[libgd] icon-utils: add a method to embed an image in a frame

[Cosimo Cecchi <cosimoc src gnome org>]

commit e94e04def45bc2cbcaf715c15e0fc0081897a43c
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Mon Oct 1 09:26:05 2012 -0400

    icon-utils: add a method to embed an image in a frame
    
    Exports the method we have in the private gnome-documents library for this to libgd.

 Makefile.am                                        |    4 +-
 libgd/gd-create-symbolic-icon.c                    |  101 -----------
 libgd/gd-icon-utils.c                              |  186 ++++++++++++++++++++
 .../{gd-create-symbolic-icon.h => gd-icon-utils.h} |    5 +
 libgd/gd.h                                         |    2 +-
 5 files changed, 194 insertions(+), 104 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index dcbb849..47e7540 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -32,8 +32,8 @@ if LIBGD_GTK_HACKS
 gtk_hacks_sources =                             \
         libgd/gd-entry-focus-hack.c             \
         libgd/gd-entry-focus-hack.h             \
-        libgd/gd-create-symbolic-icon.c         \
-        libgd/gd-create-symbolic-icon.h         \
+        libgd/gd-icon-utils.c		        \
+        libgd/gd-icon-utils.h			\
         $(NULL)
 
 nodist_libgd_la_SOURCES += $(gtk_hacks_sources)
diff --git a/libgd/gd-icon-utils.c b/libgd/gd-icon-utils.c
new file mode 100644
index 0000000..79611d2
--- /dev/null
+++ b/libgd/gd-icon-utils.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2011, 2012 Red Hat, Inc.
+ *
+ * Gnome Documents is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * Gnome Documents 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 General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Gnome Documents; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Author: Cosimo Cecchi <cosimoc redhat com>
+ *
+ */
+
+#include "gd-icon-utils.h"
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <string.h>
+#include <math.h>
+
+#define _BG_MIN_SIZE 20
+#define _EMBLEM_MIN_SIZE 8
+
+/**
+ * gd_create_symbolic_icon:
+ * @name:
+ *
+ * Returns: (transfer full):
+ */
+GIcon *
+gd_create_symbolic_icon (const gchar *name,
+                         gint base_size)
+{
+  gchar *symbolic_name;
+  GIcon *icon, *retval = NULL;
+  cairo_surface_t *surface;
+  cairo_t *cr;
+  GtkStyleContext *style;
+  GtkWidgetPath *path;
+  GdkPixbuf *pixbuf;
+  GtkIconTheme *theme;
+  GtkIconInfo *info;
+  gint bg_size;
+  gint emblem_size;
+  gint total_size;
+
+  total_size = base_size / 2;
+  bg_size = MAX (total_size / 2, _BG_MIN_SIZE);
+  emblem_size = MAX (bg_size - 8, _EMBLEM_MIN_SIZE);
+
+  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, total_size, total_size);
+  cr = cairo_create (surface);
+
+  style = gtk_style_context_new ();
+
+  path = gtk_widget_path_new ();
+  gtk_widget_path_append_type (path, GTK_TYPE_ICON_VIEW);
+  gtk_style_context_set_path (style, path);
+  gtk_widget_path_unref (path);
+
+  gtk_style_context_add_class (style, "documents-icon-bg");
+
+  gtk_render_background (style, cr, (total_size - bg_size) / 2, (total_size - bg_size) / 2, bg_size, bg_size);
+
+  symbolic_name = g_strconcat (name, "-symbolic", NULL);
+  icon = g_themed_icon_new_with_default_fallbacks (symbolic_name);
+  g_free (symbolic_name);
+
+  theme = gtk_icon_theme_get_default();
+  info = gtk_icon_theme_lookup_by_gicon (theme, icon, emblem_size,
+                                         GTK_ICON_LOOKUP_FORCE_SIZE);
+  g_object_unref (icon);
+
+  if (info == NULL)
+    goto out;
+
+  pixbuf = gtk_icon_info_load_symbolic_for_context (info, style, NULL, NULL);
+  gtk_icon_info_free (info);
+
+  if (pixbuf == NULL)
+    goto out;
+
+  gtk_render_icon (style, cr, pixbuf, (total_size - emblem_size) / 2,  (total_size - emblem_size) / 2);
+  g_object_unref (pixbuf);
+
