coral / mtk-gst-plugins-bad / 8ad57f24078ca3c49776969bb1017520c0277428 / . / gst / geometrictransform / gstfisheye.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 | |

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* 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, | |

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* 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-fisheye | |

* @title: fisheye | |

* @see_also: geometrictransform | |

* | |

* Fisheye is a geometric image transform element. It simulates a fisheye lens | |

* by zooming on the center of the image and compressing the edges. | |

* | |

* ## Example launch line | |

* |[ | |

* gst-launch-1.0 -v videotestsrc ! fisheye ! videoconvert ! autovideosink | |

* ]| | |

* | |

*/ | |

#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 | |

#define gst_fisheye_parent_class parent_class | |

G_DEFINE_TYPE (GstFisheye, gst_fisheye, GST_TYPE_GEOMETRIC_TRANSFORM); | |

static gboolean | |

fisheye_map (GstGeometricTransform * gt, gint x, gint y, gdouble * in_x, | |

gdouble * in_y) | |

{ | |

#ifndef GST_DISABLE_GST_DEBUG | |

GstFisheye *fisheye = GST_FISHEYE_CAST (gt); | |

#endif | |

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) | |

{ | |

GstElementClass *gstelement_class; | |

GstGeometricTransformClass *gstgt_class; | |

gstelement_class = (GstElementClass *) klass; | |

gstgt_class = (GstGeometricTransformClass *) klass; | |

gst_element_class_set_static_metadata (gstelement_class, | |

"fisheye", | |

"Transform/Effect/Video", | |

"Simulate a fisheye lens by zooming on the center of the image and compressing the edges", | |

"Filippo Argiolas <filippo.argiolas@gmail.com>"); | |

gstgt_class->map_func = fisheye_map; | |

} | |

static void | |

gst_fisheye_init (GstFisheye * filter) | |

{ | |

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); | |

} |