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libgimpwidgets: add gimp_scroll_adjustment_values() 

and use it in GimpScrolledPreview. It supports smooth scrolling and
does roughly the same as a whole lot of magic code in GtkScrolledWindow
and GtkRange, resulting in the same scrolling behavior as in stock
GTK+ widgets.
This commit is contained in:
Michael Natterer 2018-05-10 23:24:29 +02:00
parent 97e19eb385
commit 4a979995a3
2 changed files with 97 additions and 45 deletions
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135
libgimpwidgets/gimpscrolledpreview.c
View File

@ -470,58 +470,25 @@ gimp_scrolled_preview_area_event (GtkWidget *area,
case GDK_SCROLL:
{
GdkEventScroll *sevent = (GdkEventScroll *) event;
GdkScrollDirection direction = sevent->direction;
GtkAdjustment *adj;
gfloat value;
GdkEventScroll *sevent = (GdkEventScroll *) event;
GtkAdjustment *adj_x;
GtkAdjustment *adj_y;
gdouble value_x;
gdouble value_y;
/* Ctrl-Scroll is reserved for zooming */
if (sevent->state & GDK_CONTROL_MASK)
return FALSE;
if (sevent->state & GDK_SHIFT_MASK)
switch (direction)
{
case GDK_SCROLL_UP: direction = GDK_SCROLL_LEFT; break;
case GDK_SCROLL_DOWN: direction = GDK_SCROLL_RIGHT; break;
case GDK_SCROLL_LEFT: direction = GDK_SCROLL_UP; break;
case GDK_SCROLL_RIGHT: direction = GDK_SCROLL_DOWN; break;
}
adj_x = gtk_range_get_adjustment (GTK_RANGE (priv->hscr));
adj_y = gtk_range_get_adjustment (GTK_RANGE (priv->vscr));
switch (direction)
{
case GDK_SCROLL_UP:
case GDK_SCROLL_DOWN:
default:
adj = gtk_range_get_adjustment (GTK_RANGE (priv->vscr));
break;
gimp_scroll_adjustment_values (sevent,
adj_x, adj_y,
&value_x, &value_y);
case GDK_SCROLL_RIGHT:
case GDK_SCROLL_LEFT:
adj = gtk_range_get_adjustment (GTK_RANGE (priv->hscr));
break;
}
value = gtk_adjustment_get_value (adj);
switch (direction)
{
case GDK_SCROLL_UP:
case GDK_SCROLL_LEFT:
value -= gtk_adjustment_get_page_increment (adj) / 2;
break;
case GDK_SCROLL_DOWN:
case GDK_SCROLL_RIGHT:
value += gtk_adjustment_get_page_increment (adj) / 2;
break;
}
gtk_adjustment_set_value (adj,
CLAMP (value,
gtk_adjustment_get_lower (adj),
gtk_adjustment_get_upper (adj) -
gtk_adjustment_get_page_size (adj)));
gtk_adjustment_set_value (adj_x, value_x);
gtk_adjustment_set_value (adj_y, value_y);
}
break;
@ -986,3 +953,81 @@ gimp_scrolled_preview_thaw (GimpScrolledPreview *preview)
gimp_preview_invalidate (GIMP_PREVIEW (preview));
}
}
void
gimp_scroll_adjustment_values (GdkEventScroll *sevent,
GtkAdjustment *hadj,
GtkAdjustment *vadj,
gdouble *hvalue,
gdouble *vvalue)
{
GtkAdjustment *adj_x;
GtkAdjustment *adj_y;
gdouble page_size_x;
gdouble page_size_y;
gdouble value_x = 0.0;
gdouble value_y = 0.0;
g_return_if_fail (sevent != NULL);
g_return_if_fail (GTK_IS_ADJUSTMENT (hadj));
g_return_if_fail (GTK_IS_ADJUSTMENT (vadj));
if (sevent->state & GDK_SHIFT_MASK)
{
adj_x = vadj;
adj_y = hadj;
}
else
{
adj_x = hadj;
adj_y = vadj;
}
page_size_x = gtk_adjustment_get_page_size (adj_x);
page_size_y = gtk_adjustment_get_page_size (adj_y);
switch (sevent->direction)
{
case GDK_SCROLL_LEFT:
value_x = -pow (page_size_x, 2.0 / 3.0);
break;
case GDK_SCROLL_RIGHT:
value_x = pow (page_size_x, 2.0 / 3.0);
break;
case GDK_SCROLL_UP:
value_y = -pow (page_size_y, 2.0 / 3.0);
break;
case GDK_SCROLL_DOWN:
value_y = pow (page_size_y, 2.0 / 3.0);
break;
case GDK_SCROLL_SMOOTH:
gdk_event_get_scroll_deltas ((GdkEvent *) sevent, &value_x, &value_y);
}
value_x = CLAMP (value_x +
gtk_adjustment_get_value (adj_x),
gtk_adjustment_get_lower (adj_x),
gtk_adjustment_get_upper (adj_x) -
gtk_adjustment_get_page_size (adj_x));
value_y = CLAMP (value_y +
gtk_adjustment_get_value (adj_y),
gtk_adjustment_get_lower (adj_y),
gtk_adjustment_get_upper (adj_y) -
gtk_adjustment_get_page_size (adj_y));
if (sevent->state & GDK_SHIFT_MASK)
{
if (hvalue) *hvalue = value_y;
if (vvalue) *vvalue = value_x;
}
else
{
if (hvalue) *hvalue = value_x;
if (vvalue) *vvalue = value_y;
}
}

7
libgimpwidgets/gimpscrolledpreview.h
View File

@ -84,6 +84,13 @@ void gimp_scrolled_preview_get_adjustments (GimpScrolledPreview *preview,
void gimp_scrolled_preview_freeze (GimpScrolledPreview *preview);
void gimp_scrolled_preview_thaw (GimpScrolledPreview *preview);
/* utility function for scrolled-window like gimp widgets like the canvas */
void gimp_scroll_adjustment_values (GdkEventScroll *sevent,
GtkAdjustment *hadj,
GtkAdjustment *vadj,
gdouble *hvalue,
gdouble *vvalue);
G_END_DECLS