geometrictransform: new filter "fisheye"

Ports gleffects "fisheye" filter to geometrictransform.
Fake fisheye lens filter. Somewhat empiric implementation because I
didn't find any good algorithm that does it with nice results.

https://bugzilla.gnome.org/show_bug.cgi?id=625722

gst/geometrictransform/Makefile.am

@@ -16,7 +16,8 @@ libgstgeometrictransform_la_SOURCES = plugin.c \
                                       gstbulge.c \
                                       gsttunnel.c \
                                       gstsquare.c \
-                                      gstmirror.c
+                                      gstmirror.c \
+                                      gstfisheye.c
 
 libgstgeometrictransform_la_CFLAGS = $(GST_CFLAGS) $(GST_BASE_CFLAGS) \
 			    $(GST_PLUGINS_BASE_CFLAGS) \
@@ -45,4 +46,5 @@ noinst_HEADERS = gstgeometrictransform.h \
                  gstbulge.h \
                  gsttunnel.h \
                  gstsquare.h \
-                 gstmirror.h
+                 gstmirror.h \
+                 gstfisheye.h

gst/geometrictransform/gstfisheye.c

@@ -0,0 +1,150 @@
+/*
+ * GStreamer
+ * Copyright (C) 2010 Filippo Argiolas <filippo.argiolas@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Alternatively, the contents of this file may be used under the
+ * GNU Lesser General Public License Version 2.1 (the "LGPL"), in
+ * which case the following provisions apply instead of the ones
+ * mentioned above:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <gst/gst.h>
+#include <math.h>
+
+#include "gstfisheye.h"
+
+GST_DEBUG_CATEGORY_STATIC (gst_fisheye_debug);
+#define GST_CAT_DEFAULT gst_fisheye_debug
+
+GST_BOILERPLATE (GstFisheye, gst_fisheye, GstGeometricTransform,
+    GST_TYPE_GEOMETRIC_TRANSFORM);
+
+/* GObject vmethod implementations */
+
+static void
+gst_fisheye_base_init (gpointer gclass)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (gclass);
+
+  gst_element_class_set_details_simple (element_class,
+      "fisheye",
+      "Transform/Effect/Video",
+      "Split the image into two halves and reflect one over each other",
+      "Filippo Argiolas <filippo.argiolas@gmail.com");
+}
+
+static gboolean
+fisheye_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
+    gdouble * in_y)
+{
+  GstFisheye *fisheye = GST_FISHEYE_CAST (gt);
+  gdouble norm_x;
+  gdouble norm_y;
+  gdouble r;
+
+  gdouble width = gt->width;
+  gdouble height = gt->height;
+
+  /* normalize in ((-1.0, -1.0), (1.0, 1.0) */
+  norm_x = 2.0 * x / width - 1.0;
+  norm_y = 2.0 * y / height - 1.0;
+
+  /* normalize radius to 1, simplifies following formula */
+  r = sqrt ((norm_x * norm_x + norm_y * norm_y) / 2.0);
+
+  /* the idea is roughly to map r to tan(r) */
+  /* to avoid switching back and forth to polar coordinates use
+     tangent expansion */
+  /*   r = a*r + br^3 + cr^5 + dr^7 + o(8)) */
+  /*     = r(a + br^2 + cr^4 + dr^6) */
+  /* so we can just multiply both x and y by the quantity in parenthesis */
+  /* forgetting about the tangent thing and simplifying things a
+     little bit we have a first linear term that, inverted, gives
+     the zoom amount in the center region (3x here), than a high
+     power term that makes the function blow up at the edges and a
+     quadratic term smooths the middle region */
+  /* coefficients must sum up to 1 to keep vertices in the +-1
+     square */
+  /* obviously this is a poor and arbitrary implementation of a
+     fisheye filter, if you have a more rigorous method or one
+     that gives better results please step up */
+  norm_x *= (0.33 + 0.1 * r * r + 0.57 * pow (r, 6.0));
+  norm_y *= (0.33 + 0.1 * r * r + 0.57 * pow (r, 6.0));
+
+  /* unnormalize */
+  *in_x = 0.5 * (norm_x + 1.0) * width;
+  *in_y = 0.5 * (norm_y + 1.0) * height;
+
+  GST_DEBUG_OBJECT (fisheye, "Inversely mapped %d %d into %lf %lf",
+      x, y, *in_x, *in_y);
+
+  return TRUE;
+}
+
+static void
+gst_fisheye_class_init (GstFisheyeClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstGeometricTransformClass *gstgt_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstgt_class = (GstGeometricTransformClass *) klass;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gstgt_class->map_func = fisheye_map;
+}
+
+static void
+gst_fisheye_init (GstFisheye * filter, GstFisheyeClass * gclass)
+{
+  GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);
+
+  gt->off_edge_pixels = GST_GT_OFF_EDGES_PIXELS_CLAMP;
+}
+
+gboolean
+gst_fisheye_plugin_init (GstPlugin * plugin)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_fisheye_debug, "fisheye", 0, "fisheye");
+
+  return gst_element_register (plugin, "fisheye", GST_RANK_NONE,
+      GST_TYPE_FISHEYE);
+}

gst/geometrictransform/gstfisheye.h

@@ -0,0 +1,83 @@
+/*
+ * GStreamer
+ * Copyright (C) 2010 Filippo Argiolas <filippo.argiolas@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Alternatively, the contents of this file may be used under the
+ * GNU Lesser General Public License Version 2.1 (the "LGPL"), in
+ * which case the following provisions apply instead of the ones
+ * mentioned above:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_FISHEYE_H__
+#define __GST_FISHEYE_H__
+
+#include <gst/gst.h>
+#include "gstgeometrictransform.h"
+#include "geometricmath.h"
+
+G_BEGIN_DECLS
+/* #defines don't like whitespacey bits */
+#define GST_TYPE_FISHEYE \
+  (gst_fisheye_get_type())
+#define GST_FISHEYE(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_FISHEYE,GstFisheye))
+#define GST_FISHEYE_CAST(obj) \
+  ((GstFisheye *)(obj))
+#define GST_FISHEYE_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_FISHEYE,GstFisheyeClass))
+#define GST_IS_FISHEYE(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_FISHEYE))
+#define GST_IS_FISHEYE_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_FISHEYE))
+typedef struct _GstFisheye GstFisheye;
+typedef struct _GstFisheyeClass GstFisheyeClass;
+
+struct _GstFisheye
+{
+  GstGeometricTransform element;
+};
+
+struct _GstFisheyeClass
+{
+  GstGeometricTransformClass parent_class;
+};
+
+GType gst_fisheye_get_type (void);
+
+gboolean gst_fisheye_plugin_init (GstPlugin * plugin);
+
+G_END_DECLS
+#endif /* __GST_FISHEYE_H__ */

gst/geometrictransform/plugin.c

@@ -34,6 +34,7 @@
 #include "gsttunnel.h"
 #include "gstsquare.h"
 #include "gstmirror.h"
+#include "gstfisheye.h"
 
 static gboolean
 plugin_init (GstPlugin * plugin)
@@ -77,6 +78,9 @@ plugin_init (GstPlugin * plugin)
   if (!gst_mirror_plugin_init (plugin))
     return FALSE;
 
+  if (!gst_fisheye_plugin_init (plugin))
+    return FALSE;
+
   return TRUE;
 }