/*

  * Copyright (c) 2008 vmrsss
  * Copyright (c) 2009 Stefano Sabatini

  *
  * 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

  * video padding filter

  */
 
 #include "avfilter.h"

 #include "formats.h"

 #include "internal.h"

 #include "video.h"

 #include "libavutil/avstring.h"

 #include "libavutil/common.h"

 #include "libavutil/eval.h"

 #include "libavutil/pixdesc.h"

 #include "libavutil/colorspace.h"

 #include "libavutil/avassert.h"

 #include "libavutil/imgutils.h"
 #include "libavutil/parseutils.h"

 #include "libavutil/mathematics.h"

 #include "drawutils.h"

 static const char *const var_names[] = {

     "in_w",   "iw",
     "in_h",   "ih",
     "out_w",  "ow",
     "out_h",  "oh",
     "x",
     "y",

     "a",

     "sar",

     "dar",

     "hsub",
     "vsub",
     NULL
 };
 
 enum var_name {
     VAR_IN_W,   VAR_IW,
     VAR_IN_H,   VAR_IH,
     VAR_OUT_W,  VAR_OW,
     VAR_OUT_H,  VAR_OH,
     VAR_X,
     VAR_Y,

     VAR_A,

     VAR_SAR,

     VAR_DAR,

     VAR_HSUB,
     VAR_VSUB,
     VARS_NB
 };
 

 static int query_formats(AVFilterContext *ctx)
 {

     ff_set_common_formats(ctx, ff_draw_supported_pixel_formats(0));

     return 0;
 }
 

 typedef struct {
     int w, h;               ///< output dimensions, a value of 0 will result in the input size
     int x, y;               ///< offsets of the input area with respect to the padded area
     int in_w, in_h;         ///< width and height for the padded input video, which has to be aligned to the chroma values in order to avoid chroma issues
 

     char w_expr[256];       ///< width  expression string
     char h_expr[256];       ///< height expression string
     char x_expr[256];       ///< width  expression string
     char y_expr[256];       ///< height expression string
 

     uint8_t rgba_color[4];  ///< color for the padding area
     FFDrawContext draw;
     FFDrawColor color;

     int needs_copy;

 } PadContext;
 

 static av_cold int init(AVFilterContext *ctx, const char *args)

 {
     PadContext *pad = ctx->priv;
     char color_string[128] = "black";
 

     av_strlcpy(pad->w_expr, "iw", sizeof(pad->w_expr));
     av_strlcpy(pad->h_expr, "ih", sizeof(pad->h_expr));
     av_strlcpy(pad->x_expr, "0" , sizeof(pad->w_expr));
     av_strlcpy(pad->y_expr, "0" , sizeof(pad->h_expr));
 

     if (args)

         sscanf(args, "%255[^:]:%255[^:]:%255[^:]:%255[^:]:%127s",

                pad->w_expr, pad->h_expr, pad->x_expr, pad->y_expr, color_string);

     if (av_parse_color(pad->rgba_color, color_string, -1, ctx) < 0)

         return AVERROR(EINVAL);

 
     return 0;
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     PadContext *pad = ctx->priv;

     int ret;

     double var_values[VARS_NB], res;
     char *expr;

     ff_draw_init(&pad->draw, inlink->format, 0);
     ff_draw_color(&pad->draw, &pad->color, pad->rgba_color);

     var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
     var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
     var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
     var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;

     var_values[VAR_A]     = (float) inlink->w / inlink->h;

     var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
         (float) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;

     var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];

     var_values[VAR_HSUB]  = 1 << pad->draw.hsub_max;
     var_values[VAR_VSUB]  = 1 << pad->draw.vsub_max;

 
     /* evaluate width and height */
     av_expr_parse_and_eval(&res, (expr = pad->w_expr),
                            var_names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, ctx);
     pad->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
     if ((ret = av_expr_parse_and_eval(&res, (expr = pad->h_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto eval_fail;
     pad->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
     /* evaluate the width again, as it may depend on the evaluated output height */
     if ((ret = av_expr_parse_and_eval(&res, (expr = pad->w_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto eval_fail;
     pad->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
 
     /* evaluate x and y */
     av_expr_parse_and_eval(&res, (expr = pad->x_expr),
                            var_names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, ctx);
     pad->x = var_values[VAR_X] = res;
     if ((ret = av_expr_parse_and_eval(&res, (expr = pad->y_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto eval_fail;
     pad->y = var_values[VAR_Y] = res;
     /* evaluate x again, as it may depend on the evaluated y value */
     if ((ret = av_expr_parse_and_eval(&res, (expr = pad->x_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         goto eval_fail;
     pad->x = var_values[VAR_X] = res;
 
