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/*

 * Copyright (C) 2010 Georg Martius 

 * Copyright (C) 2010 Daniel G. Taylor 

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * transform input video

 */

#include "libavutil/common.h"

#include "libavutil/avassert.h"

#include "transform.h"

#define INTERPOLATE_METHOD(name) \

    static uint8_t name(float x, float y, const uint8_t *src, \

                        int width, int height, int stride, uint8_t def)

#define PIXEL(img, x, y, w, h, stride, def) \

    ((x) < 0 || (y) < 0) ? (def) : \

    (((x) >= (w) || (y) >= (h)) ? (def) : \

    img[(x) + (y) * (stride)])

/**

 * Nearest neighbor interpolation

 */

INTERPOLATE_METHOD(interpolate_nearest)

{

    return PIXEL(src, (int)(x + 0.5), (int)(y + 0.5), width, height, stride, def);

}

/**

 * Bilinear interpolation

 */

INTERPOLATE_METHOD(interpolate_bilinear)

{

    int x_c, x_f, y_c, y_f;

    int v1, v2, v3, v4;

    if (x < -1 || x > width || y < -1 || y > height) {

        return def;

    } else {

        x_f = (int)x;

        x_c = x_f + 1;

        y_f = (int)y;

        y_c = y_f + 1;

        v1 = PIXEL(src, x_c, y_c, width, height, stride, def);

        v2 = PIXEL(src, x_c, y_f, width, height, stride, def);

        v3 = PIXEL(src, x_f, y_c, width, height, stride, def);

        v4 = PIXEL(src, x_f, y_f, width, height, stride, def);

        return (v1*(x - x_f)*(y - y_f) + v2*((x - x_f)*(y_c - y)) +

                v3*(x_c - x)*(y - y_f) + v4*((x_c - x)*(y_c - y)));

    }

}

/**

 * Biquadratic interpolation

 */

INTERPOLATE_METHOD(interpolate_biquadratic)

{

    int     x_c, x_f, y_c, y_f;

    uint8_t v1,  v2,  v3,  v4;

    float   f1,  f2,  f3,  f4;

    if (x < - 1 || x > width || y < -1 || y > height)

        return def;

    else {

        x_f = (int)x;

        x_c = x_f + 1;

        y_f = (int)y;

        y_c = y_f + 1;

        v1 = PIXEL(src, x_c, y_c, width, height, stride, def);

        v2 = PIXEL(src, x_c, y_f, width, height, stride, def);

        v3 = PIXEL(src, x_f, y_c, width, height, stride, def);

        v4 = PIXEL(src, x_f, y_f, width, height, stride, def);

        f1 = 1 - sqrt((x_c - x) * (y_c - y));

        f2 = 1 - sqrt((x_c - x) * (y - y_f));

        f3 = 1 - sqrt((x - x_f) * (y_c - y));

        f4 = 1 - sqrt((x - x_f) * (y - y_f));

        return (v1 * f1 + v2 * f2 + v3 * f3 + v4 * f4) / (f1 + f2 + f3 + f4);

    }

}

void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix) {

    matrix[0] = zoom * cos(angle);

    matrix[1] = -sin(angle);

    matrix[2] = x_shift;

    matrix[3] = -matrix[1];

    matrix[4] = matrix[0];

    matrix[5] = y_shift;

    matrix[6] = 0;

    matrix[7] = 0;

    matrix[8] = 1;

}

void avfilter_add_matrix(const float *m1, const float *m2, float *result)

{

    int i;

    for (i = 0; i < 9; i++)

        result[i] = m1[i] + m2[i];

}

void avfilter_sub_matrix(const float *m1, const float *m2, float *result)

{

    int i;

    for (i = 0; i < 9; i++)

        result[i] = m1[i] - m2[i];

}

void avfilter_mul_matrix(const float *m1, float scalar, float *result)

{

    int i;

    for (i = 0; i < 9; i++)

        result[i] = m1[i] * scalar;

}

static inline int mirror(int v, int m)

{

    while ((unsigned)v > (unsigned)m) {

        v = -v;

        if (v < 0)

            v += 2 * m;

    }

    return v;

}

int avfilter_transform(const uint8_t *src, uint8_t *dst,

                        int src_stride, int dst_stride,

                        int width, int height, const float *matrix,

                        enum InterpolateMethod interpolate,

                        enum FillMethod fill)

{

    int x, y;

    float x_s, y_s;

    uint8_t def = 0;

    uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;

    switch(interpolate) {

        case INTERPOLATE_NEAREST:

            func = interpolate_nearest;

            break;

        case INTERPOLATE_BILINEAR:

            func = interpolate_bilinear;

            break;

        case INTERPOLATE_BIQUADRATIC:

            func = interpolate_biquadratic;

            break;

        default:

            return AVERROR(EINVAL);

    }

    for (y = 0; y < height; y++) {

        for(x = 0; x < width; x++) {

            x_s = x * matrix[0] + y * matrix[1] + matrix[2];

            y_s = x * matrix[3] + y * matrix[4] + matrix[5];

            switch(fill) {

                case FILL_ORIGINAL:

                    def = src[y * src_stride + x];

                    break;

                case FILL_CLAMP:

                    y_s = av_clipf(y_s, 0, height - 1);

                    x_s = av_clipf(x_s, 0, width - 1);

                    def = src[(int)y_s * src_stride + (int)x_s];

                    break;

                case FILL_MIRROR:

                    x_s = mirror(x_s,  width-1);

                    y_s = mirror(y_s, height-1);

                    av_assert2(x_s >= 0 && y_s >= 0);

                    av_assert2(x_s < width && y_s < height);

                    def = src[(int)y_s * src_stride + (int)x_s];

            }

            dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);

        }

    }

    return 0;

}