gstreamer/gst/geometrictransform/gststretch.c
Filippo Argiolas 2edd185a9a geometrictransform: new filter "stretch"
Ports gleffects "stretch" filter to geometrictransform.
Shrinks the image around the center and gradually return to normal zoom
creating funny caricatures.

https://bugzilla.gnome.org/show_bug.cgi?id=625722
2010-08-02 20:09:26 +02:00

158 lines
5.4 KiB
C

/*
* 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 "gststretch.h"
#include "geometricmath.h"
GST_DEBUG_CATEGORY_STATIC (gst_stretch_debug);
#define GST_CAT_DEFAULT gst_stretch_debug
GST_BOILERPLATE (GstStretch, gst_stretch, GstCircleGeometricTransform,
GST_TYPE_CIRCLE_GEOMETRIC_TRANSFORM);
/* Clean up */
static void
gst_stretch_finalize (GObject * obj)
{
G_OBJECT_CLASS (parent_class)->finalize (obj);
}
/* GObject vmethod implementations */
static void
gst_stretch_base_init (gpointer gclass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (gclass);
gst_element_class_set_details_simple (element_class,
"stretch",
"Transform/Effect/Video",
"Stretch the image in a circle around the center point",
"Filippo Argiolas <filippo.argiolas@gmail.com>");
}
static gboolean
stretch_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x,
gdouble * in_y)
{
GstCircleGeometricTransform *cgt = GST_CIRCLE_GEOMETRIC_TRANSFORM_CAST (gt);
GstStretch *stretch = GST_STRETCH_CAST (gt);
gdouble norm_x, norm_y;
gdouble r;
gdouble width = gt->width;
gdouble height = gt->height;
/* normalize in ((-1.0, -1.0), (1.0, 1.0) and traslate the center */
norm_x = 2.0 * (x / width - cgt->x_center);
norm_y = 2.0 * (y / height - cgt->y_center);
r = sqrt (norm_x * norm_x + norm_y * norm_y);
/* TODO: make it customizable, 0.7 is the radius of the stretch
* ellipse, with current way of setting radius (absolute value) it
* would be sqrt(hw*hw + hh*hh)/radius*radius but currently I prefer
* leaving it hardcoded because I don't think absolute radius makes
* any sense: the user either knows the video size and can easily
* calculate the fractional radius and set that or doesn't know the
* size a priori and wants to obtain the same effect no matter of
* the video dimensions */
/* actually "stretch" name is a bit misleading, what the transform
* really does is shrink the center and gradually return to normal
* size while r increases. The shrink thing drags pixels giving
* stretching the image around the center */
/* 2.0 is the shrink amount. Make it customizable? */
norm_x *= 2.0 - smoothstep (0.0, 0.7, r);
norm_y *= 2.0 - smoothstep (0.0, 0.7, r);
/* unnormalize */
*in_x = (0.5 * norm_x + cgt->x_center) * width;
*in_y = (0.5 * norm_y + cgt->y_center) * height;
GST_DEBUG_OBJECT (stretch, "Inversely mapped %d %d into %lf %lf",
x, y, *in_x, *in_y);
return TRUE;
}
static void
gst_stretch_class_init (GstStretchClass * klass)
{
GObjectClass *gobject_class;
GstGeometricTransformClass *gstgt_class;
gobject_class = (GObjectClass *) klass;
gstgt_class = (GstGeometricTransformClass *) klass;
parent_class = g_type_class_peek_parent (klass);
gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_stretch_finalize);
gstgt_class->map_func = stretch_map;
}
static void
gst_stretch_init (GstStretch * filter, GstStretchClass * gclass)
{
GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);
gt->off_edge_pixels = GST_GT_OFF_EDGES_PIXELS_CLAMP;
}
gboolean
gst_stretch_plugin_init (GstPlugin * plugin)
{
GST_DEBUG_CATEGORY_INIT (gst_stretch_debug, "stretch", 0, "stretch");
return gst_element_register (plugin, "stretch", GST_RANK_NONE,
GST_TYPE_STRETCH);
}