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gtk,scrolledwindow: Clamp early overshooting when snapping back

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Fixes the situation where overshooting in scrolled windows with a
small viewport could end up overshooting right to the opposite
side, and then back again indefinitely.
This commit is contained in:
Carlos Garnacho
2011-11-26 20:23:08 +01:00
parent 76b285f475
commit 001a1517da
1 changed files with 34 additions and 46 deletions
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80
gtk/gtkscrolledwindow.c
View File

@@ -286,7 +286,8 @@ static void gtk_scrolled_window_auto_hide_scrollbars_stop (GtkScrolledWindo
static gboolean _gtk_scrolled_window_set_adjustment_value (GtkScrolledWindow *scrolled_window,
GtkAdjustment *adjustment,
gdouble value,
gboolean allow_overshooting);
gboolean allow_overshooting,
gboolean snap_to_border);
static guint signals[LAST_SIGNAL] = {0};
@@ -2276,37 +2277,41 @@ static gboolean
_gtk_scrolled_window_set_adjustment_value (GtkScrolledWindow *scrolled_window,
GtkAdjustment *adjustment,
gdouble value,
gboolean allow_overshooting)
gboolean allow_overshooting,
gboolean snap_to_border)
{
GtkScrolledWindowPrivate *priv = scrolled_window->priv;
gdouble lower, upper;
gdouble lower, upper, *prev_value;
lower = gtk_adjustment_get_lower (adjustment);
upper = gtk_adjustment_get_upper (adjustment) -
gtk_adjustment_get_page_size (adjustment);
if (adjustment == gtk_range_get_adjustment (GTK_RANGE (priv->hscrollbar)))
prev_value = &priv->unclamped_hadj_value;
else if (adjustment == gtk_range_get_adjustment (GTK_RANGE (priv->vscrollbar)))
prev_value = &priv->unclamped_vadj_value;
else
return FALSE;
if (snap_to_border)
{
if (*prev_value < 0 && value > 0)
value = 0;
else if (*prev_value > upper && value < upper)
value = upper;
}
if (allow_overshooting)
{
lower -= MAX_OVERSHOOT_DISTANCE;
upper += MAX_OVERSHOOT_DISTANCE;
}
if (adjustment == gtk_range_get_adjustment (GTK_RANGE (priv->hscrollbar)))
{
priv->unclamped_hadj_value = CLAMP (value, lower, upper);
gtk_adjustment_set_value (adjustment, value);
*prev_value = CLAMP (value, lower, upper);
gtk_adjustment_set_value (adjustment, value);
return (priv->unclamped_hadj_value != value);
}
else if (adjustment == gtk_range_get_adjustment (GTK_RANGE (priv->vscrollbar)))
{
priv->unclamped_vadj_value = CLAMP (value, lower, upper);
gtk_adjustment_set_value (adjustment, value);
return (priv->unclamped_vadj_value != value);
}
return FALSE;
return (*prev_value != value);
}
static gboolean
@@ -2317,7 +2322,7 @@ scrolled_window_deceleration_cb (gpointer user_data)
GtkScrolledWindowPrivate *priv = scrolled_window->priv;
GtkAdjustment *hadjustment, *vadjustment;
gint old_overshoot_x, old_overshoot_y, overshoot_x, overshoot_y;
gdouble value, clamp_value;
gdouble value;
gint64 current_time;
guint elapsed;
@@ -2337,7 +2342,7 @@ scrolled_window_deceleration_cb (gpointer user_data)
if (_gtk_scrolled_window_set_adjustment_value (scrolled_window,
hadjustment,
value, TRUE))
value, TRUE, TRUE))
data->x_velocity = 0;
}
else
@@ -2349,7 +2354,7 @@ scrolled_window_deceleration_cb (gpointer user_data)
if (_gtk_scrolled_window_set_adjustment_value (scrolled_window,
vadjustment,
value, TRUE))
value, TRUE, TRUE))
data->y_velocity = 0;
}
else
@@ -2362,17 +2367,7 @@ scrolled_window_deceleration_cb (gpointer user_data)
{
if (old_overshoot_x != 0)
{
/* Overshooting finished, clamp to border */
clamp_value = (old_overshoot_x < 0) ?
gtk_adjustment_get_lower (hadjustment) :
gtk_adjustment_get_upper (hadjustment) -
gtk_adjustment_get_page_size (hadjustment);
_gtk_scrolled_window_set_adjustment_value (scrolled_window,
hadjustment,
clamp_value,
FALSE);
/* Overshooting finished snapping back */
data->x_velocity = 0;
}
else if (data->x_velocity > 0)
@@ -2395,16 +2390,7 @@ scrolled_window_deceleration_cb (gpointer user_data)
{
if (old_overshoot_y != 0)
{
/* Overshooting finished, clamp to border */
clamp_value = (old_overshoot_y < 0) ?
gtk_adjustment_get_lower (vadjustment) :
gtk_adjustment_get_upper (vadjustment) -
gtk_adjustment_get_page_size (vadjustment);
_gtk_scrolled_window_set_adjustment_value (scrolled_window,
vadjustment,
clamp_value,
FALSE);
/* Overshooting finished snapping back */
data->y_velocity = 0;
}
else if (data->y_velocity > 0)
@@ -2470,11 +2456,11 @@ gtk_scrolled_window_cancel_deceleration (GtkScrolledWindow *scrolled_window)
_gtk_scrolled_window_set_adjustment_value (scrolled_window,
vadjustment,
gtk_adjustment_get_value (vadjustment),
FALSE);
FALSE, TRUE);
_gtk_scrolled_window_set_adjustment_value (scrolled_window,
hadjustment,
gtk_adjustment_get_value (hadjustment),
FALSE);
FALSE, TRUE);
}
}
@@ -2675,14 +2661,16 @@ gtk_scrolled_window_motion_notify_event (GtkWidget *widget,
if (hadjustment && priv->hscrollbar_visible)
{
dx = (priv->last_motion_event_x_root - event->x_root) + priv->unclamped_hadj_value;
_gtk_scrolled_window_set_adjustment_value (scrolled_window, hadjustment, dx, TRUE);
_gtk_scrolled_window_set_adjustment_value (scrolled_window, hadjustment,
dx, TRUE, FALSE);
}
vadjustment = gtk_range_get_adjustment (GTK_RANGE (priv->vscrollbar));
if (vadjustment && priv->vscrollbar_visible)
{
dy = (priv->last_motion_event_y_root - event->y_root) + priv->unclamped_vadj_value;
_gtk_scrolled_window_set_adjustment_value (scrolled_window, vadjustment, dy, TRUE);
_gtk_scrolled_window_set_adjustment_value (scrolled_window, vadjustment,
dy, TRUE, FALSE);
}
_gtk_scrolled_window_get_overshoot (scrolled_window,