forked from AuroraMiddleware/gtk
542 lines
17 KiB
C
542 lines
17 KiB
C
/* gtksizerequest.c
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* Copyright (C) 2007-2010 Openismus GmbH
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*
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* Authors:
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* Mathias Hasselmann <mathias@openismus.com>
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* Tristan Van Berkom <tristan.van.berkom@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/**
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* SECTION:gtksizerequest
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* @Short_Description: Height-for-width geometry management
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* @Title: GtkSizeRequest
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*
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* The GtkSizeRequest interface is GTK+'s height-for-width (and width-for-height)
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* geometry management system. Height-for-width means that a widget can
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* change how much vertical space it needs, depending on the amount
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* of horizontal space that it is given (and similar for width-for-height).
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* The most common example is a label that reflows to fill up the available
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* width, wraps to fewer lines, and therefore needs less height.
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*
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* GTK+'s traditional two-pass <link linkend="size-allocation">size-allocation</link>
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* algorithm does not allow this flexibility. #GtkWidget provides a default
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* implementation of the #GtkSizeRequest interface for existing widgets,
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* which always requests the same height, regardless of the available width.
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*
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* <refsect2>
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* <title>Implementing GtkSizeRequest</title>
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* <para>
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* Some important things to keep in mind when implementing
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* the GtkSizeRequest interface and when using it in container
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* implementations.
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*
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* The geometry management system will query a logical hierarchy in
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* only one orientation at a time. When widgets are initially queried
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* for their minimum sizes it is generally done in a dual pass
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* in the direction chosen by the toplevel.
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*
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* For instance when queried in the normal height-for-width mode:
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* First the default minimum and natural width for each widget
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* in the interface will computed and collectively returned to
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* the toplevel by way of gtk_size_request_get_desired_width().
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* Next, the toplevel will use the minimum width to query for the
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* minimum height contextual to that width using
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* gtk_size_request_get_height_for_width(), which will also be a
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* highly recursive operation. This minimum-for-minimum size can be
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* used to set the minimum size constraint on the toplevel.
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*
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* When allocating, each container can use the minimum and natural
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* sizes reported by their children to allocate natural sizes and
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* expose as much content as possible with the given allocation.
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*
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* That means that the request operation at allocation time will
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* usually fire again in contexts of different allocated sizes than
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* the ones originally queried for. #GtkSizeRequest caches a
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* small number of results to avoid re-querying for the same
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* allocated size in one allocation cycle.
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*
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* A widget that does not actually do height-for-width
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* or width-for-height size negotiations only has to implement
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* get_width() and get_height().
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*
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* If a widget does move content around to smartly use up the
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* allocated size, then it must support the request properly in
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* both orientations; even if the request only makes sense in
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* one orientation.
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*
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* For instance, a GtkLabel that does height-for-width word wrapping
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* will not expect to have get_height() called because that
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* call is specific to a width-for-height request, in this case the
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* label must return the heights contextual to its minimum possible
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* width. By following this rule any widget that handles height-for-width
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* or width-for-height requests will always be allocated at least
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* enough space to fit its own content.
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* </para>
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* </refsect2>
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*/
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#include <config.h>
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#include "gtksizerequest.h"
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#include "gtksizegroup.h"
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#include "gtkprivate.h"
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#include "gtkintl.h"
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#include "gtkalias.h"
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/* With GtkSizeRequest, a widget may be requested
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* its width for 2 or maximum 3 heights in one resize
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*/
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#define N_CACHED_SIZES 3
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typedef struct
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{
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guint age;
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gint for_size;
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gint minimum_size;
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gint natural_size;
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} SizeRequest;
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typedef struct {
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SizeRequest widths[N_CACHED_SIZES];
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SizeRequest heights[N_CACHED_SIZES];
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guint8 cached_width_age;
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guint8 cached_height_age;
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} SizeRequestCache;
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static GQuark quark_cache = 0;
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GType
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gtk_size_request_get_type (void)
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{
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static GType size_request_type = 0;
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if (G_UNLIKELY(!size_request_type))
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{
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size_request_type =
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g_type_register_static_simple (G_TYPE_INTERFACE, I_("GtkSizeRequest"),
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sizeof (GtkSizeRequestIface),
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NULL, 0, NULL, 0);
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g_type_interface_add_prerequisite (size_request_type, GTK_TYPE_WIDGET);
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quark_cache = g_quark_from_static_string ("gtk-size-request-cache");
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}
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return size_request_type;
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}
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/* looks for a cached size request for this for_size. If not
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* found, returns the oldest entry so it can be overwritten
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*
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* Note that this caching code was directly derived from
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* the Clutter toolkit.
