pager: workaround for aspect ratio error in WNCK pager in deskbar mode.

This is caused by current limitation of WNCK pager. We can remove
or disable this hack once WNCK pager supports different orientation
of the pager and panel.

1 files changed, 87 insertions, 0 deletions

diff --git a/plugins/pager/pager.c b/plugins/pager/pager.c
index ae24173a..979df971 100644
--- a/plugins/pager/pager.c
+++ b/plugins/pager/pager.c
@@ -21,6 +21,10 @@
 #include <config.h>
 #endif
 
+#ifdef HAVE_MATH_H
+#include <math.h>
+#endif
+
 #include <gtk/gtk.h>
 #include <libxfce4panel/libxfce4panel.h>
 #include <libxfce4util/libxfce4util.h>
@@ -62,6 +66,10 @@ static void     pager_plugin_mode_changed                 (XfcePanelPlugin     *
 static void     pager_plugin_configure_workspace_settings (GtkWidget         *button);
 static void     pager_plugin_configure_plugin             (XfcePanelPlugin   *panel_plugin);
 static void     pager_plugin_screen_layout_changed        (PagerPlugin       *plugin);
+static void     pager_plugin_size_request                 (GtkWidget         *widget,
+                                                           GtkRequisition    *requisition);
+static void     pager_plugin_size_allocate                (GtkWidget         *widget,
+                                                           GtkAllocation     *allocation);
 
 
 
@@ -82,6 +90,12 @@ struct _PagerPlugin
   guint          scrolling : 1;
   guint          miniature_view : 1;
   gint           rows;
+
+  /* panel size */
+  gint           size;
+
+  /* WNCK pager aspect ratio */
+  gdouble        aspect;
 };
 
 enum
@@ -113,6 +127,8 @@ pager_plugin_class_init (PagerPluginClass *klass)
 
   widget_class = GTK_WIDGET_CLASS (klass);
   widget_class->scroll_event = pager_plugin_scroll_event;
+  widget_class->size_request = pager_plugin_size_request;
+  widget_class->size_allocate = pager_plugin_size_allocate;
 
   plugin_class = XFCE_PANEL_PLUGIN_CLASS (klass);
   plugin_class->construct = pager_plugin_construct;
@@ -153,6 +169,8 @@ pager_plugin_init (PagerPlugin *plugin)
   plugin->miniature_view = TRUE;
   plugin->rows = 1;
   plugin->pager = NULL;
+  plugin->size = 0;
+  plugin->aspect = 1.;
 }
 
 
@@ -384,10 +402,79 @@ pager_plugin_free_data (XfcePanelPlugin *panel_plugin)
 
 
 
+static void
+pager_plugin_size_request (GtkWidget      *widget,
+                           GtkRequisition *requisition)
+{
+  PagerPlugin        *plugin = XFCE_PAGER_PLUGIN (widget);
+  XfcePanelPlugin    *panel_plugin = XFCE_PANEL_PLUGIN (widget);
+  gdouble             aspect = 1.0;
+
+  /* propagate the size request as normal */
+  gtk_widget_size_request (GTK_WIDGET (plugin->pager), requisition);
+
+  /* if in deskbar mode, memorize the aspect ratio of the WNCK pager     */
+  /* WNCK pager assumes that orientation of the panel is always same     */
+  /* as orientation of the pager, which is not true in the deskbar mode. */
+  if (plugin->miniature_view &&
+      xfce_panel_plugin_get_mode (panel_plugin) == XFCE_PANEL_PLUGIN_MODE_DESKBAR)
+    {
+      if (requisition->width > 1)
+        aspect = (gdouble) requisition->height / (gdouble) requisition->width;
+
+      /* Update the memorized aspect value only if change is big enough */
+      /* WNCK pager requests resizing if the allocated vertical dimension */
+      /* is different from the previously allocated vertical dimension. */
+      /* Therefore, we only want to change the aspect ratio (and allocation) */
+      /* when it corresponds to a "real" aspect ratio change. */
+      /* The threshold is arbitrary - small value may cause infinite looping, */
+      /* large value reduces accuracy of pager scaling. */
+      if (fabs ((plugin->aspect - aspect) * plugin->size) > 3.0)
+        plugin->aspect = aspect;
+
+      requisition->width = plugin->size;
+      requisition->height = rint (requisition->width * plugin->aspect);
+    }
+}
+
+
+
+static void
+pager_plugin_size_allocate (GtkWidget      *widget,
+                            GtkAllocation  *allocation)
+{
+  PagerPlugin        *plugin = XFCE_PAGER_PLUGIN (widget);
+  XfcePanelPlugin    *panel_plugin = XFCE_PANEL_PLUGIN (widget);
+
+  /* if in deskbar mode, force the allocation based on memorized aspect ratio. */
+  /* WNCK pager will request resizing if it differs from previous allocation.  */
+  if (plugin->miniature_view &&
+      xfce_panel_plugin_get_mode (panel_plugin) == XFCE_PANEL_PLUGIN_MODE_DESKBAR)
+    {
+      allocation->width = plugin->size;
+      allocation->height = rint (allocation->width * plugin->aspect);
+    }
+  gtk_widget_size_allocate (plugin->pager, allocation);
+}
+
+
+
 static gboolean
 pager_plugin_size_changed (XfcePanelPlugin *panel_plugin,
                            gint             size)
 {
+  PagerPlugin        *plugin = XFCE_PAGER_PLUGIN (panel_plugin);
+
+  /* request resize when using WNCK pager */
+  /* (its height depends on width)        */
+  if (plugin->miniature_view &&
+      plugin->size != size &&
+      xfce_panel_plugin_get_mode (panel_plugin) == XFCE_PANEL_PLUGIN_MODE_DESKBAR)
+    {
+      plugin->size = size;
+      gtk_widget_queue_resize (GTK_WIDGET (panel_plugin));
+    }
+
   /* do not set fixed size */
   return TRUE;
 }