[byzanz/0.2: 10/14] Add a workaround for a Cairo bug

[Benjamin Otte <otte src gnome org>]

commit 161e709be48559d729748bc92df4f28a95f3cecf
Author: Benjamin Otte <otte redhat com>
Date:   Mon Feb 21 17:18:36 2011 +0100

    Add a workaround for a Cairo bug
    
    Cairo needs to copy from the root window using IncludeInferiors, but
    before Cairo 1.8.10, this wasn't done.
    So with this, the code can work with older cairo versions, in particular
    the version shipped in RHEL6.

 configure.ac            |    2 +-
 src/byzanzlayerwindow.c |   50 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 1ef93cd..665072d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -63,7 +63,7 @@ AC_DEFINE_DIR(DATADIR, "${datadir}", [datadir])
 dnl Check for essential libraries first:
 dnl ====================================
 
-CAIRO_REQ="1.8.10"
+CAIRO_REQ="1.8.0"
 GTK_REQ="2.17.10"
 GTHREAD_REQ="2.6.0"
 APPLET_REQ="2.10.0"
diff --git a/src/byzanzlayerwindow.c b/src/byzanzlayerwindow.c
index f7d4188..e8737e8 100644
--- a/src/byzanzlayerwindow.c
+++ b/src/byzanzlayerwindow.c
@@ -23,6 +23,7 @@
 
 #include "byzanzlayerwindow.h"
 
+#include <math.h>
 #include <gdk/gdkx.h>
 
 G_DEFINE_TYPE (ByzanzLayerWindow, byzanz_layer_window, BYZANZ_TYPE_LAYER)
@@ -96,14 +97,62 @@ byzanz_layer_window_snapshot (ByzanzLayer *layer)
   return region;
 }
 
+#if CAIRO_VERSION < CAIRO_VERSION_ENCODE (1, 8, 8)
+  /* This fix is for RHEL6 only */
+static void
+byzanz_layer_window_render (ByzanzLayer *layer,
+                            cairo_t *    cr)
+{
+  cairo_t *tmp;
+
+  byzanz_cairo_set_source_window (cr, layer->recorder->window, 0, 0);
+  cairo_paint (cr);
+}
+#else
 static void
 byzanz_cairo_set_source_window (cairo_t *cr, GdkWindow *window, double x, double y)
 {
+#if CAIRO_VERSION < CAIRO_VERSION_ENCODE (1, 80, 10)
+  /* This fix is for RHEL6 only */
+  {
+    static const cairo_user_data_key_t key;
+    double x1, y1_, x2, y2;
+    int w, h;
+    GdkPixmap *pixmap;
+    GdkGC *gc;
+    
+    cairo_clip_extents (cr, &x1, &y1_, &x2, &y2);
+    gdk_drawable_get_size (window, &w, &h);
+    
+    x1 = floor (x1);
+    y1_ = floor (y1_);
+    x2 = floor (x2);
+    y2 = floor (y2);
+    x1 = MAX (x1, 0);
+    y1_ = MAX (y1_, 0);
+    x2 = MIN (x2, w);
+    y2 = MIN (y2, h);
+
+    pixmap = gdk_pixmap_new (window, x2 - x1, y2 - y1_, -1);
+    gc = gdk_gc_new (pixmap);
+    gdk_gc_set_subwindow (gc, GDK_INCLUDE_INFERIORS);
+
+    gdk_draw_drawable (pixmap, gc, window,
+                       x1, y1_,
+                       0, 0,
+                       x2 - x1, y2 - y1_);
+    gdk_cairo_set_source_pixmap (cr, pixmap, x1, y1_);
+
+    g_object_unref (gc);
+    cairo_set_user_data (cr, &key, pixmap, g_object_unref);
+  }
+#else
   cairo_t *tmp;
 
   tmp = gdk_cairo_create (window);
   cairo_set_source_surface (cr, cairo_get_target (tmp), x, y);
   cairo_destroy (tmp);
+#endif
 }
 
 static void
@@ -113,6 +162,7 @@ byzanz_layer_window_render (ByzanzLayer *layer,
   byzanz_cairo_set_source_window (cr, layer->recorder->window, 0, 0);
   cairo_paint (cr);
 }
+#endif
 
 static void
 byzanz_layer_window_finalize (GObject *object)