388 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			388 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* GTK - The GIMP Toolkit
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|  * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
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|  *
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|  * GtkAspectFrame: Ensure that the child window has a specified aspect ratio
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|  *    or, if obey_child, has the same aspect ratio as its requested size
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|  *
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|  *     Copyright Owen Taylor                          4/9/97
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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 Lesser 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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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with this library. If not, see <http://www.gnu.org/licenses/>.
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|  */
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| 
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| /*
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|  * Modified by the GTK+ Team and others 1997-2001.  See the AUTHORS
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|  * file for a list of people on the GTK+ Team.  See the ChangeLog
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|  * files for a list of changes.  These files are distributed with
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|  * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
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|  */
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| 
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| /**
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|  * SECTION:gtkaspectframe
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|  * @Short_description: A frame that constrains its child to a particular aspect ratio
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|  * @Title: GtkAspectFrame
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|  *
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|  * The #GtkAspectFrame is useful when you want
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|  * pack a widget so that it can resize but always retains
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|  * the same aspect ratio. For instance, one might be
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|  * drawing a small preview of a larger image. #GtkAspectFrame
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|  * derives from #GtkFrame, so it can draw a label and
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|  * a frame around the child. The frame will be
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|  * "shrink-wrapped" to the size of the child.
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|  */
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| 
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| #include "config.h"
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| 
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| #include "gtkaspectframe.h"
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| 
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| #include "gtksizerequest.h"
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| 
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| #include "gtkprivate.h"
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| #include "gtkintl.h"
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| 
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| 
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| 
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| struct _GtkAspectFramePrivate
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| {
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|   GtkAllocation center_allocation;
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| 
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|   gboolean      obey_child;
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|   gfloat        xalign;
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|   gfloat        yalign;
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|   gfloat        ratio;
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| };
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| 
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| 
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| enum {
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|   PROP_0,
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|   PROP_XALIGN,
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|   PROP_YALIGN,
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|   PROP_RATIO,
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|   PROP_OBEY_CHILD
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| };
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| 
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| static void gtk_aspect_frame_set_property (GObject         *object,
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| 					   guint            prop_id,
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| 					   const GValue    *value,
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| 					   GParamSpec      *pspec);
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| static void gtk_aspect_frame_get_property (GObject         *object,
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| 					   guint            prop_id,
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| 					   GValue          *value,
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| 					   GParamSpec      *pspec);
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| static void gtk_aspect_frame_compute_child_allocation (GtkFrame            *frame,
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| 						       GtkAllocation       *child_allocation);
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| 
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| #define MAX_RATIO 10000.0
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| #define MIN_RATIO 0.0001
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| 
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| G_DEFINE_TYPE (GtkAspectFrame, gtk_aspect_frame, GTK_TYPE_FRAME)
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| 
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| static void
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| gtk_aspect_frame_class_init (GtkAspectFrameClass *class)
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| {
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|   GObjectClass *gobject_class;
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|   GtkFrameClass *frame_class;
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|   
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|   gobject_class = (GObjectClass*) class;
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|   frame_class = (GtkFrameClass*) class;
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|   
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|   gobject_class->set_property = gtk_aspect_frame_set_property;
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|   gobject_class->get_property = gtk_aspect_frame_get_property;
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| 
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|   frame_class->compute_child_allocation = gtk_aspect_frame_compute_child_allocation;
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| 
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|   g_object_class_install_property (gobject_class,
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|                                    PROP_XALIGN,
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|                                    g_param_spec_float ("xalign",
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|                                                        P_("Horizontal Alignment"),
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|                                                        P_("X alignment of the child"),
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|                                                        0.0, 1.0, 0.5,
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|                                                        GTK_PARAM_READWRITE));
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|   g_object_class_install_property (gobject_class,
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|                                    PROP_YALIGN,
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|                                    g_param_spec_float ("yalign",
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|                                                        P_("Vertical Alignment"),
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|                                                        P_("Y alignment of the child"),
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|                                                        0.0, 1.0, 0.5,
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|                                                        GTK_PARAM_READWRITE));
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|   g_object_class_install_property (gobject_class,
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|                                    PROP_RATIO,
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|                                    g_param_spec_float ("ratio",
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|                                                        P_("Ratio"),
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|                                                        P_("Aspect ratio if obey_child is FALSE"),
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|                                                        MIN_RATIO, MAX_RATIO, 1.0,
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|                                                        GTK_PARAM_READWRITE));
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|   g_object_class_install_property (gobject_class,
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|                                    PROP_OBEY_CHILD,
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|                                    g_param_spec_boolean ("obey-child",
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|                                                          P_("Obey child"),
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|                                                          P_("Force aspect ratio to match that of the frame's child"),
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|                                                          TRUE,
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|                                                          GTK_PARAM_READWRITE));
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| 
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|   g_type_class_add_private (class, sizeof (GtkAspectFramePrivate));
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| }
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| 
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| static void
