geometrictransform: Add a 2D perspective transform plugin

The perspective plugin applies a 2D perspective (also called projective)
transform to the frame buffer.

A perspective transform can be used for instance to perform keystone
correction when playing the content with a video projector.

https://bugzilla.gnome.org/show_bug.cgi?id=710810

gst/geometrictransform/Makefile.am

@@ -18,7 +18,8 @@ libgstgeometrictransform_la_SOURCES = plugin.c \
                                       gsttunnel.c \
                                       gstsquare.c \
                                       gstmirror.c \
-                                      gstfisheye.c
+                                      gstfisheye.c \
+                                      gstperspective.c
 
 libgstgeometrictransform_la_CFLAGS = $(GST_CFLAGS) $(GST_BASE_CFLAGS) \
 			    $(GST_PLUGINS_BASE_CFLAGS)
@@ -46,7 +47,8 @@ noinst_HEADERS = gstgeometrictransform.h \
                  gsttunnel.h \
                  gstsquare.h \
                  gstmirror.h \
-                 gstfisheye.h
+                 gstfisheye.h \
+                 gstperspective.h
 
 Android.mk: Makefile.am $(BUILT_SOURCES)
 	androgenizer \

gst/geometrictransform/gstperspective.c

@@ -0,0 +1,264 @@
+/*
+ * GStreamer
+ * Copyright (C) 2010 Thiago Santos <thiago.sousa.santos@collabora.co.uk>
+ * Copyright (C) 2013 Antonio Ospite <ospite@studenti.unina.it>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+/*
+ * Perspective matrix multiplication taken from:
+ * http://docs.oracle.com/cd/E17802_01/products/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/PerspectiveTransform.html
+ */
+
+/* FIXME: suppress warnings for deprecated API such as GValueArray
+ * with newer GLib versions (>= 2.31.0)
+ *
+ * It is just not possible to switch to GArray yet because the python API in
+ * 1.2.0 still passes iterable properties as GValueArray */
+#define GLIB_DISABLE_DEPRECATION_WARNINGS
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <gst/gst.h>
+
+#include "gstperspective.h"
+
+GST_DEBUG_CATEGORY_STATIC (gst_perspective_debug);
+#define GST_CAT_DEFAULT gst_perspective_debug
+
+enum
+{
+  PROP_0,
+  PROP_MATRIX
+};
+
+
+#define gst_perspective_parent_class parent_class
+G_DEFINE_TYPE (GstPerspective, gst_perspective, GST_TYPE_GEOMETRIC_TRANSFORM);
+
+static GValueArray *
+get_array_from_matrix (GstPerspective * self)
+{
+  GValue v = { 0, };
+  GValueArray *va;
+
+  va = g_value_array_new (1);
+
+  for (int i = 0; i < 9; i++) {
+    g_value_init (&v, G_TYPE_DOUBLE);
+    g_value_set_double (&v, self->matrix[i]);
+    g_value_array_append (va, &v);
+    g_value_unset (&v);
+  }
+
+  return va;
+}
+
+static gboolean
+set_matrix_from_array (GstPerspective * self, GValueArray * va)
+{
+  guint i;
+
+  if (!va) {
+    GST_WARNING ("Invalid parameter");
+    return FALSE;
+  }
+
+  if (va->n_values != 9) {
+    GST_WARNING ("Invalid number of elements: %d", va->n_values);
+    return FALSE;
+  }
+
+  for (i = 0; i < va->n_values; i++) {
+    GValue *v = g_value_array_get_nth (va, i);
+    self->matrix[i] = g_value_get_double (v);
+  }
+
+  return TRUE;
+}
+
+static void
+gst_perspective_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstPerspective *perspective;
+  GstGeometricTransform *gt;
+  gboolean matrix_ok;
+
+  gt = GST_GEOMETRIC_TRANSFORM_CAST (object);
+  perspective = GST_PERSPECTIVE_CAST (object);
+
+  GST_OBJECT_LOCK (perspective);
+  switch (prop_id) {
+    case PROP_MATRIX:
+      matrix_ok =
+          set_matrix_from_array (perspective, g_value_get_boxed (value));
+      if (matrix_ok) {
+        gst_geometric_transform_set_need_remap (gt);
+      }
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+  GST_OBJECT_UNLOCK (perspective);
+}
+
+static void
+gst_perspective_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstPerspective *perspective;
+
+  perspective = GST_PERSPECTIVE_CAST (object);
+
+  switch (prop_id) {
+    case PROP_MATRIX:
+      g_value_set_boxed (value, get_array_from_matrix (perspective));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+/* Clean up */
+static void
+gst_perspective_finalize (GObject * obj)
+{
+  G_OBJECT_CLASS (parent_class)->finalize (obj);
+}
+
+static gboolean
+perspective_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
+    gdouble * in_y)
+{
+  GstPerspective *perspective = GST_PERSPECTIVE_CAST (gt);
+  gdouble *m;
+  gdouble xp, yp, w, xi, yi;
+
+  m = perspective->matrix;
+
+  /* Matrix multiplication */
+  xp = (m[0] * x + m[1] * y + m[2]);
+  yp = (m[3] * x + m[4] * y + m[5]);
+  w = (m[6] * x + m[7] * y + m[8]);
+
+  /* Perspective division */
+  xi = xp / w;
+  yi = yp / w;
+
+  /* return values to caller */
+  *in_x = xi;
+  *in_y = yi;
+
+  GST_DEBUG_OBJECT (perspective, "Inversely mapped %d %d into %lf %lf",
+      x, y, *in_x, *in_y);
+
+  return TRUE;
+}
+
+static void
+gst_perspective_class_init (GstPerspectiveClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+  GstGeometricTransformClass *gstgt_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+  gstgt_class = (GstGeometricTransformClass *) klass;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+  gst_element_class_set_static_metadata (gstelement_class,
+      "perspective",
+      "Transform/Effect/Video",
+      "Apply a 2D perspective transform",
+      "Antonio Ospite <ospite@studenti.unina.it>");
+
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_perspective_finalize);
+  gobject_class->set_property =
+      GST_DEBUG_FUNCPTR (gst_perspective_set_property);
+  gobject_class->get_property =
+      GST_DEBUG_FUNCPTR (gst_perspective_get_property);
+
+  g_object_class_install_property (gobject_class, PROP_MATRIX,
+      g_param_spec_value_array ("matrix",
+          "Matrix",
+          "Matrix of dimension 3x3 to use in the 2D transform, passed as an array of 9 elements in row-major order",
+          g_param_spec_double ("Element",
+              "Transformation matrix element",
+              "Element of the transformation matrix",
+              -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,
+              G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  gstgt_class->map_func = perspective_map;
+}
+
+static void
+gst_perspective_init (GstPerspective * filter)
+{
+  /* set the Identity matrix as default */
+  filter->matrix[0] = 1;
+  filter->matrix[1] = 0;
+  filter->matrix[2] = 0;
+
+  filter->matrix[3] = 0;
+  filter->matrix[4] = 1;
+  filter->matrix[5] = 0;
+
+  filter->matrix[6] = 0;
+  filter->matrix[7] = 0;
+  filter->matrix[8] = 1;
+}
+
+gboolean
+gst_perspective_plugin_init (GstPlugin * plugin)
+{
+  GST_DEBUG_CATEGORY_INIT (gst_perspective_debug, "perspective", 0,
+      "perspective");
+
+  return gst_element_register (plugin, "perspective", GST_RANK_NONE,
+      GST_TYPE_PERSPECTIVE);
+}