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*/
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static gboolean
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get_cached_size (gint for_size,
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SizeRequest *cached_sizes,
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SizeRequest **result)
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{
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guint i;
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*result = &cached_sizes[0];
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for (i = 0; i < N_CACHED_SIZES; i++)
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{
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SizeRequest *cs;
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cs = &cached_sizes[i];
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if (cs->age > 0 && cs->for_size == for_size)
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{
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*result = cs;
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return TRUE;
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}
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else if (cs->age < (*result)->age)
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{
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*result = cs;
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}
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}
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return FALSE;
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}
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static void
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destroy_cache (SizeRequestCache *cache)
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{
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g_slice_free (SizeRequestCache, cache);
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}
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static SizeRequestCache *
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get_cache (GtkSizeRequest *widget,
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gboolean create)
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{
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SizeRequestCache *cache;
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cache = g_object_get_qdata (G_OBJECT (widget), quark_cache);
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if (!cache && create)
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{
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cache = g_slice_new0 (SizeRequestCache);
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cache->cached_width_age = 1;
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cache->cached_height_age = 1;
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g_object_set_qdata_full (G_OBJECT (widget), quark_cache, cache,
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(GDestroyNotify)destroy_cache);
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}
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return cache;
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}
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static void
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do_size_request (GtkWidget *widget)
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{
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if (GTK_WIDGET_REQUEST_NEEDED (widget))
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{
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gtk_widget_ensure_style (widget);
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GTK_PRIVATE_UNSET_FLAG (widget, GTK_REQUEST_NEEDED);
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g_signal_emit_by_name (widget,
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"size-request",
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&widget->requisition);
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}
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}
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static void
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compute_size_for_orientation (GtkSizeRequest *request,
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GtkSizeGroupMode orientation,
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gint for_size,
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gint *minimum_size,
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gint *natural_size)
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{
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SizeRequestCache *cache;
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SizeRequest *cached_size;
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GtkWidget *widget;
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gboolean found_in_cache = FALSE;
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g_return_if_fail (GTK_IS_SIZE_REQUEST (request));
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g_return_if_fail (minimum_size != NULL || natural_size != NULL);
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widget = GTK_WIDGET (request);
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cache = get_cache (request, TRUE);
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if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
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{
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cached_size = &cache->widths[0];
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if (!GTK_WIDGET_WIDTH_REQUEST_NEEDED (request))
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found_in_cache = get_cached_size (for_size, cache->widths, &cached_size);
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else
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{
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memset (cache->widths, 0, N_CACHED_SIZES * sizeof (SizeRequest));
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cache->cached_width_age = 1;
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}
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}
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else
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{
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cached_size = &cache->heights[0];
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if (!GTK_WIDGET_HEIGHT_REQUEST_NEEDED (request))
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found_in_cache = get_cached_size (for_size, cache->heights, &cached_size);
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else
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{
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memset (cache->heights, 0, N_CACHED_SIZES * sizeof (SizeRequest));
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cache->cached_height_age = 1;
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}
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}
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if (!found_in_cache)
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{
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gint min_size = 0, nat_size = 0;
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gint group_size, requisition_size;
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/* Unconditional size request runs but is often unhandled. */
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do_size_request (widget);
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if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
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{
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requisition_size = widget->requisition.width;
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if (for_size < 0)
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GTK_SIZE_REQUEST_GET_IFACE (request)->get_width (request, &min_size, &nat_size);
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else
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GTK_SIZE_REQUEST_GET_IFACE (request)->get_width_for_height (request, for_size,
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&min_size, &nat_size);
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}
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else
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{
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requisition_size = widget->requisition.height;
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if (for_size < 0)
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GTK_SIZE_REQUEST_GET_IFACE (request)->get_height (request, &min_size, &nat_size);
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else
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GTK_SIZE_REQUEST_GET_IFACE (request)->get_height_for_width (request, for_size,
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&min_size, &nat_size);
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}
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/* Support for dangling "size-request" signals and forward derived
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* classes that will not default to a ->get_width() that
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* returns the values in the ->requisition cache.