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| gtk_aspect_frame_init (GtkAspectFrame *aspect_frame)
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| {
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|   GtkAspectFramePrivate *priv;
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| 
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|   aspect_frame->priv = G_TYPE_INSTANCE_GET_PRIVATE (aspect_frame,
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|                                                     GTK_TYPE_ASPECT_FRAME,
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|                                                     GtkAspectFramePrivate);
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|   priv = aspect_frame->priv;
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| 
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|   priv->xalign = 0.5;
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|   priv->yalign = 0.5;
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|   priv->ratio = 1.0;
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|   priv->obey_child = TRUE;
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| }
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| 
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| static void
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| gtk_aspect_frame_set_property (GObject         *object,
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| 			       guint            prop_id,
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| 			       const GValue    *value,
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| 			       GParamSpec      *pspec)
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| {
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|   GtkAspectFrame *aspect_frame = GTK_ASPECT_FRAME (object);
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|   GtkAspectFramePrivate *priv = aspect_frame->priv;
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|   
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|   switch (prop_id)
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|     {
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|       /* g_object_notify is handled by the _frame_set function */
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|     case PROP_XALIGN:
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|       gtk_aspect_frame_set (aspect_frame,
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| 			    g_value_get_float (value),
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| 			    priv->yalign,
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| 			    priv->ratio,
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| 			    priv->obey_child);
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|       break;
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|     case PROP_YALIGN:
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|       gtk_aspect_frame_set (aspect_frame,
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| 			    priv->xalign,
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| 			    g_value_get_float (value),
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| 			    priv->ratio,
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| 			    priv->obey_child);
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|       break;
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|     case PROP_RATIO:
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|       gtk_aspect_frame_set (aspect_frame,
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| 			    priv->xalign,
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| 			    priv->yalign,
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| 			    g_value_get_float (value),
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| 			    priv->obey_child);
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|       break;
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|     case PROP_OBEY_CHILD:
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|       gtk_aspect_frame_set (aspect_frame,
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| 			    priv->xalign,
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| 			    priv->yalign,
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| 			    priv->ratio,
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| 			    g_value_get_boolean (value));
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|       break;
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|     default:
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|        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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|       break;
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|     }
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| }
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| 
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| static void
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| gtk_aspect_frame_get_property (GObject         *object,
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| 			       guint            prop_id,
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| 			       GValue          *value,
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| 			       GParamSpec      *pspec)
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| {
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|   GtkAspectFrame *aspect_frame = GTK_ASPECT_FRAME (object);
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|   GtkAspectFramePrivate *priv = aspect_frame->priv;
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|   
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|   switch (prop_id)
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|     {
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|     case PROP_XALIGN:
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|       g_value_set_float (value, priv->xalign);
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|       break;
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|     case PROP_YALIGN:
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|       g_value_set_float (value, priv->yalign);
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|       break;
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|     case PROP_RATIO:
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|       g_value_set_float (value, priv->ratio);
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|       break;
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|     case PROP_OBEY_CHILD:
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|       g_value_set_boolean (value, priv->obey_child);
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|       break;
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|     default:
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|        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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|       break;
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|     }
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| }
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| 
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| /**
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|  * gtk_aspect_frame_new:
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|  * @label: Label text.
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|  * @xalign: Horizontal alignment of the child within the allocation of
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|  *  the #GtkAspectFrame. This ranges from 0.0 (left aligned)
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|  *  to 1.0 (right aligned)
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|  * @yalign: Vertical alignment of the child within the allocation of
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|  *  the #GtkAspectFrame. This ranges from 0.0 (top aligned)
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|  *  to 1.0 (bottom aligned)
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|  * @ratio: The desired aspect ratio.
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|  * @obey_child: If %TRUE, @ratio is ignored, and the aspect
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|  *  ratio is taken from the requistion of the child.
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|  *
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|  * Create a new #GtkAspectFrame.
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|  *
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|  * Returns: the new #GtkAspectFrame.
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|  */
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| GtkWidget*
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| gtk_aspect_frame_new (const gchar *label,
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| 		      gfloat       xalign,
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| 		      gfloat       yalign,
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| 		      gfloat       ratio,
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| 		      gboolean     obey_child)
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| {
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|   GtkAspectFrame *aspect_frame;
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|   GtkAspectFramePrivate *priv;
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| 
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|   aspect_frame = g_object_new (GTK_TYPE_ASPECT_FRAME, NULL);
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| 
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|   priv = aspect_frame->priv;
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| 
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|   priv->xalign = CLAMP (xalign, 0.0, 1.0);
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|   priv->yalign = CLAMP (yalign, 0.0, 1.0);
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|   priv->ratio = CLAMP (ratio, MIN_RATIO, MAX_RATIO);
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|   priv->obey_child = obey_child != FALSE;
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| 
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|   gtk_frame_set_label (GTK_FRAME(aspect_frame), label);
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| 
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|   return GTK_WIDGET (aspect_frame);
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| }
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| 
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| /**
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|  * gtk_aspect_frame_set:
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|  * @aspect_frame: a #GtkAspectFrame
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|  * @xalign: Horizontal alignment of the child within the allocation of
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|  *  the #GtkAspectFrame. This ranges from 0.0 (left aligned)
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|  *  to 1.0 (right aligned)
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|  * @yalign: Vertical alignment of the child within the allocation of
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|  *  the #GtkAspectFrame. This ranges from 0.0 (top aligned)
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|  *  to 1.0 (bottom aligned)
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|  * @ratio: The desired aspect ratio.
