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st-scroll-view: Add proper smooth scrolling

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The code here before was added as dummy code to satisfy an error
in the missing switch, and wasn't ever tested due to the lack of XI2
in mutter. Use the same math as GtkRange does to calculate scroll bar
positions from raw XI2 deltas to allow for proper smooth scrolling.

https://bugzilla.gnome.org/show_bug.cgi?id=687573
This commit is contained in:
Jasper St. Pierre 2012-11-04 10:10:50 -05:00
parent ca73017100
commit 165265f4fb
1 changed files with 47 additions and 36 deletions
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83
src/st/st-scroll-view.c
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@ -665,6 +665,45 @@ st_scroll_view_allocate (ClutterActor *actor,
}
static void
adjust_with_delta (StAdjustment *adj,
gdouble delta)
{
gdouble new_value, page_size, scroll_unit;
g_object_get (adj,
"page-size", &page_size,
NULL);
scroll_unit = pow (page_size, 2.0 / 3.0);
new_value = st_adjustment_get_value (adj) + delta * scroll_unit;
st_adjustment_set_value (adj, new_value);
}
static void
adjust_with_direction (StAdjustment *adj,
ClutterScrollDirection direction)
{
gdouble delta;
switch (direction)
{
case CLUTTER_SCROLL_UP:
case CLUTTER_SCROLL_LEFT:
delta = -1.0;
break;
case CLUTTER_SCROLL_RIGHT:
case CLUTTER_SCROLL_DOWN:
delta = 1.0;
break;
case CLUTTER_SCROLL_SMOOTH:
g_assert_not_reached ();
break;
}
adjust_with_delta (adj, delta);
}
static void
st_scroll_view_style_changed (StWidget *widget)
{
@ -687,57 +726,29 @@ st_scroll_view_scroll_event (ClutterActor *self,
ClutterScrollEvent *event)
{
StScrollViewPrivate *priv = ST_SCROLL_VIEW (self)->priv;
gdouble value, step, hvalue, vvalue, delta_x, delta_y;
/* don't handle scroll events if requested not to */
if (!priv->mouse_scroll)
return FALSE;
switch (event->direction)
{
case CLUTTER_SCROLL_SMOOTH:
clutter_event_get_scroll_delta ((ClutterEvent *)event,
&delta_x, &delta_y);
g_object_get (priv->hadjustment,
"value", &hvalue,
NULL);
g_object_get (priv->vadjustment,
"value", &vvalue,
NULL);
break;
case CLUTTER_SCROLL_UP:
case CLUTTER_SCROLL_DOWN:
g_object_get (priv->vadjustment,
"step-increment", &step,
"value", &value,
NULL);
break;
case CLUTTER_SCROLL_LEFT:
case CLUTTER_SCROLL_RIGHT:
g_object_get (priv->hadjustment,
"step-increment", &step,
"value", &value,
NULL);
break;
}
switch (event->direction)
{
case CLUTTER_SCROLL_SMOOTH:
st_adjustment_set_value (priv->hadjustment, hvalue + delta_x);
st_adjustment_set_value (priv->vadjustment, vvalue + delta_y);
{
gdouble delta_x, delta_y;
clutter_event_get_scroll_delta ((ClutterEvent *)event, &delta_x, &delta_y);
adjust_with_delta (priv->hadjustment, delta_x);
adjust_with_delta (priv->vadjustment, delta_y);
}
break;
case CLUTTER_SCROLL_UP:
st_adjustment_set_value (priv->vadjustment, value - step);
break;
case CLUTTER_SCROLL_DOWN:
st_adjustment_set_value (priv->vadjustment, value + step);
adjust_with_direction (priv->vadjustment, event->direction);
break;
case CLUTTER_SCROLL_LEFT:
st_adjustment_set_value (priv->hadjustment, value - step);
break;
case CLUTTER_SCROLL_RIGHT:
st_adjustment_set_value (priv->hadjustment, value + step);
adjust_with_direction (priv->hadjustment, event->direction);
break;
}