+  retval = G_ICON (gdk_pixbuf_get_from_surface (surface, 0, 0, total_size, total_size));
+
+ out:
+  g_object_unref (style);
+  cairo_surface_destroy (surface);
+  cairo_destroy (cr);
+
+  return retval;
+}
+
+/**
+ * gd_embed_image_in_frame:
+ * @source_image:
+ * @frame_image_url:
+ * @slice_width:
+ * @border_width:
+ *
+ * Returns: (transfer full):
+ */
+GdkPixbuf *
+gd_embed_image_in_frame (GdkPixbuf *source_image,
+                         const gchar *frame_image_url,
+                         GtkBorder *slice_width,
+                         GtkBorder *border_width)
+{
+  cairo_surface_t *surface;
+  cairo_t *cr;
+  int source_width, source_height;
+  int dest_width, dest_height;
+  gchar *css_str;
+  GtkCssProvider *provider;
+  GtkStyleContext *context;
+  GError *error = NULL;
+  GdkPixbuf *retval;
+  GtkWidgetPath *path;
+
+  source_width = gdk_pixbuf_get_width (source_image);
+  source_height = gdk_pixbuf_get_height (source_image);
+
+  dest_width = source_width +  border_width->left + border_width->right;
+  dest_height = source_height + border_width->top + border_width->bottom;
+
+  css_str = g_strdup_printf (".embedded-image { border-image: url(\"%s\") %d %d %d %d / %dpx %dpx %dpx %dpx }",
+                             frame_image_url,
+                             slice_width->top, slice_width->right, slice_width->bottom, slice_width->left,
+                             border_width->top, border_width->right, border_width->bottom, border_width->left);
+  provider = gtk_css_provider_new ();
+  gtk_css_provider_load_from_data (provider, css_str, -1, &error);
+
+  if (error != NULL)
+    {
+      g_warning ("Unable to create the thumbnail frame image: %s", error->message);
+      g_error_free (error);
+      g_free (css_str);
+
+      return g_object_ref (source_image);
+    }
+
+  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, dest_width, dest_height);
+  cr = cairo_create (surface);
+
+  context = gtk_style_context_new ();
+  path = gtk_widget_path_new ();
+  gtk_widget_path_append_type (path, GTK_TYPE_ICON_VIEW);
+
+  gtk_style_context_set_path (context, path);
+  gtk_style_context_add_provider (context, GTK_STYLE_PROVIDER (provider), 600);
+
+  gtk_render_icon (context, cr,
+                   source_image,
+                   border_width->left, border_width->top);
+
+  gtk_style_context_save (context);
+  gtk_style_context_add_class (context, "embedded-image");
+
+  gtk_render_frame (context, cr,
+                    0, 0,
+                    dest_width, dest_height);
+
+  gtk_style_context_restore (context);
+
+  retval = gdk_pixbuf_get_from_surface (surface,
+                                        0, 0, dest_width, dest_height);
+
+  cairo_surface_destroy (surface);
+  cairo_destroy (cr);
+
+  gtk_widget_path_unref (path);
+  g_object_unref (provider);
+  g_object_unref (context);
+  g_free (css_str);
+
+  return retval;
+}
diff --git a/libgd/gd-create-symbolic-icon.h b/libgd/gd-icon-utils.h
similarity index 81%
rename from libgd/gd-create-symbolic-icon.h
rename to libgd/gd-icon-utils.h
index ef98a26..c5796f7 100644
--- a/libgd/gd-create-symbolic-icon.h
+++ b/libgd/gd-icon-utils.h
@@ -27,4 +27,9 @@
 GIcon *gd_create_symbolic_icon (const gchar *name,
                                 gint base_size);
 
+GdkPixbuf *gd_embed_image_in_frame (GdkPixbuf *source_image,
+                                    const gchar *frame_image_url,
+                                    GtkBorder *slice_width,
+                                    GtkBorder *border_width);
+
 #endif /* __GD_CREATE_SYMBOLIC_ICON_H__ */
diff --git a/libgd/gd.h b/libgd/gd.h
index 06e9b09..065c1b9 100644
--- a/libgd/gd.h
+++ b/libgd/gd.h
@@ -29,7 +29,7 @@
 G_BEGIN_DECLS
 
 #ifdef LIBGD_GTK_HACKS
-# include <libgd/gd-create-symbolic-icon.h>
+# include <libgd/gd-icon-utils.h>
 # include <libgd/gd-entry-focus-hack.h>
 #endif