libavfilter: image transform code
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
danielgtaylor
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Michael Niedermayer
Michael Niedermayer
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eaa21b6870
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7985381e23
182
libavfilter/transform.c
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182
libavfilter/transform.c
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/*
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* Copyright (C) 2010 Georg Martius <georg.martius@web.de>
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* Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file libavfilter/transform.c
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* transform input video
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*/
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#include "libavutil/common.h"
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#include "transform.h"
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#define INTERPOLATE_METHOD(name) \
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static uint8_t name(float x, float y, const uint8_t *src, \
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int width, int height, int stride, uint8_t def)
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#define PIXEL(img, x, y, w, h, stride, def) \
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((x) < 0 || (y) < 0) ? (def) : \
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(((x) >= (w) || (y) >= (h)) ? (def) : \
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img[(x) + (y) * (stride)])
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/**
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* Nearest neighbor interpolation
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*/
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INTERPOLATE_METHOD(interpolate_nearest)
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{
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return PIXEL(src, (int)(x + 0.5), (int)(y + 0.5), width, height, stride, def);
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}
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/**
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* Bilinear interpolation
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*/
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INTERPOLATE_METHOD(interpolate_bilinear)
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{
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int x_c, x_f, y_c, y_f;
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int v1, v2, v3, v4;
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if (x < -1 || x > width || y < -1 || y > height) {
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return def;
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} else {
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x_f = (int)x;
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x_c = x_f + 1;
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y_f = (int)y;
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y_c = y_f + 1;
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v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
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v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
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v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
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v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
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return (v1*(x - x_f)*(y - y_f) + v2*((x - x_f)*(y_c - y)) +
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v3*(x_c - x)*(y - y_f) + v4*((x_c - x)*(y_c - y)));
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}
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}
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/**
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* Biquadratic interpolation
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*/
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INTERPOLATE_METHOD(interpolate_biquadratic)
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{
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int x_c, x_f, y_c, y_f;
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uint8_t v1, v2, v3, v4;
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float f1, f2, f3, f4;
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if (x < - 1 || x > width || y < -1 || y > height)
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return def;
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else {
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x_f = (int)x;
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x_c = x_f + 1;
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y_f = (int)y;
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y_c = y_f + 1;
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v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
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v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
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v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
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v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
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f1 = 1 - sqrt((x_c - x) * (y_c - y));
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f2 = 1 - sqrt((x_c - x) * (y - y_f));
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f3 = 1 - sqrt((x - x_f) * (y_c - y));
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f4 = 1 - sqrt((x - x_f) * (y - y_f));
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return (v1 * f1 + v2 * f2 + v3 * f3 + v4 * f4) / (f1 + f2 + f3 + f4);
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}
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}
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void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix) {
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matrix[0] = zoom * cos(angle);
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matrix[1] = -sin(angle);
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matrix[2] = x_shift;
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matrix[3] = -matrix[1];
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matrix[4] = matrix[0];
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matrix[5] = y_shift;
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matrix[6] = 0;
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matrix[7] = 0;
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matrix[8] = 1;
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}
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void avfilter_add_matrix(const float *m1, const float *m2, float *result)
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{
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for (int i = 0; i < 9; i++)
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result[i] = m1[i] + m2[i];
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}
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void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
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{
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for (int i = 0; i < 9; i++)
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result[i] = m1[i] - m2[i];
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}
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void avfilter_mul_matrix(const float *m1, float scalar, float *result)
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{
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for (int i = 0; i < 9; i++)
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result[i] = m1[i] * scalar;
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}
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void avfilter_transform(const uint8_t *src, uint8_t *dst,
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int src_stride, int dst_stride,
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int width, int height, const float *matrix,
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enum InterpolateMethod interpolate,
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enum FillMethod fill)
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{
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int x, y;
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float x_s, y_s;
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uint8_t def = 0;
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uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;
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switch(interpolate) {
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case INTERPOLATE_NEAREST:
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func = interpolate_nearest;
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break;
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case INTERPOLATE_BILINEAR:
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func = interpolate_bilinear;
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break;
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case INTERPOLATE_BIQUADRATIC:
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func = interpolate_biquadratic;
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break;
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}
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for (y = 0; y < height; y++) {
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for(x = 0; x < width; x++) {
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x_s = x * matrix[0] + y * matrix[1] + matrix[2];
