[gtk+/wip/renderops: 1/6] renderops: Add a simple functionality to track rendering operations

[Benjamin Otte <otte src gnome org>]

commit fc9b67a7396821d6fae107a631f1557f9f365448
Author: Benjamin Otte <otte redhat com>
Date:   Sat Jun 27 05:25:36 2015 +0200

    renderops: Add a simple functionality to track rendering operations

 gtk/Makefile.am           |    2 +
 gtk/gtkrenderops.c        |  107 +++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkrenderopsprivate.h |   72 ++++++++++++++++++++++++++++++
 gtk/gtktypes.h            |    2 +
 gtk/gtkwidget.c           |    8 +++-
 5 files changed, 190 insertions(+), 1 deletions(-)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index 50e8efb..5a27f7b 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -482,6 +482,7 @@ gtk_private_h_sources =             \
        gtkpixelcacheprivate.h  \
        gtkquery.h              \
        gtkrangeprivate.h       \
+       gtkrenderopsprivate.h   \
        gtkrbtree.h             \
        gtkrecentchooserdefault.h \
        gtkrecentchooserprivate.h \
@@ -782,6 +783,7 @@ gtk_base_c_sources =                \
        gtkrenderbackground.c   \
        gtkrenderborder.c       \
        gtkrendericon.c         \
+       gtkrenderops.c          \
        gtkresources.c          \
        gtkrevealer.c           \
        gtkroundedbox.c         \
diff --git a/gtk/gtkrenderops.c b/gtk/gtkrenderops.c
new file mode 100644
index 0000000..8515bdf
--- /dev/null
+++ b/gtk/gtkrenderops.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright © 2011 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte gnome org>
+ */
+
+#include "config.h"
+
+#include "gtkrenderopsprivate.h"
+
+G_DEFINE_TYPE (GtkRenderOps, gtk_render_ops, G_TYPE_OBJECT)
+
+static cairo_t *
+gtk_render_ops_real_begin_draw_widget (GtkRenderOps *ops,
+                                       GtkWidget    *widget,
+                                       cairo_t      *cr)
+{
+  return cairo_reference (cr);
+}
+
+static void
+gtk_render_ops_real_end_draw_widget (GtkRenderOps *ops,
+                                     GtkWidget    *widget,
+                                     cairo_t      *draw_cr,
+                                     cairo_t      *original_cr)
+{
+  cairo_destroy (draw_cr);
+}
+
+static void
+gtk_render_ops_class_init (GtkRenderOpsClass *klass)
+{
+  klass->begin_draw_widget = gtk_render_ops_real_begin_draw_widget;
+  klass->end_draw_widget = gtk_render_ops_real_end_draw_widget;
+}
+
+static void
+gtk_render_ops_init (GtkRenderOps *image)
+{
+}
+
+static const cairo_user_data_key_t render_ops_key;
+
+static GtkRenderOps *
+gtk_cairo_get_render_ops (cairo_t *cr)
+{
+  return cairo_get_user_data (cr, &render_ops_key);
+}
+
+/* public API */
+void
+gtk_cairo_set_render_ops (cairo_t      *cr,
+                          GtkRenderOps *ops)
+{
+  if (ops)
+    {
+      g_object_ref (ops);
+      cairo_set_user_data (cr, &render_ops_key, ops, g_object_unref);
+    }
+  else
+    {
+      cairo_set_user_data (cr, &render_ops_key, NULL, NULL);
+    }
+}
+
+cairo_t *
+gtk_render_ops_begin_draw_widget (GtkWidget *widget,
+                                  cairo_t   *cr)
+{
+  GtkRenderOps *ops;
+
+  ops = gtk_cairo_get_render_ops (cr);
+  if (ops == NULL)
+    return gtk_render_ops_real_begin_draw_widget (NULL, widget, cr);
+
+  return GTK_RENDER_OPS_GET_CLASS (ops)->begin_draw_widget (ops, widget, cr);
+}
+
+void
+gtk_render_ops_end_draw_widget (GtkWidget *widget,
+                                cairo_t   *draw_cr,
+                                cairo_t   *original_cr)
+{
+  GtkRenderOps *ops;
+
+  ops = gtk_cairo_get_render_ops (original_cr);
+  if (ops == NULL)
+    {
+      gtk_render_ops_real_end_draw_widget (NULL, widget, draw_cr, original_cr);
+      return;
+    }
+
+  GTK_RENDER_OPS_GET_CLASS (ops)->end_draw_widget (ops, widget, draw_cr, original_cr);
+}
diff --git a/gtk/gtkrenderopsprivate.h b/gtk/gtkrenderopsprivate.h
new file mode 100644
index 0000000..f149d00
--- /dev/null
+++ b/gtk/gtkrenderopsprivate.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright © 2014 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte gnome org>
+ */
+
+#ifndef __GTK_RENDER_OPS_PRIVATE_H__
+#define __GTK_RENDER_OPS_PRIVATE_H__
+
+#include <cairo.h>
+
+#include <gtk/gtktypes.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_RENDER_OPS           (gtk_render_ops_get_type ())
+#define GTK_RENDER_OPS(obj)           (G_TYPE_CHECK_INSTANCE_CAST (obj, GTK_TYPE_RENDER_OPS, GtkRenderOps))
+#define GTK_RENDER_OPS_CLASS(cls)     (G_TYPE_CHECK_CLASS_CAST (cls, GTK_TYPE_RENDER_OPS, GtkRenderOpsClass))
+#define GTK_IS_RENDER_OPS(obj)        (G_TYPE_CHECK_INSTANCE_TYPE (obj, GTK_TYPE_RENDER_OPS))
+#define GTK_IS_RENDER_OPS_CLASS(obj)  (G_TYPE_CHECK_CLASS_TYPE (obj, GTK_TYPE_RENDER_OPS))
+#define GTK_RENDER_OPS_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_RENDER_OPS, 
GtkRenderOpsClass))
+
+typedef struct _GtkRenderOps           GtkRenderOps;
+typedef struct _GtkRenderOpsClass      GtkRenderOpsClass;
+
+struct _GtkRenderOps
+{
+  GObject parent;
+};
+
+struct _GtkRenderOpsClass
+{
+  GObjectClass parent_class;
+
+  cairo_t *     (* begin_draw_widget)                  (GtkRenderOps            *ops,
+                                                        GtkWidget               *widget,
+                                                        cairo_t                 *cr);
+  void          (* end_draw_widget)                    (GtkRenderOps            *ops,
+                                                        GtkWidget               *widget,
+                                                        cairo_t                 *draw_cr,
+                                                        cairo_t                 *original_cr);
+};
+
+GType           gtk_render_ops_get_type                (void) G_GNUC_CONST;
+
+/* public API */
+void            gtk_cairo_set_render_ops               (cairo_t                 *cr,
+                                                        GtkRenderOps            *ops);
+
+/* calls from inside GTK */
+cairo_t *       gtk_render_ops_begin_draw_widget       (GtkWidget               *widget,
+                                                        cairo_t                 *cr);
+void            gtk_render_ops_end_draw_widget         (GtkWidget               *widget,
+                                                        cairo_t                 *draw_cr,
+                                                        cairo_t                 *original_cr);
+
+G_END_DECLS
+
+#endif /* __GTK_RENDER_OPS_PRIVATE_H__ */
diff --git a/gtk/gtktypes.h b/gtk/gtktypes.h
index f1b645a..95e4506 100644
--- a/gtk/gtktypes.h
+++ b/gtk/gtktypes.h
@@ -29,6 +29,8 @@
 #error "Only <gtk/gtk.h> can be included directly."
 #endif
 
