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gtk2/gtk/gtkextendedlayout.c

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/* gtkextendedlayout.c
* Copyright (C) 2007-2010 Openismus GmbH
*
* Authors:
* Mathias Hasselmann <mathias@openismus.com>
* Tristan Van Berkom <tristan.van.berkom@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gtkextendedlayout
* @Short_Description: Height for Width Geometry management
* @Title: GtkExtendedLayout
*
* The extended layout is GTK+'s height for width geometry management
* system.
*
* <refsect2>
* <title>Implementing GtkExtendedLayout</title>
* <para>
* Some important things to keep in mind when implementing
* or using the extended layout.
*
* The Extended Layout system will query a logical heirarchy in
* only one orientation at a time. When widgets are initially queried
* for their minimum sizes it is generally done in a dual pass
* in the direction chosen by the toplevel.
*
* For instance when queried in the normal height-for-width mode:
* First the default minimum and natural width for each widget
* in the interface will computed and collectively returned to
* the toplevel by way of gtk_extended_layout_get_desired_width().
* Next; the toplevel will use the minimum width to query for the
* minimum height contextual to that width using gtk_extended_layout_get_height_for_width()
* which will also be a highly recursive operation. This minimum
* for minimum size can be used to set the minimum size constraint
* on the toplevel.
*
* When allocating; each container can use the minimum and natural
* sizes reported by thier children to allocate natural sizes and
* expose as much content as possible with the given allocation.
*
* That means that the request operation at allocation time will
* usually fire again in contexts of different allocated sizes than
* the ones originally queried for.
*
* A Widget that does not actually do height-for-width
* or width-for-height size negotiations only has to implement
* get_desired_width() and get_desired_height()
*
* If a widget does move content around to smartly use up the
* allocated size, then it must support the request properly in
* both orientations; even if the request only makes sense in
* one orientation.
*
* For instance; a GtkLabel that does height-for-width word wrapping
* will not expect to have get_desired_height() called because that
* call is specific to a width-for-height request, in this case the
* label must return the heights contextual to its minimum possible
* width. By following this rule any widget that handles height-for-width
* or width-for-height requests will always be allocated at least
* enough space to fit its own content.
* </para>
* </refsect2>
*/
#include <config.h>
#include "gtkextendedlayout.h"
#include "gtksizegroup.h"
#include "gtkprivate.h"
#include "gtkintl.h"
#include "gtkalias.h"
/* With extended layout, a widget may be requested
* its width for 2 or maximum 3 heights in one resize
*/
#define N_CACHED_SIZES 3
typedef struct
{
guint age;
gint for_size;
gint minimum_size;
gint natural_size;
} DesiredSize;
typedef struct {
DesiredSize desired_widths[N_CACHED_SIZES];
DesiredSize desired_heights[N_CACHED_SIZES];
guint8 cached_width_age;
guint8 cached_height_age;
} ExtendedLayoutCache;
static GQuark quark_cache = 0;
GType
gtk_extended_layout_get_type (void)
{
static GType extended_layout_type = 0;
if (G_UNLIKELY(!extended_layout_type))
{
extended_layout_type =
g_type_register_static_simple (G_TYPE_INTERFACE, I_("GtkExtendedLayout"),
sizeof (GtkExtendedLayoutIface),
NULL, 0, NULL, 0);
g_type_interface_add_prerequisite (extended_layout_type, GTK_TYPE_WIDGET);
quark_cache = g_quark_from_static_string ("gtk-extended-layout-cache");
}
return extended_layout_type;
}
/* looks for a cached size request for this for_size. If not
* found, returns the oldest entry so it can be overwritten
*
* Note that this caching code was directly derived from
* the Clutter toolkit.
