/*

 * This file is part of mpv.

 *

 * mpv 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.

 *

 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

/* Stuff for correct aspect scaling. */

#include "aspect.h"

#include "math.h"

#include "vo.h"

#include "common/msg.h"

#include "options/options.h"

#include "video/mp_image.h"

#include "vo.h"

#include "sub/osd.h"

static void aspect_calc_panscan(struct mp_vo_opts *opts,

                                int w, int h, int d_w, int d_h, int unscaled,

                                int window_w, int window_h, double monitor_par,

                                int *out_w, int *out_h)

{

    int fwidth = window_w;

    int fheight = (float)window_w / d_w * d_h / monitor_par;

    if (fheight > window_h || fheight < h) {

        int tmpw = (float)window_h / d_h * d_w * monitor_par;

        if (tmpw <= window_w) {

            fheight = window_h;

            fwidth = tmpw;

        }

    }

    int vo_panscan_area = window_h - fheight;

    double f_w = fwidth / (double)MPMAX(fheight, 1);

    double f_h = 1;

    if (vo_panscan_area == 0) {

        vo_panscan_area = window_w - fwidth;

        f_w = 1;

        f_h = fheight / (double)MPMAX(fwidth, 1);

    }

    if (unscaled) {

        vo_panscan_area = 0;

        if (unscaled != 2 || (d_w <= window_w && d_h <= window_h)) {

            fwidth = d_w * monitor_par;

            fheight = d_h;

        }

    }

    *out_w = fwidth + vo_panscan_area * opts->panscan * f_w;

    *out_h = fheight + vo_panscan_area * opts->panscan * f_h;

}

// Clamp [start, end) to range [0, size) with various fallbacks.

static void clamp_size(int size, int *start, int *end)

{

    *start = MPMAX(0, *start);

    *end = MPMIN(size, *end);

    if (*start >= *end) {

        *start = 0;

        *end = 1;

    }

}

static void src_dst_split_scaling(int src_size, int dst_size,

                                  int scaled_src_size,

                                  float zoom, float align, float pan, float scale,

                                  bool recenter,

                                  int *src_start, int *src_end,

                                  int *dst_start, int *dst_end,

                                  int *osd_margin_a, int *osd_margin_b)

{

    scaled_src_size *= powf(2, zoom) * scale;

    scaled_src_size = MPMAX(scaled_src_size, 1);

    if (recenter && dst_size >= scaled_src_size)

        align = 0;

    align = (align + 1) / 2;

    *dst_start = (dst_size - scaled_src_size) * align + pan * scaled_src_size;

    *dst_end = *dst_start + scaled_src_size;

    // Distance of screen frame to video

    *osd_margin_a = *dst_start;

    *osd_margin_b = dst_size - *dst_end;

    // Clip to screen

    int s_src = *src_end - *src_start;

    int s_dst = *dst_end - *dst_start;

    if (*dst_start < 0) {

        int border = -(*dst_start) * s_src / s_dst;

        *src_start += border;

        *dst_start = 0;

    }

    if (*dst_end > dst_size) {

        int border = (*dst_end - dst_size) * s_src / s_dst;

        *src_end -= border;

        *dst_end = dst_size;

    }

    // For sanity: avoid bothering VOs with corner cases

    clamp_size(src_size, src_start, src_end);

    clamp_size(dst_size, dst_start, dst_end);

}

static void calc_margin(float opts[2], int out[2], int size)

{

    out[0] = MPCLAMP((int)(opts[0] * size), 0, size);

    out[1] = MPCLAMP((int)(opts[1] * size), 0, size);

    if (out[0] + out[1] >= size) {

        // This case is not really supported. Show an error by 1 pixel.

        out[0] = 0;

        out[1] = MPMAX(0, size - 1);

    }

}

void mp_get_src_dst_rects(struct mp_log *log, struct mp_vo_opts *opts,

                          int vo_caps, struct mp_image_params *video,

                          int window_w, int window_h, double monitor_par,

                          struct mp_rect *out_src,

                          struct mp_rect *out_dst,

                          struct mp_osd_res *out_osd)

