[mutter] Add frame_x_center/frame_y_center variables for themes

[Owen Taylor <otaylor src gnome org>]

commit e8e78ebfdd000ad85b0ec269b1a3420586750523
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Thu Aug 20 13:47:05 2009 -0400

    Add frame_x_center/frame_y_center variables for themes
    
    Sometimes you want to position something (usually the title) to be centered
    with respect to the entire frame instead of centered with respect to the
    individual piece currently being drawn.
    
    This patch adds frame_x_center and frame_y_center variables that represent
    the X/Y centers of the frame in the coordinate system of the piece being
    drawn.
    
    The theme version is bumped from 3.0 to 3.1 (3.0 is just the new version
    system, 3.1 will have all the features we add for Mutter-2.28.)
    position expressions
    
    https://bugzilla.gnome.org/show_bug.cgi?id=591842

 doc/theme-format.txt  |   10 ++++++++++
 src/ui/theme-parser.c |    2 +-
 src/ui/theme.c        |   14 ++++++++++++++
 src/ui/theme.h        |    4 ++++
 4 files changed, 29 insertions(+), 1 deletions(-)
---
diff --git a/doc/theme-format.txt b/doc/theme-format.txt
index bb79d45..cefc316 100644
--- a/doc/theme-format.txt
+++ b/doc/theme-format.txt
@@ -22,6 +22,16 @@ This document has separate sections for each format version. You may
 want to read the document in reverse order, since the base features
 are discussed under version 1.
 
+New Features in Theme Format Version 3.1
+========================================
+
+Additional predefined variables are added for positioning expressions:
+
+ frame_x_center: the X center of the entire frame, with respect to the
+     piece currently being drawn.
+ frame_y_center: the Y center of the entire frame, with respect to the
+     piece currently being drawn.
+
 New Features in Theme Format Version 3
 ======================================
 
diff --git a/src/ui/theme-parser.c b/src/ui/theme-parser.c
index 9dad99f..b2d8bf7 100644
--- a/src/ui/theme-parser.c
+++ b/src/ui/theme-parser.c
@@ -38,7 +38,7 @@
  * look out for.
  */
 #define THEME_MAJOR_VERSION 3
-#define THEME_MINOR_VERSION 0
+#define THEME_MINOR_VERSION 1
 #define THEME_VERSION (1000 * THEME_MAJOR_VERSION + THEME_MINOR_VERSION)
 
 #define METACITY_THEME_FILENAME_FORMAT "metacity-theme-%d.xml"
diff --git a/src/ui/theme.c b/src/ui/theme.c
index 0bb4365..3674233 100644
--- a/src/ui/theme.c
+++ b/src/ui/theme.c
@@ -2188,6 +2188,10 @@ pos_eval_get_variable (PosToken                  *t,
         *result = env->title_width;
       else if (t->d.v.name_quark == env->theme->quark_title_height)
         *result = env->title_height;
+      else if (t->d.v.name_quark == env->theme->quark_frame_x_center)
+        *result = env->frame_x_center;
+      else if (t->d.v.name_quark == env->theme->quark_frame_y_center)
+        *result = env->frame_y_center;
       else
         {
           g_set_error (err, META_THEME_ERROR,
@@ -2229,6 +2233,10 @@ pos_eval_get_variable (PosToken                  *t,
         *result = env->title_width;
       else if (strcmp (t->d.v.name, "title_height") == 0)
         *result = env->title_height;
+      else if (strcmp (t->d.v.name, "frame_x_center") == 0)
+        *result = env->frame_x_center;
+      else if (strcmp (t->d.v.name, "frame_y_center") == 0)
+        *result = env->frame_y_center;
       else
         {
           g_set_error (err, META_THEME_ERROR,
@@ -3437,6 +3445,8 @@ fill_env (MetaPositionExprEnv *env,
       env->right_width = info->fgeom->right_width;
       env->top_height = info->fgeom->top_height;
       env->bottom_height = info->fgeom->bottom_height;
+      env->frame_x_center = info->fgeom->width / 2 - logical_region.x;
+      env->frame_y_center = info->fgeom->height / 2 - logical_region.y;
     }
   else
     {
@@ -3444,6 +3454,8 @@ fill_env (MetaPositionExprEnv *env,
       env->right_width = 0;
       env->top_height = 0;
       env->bottom_height = 0;
+      env->frame_x_center = 0;
+      env->frame_y_center = 0;
     }
   
   env->mini_icon_width = info->mini_icon ? gdk_pixbuf_get_width (info->mini_icon) : 0;
@@ -4845,6 +4857,8 @@ meta_theme_new (void)
   theme->quark_icon_height = g_quark_from_static_string ("icon_height");
   theme->quark_title_width = g_quark_from_static_string ("title_width");
   theme->quark_title_height = g_quark_from_static_string ("title_height");
+  theme->quark_frame_x_center = g_quark_from_static_string ("frame_x_center");
+  theme->quark_frame_y_center = g_quark_from_static_string ("frame_y_center");
   return theme;
 }
 
diff --git a/src/ui/theme.h b/src/ui/theme.h
index ddf777d..02a6156 100644
--- a/src/ui/theme.h
+++ b/src/ui/theme.h
@@ -819,6 +819,8 @@ struct _MetaTheme
   GQuark quark_icon_height;
   GQuark quark_title_width;
   GQuark quark_title_height;
+  GQuark quark_frame_x_center;
+  GQuark quark_frame_y_center;
 };
 
 struct _MetaPositionExprEnv
@@ -834,6 +836,8 @@ struct _MetaPositionExprEnv
   int bottom_height;
   int title_width;
   int title_height;
+  int frame_x_center;
+  int frame_y_center;
   int mini_icon_width;
   int mini_icon_height;
   int icon_width;