+#include <glib-object.h>
+
 G_BEGIN_DECLS
 
 typedef struct _GtkAdjustment          GtkAdjustment;
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index d9230f5..465ce21 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -42,6 +42,7 @@
 #include "gtkcssshadowsvalueprivate.h"
 #include "gtkintl.h"
 #include "gtkmarshalers.h"
+#include "gtkrenderopsprivate.h"
 #include "gtkselectionprivate.h"
 #include "gtksettingsprivate.h"
 #include "gtksizegroup-private.h"
@@ -6984,13 +6985,18 @@ _gtk_widget_draw_internal (GtkWidget *widget,
   if (gdk_cairo_get_clip_rectangle (cr, NULL))
     {
       gboolean result;
+      cairo_t *draw_cr;
 
       gdk_window_mark_paint_from_clip (window, cr);
 
+      draw_cr = gtk_render_ops_begin_draw_widget (widget, cr);
+
       g_signal_emit (widget, widget_signals[DRAW],
-                     0, cr,
+                     0, draw_cr,
                      &result);
 
+      gtk_render_ops_end_draw_widget (widget, draw_cr, cr);
+
 #ifdef G_ENABLE_DEBUG
       if (G_UNLIKELY (gtk_get_debug_flags () & GTK_DEBUG_BASELINES))
        {