range: Have slider jump to the pointer coordinates on touch devices

This widget is too narrow to make touch interaction tricky enough, so
don't add the penalty of having the slider run farther from the touch
coordinates if it happens to miss the slider.

1 files changed, 14 insertions, 9 deletions

diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 23a4991306..b920d001d5 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2522,7 +2522,8 @@ gtk_range_button_press (GtkWidget      *widget,
 {
   GtkRange *range = GTK_RANGE (widget);
   GtkRangePrivate *priv = range->priv;
-  GdkDevice *device;
+  GdkDevice *device, *source_device;
+  GdkInputSource source;
 
   if (!gtk_widget_has_focus (widget))
     gtk_widget_grab_focus (widget);
@@ -2532,6 +2533,9 @@ gtk_range_button_press (GtkWidget      *widget,
     return FALSE;
 
   device = gdk_event_get_device ((GdkEvent *) event);
+  source_device = gdk_event_get_source_device ((GdkEvent *) event);
+  source = gdk_device_get_source (source_device);
+
   priv->mouse_x = event->x;
   priv->mouse_y = event->y;
 
@@ -2548,23 +2552,24 @@ gtk_range_button_press (GtkWidget      *widget,
       return TRUE;
     }
 
-  if (priv->mouse_location == MOUSE_TROUGH  &&
+  if (source != GDK_SOURCE_TOUCHSCREEN &&
+      priv->mouse_location == MOUSE_TROUGH &&
       event->button == GDK_BUTTON_PRIMARY)
     {
       /* button 1 steps by page increment, as with button 2 on a stepper
        */
       GtkScrollType scroll;
       gdouble click_value;
-      
+
       click_value = coord_to_value (range,
                                     priv->orientation == GTK_ORIENTATION_VERTICAL ?
                                     event->y : event->x);
 
       priv->trough_click_forward = click_value > gtk_adjustment_get_value (priv->adjustment);
       range_grab_add (range, device, MOUSE_TROUGH, event->button);
-      
+
       scroll = range_get_scroll_for_grab (range);
-      
+
       gtk_range_add_step_timer (range, scroll);
 
       return TRUE;
@@ -2599,17 +2604,17 @@ gtk_range_button_press (GtkWidget      *widget,
       return TRUE;
     }
   else if ((priv->mouse_location == MOUSE_TROUGH &&
-            event->button == GDK_BUTTON_MIDDLE) ||
+            (source == GDK_SOURCE_TOUCHSCREEN || event->button == GDK_BUTTON_MIDDLE)) ||
            priv->mouse_location == MOUSE_SLIDER)
     {
       gboolean need_value_update = FALSE;
 
       /* Any button can be used to drag the slider, but you can start
        * dragging the slider with a trough click using button 2;
-       * On button 2 press, we warp the slider to mouse position,
-       * then begin the slider drag.
+       * On button 2 press and touch devices, we warp the slider to
+       * mouse position, then begin the slider drag.
        */
-      if (event->button == GDK_BUTTON_MIDDLE)
+      if (event->button == GDK_BUTTON_MIDDLE || source == GDK_SOURCE_TOUCHSCREEN)
         {
           gdouble slider_low_value, slider_high_value, new_value;