[gtk+/wip/matthiasc/zoom-scroll-improvements: 3/4] range: Make steppers use smooth autoscrolling

[Matthias Clasen <matthiasc src gnome org>]

commit 05c67b1d2fa08e305d86244265f39140b691e741
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Feb 22 20:02:02 2015 -0500

    range: Make steppers use smooth autoscrolling
    
    This makes them work much nicer than the old timer-based
    implementation.

 gtk/gtkrange.c |   73 ++++++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 53 insertions(+), 20 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 761353c..0ed0362 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -244,6 +244,8 @@ static void update_slider_position   (GtkRange             *range,
                                      gint              mouse_x,
                                      gint              mouse_y);
 static void stop_scrolling           (GtkRange         *range);
+static void add_autoscroll           (GtkRange         *range);
+static void remove_autoscroll        (GtkRange         *range);
 
 /* Range methods */
 
@@ -1842,7 +1844,7 @@ draw_stepper (GtkRange     *range,
 
   gtk_style_context_save (context);
 
-  /* don't set juction sides on scrollbar steppers */
+  /* don't set junction sides on scrollbar steppers */
   if (gtk_style_context_has_class (context, GTK_STYLE_CLASS_SCROLLBAR))
     gtk_style_context_set_junction_sides (context, GTK_JUNCTION_NONE);
   else
@@ -2429,6 +2431,13 @@ gtk_range_key_press (GtkWidget   *widget,
 
       return TRUE;
     }
+  else if (priv->in_drag &&
+           (event->keyval == GDK_KEY_Shift_L ||
+            event->keyval == GDK_KEY_Shift_R))
+    {
+      update_zoom_state (range, !priv->zoom);
+      return TRUE;
+    }
 
   return GTK_WIDGET_CLASS (gtk_range_parent_class)->key_press_event (widget, event);
 }
@@ -2439,7 +2448,12 @@ gtk_range_long_press_gesture_pressed (GtkGestureLongPress *gesture,
                                       gdouble              y,
                                       GtkRange            *range)
 {
-  update_zoom_state (range, TRUE);
+  GtkRangePrivate *priv = range->priv;
+
+  gtk_range_update_mouse_location (range);
+
+  if (priv->mouse_location == MOUSE_SLIDER)
+    update_zoom_state (range, TRUE);
 }
 
 static void
@@ -2533,8 +2547,14 @@ gtk_range_multipress_gesture_pressed (GtkGestureMultiPress *gesture,
       gtk_range_queue_draw_location (range, priv->mouse_location);
 
       scroll = range_get_scroll_for_grab (range);
-      if (scroll != GTK_SCROLL_NONE)
-        gtk_range_add_step_timer (range, scroll);
+      if (scroll == GTK_SCROLL_START || scroll == GTK_SCROLL_END)
+        gtk_range_scroll (range, scroll);
+      else if (scroll != GTK_SCROLL_NONE)
+        {
+          remove_autoscroll (range);
+          range->priv->autoscroll_mode = scroll;
+          add_autoscroll (range);
+        }
     }
   else if ((priv->mouse_location == MOUSE_TROUGH &&
             (source == GDK_SOURCE_TOUCHSCREEN ||
@@ -2717,21 +2737,36 @@ autoscroll_cb (GtkWidget     *widget,
                GdkFrameClock *frame_clock,
                gpointer       data)
 {
-  GtkRange *range;
+  GtkRange *range = GTK_RANGE (data);
+  GtkRangePrivate *priv = range->priv;
+  GtkAdjustment *adj = priv->adjustment;
   gdouble increment;
   gdouble value;
   gboolean handled;
 
-  range = GTK_RANGE (data);
-
-  increment = gtk_adjustment_get_step_increment (range->priv->adjustment) / AUTOSCROLL_FACTOR;
-  if (range->priv->autoscroll_mode == GTK_SCROLL_STEP_BACKWARD)
-    increment *= -1;
+  switch (priv->autoscroll_mode)
+    {
+    case GTK_SCROLL_STEP_FORWARD:
+      increment = gtk_adjustment_get_step_increment (adj) / AUTOSCROLL_FACTOR;
+      break;
+    case GTK_SCROLL_PAGE_FORWARD:
+      increment = gtk_adjustment_get_page_increment (adj) / AUTOSCROLL_FACTOR;
+      break;
+    case GTK_SCROLL_STEP_BACKWARD:
+      increment = - gtk_adjustment_get_step_increment (adj) / AUTOSCROLL_FACTOR;
+      break;
+    case GTK_SCROLL_PAGE_BACKWARD:
+      increment = - gtk_adjustment_get_page_increment (adj) / AUTOSCROLL_FACTOR;
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+    }
 
-  value = gtk_adjustment_get_value (range->priv->adjustment);
+  value = gtk_adjustment_get_value (adj);
   value += increment;
-  g_signal_emit (range, signals[CHANGE_VALUE], 0, GTK_SCROLL_JUMP, value,
-                 &handled);
+
+  g_signal_emit (range, signals[CHANGE_VALUE], 0, GTK_SCROLL_JUMP, value, &handled);
 
   return G_SOURCE_CONTINUE;
 }
@@ -2741,14 +2776,12 @@ add_autoscroll (GtkRange *range)
 {
   GtkRangePrivate *priv = range->priv;
 
-  if (priv->autoscroll_id != 0
-      || priv->autoscroll_mode == GTK_SCROLL_NONE)
+  if (priv->autoscroll_id != 0 ||
+      priv->autoscroll_mode == GTK_SCROLL_NONE)
     return;
 
   priv->autoscroll_id = gtk_widget_add_tick_callback (GTK_WIDGET (range),
-                                                      autoscroll_cb,
-                                                      range,
-                                                      NULL);
+                                                      autoscroll_cb, range, NULL);
 }
 
 static void
@@ -4012,11 +4045,11 @@ gtk_range_real_change_value (GtkRange      *range,
       power = 1;
       while (i--)
         power *= 10;
-      
+
       value = floor ((value * power) + 0.5) / power;
     }
 
-  if (priv->in_drag)
+  if (priv->in_drag || priv->autoscroll_id)
     gtk_adjustment_set_value (priv->adjustment, value);
   else
     gtk_adjustment_animate_to_value (priv->adjustment, value);