text: /*
   * Copyright (c) 2008 Affine Systems, Inc (Michael Sullivan, Bobby Impollonia)
   * Copyright (c) 2013 Andrey Utkin <andrey.krieger.utkin gmail com>
   *
   * 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
   * Box and grid drawing filters. Also a nice template for a filter
   * that needs to write in the input frame.
   */
  
  #include "libavutil/colorspace.h"
  #include "libavutil/common.h"
  #include "libavutil/opt.h"
  #include "libavutil/eval.h"
  #include "libavutil/pixdesc.h"
  #include "libavutil/parseutils.h"
  #include "avfilter.h"
  #include "formats.h"
  #include "internal.h"
  #include "video.h"
  
  static const char *const var_names[] = {
      "dar",
      "hsub", "vsub",
      "in_h", "ih",      ///< height of the input video
      "in_w", "iw",      ///< width  of the input video
      "sar",
      "x",
      "y",
      "h",              ///< height of the rendered box
      "w",              ///< width  of the rendered box
      "t",
      "max",
      NULL
  };
  
  enum { Y, U, V, A };
  
  enum var_name {
      VAR_DAR,
      VAR_HSUB, VAR_VSUB,
      VAR_IN_H, VAR_IH,
      VAR_IN_W, VAR_IW,
      VAR_SAR,
      VAR_X,
      VAR_Y,
      VAR_H,
      VAR_W,
      VAR_T,
      VAR_MAX,
      VARS_NB
  };
  
  typedef struct DrawBoxContext {
      const AVClass *class;
      int x, y, w, h;
      int thickness;
      char *color_str;
      unsigned char yuv_color[4];
      int invert_color; ///< invert luma color
      int vsub, hsub;   ///< chroma subsampling
      char *x_expr, *y_expr; ///< expression for x and y
      char *w_expr, *h_expr; ///< expression for width and height
      char *t_expr;          ///< expression for thickness
  } DrawBoxContext;
  
  static const int NUM_EXPR_EVALS = 5;
  
  static av_cold int init(AVFilterContext *ctx)
  {
      DrawBoxContext *s = ctx->priv;
      uint8_t rgba_color[4];
  
      if (!strcmp(s->color_str, "invert"))
          s->invert_color = 1;
      else if (av_parse_color(rgba_color, s->color_str, -1, ctx) < 0)
          return AVERROR(EINVAL);
  
      if (!s->invert_color) {
          s->yuv_color[Y] = RGB_TO_Y_CCIR(rgba_color[0], rgba_color[1], rgba_color[2]);
          s->yuv_color[U] = RGB_TO_U_CCIR(rgba_color[0], rgba_color[1], rgba_color[2], 0);
          s->yuv_color[V] = RGB_TO_V_CCIR(rgba_color[0], rgba_color[1], rgba_color[2], 0);
          s->yuv_color[A] = rgba_color[3];
      }
  
      return 0;
  }
  
  static int query_formats(AVFilterContext *ctx)
  {
      static const enum AVPixelFormat pix_fmts[] = {
          AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
          AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
          AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
          AV_PIX_FMT_YUV440P,  AV_PIX_FMT_YUVJ440P,
          AV_PIX_FMT_NONE
      };
      AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
      if (!fmts_list)
          return AVERROR(ENOMEM);
      return ff_set_common_formats(ctx, fmts_list);
  }
  
  static int config_input(AVFilterLink *inlink)
  {
      AVFilterContext *ctx = inlink->dst;
      DrawBoxContext *s = ctx->priv;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
      double var_values[VARS_NB], res;
      char *expr;
      int ret;
      int i;
  
      s->hsub = desc->log2_chroma_w;
      s->vsub = desc->log2_chroma_h;
  
      var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
      var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
      var_values[VAR_SAR]  = inlink->sample_aspect_ratio.num ? av_q2d(inlink->sample_aspect_ratio) : 1;
      var_values[VAR_DAR]  = (double)inlink->w / inlink->h * var_values[VAR_SAR];
      var_values[VAR_HSUB] = s->hsub;
      var_values[VAR_VSUB] = s->vsub;
      var_values[VAR_X] = NAN;
      var_values[VAR_Y] = NAN;
      var_values[VAR_H] = NAN;
      var_values[VAR_W] = NAN;
      var_values[VAR_T] = NAN;
  
      for (i = 0; i <= NUM_EXPR_EVALS; i++) {
          /* evaluate expressions, fail on last iteration */
          var_values[VAR_MAX] = inlink->w;
          if ((ret = av_expr_parse_and_eval(&res, (expr = s->x_expr),
                                            var_names, var_values,
                                            NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0 && i == NUM_EXPR_EVALS)
              goto fail;
          s->x = var_values[VAR_X] = res;
  
          var_values[VAR_MAX] = inlink->h;
          if ((ret = av_expr_parse_and_eval(&res, (expr = s->y_expr),
                                            var_names, var_values,
                                            NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0 && i == NUM_EXPR_EVALS)
              goto fail;
          s->y = var_values[VAR_Y] = res;
  