*/
static gboolean
get_cached_desired_size (gint for_size,
DesiredSize *cached_sizes,
DesiredSize **result)
{
guint i;
*result = &cached_sizes[0];
for (i = 0; i < N_CACHED_SIZES; i++)
{
DesiredSize *cs;
cs = &cached_sizes[i];
if (cs->age > 0 &&
cs->for_size == for_size)
{
*result = cs;
return TRUE;
}
else if (cs->age < (*result)->age)
{
*result = cs;
}
}
return FALSE;
}
static void
destroy_cache (ExtendedLayoutCache *cache)
{
g_slice_free (ExtendedLayoutCache, cache);
}
ExtendedLayoutCache *
get_cache (GtkExtendedLayout *layout, gboolean create)
{
ExtendedLayoutCache *cache;
cache = g_object_get_qdata (G_OBJECT (layout), quark_cache);
if (!cache && create)
{
cache = g_slice_new0 (ExtendedLayoutCache);
cache->cached_width_age = 1;
cache->cached_height_age = 1;
g_object_set_qdata_full (G_OBJECT (layout), quark_cache, cache,
(GDestroyNotify)destroy_cache);
}
return cache;
}
static void
do_size_request (GtkWidget *widget)
{
if (GTK_WIDGET_REQUEST_NEEDED (widget))
{
gtk_widget_ensure_style (widget);
GTK_PRIVATE_UNSET_FLAG (widget, GTK_REQUEST_NEEDED);
g_signal_emit_by_name (widget,
"size-request",
&widget->requisition);
}
}
static void
compute_size_for_orientation (GtkExtendedLayout *layout,
GtkSizeGroupMode orientation,
gint for_size,
gint *minimum_size,
gint *natural_size)
{
ExtendedLayoutCache *cache;
DesiredSize *cached_size;
GtkWidget *widget;
gboolean found_in_cache = FALSE;
g_return_if_fail (GTK_IS_EXTENDED_LAYOUT (layout));
g_return_if_fail (minimum_size != NULL || natural_size != NULL);
widget = GTK_WIDGET (layout);
cache = get_cache (layout, TRUE);
if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
{
cached_size = &cache->desired_widths[0];
if (GTK_WIDGET_WIDTH_REQUEST_NEEDED (layout) == FALSE)
found_in_cache = get_cached_desired_size (for_size, cache->desired_widths, &cached_size);
else
{
memset (cache->desired_widths, 0x0, N_CACHED_SIZES * sizeof (DesiredSize));
cache->cached_width_age = 1;
}
}
else
{
cached_size = &cache->desired_heights[0];
if (GTK_WIDGET_HEIGHT_REQUEST_NEEDED (layout) == FALSE)
found_in_cache = get_cached_desired_size (for_size, cache->desired_heights, &cached_size);
else
{
memset (cache->desired_heights, 0x0, N_CACHED_SIZES * sizeof (DesiredSize));
cache->cached_height_age = 1;
}
}
if (!found_in_cache)
{
gint min_size = 0, nat_size = 0;
gint group_size, requisition_size;
/* Unconditional size request runs but is often unhandled. */
do_size_request (widget);
if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
{
requisition_size = widget->requisition.width;
if (for_size < 0)
GTK_EXTENDED_LAYOUT_GET_IFACE (layout)->get_desired_width (layout, &min_size, &nat_size);
else
GTK_EXTENDED_LAYOUT_GET_IFACE (layout)->get_width_for_height (layout, for_size, &min_size, &nat_size);
}
else
{
requisition_size = widget->requisition.height;
if (for_size < 0)
GTK_EXTENDED_LAYOUT_GET_IFACE (layout)->get_desired_height (layout, &min_size, &nat_size);
else
GTK_EXTENDED_LAYOUT_GET_IFACE (layout)->get_height_for_width (layout, for_size, &min_size, &nat_size);
}
/* Support for dangling "size-request" signals and forward derived
* classes that will not default to a ->get_desired_width() that
* returns the values in the ->requisition cache.
*/
min_size = MAX (min_size, requisition_size);
nat_size = MAX (nat_size, requisition_size);
cached_size->minimum_size = min_size;
cached_size->natural_size = nat_size;
cached_size->for_size = for_size;
if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
{
cached_size->age = cache->cached_width_age;
cache->cached_width_age++;
GTK_PRIVATE_UNSET_FLAG (layout, GTK_WIDTH_REQUEST_NEEDED);
}
else
{
cached_size->age = cache->cached_height_age;
cache->cached_height_age++;
GTK_PRIVATE_UNSET_FLAG (layout, GTK_HEIGHT_REQUEST_NEEDED);
}
/* Get size groups to compute the base requisition once one of the values have been cached,
* then go ahead and update the cache with the sizegroup computed value.
*
* Note this is also where values from gtk_widget_set_size_request() are considered.
*/
group_size =
_gtk_size_group_bump_requisition (GTK_WIDGET (layout),
orientation, cached_size->minimum_size);
cached_size->minimum_size = MAX (cached_size->minimum_size, group_size);
cached_size->natural_size = MAX (cached_size->natural_size, group_size);
}
if (minimum_size)
*minimum_size = cached_size->minimum_size;
if (natural_size)
*natural_size = cached_size->natural_size;
g_assert (cached_size->minimum_size <= cached_size->natural_size);
GTK_NOTE (EXTENDED_LAYOUT,
g_print ("[%p] %s\t%s: %d is minimum %d and natural: %d (hit cache: %s)\n",
layout, G_OBJECT_TYPE_NAME (layout),
orientation == GTK_SIZE_GROUP_HORIZONTAL ?
"width for height" : "height for width" ,
for_size,
cached_size->minimum_size,
cached_size->natural_size,
found_in_cache ? "yes" : "no"));
}
/**
* gtk_extended_layout_is_height_for_width:
* @layout: a #GtkExtendedLayout instance
*
* Gets whether the widget prefers a height-for-width layout
* or a width-for-height layout
*
* Returns: %TRUE if the widget prefers height-for-width, %FALSE if
* the widget should be treated with a width-for-height preference.
