Feb 16 06:25:44 2015 +0100

    switch: Change handle_x to handle_pos
    
    Make that variable go from 0.0 to 1.0 where 0.0 means inactive (slider
    is on the left) and 1.0 means active (slider is on the right).
    
    The math is simpler that way and most importantly the value is
    independent of size.

 gtk/gtkswitch.c |   57 +++++++++++++++---------------------------------------
 1 files changed, 16 insertions(+), 41 deletions(-)
---
diff --git a/gtk/gtkswitch.c b/gtk/gtkswitch.c
index c4b8bf2..d3a9a06 100644
--- a/gtk/gtkswitch.c
+++ b/gtk/gtkswitch.c
@@ -66,7 +66,7 @@ struct _GtkSwitchPrivate
   GtkGesture *pan_gesture;
   GtkGesture *multipress_gesture;
 
-  gint handle_x;
+  double handle_pos;
   gint64 start_time;
   gint64 end_time;
   guint tick_id;
@@ -149,22 +149,13 @@ gtk_switch_on_frame_clock_update (GtkWidget     *widget,
   if (now < priv->end_time)
     {
       gdouble t;
-      gint dest_offset, start_offset;
-
-      if (priv->is_active)
-        {
-          start_offset = gtk_widget_get_allocated_width (GTK_WIDGET (sw)) / 2;
-          dest_offset = 0;
-        }
-      else
-        {
-          start_offset = 0;
-          dest_offset = gtk_widget_get_allocated_width (GTK_WIDGET (sw)) / 2;
-        }
 
       t = (now - priv->start_time) / (gdouble) (priv->end_time - priv->start_time);
       t = ease_out_cubic (t);
-      priv->handle_x = start_offset + t * (dest_offset - start_offset);
+      if (priv->is_active)
+        priv->handle_pos = 1.0 - t;
+      else
+        priv->handle_pos = t;
     }
   else
     {
@@ -253,7 +244,7 @@ gtk_switch_pan_gesture_pan (GtkGesturePan   *gesture,
   GtkStyleContext *context;
   GtkStateFlags state;
   GtkBorder padding;
-  gint width, position;
+  gint width;
 
   if (direction == GTK_PAN_DIRECTION_LEFT)
     offset = -offset;
@@ -272,17 +263,11 @@ gtk_switch_pan_gesture_pan (GtkGesturePan   *gesture,
   width = gtk_widget_get_allocated_width (widget);
 
   if (priv->is_active)
-    position = width / 2 + offset;
-  else
-    position = offset;
-
+    offset += width / 2;
+  
+  offset /= width / 2;
   /* constrain the handle within the trough width */
-  if (position > (width / 2) - padding.right)
-    priv->handle_x = width / 2 - padding.right;
-  else if (position < padding.left)
-    priv->handle_x = 0;
-  else
-    priv->handle_x = position;
+  priv->handle_pos = CLAMP (offset, 0, 1.0);
 
   /* we need to redraw the handle */
   gtk_widget_queue_draw (widget);
@@ -297,7 +282,7 @@ gtk_switch_pan_gesture_drag_end (GtkGestureDrag *gesture,
   GtkSwitchPrivate *priv = sw->priv;
   GdkEventSequence *sequence;
   GtkAllocation allocation;
-  gboolean active = FALSE;
+  gboolean active;
 
   sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
 
@@ -308,19 +293,14 @@ gtk_switch_pan_gesture_drag_end (GtkGestureDrag *gesture,
       /* if half the handle passed the middle of the switch, then we
        * consider it to be on
        */
-      if ((priv->handle_x + (allocation.width / 4)) >= (allocation.width / 2))
-        active = TRUE;
+      active = priv->handle_pos >= 0.5;
     }
   else if (!gtk_gesture_handles_sequence (priv->multipress_gesture, sequence))
     active = priv->is_active;
   else
     return;
 
-  if (active)
-    priv->handle_x = allocation.width / 2;
-  else
-    priv->handle_x = 0;
-
+  priv->handle_pos = active ? 1.0 : 0.0;
   gtk_switch_set_active (sw, active);
   gtk_widget_queue_draw (GTK_WIDGET (sw));
 }
@@ -478,11 +458,6 @@ gtk_switch_size_allocate (GtkWidget     *widget,
                             allocation->width,
                             allocation->height);
 
-  if (priv->is_active)
-    priv->handle_x = gtk_widget_get_allocated_width (widget) / 2;
-  else
-    priv->handle_x = 0;
-
   _gtk_widget_set_simple_clip (widget, NULL);
 }
 
@@ -655,7 +630,7 @@ gtk_switch_draw (GtkWidget *widget,
 
   g_object_unref (layout);
 
-  handle.x = x + priv->handle_x;
+  handle.x = x + round (priv->handle_pos * width / 2);
 
   gtk_switch_paint_handle (widget, cr, &handle);
 
@@ -1098,9 +1073,9 @@ gtk_switch_set_active (GtkSwitch *sw,
       priv->is_active = is_active;
 
       if (priv->is_active)
-        priv->handle_x = gtk_widget_get_allocated_width (GTK_WIDGET (sw)) / 2;
+        priv->handle_pos = 1.0;
       else
-        priv->handle_x = 0;
+        priv->handle_pos = 0.0;
 
       g_object_notify_by_pspec (G_OBJECT (sw), switch_props[PROP_ACTIVE]);