{

    int src_w = video->w;

    int src_h = video->h;

    int src_dw, src_dh;

    mp_image_params_get_dsize(video, &src_dw, &src_dh);

    window_w = MPMAX(1, window_w);

    window_h = MPMAX(1, window_h);

    int margin_x[2] = {0};

    int margin_y[2] = {0};

    if (opts->keepaspect) {

        calc_margin(opts->margin_x, margin_x, window_w);

        calc_margin(opts->margin_y, margin_y, window_h);

    }

    int vid_window_w = window_w - margin_x[0] - margin_x[1];

    int vid_window_h = window_h - margin_y[0] - margin_y[1];

    struct mp_rect dst = {0, 0, window_w, window_h};

    struct mp_rect src = {0, 0, src_w,    src_h};

    if (mp_image_crop_valid(video))

        src = video->crop;

    if (vo_caps & VO_CAP_ROTATE90) {

        if (video->rotate % 180 == 90) {

            MPSWAP(int, src_w, src_h);

            MPSWAP(int, src_dw, src_dh);

        }

        mp_rect_rotate(&src, src_w, src_h, video->rotate);

    }

    struct mp_osd_res osd = {

        .w = window_w,

        .h = window_h,

        .display_par = monitor_par,

    };

    if (opts->keepaspect) {

        int scaled_width, scaled_height;

        aspect_calc_panscan(opts, src_w, src_h, src_dw, src_dh, opts->unscaled,

                            vid_window_w, vid_window_h, monitor_par,

                            &scaled_width, &scaled_height);

        src_dst_split_scaling(src_w, vid_window_w, scaled_width,

                              opts->zoom, opts->align_x, opts->pan_x, opts->scale_x,

                              opts->recenter,

                              &src.x0, &src.x1, &dst.x0, &dst.x1,

                              &osd.ml, &osd.mr);

        src_dst_split_scaling(src_h, vid_window_h, scaled_height,

                              opts->zoom, opts->align_y, opts->pan_y, opts->scale_y,

                              opts->recenter,

                              &src.y0, &src.y1, &dst.y0, &dst.y1,

                              &osd.mt, &osd.mb);

    }

    dst.x0 += margin_x[0];

    dst.y0 += margin_y[0];

    dst.x1 += margin_x[0];

    dst.y1 += margin_y[0];

    // OSD really uses the full window, but was computed on the margin-cut

    // video sub-window. Correct it to the full window.

    osd.ml += margin_x[0];

    osd.mr += margin_x[1];

    osd.mt += margin_y[0];

    osd.mb += margin_y[1];

    *out_src = src;

    *out_dst = dst;

    *out_osd = osd;

    int sw = src.x1 - src.x0, sh = src.y1 - src.y0;

    int dw = dst.x1 - dst.x0, dh = dst.y1 - dst.y0;

    mp_verbose(log, "Window size: %dx%d (Borders: l=%d t=%d r=%d b=%d)\n",

               window_w, window_h,

               margin_x[0], margin_y[0], margin_x[1], margin_y[1]);

    mp_verbose(log, "Video source: %dx%d (%d:%d)\n",

               video->w, video->h, video->p_w, video->p_h);

    mp_verbose(log, "Video display: (%d, %d) %dx%d -> (%d, %d) %dx%d\n",

               src.x0, src.y0, sw, sh, dst.x0, dst.y0, dw, dh);

    mp_verbose(log, "Video scale: %f/%f\n",

               (double)dw / sw, (double)dh / sh);

    mp_verbose(log, "OSD borders: l=%d t=%d r=%d b=%d\n",

               osd.ml, osd.mt, osd.mr, osd.mb);

    mp_verbose(log, "Video borders: l=%d t=%d r=%d b=%d\n",

               dst.x0, dst.y0, window_w - dst.x1, window_h - dst.y1);

}