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*/
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min_size = MAX (min_size, requisition_size);
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nat_size = MAX (nat_size, requisition_size);
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cached_size->minimum_size = min_size;
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cached_size->natural_size = nat_size;
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cached_size->for_size = for_size;
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if (orientation == GTK_SIZE_GROUP_HORIZONTAL)
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{
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cached_size->age = cache->cached_width_age;
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cache->cached_width_age++;
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GTK_PRIVATE_UNSET_FLAG (request, GTK_WIDTH_REQUEST_NEEDED);
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}
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else
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{
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cached_size->age = cache->cached_height_age;
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cache->cached_height_age++;
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GTK_PRIVATE_UNSET_FLAG (request, GTK_HEIGHT_REQUEST_NEEDED);
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}
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/* Get size groups to compute the base requisition once one
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* of the values have been cached, then go ahead and update
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* the cache with the sizegroup computed value.
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*
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* Note this is also where values from gtk_widget_set_size_request()
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* are considered.
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*/
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group_size =
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_gtk_size_group_bump_requisition (GTK_WIDGET (request),
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orientation, cached_size->minimum_size);
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cached_size->minimum_size = MAX (cached_size->minimum_size, group_size);
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cached_size->natural_size = MAX (cached_size->natural_size, group_size);
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}
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if (minimum_size)
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*minimum_size = cached_size->minimum_size;
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if (natural_size)
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*natural_size = cached_size->natural_size;
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g_assert (cached_size->minimum_size <= cached_size->natural_size);
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GTK_NOTE (SIZE_REQUEST,
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g_print ("[%p] %s\t%s: %d is minimum %d and natural: %d (hit cache: %s)\n",
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request, G_OBJECT_TYPE_NAME (request),
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orientation == GTK_SIZE_GROUP_HORIZONTAL ?
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"width for height" : "height for width" ,
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for_size,
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cached_size->minimum_size,
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cached_size->natural_size,
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found_in_cache ? "yes" : "no"));
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}
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/**
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* gtk_size_request_is_height_for_width:
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* @widget: a #GtkSizeRequest instance
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*
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* Gets whether the widget prefers a height-for-width layout
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* or a width-for-height layout.
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*
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* <note><para>#GtkBin widgets generally propagate the preference of
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* their child, container widgets need to request something either in
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* context of their children or in context of their allocation
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* capabilities.</para></note>
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*
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* Returns: %TRUE if the widget prefers height-for-width, %FALSE if
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* the widget should be treated with a width-for-height preference.
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*
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* Since: 3.0
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*/
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GtkSizeRequestMode
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gtk_size_request_get_request_mode (GtkSizeRequest *widget)
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{
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GtkSizeRequestIface *iface;
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g_return_val_if_fail (GTK_IS_SIZE_REQUEST (widget), GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH);
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iface = GTK_SIZE_REQUEST_GET_IFACE (widget);
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if (iface->get_request_mode)
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return iface->get_request_mode (widget);
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/* By default widgets are height-for-width. */
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return GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH;
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}
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/**
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* gtk_size_request_get_width:
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* @widget: a #GtkSizeRequest instance
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* @minimum_width: (out) (allow-none): location to store the minimum width, or %NULL
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* @natural_width: (out) (allow-none): location to store the natural width, or %NULL
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*
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* Retrieves a widget's initial minimum and natural width.
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*
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* <note><para>This call is specific to height-for-width
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* requests.</para></note>
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*
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* Since: 3.0
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*/
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void
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gtk_size_request_get_width (GtkSizeRequest *widget,
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gint *minimum_width,
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gint *natural_width)
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{
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compute_size_for_orientation (widget, GTK_SIZE_GROUP_HORIZONTAL,
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-1, minimum_width, natural_width);
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}
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/**
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* gtk_size_request_get_height:
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* @widget: a #GtkSizeRequest instance
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* @minimum_height: (out) (allow-none): location to store the minimum height, or %NULL
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* @natural_height: (out) (allow-none): location to store the natural height, or %NULL
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*
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* Retrieves a widget's initial minimum and natural height.