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|  * @obey_child: If %TRUE, @ratio is ignored, and the aspect
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|  *  ratio is taken from the requistion of the child.
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|  *
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|  * Set parameters for an existing #GtkAspectFrame.
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|  */
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| void
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| gtk_aspect_frame_set (GtkAspectFrame *aspect_frame,
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| 		      gfloat          xalign,
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| 		      gfloat          yalign,
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| 		      gfloat          ratio,
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| 		      gboolean        obey_child)
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| {
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|   GtkAspectFramePrivate *priv;
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| 
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|   g_return_if_fail (GTK_IS_ASPECT_FRAME (aspect_frame));
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| 
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|   priv = aspect_frame->priv;
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|   
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|   xalign = CLAMP (xalign, 0.0, 1.0);
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|   yalign = CLAMP (yalign, 0.0, 1.0);
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|   ratio = CLAMP (ratio, MIN_RATIO, MAX_RATIO);
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|   obey_child = obey_child != FALSE;
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|   
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|   if (priv->xalign != xalign
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|       || priv->yalign != yalign
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|       || priv->ratio != ratio
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|       || priv->obey_child != obey_child)
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|     {
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|       g_object_freeze_notify (G_OBJECT (aspect_frame));
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| 
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|       if (priv->xalign != xalign)
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|         {
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|           priv->xalign = xalign;
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|           g_object_notify (G_OBJECT (aspect_frame), "xalign");
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|         }
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|       if (priv->yalign != yalign)
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|         {
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|           priv->yalign = yalign;
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|           g_object_notify (G_OBJECT (aspect_frame), "yalign");
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|         }
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|       if (priv->ratio != ratio)
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|         {
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|           priv->ratio = ratio;
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|           g_object_notify (G_OBJECT (aspect_frame), "ratio");
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|         }
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|       if (priv->obey_child != obey_child)
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|         {
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|           priv->obey_child = obey_child;
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|           g_object_notify (G_OBJECT (aspect_frame), "obey-child");
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|         }
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|       g_object_thaw_notify (G_OBJECT (aspect_frame));
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| 
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|       gtk_widget_queue_resize (GTK_WIDGET (aspect_frame));
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|     }
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| }
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| 
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| static void
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| gtk_aspect_frame_compute_child_allocation (GtkFrame      *frame,
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| 					   GtkAllocation *child_allocation)
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| {
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|   GtkAspectFrame *aspect_frame = GTK_ASPECT_FRAME (frame);
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|   GtkAspectFramePrivate *priv = aspect_frame->priv;
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|   GtkBin *bin = GTK_BIN (frame);
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|   GtkWidget *child;
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|   gdouble ratio;
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| 
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|   child = gtk_bin_get_child (bin);
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|   if (child && gtk_widget_get_visible (child))
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|     {
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|       GtkAllocation full_allocation;
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|       
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|       if (priv->obey_child)
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| 	{
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| 	  GtkRequisition child_requisition;
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| 
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|           gtk_widget_get_preferred_size (child, &child_requisition, NULL);
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| 	  if (child_requisition.height != 0)
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| 	    {
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| 	      ratio = ((gdouble) child_requisition.width /
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| 		       child_requisition.height);
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| 	      if (ratio < MIN_RATIO)
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| 		ratio = MIN_RATIO;
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| 	    }
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| 	  else if (child_requisition.width != 0)
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| 	    ratio = MAX_RATIO;
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| 	  else
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| 	    ratio = 1.0;
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| 	}
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|       else
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| 	ratio = priv->ratio;
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| 
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|       GTK_FRAME_CLASS (gtk_aspect_frame_parent_class)->compute_child_allocation (frame, &full_allocation);
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|       
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|       if (ratio * full_allocation.height > full_allocation.width)
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| 	{
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| 	  child_allocation->width = full_allocation.width;
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| 	  child_allocation->height = full_allocation.width / ratio + 0.5;
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| 	}
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|       else
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| 	{
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| 	  child_allocation->width = ratio * full_allocation.height + 0.5;
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| 	  child_allocation->height = full_allocation.height;
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| 	}
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|       
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|       child_allocation->x = full_allocation.x + priv->xalign * (full_allocation.width - child_allocation->width);
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|       child_allocation->y = full_allocation.y + priv->yalign * (full_allocation.height - child_allocation->height);
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|     }
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|   else
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|     GTK_FRAME_CLASS (gtk_aspect_frame_parent_class)->compute_child_allocation (frame, child_allocation);
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| }
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