[gegl-gtk] Examples: Add gegl-gtk-warp, demonstrating the GEGL warp operation

[Jon Nordby <jonnor src gnome org>]

commit 101c84c1d064e0e0a8cf1c555dfcec4307199e5f
Author: Michael Murà <batolettre gmail com>
Date:   Thu Jul 21 18:02:10 2011 +0200

    Examples: Add gegl-gtk-warp, demonstrating the GEGL warp operation
    
    Developed as part of the 2011 GSOC to add a warp operation to GIMP.
    Note: requires the gegl:warp operation, which currently is a part
    of the workshop operations in GEGL and is not built by default.

 examples/.gitignore        |    1 +
 examples/c/gegl-gtk-warp.c |  203 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 204 insertions(+), 0 deletions(-)
---
diff --git a/examples/.gitignore b/examples/.gitignore
index 264e3fe..944a61e 100644
--- a/examples/.gitignore
+++ b/examples/.gitignore
@@ -1,3 +1,4 @@
 gegl-gtk-paint
 gegl-gtk-basic
 gegl-gtk-display-op
+gegl-gtk-warp
diff --git a/examples/c/gegl-gtk-warp.c b/examples/c/gegl-gtk-warp.c
new file mode 100644
index 0000000..23aed5d
--- /dev/null
+++ b/examples/c/gegl-gtk-warp.c
@@ -0,0 +1,203 @@
+/* This file is part of GEGL-GTK
+ *
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) 2011 Michael Murà <batolettre gmail com>
+ */
+
+#include <string.h>
+#include <glib.h>
+#include <gegl.h>
+#include <gtk/gtk.h>
+#include <gegl-gtk.h>
+
+/* Tool */
+static gdouble         cursor_x; /* Hold the cursor x position */
+static gdouble         cursor_y; /* Hold the cursor y position */
+
+static GeglBuffer     *coords_buffer; /* Gegl buffer where coordinates are stored */
+
+static GeglNode       *graph; /* Top level GeglNode. All others node are child of it */
+static GeglNode       *read_coords_buffer_node; /* Gegl node that read in the coords buffer */
+static GeglNode       *render_node; /* Gegl node to render the transformation */
+
+static GeglPath       *current_stroke;
+static guint           stroke_timer;
+
+#define STROKE_PERIOD 100
+
+/* Tool options */
+static gdouble          strength = 100;
+static gdouble          size = 40;
+static gdouble          hardness = 0.5;
+static GeglWarpBehavior behavior = GEGL_WARP_BEHAVIOR_MOVE;
+
+/* gegl-gtk stuff */
+GtkWidget               *window;
+GtkWidget               *view;
+GtkWidget               *eventbox;
+
+static GeglRectangle     rect; /* size for the view/window */
+static GeglBuffer       *original_buffer = NULL; /* image to be warped */
+static GeglNode         *readbuf; /* node to read this image */
+
+static gboolean
+add_event_timer (gpointer data)
+{
+  gegl_path_append (current_stroke,
+                    'L', cursor_x, cursor_y);
+  return TRUE;
+}
+
+static void
+add_op ()
+{
+  GeglNode *new_op, *last_op;
+
+  new_op = gegl_node_new_child (graph,
+                                "operation", "gegl:warp",
+                                "behavior", behavior,
+                                "strength", strength,
+                                "size", size,
+                                "hardness", hardness,
+                                "stroke", current_stroke,
+                                NULL);
+
+  last_op = gegl_node_get_producer (render_node, "aux", NULL);
+
+  gegl_node_disconnect (render_node, "aux");
+
+  gegl_node_connect_to (last_op, "output", new_op, "input");
+  gegl_node_connect_to (new_op, "output", render_node, "aux");
+}
+
+static gboolean paint_press (GtkWidget      *widget,
+                             GdkEventButton *event)
+{
+  if (current_stroke)
+    g_object_unref (current_stroke);
+
+  current_stroke = gegl_path_new ();
+  gegl_path_append (current_stroke,
+                    'M', event->x, event->y);
+
+  cursor_x = event->x;
+  cursor_y = event->y;
+
+  add_op ();
+
+  stroke_timer = g_timeout_add (STROKE_PERIOD, add_event_timer, NULL);
+  return TRUE;
+}
+
+
+static gboolean paint_motion (GtkWidget      *widget,
+                              GdkEventMotion *event)
+{
+  cursor_x = event->x;
+  cursor_y = event->y;
+
+  return FALSE;
+}
+
+
+static gboolean paint_release (GtkWidget      *widget,
+                               GdkEventButton *event)
+{
+  g_source_remove (stroke_timer);
+
+  return TRUE;
+}
+
+static void
+create_graph ()
+{
+  printf ("Initialize coordinate buffer (%d,%d) at %d,%d\n", rect.width, rect.height, rect.x, rect.y);
+  coords_buffer = gegl_buffer_new (&rect, babl_format_n (babl_type ("float"), 2));
+
+  graph = gegl_node_new ();
+
+  readbuf = gegl_node_new_child (graph,
+                                 "operation", "gegl:buffer-source",
+                                 "buffer",    original_buffer,
+                                 NULL);
+
+  read_coords_buffer_node = gegl_node_new_child (graph,
+                                                 "operation", "gegl:buffer-source",
+                                                 "buffer",    coords_buffer,
+                                                 NULL);
+
+  render_node = gegl_node_new_child (graph,
+                                     "operation", "gegl:map-relative",
+                                     NULL);
+
+
+  gegl_node_connect_to (readbuf, "output",
+                        render_node, "input");
+
+  gegl_node_connect_to (read_coords_buffer_node, "output",
+                        render_node, "aux");
+}
+
+gint
+main (gint    argc,
+      gchar **argv)
+{
+  if (argv[1] == NULL)
+    {
+      printf("usage: %s filename.gegl\n", argv[0]);
+      printf("filename.gegl must be a Gegl buffer file, for instance created with the 2geglbuffer example from Gegl.\n");
+      return 0;
+    }
+
+  g_thread_init (NULL);
+  gtk_init (&argc, &argv);
+  gegl_init (&argc, &argv);
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_title (GTK_WINDOW (window), "Warp example");
+
+  original_buffer = gegl_buffer_open (argv[1]);
+  rect = *gegl_buffer_get_extent(original_buffer);
+
+  create_graph ();
+
+  view = g_object_new (GEGL_GTK_TYPE_VIEW, "node", render_node, NULL);
+
+  eventbox = gtk_event_box_new ();
+
+  g_signal_connect (G_OBJECT (eventbox), "motion-notify-event",
+                    (GCallback) paint_motion, NULL);
+  g_signal_connect (G_OBJECT (eventbox), "button-press-event",
+                    (GCallback) paint_press, NULL);
+  g_signal_connect (G_OBJECT (eventbox), "button-release-event",
+                    (GCallback) paint_release, NULL);
+  gtk_widget_add_events (eventbox, GDK_BUTTON_RELEASE_MASK);
+
+  gtk_container_add (GTK_CONTAINER (eventbox), view);
+  gtk_container_add (GTK_CONTAINER (window), eventbox);
+  gtk_widget_set_size_request (view, rect.width, rect.height);
+
+  g_signal_connect (G_OBJECT (window), "delete-event",
+                    G_CALLBACK (gtk_main_quit), window);
+  gtk_widget_show_all (window);
+
+  gtk_main ();
+  g_object_unref (graph);
+  gegl_buffer_destroy (original_buffer);
+  gegl_buffer_destroy (coords_buffer);
+
+  gegl_exit ();
+  return 0;
+}