gst/geometrictransform/gstperspective.h

@@ -0,0 +1,88 @@
+/*
+ * GStreamer
+ * Copyright (C) 2010 Thiago Santos <thiago.sousa.santos@collabora.co.uk>
+ * Copyright (C) 2013 Antonio Ospite <ospite@studenti.unina.it>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_PERSPECTIVE_H__
+#define __GST_PERSPECTIVE_H__
+
+#include <gst/gst.h>
+#include "gstgeometrictransform.h"
+
+G_BEGIN_DECLS
+
+/* #defines don't like whitespacey bits */
+#define GST_TYPE_PERSPECTIVE \
+  (gst_perspective_get_type())
+#define GST_PERSPECTIVE(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_PERSPECTIVE,GstPerspective))
+#define GST_PERSPECTIVE_CAST(obj) \
+  ((GstPerspective *)(obj))
+#define GST_PERSPECTIVE_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_PERSPECTIVE,GstPerspectiveClass))
+#define GST_IS_PERSPECTIVE(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_PERSPECTIVE))
+#define GST_IS_PERSPECTIVE_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_PERSPECTIVE))
+
+typedef struct _GstPerspective      GstPerspective;
+typedef struct _GstPerspectiveClass GstPerspectiveClass;
+
+struct _GstPerspective
+{
+  GstGeometricTransform element;
+
+  gdouble matrix[9];
+};
+
+struct _GstPerspectiveClass
+{
+  GstGeometricTransformClass parent_class;
+};
+
+GType gst_perspective_get_type (void);
+
+gboolean gst_perspective_plugin_init (GstPlugin * plugin);
+
+G_END_DECLS
+
+#endif /* __GST_PERSPECTIVE_H__ */

gst/geometrictransform/plugin.c

@@ -36,6 +36,7 @@
 #include "gstsquare.h"
 #include "gstmirror.h"
 #include "gstfisheye.h"
+#include "gstperspective.h"
 
 static gboolean
 plugin_init (GstPlugin * plugin)
@@ -85,6 +86,9 @@ plugin_init (GstPlugin * plugin)
   if (!gst_fisheye_plugin_init (plugin))
     return FALSE;
 
+  if (!gst_perspective_plugin_init (plugin))
+    return FALSE;
+
   return TRUE;
 }