*
* <note><para>#GtkBin widgets generally propagate the preference of thier child,
* container widgets need to request something either in context of their
* children or in context of their allocation capabilities.</para></note>
*
* Since: 3.0
*/
gboolean
gtk_extended_layout_is_height_for_width (GtkExtendedLayout *layout)
{
GtkExtendedLayoutIface *iface;
g_return_val_if_fail (GTK_IS_EXTENDED_LAYOUT (layout), FALSE);
iface = GTK_EXTENDED_LAYOUT_GET_IFACE (layout);
if (iface->is_height_for_width)
return iface->is_height_for_width (layout);
/* By default widgets are height-for-width. */
return TRUE;
}
/**
* gtk_extended_layout_get_desired_width:
* @layout: a #GtkExtendedLayout instance
* @minimum_width: location to store the minimum size, or %NULL
* @natural_width: location to store the natural size, or %NULL
*
* Retreives a widget's initial minimum and natural width.
*
* <note><para>This call is specific to height for width requests.</para></note>
*
* Since: 3.0
*/
void
gtk_extended_layout_get_desired_width (GtkExtendedLayout *layout,
gint *minimum_width,
gint *natural_width)
{
compute_size_for_orientation (layout, GTK_SIZE_GROUP_HORIZONTAL, -1, minimum_width, natural_width);
}
/**
* gtk_extended_layout_get_desired_height:
* @layout: a #GtkExtendedLayout instance
* @minimum_width: location to store the minimum size, or %NULL
* @natural_width: location to store the natural size, or %NULL
*
* Retreives a widget's minimum and natural size in a single dimension.
*
* <note><para>This call is specific to width for height requests.</para></note>
*
* Since: 3.0
*/
void
gtk_extended_layout_get_desired_height (GtkExtendedLayout *layout,
gint *minimum_height,
gint *natural_height)
{
compute_size_for_orientation (layout, GTK_SIZE_GROUP_VERTICAL, -1, minimum_height, natural_height);
}
/**
* gtk_extended_layout_get_width_for_height:
* @layout: a #GtkExtendedLayout instance
* @height: the size which is available for allocation
* @minimum_size: location for storing the minimum size, or %NULL
* @natural_size: location for storing the natural size, or %NULL
*
* Retreives a widget's desired width if it would be given
* the specified @height.
*
* Since: 3.0
*/
void
gtk_extended_layout_get_width_for_height (GtkExtendedLayout *layout,
gint height,
gint *minimum_width,
gint *natural_width)
{
compute_size_for_orientation (layout, GTK_SIZE_GROUP_HORIZONTAL, height, minimum_width, natural_width);
}
/**
* gtk_extended_layout_get_height_for_width:
* @layout: a #GtkExtendedLayout instance
* @width: the size which is available for allocation
* @minimum_size: location for storing the minimum size, or %NULL
* @natural_size: location for storing the natural size, or %NULL
*
* Retreives a widget's desired height if it would be given
* the specified @width.
*
* Since: 3.0
*/
void
gtk_extended_layout_get_height_for_width (GtkExtendedLayout *layout,
gint width,
gint *minimum_height,
gint *natural_height)
{
compute_size_for_orientation (layout, GTK_SIZE_GROUP_VERTICAL, width, minimum_height, natural_height);
}
/**
* gtk_extended_layout_get_desired_size:
* @layout: a #GtkExtendedLayout instance
* @width: the size which is available for allocation
* @request_natural: Whether to base the contextual request off of the
* base natural or the base minimum
* @minimum_size: location for storing the minimum size, or %NULL
* @natural_size: location for storing the natural size, or %NULL
*
* Retreives the minimum and natural size of a widget taking
* into account the widget's preference for height-for-width management.
*
* If request_natural is specified, the non-contextual natural value will
* be used to make the contextual request; otherwise the minimum will be used.
*
* This is used to retreive a suitable size by container widgets whom dont
* impose any restrictions on the child placement, examples of these are
* #GtkWindow and #GtkScrolledWindow.
*
* Since: 3.0
*/
void
gtk_extended_layout_get_desired_size (GtkExtendedLayout *layout,
gboolean request_natural,
GtkRequisition *minimum_size,
GtkRequisition *natural_size)
{
gint min_width, nat_width;
gint min_height, nat_height;
g_return_if_fail (GTK_IS_EXTENDED_LAYOUT (layout));
if (gtk_extended_layout_is_height_for_width (layout))
{
gtk_extended_layout_get_desired_width (layout, &min_width, &nat_width);
gtk_extended_layout_get_height_for_width (layout,
request_natural ? nat_width : min_width,
&min_height, &nat_height);
}
else
{
gtk_extended_layout_get_desired_height (layout, &min_height, &nat_height);
gtk_extended_layout_get_width_for_height (layout,
request_natural ? nat_height : min_height,
&min_width, &nat_width);
}
if (minimum_size)
{
minimum_size->width = min_width;
minimum_size->height = min_height;
}
if (natural_size)
{
natural_size->width = nat_width;
natural_size->height = nat_height;
}
}
#define __GTK_EXTENDED_LAYOUT_C__
#include "gtkaliasdef.c"
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