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y_s = x * matrix[3] + y * matrix[4] + matrix[5];
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switch(fill) {
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case FILL_ORIGINAL:
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def = src[y * src_stride + x];
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break;
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case FILL_CLAMP:
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y_s = av_clipf(y_s, 0, height - 1);
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x_s = av_clipf(x_s, 0, width - 1);
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def = src[(int)y_s * src_stride + (int)x_s];
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break;
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case FILL_MIRROR:
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y_s = (y_s < 0) ? -y_s : (y_s >= height) ? (height + height - y_s) : y_s;
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x_s = (x_s < 0) ? -x_s : (x_s >= width) ? (width + width - x_s) : x_s;
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def = src[(int)y_s * src_stride + (int)x_s];
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}
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dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);
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}
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}
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}
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125
libavfilter/transform.h
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125
libavfilter/transform.h
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@@ -0,0 +1,125 @@
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/*
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* Copyright (C) 2010 Georg Martius <georg.martius@web.de>
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* Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file libavfilter/transform.h
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* transform input video
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*
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* All matrices are defined as a single 9-item block of contiguous memory. For
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* example, the identity matrix would be:
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*
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* float *matrix = {1, 0, 0,
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* 0, 1, 0,
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* 0, 0, 1};
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*/
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enum InterpolateMethod {
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INTERPOLATE_NEAREST, //< Nearest-neighbor (fast)
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INTERPOLATE_BILINEAR, //< Bilinear
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INTERPOLATE_BIQUADRATIC, //< Biquadratic (best)
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INTERPOLATE_COUNT, //< Number of interpolation methods
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};
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// Shortcuts for the fastest and best interpolation methods
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#define INTERPOLATE_DEFAULT INTERPOLATE_BILINEAR
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#define INTERPOLATE_FAST INTERPOLATE_NEAREST
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#define INTERPOLATE_BEST INTERPOLATE_BIQUADRATIC
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enum FillMethod {
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FILL_BLANK, //< Fill zeroes at blank locations
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FILL_ORIGINAL, //< Original image at blank locations
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FILL_CLAMP, //< Extruded edge value at blank locations
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FILL_MIRROR, //< Mirrored edge at blank locations
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FILL_COUNT, //< Number of edge fill methods
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};
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// Shortcuts for fill methods
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#define FILL_DEFAULT FILL_ORIGINAL
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/**
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* Get an affine transformation matrix from a given translation, rotation, and
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* zoom factor. The matrix will look like:
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*
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* [ zoom * cos(angle), -sin(angle), x_shift,
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* sin(angle), zoom * cos(angle), y_shift,
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0, 0, 1 ]
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*
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* Paramters:
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* x_shift: Horizontal translation
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* y_shift: Vertical translation
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* angle: Rotation in radians
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* zoom: Scale percent (1.0 = 100%)
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* matrix: 9-item affine transformation matrix
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*/
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void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix);
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/**
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* Add two matrices together. result = m1 + m2.
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*
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* Parameters:
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* m1: 9-item transformation matrix
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* m2: 9-item transformation matrix
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* result: 9-item transformation matrix
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*/
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void avfilter_add_matrix(const float *m1, const float *m2, float *result);
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/**
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* Subtract one matrix from another. result = m1 - m2.
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*
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* Parameters:
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* m1: 9-item transformation matrix
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* m2: 9-item transformation matrix
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* result: 9-item transformation matrix
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*/
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void avfilter_sub_matrix(const float *m1, const float *m2, float *result);
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/**
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* Multiply a matrix by a scalar value. result = m1 * scalar.
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*
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* Parameters:
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* m1: 9-item transformation matrix
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* scalar: A number
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* result: 9-item transformation matrix
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*/
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void avfilter_mul_matrix(const float *m1, float scalar, float *result);
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/**
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* Do an affine transformation with the given interpolation method. This
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* multiplies each vector [x,y,1] by the matrix and then interpolates to
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* get the final value.
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*
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* Parameters:
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* src: Source image
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* dst: Destination image
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* src_stride: Source image line size in bytes
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* dst_stride: Destination image line size in bytes
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* width: Image width in pixels
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* height: Image height in pixels
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* matrix: 9-item affine transformation matrix
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* interpolate: Pixel interpolation method
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* fill: Edge fill method
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*/
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void avfilter_transform(const uint8_t *src, uint8_t *dst,
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int src_stride, int dst_stride,
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int width, int height, const float *matrix,
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enum InterpolateMethod interpolate,
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enum FillMethod fill);
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