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*
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* <note><para>This call is specific to width-for-height requests.</para></note>
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*
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* Since: 3.0
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*/
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void
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gtk_size_request_get_height (GtkSizeRequest *widget,
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gint *minimum_height,
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gint *natural_height)
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{
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compute_size_for_orientation (widget, GTK_SIZE_GROUP_VERTICAL,
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-1, minimum_height, natural_height);
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}
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/**
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* gtk_size_request_get_width_for_height:
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* @widget: a #GtkSizeRequest instance
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* @height: the height which is available for allocation
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* @minimum_width: (out) (allow-none): location for storing the minimum width, or %NULL
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* @natural_width: (out) (allow-none): location for storing the natural width, or %NULL
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*
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* Retrieves a widget's desired width if it would be given
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* the specified @height.
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*
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* Since: 3.0
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*/
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void
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gtk_size_request_get_width_for_height (GtkSizeRequest *widget,
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gint height,
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gint *minimum_width,
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gint *natural_width)
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{
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compute_size_for_orientation (widget, GTK_SIZE_GROUP_HORIZONTAL,
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height, minimum_width, natural_width);
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}
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/**
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* gtk_size_request_get_height_for_width:
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* @widget: a #GtkSizeRequest instance
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* @width: the width which is available for allocation
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* @minimum_height: (out) (allow-none): location for storing the minimum height, or %NULL
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* @natural_height: (out) (allow-none): location for storing the natural height, or %NULL
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*
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* Retrieves a widget's desired height if it would be given
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* the specified @width.
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*
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* Since: 3.0
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*/
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void
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gtk_size_request_get_height_for_width (GtkSizeRequest *widget,
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gint width,
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gint *minimum_height,
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gint *natural_height)
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{
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compute_size_for_orientation (widget, GTK_SIZE_GROUP_VERTICAL,
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width, minimum_height, natural_height);
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}
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/**
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* gtk_size_request_get_size:
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* @widget: a #GtkSizeRequest instance
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* @minimum_size: (out) (allow-none): location for storing the minimum size, or %NULL
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* @natural_size: (out) (allow-none): location for storing the natural size, or %NULL
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*
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* Retrieves the minimum and natural size of a widget taking
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* into account the widget's preference for height-for-width management.
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*
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* This is used to retrieve a suitable size by container widgets which do
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* not impose any restrictions on the child placement.
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*
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* Since: 3.0
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*/
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void
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gtk_size_request_get_size (GtkSizeRequest *widget,
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GtkRequisition *minimum_size,
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GtkRequisition *natural_size)
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{
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gint min_width, nat_width;
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gint min_height, nat_height;
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g_return_if_fail (GTK_IS_SIZE_REQUEST (widget));
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if (gtk_size_request_get_request_mode (widget) == GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH)
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{
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gtk_size_request_get_width (widget, &min_width, &nat_width);
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if (minimum_size)
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{
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minimum_size->width = min_width;
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gtk_size_request_get_height_for_width (widget, min_width,
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&minimum_size->height, NULL);
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}
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if (natural_size)
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{
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natural_size->width = nat_width;
|
|
gtk_size_request_get_height_for_width (widget, nat_width,
|
|
NULL, &natural_size->height);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
gtk_size_request_get_height (widget, &min_height, &nat_height);
|
|
|
|
if (minimum_size)
|
|
{
|
|
minimum_size->height = min_height;
|
|
gtk_size_request_get_width_for_height (widget, min_height,
|
|
&minimum_size->width, NULL);
|
|
}
|
|
|
|
if (natural_size)
|
|
{
|
|
natural_size->height = nat_height;
|
|
gtk_size_request_get_width_for_height (widget, nat_height,
|
|
NULL, &natural_size->width);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
#define __GTK_SIZE_REQUEST_C__
|
|
#include "gtkaliasdef.c"
|