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/*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-stretch
* @title: stretch
* @see_also: geometrictransform
*
* The stretch element stretches the image in a circle around the center point.
*
* ## Example launch line
* |[
* gst-launch-1.0 -v videotestsrc ! stretch ! videoconvert ! autovideosink
* ]|
*
*/
#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
enum
{
PROP_0,
PROP_INTENSITY
};
#define DEFAULT_INTENSITY 0.5
#define MAX_SHRINK_AMOUNT 3.0
#define gst_stretch_parent_class parent_class
G_DEFINE_TYPE (GstStretch, gst_stretch, GST_TYPE_CIRCLE_GEOMETRIC_TRANSFORM);
static void
gst_stretch_set_property (GObject * object, guint prop_id, const GValue * value,
GParamSpec * pspec)
{
GstStretch *stretch;
GstGeometricTransform *gt;
gdouble v;
gt = GST_GEOMETRIC_TRANSFORM_CAST (object);
stretch = GST_STRETCH_CAST (object);
GST_OBJECT_LOCK (gt);
switch (prop_id) {
case PROP_INTENSITY:
v = g_value_get_double (value);
if (v != stretch->intensity) {
stretch->intensity = v;
gst_geometric_transform_set_need_remap (gt);
}
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
GST_OBJECT_UNLOCK (gt);
}
static void
gst_stretch_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstStretch *stretch;
stretch = GST_STRETCH_CAST (object);
switch (prop_id) {
case PROP_INTENSITY:
g_value_set_double (value, stretch->intensity);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
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;
gdouble a, b;
/* normalize in ((-1.0, -1.0), (1.0, 1.0) and translate the center */
norm_x = 2.0 * (x / width - cgt->x_center);
norm_y = 2.0 * (y / height - cgt->y_center);
/* calculate radius, normalize to 1 for future convenience */
r = sqrt (0.5 * (norm_x * norm_x + norm_y * norm_y));
/* 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 */
/* a is the current maximum shrink amount, it goes from 1.0 to
* MAX_SHRINK_AMOUNT * intensity */
/* smoothstep goes from 0.0 when r == 0 to b when r == radius */
/* total shrink factor is MAX_SHRINK_AMOUNT at center and gradually
* decreases while r goes to radius */
a = 1.0 + (MAX_SHRINK_AMOUNT - 1.0) * stretch->intensity;
b = a - 1.0;
norm_x *= a - b * gst_gm_smoothstep (0.0, cgt->radius, r);
norm_y *= a - b * gst_gm_smoothstep (0.0, cgt->radius, 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;
GstElementClass *gstelement_class;
GstGeometricTransformClass *gstgt_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gstgt_class = (GstGeometricTransformClass *) klass;
gst_element_class_set_static_metadata (gstelement_class,
"stretch",
"Transform/Effect/Video",
"Stretch the image in a circle around the center point",
"Filippo Argiolas <filippo.argiolas@gmail.com>");
gobject_class->set_property = gst_stretch_set_property;
gobject_class->get_property = gst_stretch_get_property;
g_object_class_install_property (gobject_class, PROP_INTENSITY,
g_param_spec_double ("intensity", "intensity",
"Intensity of the stretch effect",
0.0, 1.0, DEFAULT_INTENSITY,
GST_PARAM_CONTROLLABLE | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
gstgt_class->map_func = stretch_map;
}
static void
gst_stretch_init (GstStretch * filter)
{
GstGeometricTransform *gt = GST_GEOMETRIC_TRANSFORM (filter);
filter->intensity = DEFAULT_INTENSITY;
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);
}
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