Bug 445832 – pango_cairo_update_layout() always invalidates layout

2007-06-12  Behdad Esfahbod  <behdad@gnome.org>

        Bug 445832 – pango_cairo_update_layout() always invalidates layout

        * pango/pangocairo-context.c (_pango_cairo_update_context),
        (pango_cairo_update_context), (pango_cairo_update_layout):
        Don't invalidate layout if matrix and font options didn't change.


svn path=/trunk/; revision=2346

1 files changed, 56 insertions, 24 deletions

diff --git a/pango/pangocairo-context.c b/pango/pangocairo-context.c
index 6bdaa532..98558f89 100644
--- a/pango/pangocairo-context.c
+++ b/pango/pangocairo-context.c
@@ -25,6 +25,8 @@
 #include "pangocairo-private.h"
 #include "pango-impl-utils.h"
 
+#include <string.h>
+
 typedef struct _PangoCairoContextInfo PangoCairoContextInfo;
 
 struct _PangoCairoContextInfo
@@ -80,30 +82,16 @@ get_context_info (PangoContext *context,
   return info;
 }
 
-/**
- * pango_cairo_update_context:
- * @cr: a Cairo context
- * @context: a #PangoContext, from pango_cairo_font_map_create_context()
- *
- * Updates a #PangoContext previously created for use with Cairo to
- * match the current transformation and target surface of a Cairo
- * context. If any layouts have been created for the context,
- * it's necessary to call pango_layout_context_changed() on those
- * layouts.
- *
- * Since: 1.10
- **/
-void
-pango_cairo_update_context (cairo_t      *cr,
-			    PangoContext *context)
+static gboolean
+_pango_cairo_update_context (cairo_t      *cr,
+			     PangoContext *context)
 {
   PangoCairoContextInfo *info;
   cairo_matrix_t cairo_matrix;
   cairo_surface_t *target;
   PangoMatrix pango_matrix;
-
-  g_return_if_fail (cr != NULL);
-  g_return_if_fail (PANGO_IS_CONTEXT (context));
+  const PangoMatrix *layout_matrix, identity_matrix = PANGO_MATRIX_INIT;
+  gboolean changed = FALSE;
 
   info = get_context_info (context, TRUE);
 
@@ -115,19 +103,63 @@ pango_cairo_update_context (cairo_t      *cr,
   pango_matrix.x0 = cairo_matrix.x0;
   pango_matrix.y0 = cairo_matrix.y0;
 
+  layout_matrix = pango_context_get_matrix (context);
+  if (!layout_matrix)
+    layout_matrix = &identity_matrix;
+
+  if (0 != memcmp (&pango_matrix, layout_matrix, sizeof (pango_matrix)))
+    changed = TRUE;
+
   pango_context_set_matrix (context, &pango_matrix);
 
-  if (!info->surface_options)
-    info->surface_options = cairo_font_options_create ();
 
   target = cairo_get_target (cr);
-  cairo_surface_get_font_options (target, info->surface_options);
+
+  if (!info->surface_options) {
+    info->surface_options = cairo_font_options_create ();
+    changed = TRUE;
+    cairo_surface_get_font_options (target, info->surface_options);
+  } else {
+    cairo_font_options_t *surface_options = cairo_font_options_create ();
+    cairo_surface_get_font_options (target, surface_options);
+    if (!cairo_font_options_equal (surface_options, info->surface_options))
+      {
+	cairo_surface_get_font_options (target, info->surface_options);
+	changed = TRUE;
+      }
+    cairo_font_options_destroy (surface_options);
+  }
 
   if (info->merged_options)
     {
       cairo_font_options_destroy (info->merged_options);
       info->merged_options = NULL;
     }
+
+  return changed;
+}
+
+/**
+ * pango_cairo_update_context:
+ * @cr: a Cairo context
+ * @context: a #PangoContext, from pango_cairo_font_map_create_context()
+ *
+ * Updates a #PangoContext previously created for use with Cairo to
+ * match the current transformation and target surface of a Cairo
+ * context. If any layouts have been created for the context,
+ * it's necessary to call pango_layout_context_changed() on those
+ * layouts.
+ *
+ * Since: 1.10
+ **/
+void
+pango_cairo_update_context (cairo_t      *cr,
+			    PangoContext *context)
+{
+  g_return_if_fail (cr != NULL);
+  g_return_if_fail (PANGO_IS_CONTEXT (context));
+
+  (void) _pango_cairo_update_context (cr, context);
 }
 
 /**
@@ -400,7 +432,7 @@ pango_cairo_update_layout (cairo_t     *cr,
   g_return_if_fail (cr != NULL);
   g_return_if_fail (PANGO_IS_LAYOUT (layout));
 
-  pango_cairo_update_context (cr, pango_layout_get_context (layout));
-  pango_layout_context_changed (layout);
+  if (_pango_cairo_update_context (cr, pango_layout_get_context (layout)))
+    pango_layout_context_changed (layout);
 }