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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
201 lines
4.8 KiB
C
201 lines
4.8 KiB
C
/*
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* GStreamer
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* Copyright (C) 2010 Thiago Santos <thiago.sousa.santos@collabora.co.uk>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* Alternatively, the contents of this file may be used under the
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* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
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* which case the following provisions apply instead of the ones
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* mentioned above:
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/*
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* Thanks to Jerry Huxtable <http://www.jhlabs.com> work on its java
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* image editor and filters. The algorithms here were extracted from
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* his code.
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*/
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#include "geometricmath.h"
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#include <math.h>
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#define N 0x1000
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#define B 0x100
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#define BM 0xff
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struct _Noise
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{
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gdouble p[2 * B + 2];
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gdouble g2[2 * B + 2][2];
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};
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static void
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normalize_2 (gdouble * v)
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{
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gdouble s = sqrt (v[0] * v[0] + v[1] * v[1]);
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v[0] = v[0] / s;
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v[1] = v[1] / s;
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}
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Noise *
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noise_new (void)
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{
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Noise *noise = g_new0 (Noise, 1);
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gint i, j, k;
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for (i = 0; i < B; i++) {
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noise->p[i] = i;
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for (j = 0; j < 2; j++) {
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noise->g2[i][j] = ((g_random_int () % (2 * B))
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- B) / (gdouble) B;
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}
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normalize_2 (noise->g2[i]);
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}
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for (i = B - 1; i >= 0; i--) {
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k = noise->p[i];
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j = g_random_int () % B;
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noise->p[i] = noise->p[j];
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noise->p[j] = k;
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}
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for (i = 0; i < B + 2; i++) {
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noise->p[B + i] = noise->p[i];
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for (j = 0; j < 2; j++) {
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noise->g2[B + i][j] = noise->g2[i][j];
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}
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}
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return noise;
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}
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void
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noise_free (Noise * noise)
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{
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g_free (noise);
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}
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static gdouble
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s_curve (gdouble x)
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{
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return x * x * (3.0 - 2.0 * x);
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}
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static gdouble
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lerp (gdouble t, gdouble a, gdouble b)
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{
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return a + t * (b - a);
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}
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gdouble
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noise_2 (Noise * noise, gdouble x, gdouble y)
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{
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gint bx0, bx1, by0, by1, b00, b10, b01, b11;
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gdouble rx0, rx1, ry0, ry1, sx, sy, a, b, t, u, v;
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gdouble *q;
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gint i, j;
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t = x + N;
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bx0 = ((gint) t) & BM;
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bx1 = (bx0 + 1) & BM;
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rx0 = t - (gint) t;
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rx1 = rx0 - 1.0;
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t = y + N;
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by0 = ((gint) t) & BM;
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by1 = (by0 + 1) & BM;
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ry0 = t - (gint) t;
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ry1 = ry0 - 1.0;
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i = noise->p[bx0];
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j = noise->p[bx1];
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b00 = noise->p[i + by0];
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b10 = noise->p[j + by0];
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b01 = noise->p[i + by1];
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b11 = noise->p[j + by1];
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sx = s_curve (rx0);
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sy = s_curve (ry0);
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q = noise->g2[b00];
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u = rx0 * q[0] + ry0 * q[1];
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q = noise->g2[b10];
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v = rx1 * q[0] + ry0 * q[1];
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a = lerp (sx, u, v);
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q = noise->g2[b01];
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u = rx0 * q[0] + ry1 * q[1];
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q = noise->g2[b11];
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v = rx1 * q[0] + ry1 * q[1];
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b = lerp (sx, u, v);
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return 1.5 * lerp (sy, a, b);
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}
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/*
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* This differs from the % operator with respect to negative numbers
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*/
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gdouble
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mod_float (gdouble a, gdouble b)
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{
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gint n = (gint) (a / b);
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a -= n * b;
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if (a < 0)
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return a + b;
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return a;
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}
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/**
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* Returns a repeating triangle shape in the range 0..1 with wavelength 1.0
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*/
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gdouble
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geometric_math_triangle (gdouble x)
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{
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gdouble r = mod_float (x, 1.0);
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return 2.0 * (r < 0.5 ? r : 1 - r);
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}
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/**
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* Hermite interpolation
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*/
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gdouble
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smoothstep (gdouble edge0, gdouble edge1, gdouble x)
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{
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gdouble t = CLAMP ((x - edge0) / (edge1 - edge0), 0.0, 1.0);
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return t * t * (3.0 - 2.0 * t);
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}
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