          var_values[VAR_MAX] = inlink->w - s->x;
          if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),
                                            var_names, var_values,
                                            NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0 && i == NUM_EXPR_EVALS)
              goto fail;
          s->w = var_values[VAR_W] = res;
  
          var_values[VAR_MAX] = inlink->h - s->y;
          if ((ret = av_expr_parse_and_eval(&res, (expr = s->h_expr),
                                            var_names, var_values,
                                            NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0 && i == NUM_EXPR_EVALS)
              goto fail;
          s->h = var_values[VAR_H] = res;
  
          var_values[VAR_MAX] = INT_MAX;
          if ((ret = av_expr_parse_and_eval(&res, (expr = s->t_expr),
                                            var_names, var_values,
                                            NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0 && i == NUM_EXPR_EVALS)
              goto fail;
          s->thickness = var_values[VAR_T] = res;
      }
  
      /* if w or h are zero, use the input w/h */
      s->w = (s->w > 0) ? s->w : inlink->w;
      s->h = (s->h > 0) ? s->h : inlink->h;
  
      /* sanity check width and height */
      if (s->w <  0 || s->h <  0) {
          av_log(ctx, AV_LOG_ERROR, "Size values less than 0 are not acceptable.\n");
          return AVERROR(EINVAL);
      }
  
      av_log(ctx, AV_LOG_VERBOSE, "x:%d y:%d w:%d h:%d color:0x%02X%02X%02X%02X\n",
             s->x, s->y, s->w, s->h,
             s->yuv_color[Y], s->yuv_color[U], s->yuv_color[V], s->yuv_color[A]);
  
      return 0;
  
  fail:
      av_log(ctx, AV_LOG_ERROR,
             "Error when evaluating the expression '%s'.\n",
             expr);
      return ret;
  }
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
  {
      DrawBoxContext *s = inlink->dst->priv;
      int plane, x, y, xb = s->x, yb = s->y;
      unsigned char *row[4];
  
      for (y = FFMAX(yb, 0); y < frame->height && y < (yb + s->h); y++) {
          row[0] = frame->data[0] + y * frame->linesize[0];
  
          for (plane = 1; plane < 3; plane++)
              row[plane] = frame->data[plane] +
                   frame->linesize[plane] * (y >> s->vsub);
  
          if (s->invert_color) {
              for (x = FFMAX(xb, 0); x < xb + s->w && x < frame->width; x++)
                  if ((y - yb < s->thickness) || (yb + s->h - 1 - y < s->thickness) ||
                      (x - xb < s->thickness) || (xb + s->w - 1 - x < s->thickness))
                      row[0][x] = 0xff - row[0][x];
          } else {
              for (x = FFMAX(xb, 0); x < xb + s->w && x < frame->width; x++) {
                  double alpha = (double)s->yuv_color[A] / 255;
  
                  if ((y - yb < s->thickness) || (yb + s->h - 1 - y < s->thickness) ||
                      (x - xb < s->thickness) || (xb + s->w - 1 - x < s->thickness)) {
                      row[0][x                 ] = (1 - alpha) * row[0][x                 ] + alpha * s->yuv_color[Y];
                      row[1][x >> s->hsub] = (1 - alpha) * row[1][x >> s->hsub] + alpha * s->yuv_color[U];
                      row[2][x >> s->hsub] = (1 - alpha) * row[2][x >> s->hsub] + alpha * s->yuv_color[V];
                  }
              }
          }
      }
  
      return ff_filter_frame(inlink->dst->outputs[0], frame);
  }
  
  #define OFFSET(x) offsetof(DrawBoxContext, x)
  #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
  
  #if CONFIG_DRAWBOX_FILTER
  
  static const AVOption drawbox_options[] = {
      { "x",         "set horizontal position of the left box edge", OFFSET(x_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "y",         "set vertical position of the top box edge",    OFFSET(y_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "width",     "set width of the box",                         OFFSET(w_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "w",         "set width of the box",                         OFFSET(w_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "height",    "set height of the box",                        OFFSET(h_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "h",         "set height of the box",                        OFFSET(h_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "color",     "set color of the box",                         OFFSET(color_str), AV_OPT_TYPE_STRING, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
      { "c",         "set color of the box",                         OFFSET(color_str), AV_OPT_TYPE_STRING, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
      { "thickness", "set the box thickness",                        OFFSET(t_expr),    AV_OPT_TYPE_STRING, { .str="3" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "t",         "set the box thickness",                        OFFSET(t_expr),    AV_OPT_TYPE_STRING, { .str="3" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(drawbox);
  
  static const AVFilterPad drawbox_inputs[] = {
      {
          .name           = "default",
          .type           = AVMEDIA_TYPE_VIDEO,
          .config_props   = config_input,
          .filter_frame   = filter_frame,
          .needs_writable = 1,
      },
      { NULL }
  };
  
  static const AVFilterPad drawbox_outputs[] = {
      {
          .name = "default",
          .type = AVMEDIA_TYPE_VIDEO,
      },
      { NULL }
  };
  
  AVFilter ff_vf_drawbox = {
      .name          = "drawbox",
      .description   = NULL_IF_CONFIG_SMALL("Draw a colored box on the input video."),
      .priv_size     = sizeof(DrawBoxContext),
      .priv_class    = &drawbox_class,
      .init          = init,
      .query_formats = query_formats,
      .inputs        = drawbox_inputs,
      .outputs       = drawbox_outputs,
      .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
  };
  #endif /* CONFIG_DRAWBOX_FILTER */
  
  #if CONFIG_DRAWGRID_FILTER
  static av_pure av_always_inline int pixel_belongs_to_grid(DrawBoxContext *drawgrid, int x, int y)
  {
      // x is horizontal (width) coord,
      // y is vertical (height) coord
      int x_modulo;
      int y_modulo;
  
      // Abstract from the offset
      x -= drawgrid->x;
      y -= drawgrid->y;
  
      x_modulo = x % drawgrid->w;
      y_modulo = y % drawgrid->h;
  
      // If x or y got negative, fix values to preserve logics
      if (x_modulo < 0)
          x_modulo += drawgrid->w;
      if (y_modulo < 0)
          y_modulo += drawgrid->h;
  
      return x_modulo < drawgrid->thickness  // Belongs to vertical line
          || y_modulo < drawgrid->thickness;  // Belongs to horizontal line
  }
  
  static int drawgrid_filter_frame(AVFilterLink *inlink, AVFrame *frame)
  {
      DrawBoxContext *drawgrid = inlink->dst->priv;
      int plane, x, y;
      uint8_t *row[4];
  
      for (y = 0; y < frame->height; y++) {
          row[0] = frame->data[0] + y * frame->linesize[0];
  
          for (plane = 1; plane < 3; plane++)
              row[plane] = frame->data[plane] +
                   frame->linesize[plane] * (y >> drawgrid->vsub);
  
          if (drawgrid->invert_color) {
              for (x = 0; x < frame->width; x++)
                  if (pixel_belongs_to_grid(drawgrid, x, y))
                      row[0][x] = 0xff - row[0][x];
          } else {
              for (x = 0; x < frame->width; x++) {
                  double alpha = (double)drawgrid->yuv_color[A] / 255;
  
                  if (pixel_belongs_to_grid(drawgrid, x, y)) {
                      row[0][x                  ] = (1 - alpha) * row[0][x                  ] + alpha * drawgrid->yuv_color[Y];
                      row[1][x >> drawgrid->hsub] = (1 - alpha) * row[1][x >> drawgrid->hsub] + alpha * drawgrid->yuv_color[U];
                      row[2][x >> drawgrid->hsub] = (1 - alpha) * row[2][x >> drawgrid->hsub] + alpha * drawgrid->yuv_color[V];
                  }
              }
          }
      }
  
      return ff_filter_frame(inlink->dst->outputs[0], frame);
  }
  
  static const AVOption drawgrid_options[] = {
      { "x",         "set horizontal offset",   OFFSET(x_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "y",         "set vertical offset",     OFFSET(y_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "width",     "set width of grid cell",  OFFSET(w_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "w",         "set width of grid cell",  OFFSET(w_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "height",    "set height of grid cell", OFFSET(h_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "h",         "set height of grid cell", OFFSET(h_expr),    AV_OPT_TYPE_STRING, { .str="0" },       CHAR_MIN, CHAR_MAX, FLAGS },
      { "color",     "set color of the grid",   OFFSET(color_str), AV_OPT_TYPE_STRING, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
      { "c",         "set color of the grid",   OFFSET(color_str), AV_OPT_TYPE_STRING, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
      { "thickness", "set grid line thickness", OFFSET(t_expr),    AV_OPT_TYPE_STRING, {.str="1"},         CHAR_MIN, CHAR_MAX, FLAGS },
      { "t",         "set grid line thickness", OFFSET(t_expr),    AV_OPT_TYPE_STRING, {.str="1"},         CHAR_MIN, CHAR_MAX, FLAGS },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(drawgrid);
  
  static const AVFilterPad drawgrid_inputs[] = {
      {
          .name           = "default",
          .type           = AVMEDIA_TYPE_VIDEO,
          .config_props   = config_input,
          .filter_frame   = drawgrid_filter_frame,
          .needs_writable = 1,
      },
      { NULL }
  };
  
  static const AVFilterPad drawgrid_outputs[] = {
      {
          .name = "default",
          .type = AVMEDIA_TYPE_VIDEO,
      },
      { NULL }
  };
  
  AVFilter ff_vf_drawgrid = {
      .name          = "drawgrid",
      .description   = NULL_IF_CONFIG_SMALL("Draw a colored grid on the input video."),
      .priv_size     = sizeof(DrawBoxContext),
      .priv_class    = &drawgrid_class,
      .init          = init,
      .query_formats = query_formats,
      .inputs        = drawgrid_inputs,
      .outputs       = drawgrid_outputs,
      .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
  };
  
  #endif  /* CONFIG_DRAWGRID_FILTER */
  