     /* sanity check params */
     if (pad->w < 0 || pad->h < 0 || pad->x < 0 || pad->y < 0) {
         av_log(ctx, AV_LOG_ERROR, "Negative values are not acceptable.\n");
         return AVERROR(EINVAL);
     }
 

     if (!pad->w)
         pad->w = inlink->w;
     if (!pad->h)
         pad->h = inlink->h;
 

     pad->w    = ff_draw_round_to_sub(&pad->draw, 0, -1, pad->w);
     pad->h    = ff_draw_round_to_sub(&pad->draw, 1, -1, pad->h);
     pad->x    = ff_draw_round_to_sub(&pad->draw, 0, -1, pad->x);
     pad->y    = ff_draw_round_to_sub(&pad->draw, 1, -1, pad->y);
     pad->in_w = ff_draw_round_to_sub(&pad->draw, 0, -1, inlink->w);
     pad->in_h = ff_draw_round_to_sub(&pad->draw, 1, -1, inlink->h);

     av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d -> w:%d h:%d x:%d y:%d color:0x%02X%02X%02X%02X\n",

            inlink->w, inlink->h, pad->w, pad->h, pad->x, pad->y,

            pad->rgba_color[0], pad->rgba_color[1], pad->rgba_color[2], pad->rgba_color[3]);

 
     if (pad->x <  0 || pad->y <  0                      ||
         pad->w <= 0 || pad->h <= 0                      ||
         (unsigned)pad->x + (unsigned)inlink->w > pad->w ||
         (unsigned)pad->y + (unsigned)inlink->h > pad->h) {
         av_log(ctx, AV_LOG_ERROR,
                "Input area %d:%d:%d:%d not within the padded area 0:0:%d:%d or zero-sized\n",
                pad->x, pad->y, pad->x + inlink->w, pad->y + inlink->h, pad->w, pad->h);

         return AVERROR(EINVAL);

     }
 
     return 0;

 
 eval_fail:
     av_log(NULL, AV_LOG_ERROR,
            "Error when evaluating the expression '%s'\n", expr);
     return ret;
 

 }
 
 static int config_output(AVFilterLink *outlink)
 {
     PadContext *pad = outlink->src->priv;
 
     outlink->w = pad->w;
     outlink->h = pad->h;
     return 0;
 }
 

 static AVFilterBufferRef *get_video_buffer(AVFilterLink *inlink, int perms, int w, int h)

 {
     PadContext *pad = inlink->dst->priv;

     int align = (perms&AV_PERM_ALIGN) ? AVFILTER_ALIGN : 1;

     AVFilterBufferRef *picref = ff_get_video_buffer(inlink->dst->outputs[0], perms,

                                                     w + (pad->w - pad->in_w) + 4*align,

                                                     h + (pad->h - pad->in_h));

     int plane;

     if (!picref)
         return NULL;
 

     picref->video->w = w;
     picref->video->h = h;
 

     for (plane = 0; plane < 4 && picref->data[plane]; plane++)
         picref->data[plane] += FFALIGN(pad->x >> pad->draw.hsub[plane], align) * pad->draw.pixelstep[plane] +
                                       (pad->y >> pad->draw.vsub[plane])        * picref->linesize[plane];

 
     return picref;
 }
 

 static int does_clip(PadContext *pad, AVFilterBufferRef *outpicref, int plane, int hsub, int vsub, int x, int y)
 {
     int64_t x_in_buf, y_in_buf;
 
     x_in_buf =  outpicref->data[plane] - outpicref->buf->data[plane]

              +  (x >> hsub) * pad->draw.pixelstep[plane]
              +  (y >> vsub) * outpicref->linesize[plane];

     if(x_in_buf < 0 || x_in_buf % pad->draw.pixelstep[plane])

         return 1;

     x_in_buf /= pad->draw.pixelstep[plane];

 
     av_assert0(outpicref->buf->linesize[plane]>0); //while reference can use negative linesize the main buffer should not
 
     y_in_buf = x_in_buf / outpicref->buf->linesize[plane];
     x_in_buf %= outpicref->buf->linesize[plane];
 
     if(   y_in_buf<<vsub >= outpicref->buf->h
        || x_in_buf<<hsub >= outpicref->buf->w)
         return 1;
     return 0;
 }
 

 static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)

 {
     PadContext *pad = inlink->dst->priv;

     AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);

     AVFilterBufferRef *for_next_filter;

     int plane, ret = 0;
 
     if (!outpicref)
         return AVERROR(ENOMEM);

     for (plane = 0; plane < 4 && outpicref->data[plane] && pad->draw.pixelstep[plane]; plane++) {

         int hsub = pad->draw.hsub[plane];
         int vsub = pad->draw.vsub[plane];

         av_assert0(outpicref->buf->w>0 && outpicref->buf->h>0);
 
         if(outpicref->format != outpicref->buf->format) //unsupported currently
             break;
 

         outpicref->data[plane] -=   (pad->x  >> hsub) * pad->draw.pixelstep[plane]
                                   + (pad->y  >> vsub) * outpicref->linesize[plane];

 
         if(   does_clip(pad, outpicref, plane, hsub, vsub, 0, 0)
            || does_clip(pad, outpicref, plane, hsub, vsub, 0, pad->h-1)
            || does_clip(pad, outpicref, plane, hsub, vsub, pad->w-1, 0)
            || does_clip(pad, outpicref, plane, hsub, vsub, pad->w-1, pad->h-1)
           )
             break;

     }

     pad->needs_copy= plane < 4 && outpicref->data[plane] || !(outpicref->perms & AV_PERM_WRITE);

     if(pad->needs_copy){
         av_log(inlink->dst, AV_LOG_DEBUG, "Direct padding impossible allocating new frame\n");
         avfilter_unref_buffer(outpicref);

         outpicref = ff_get_video_buffer(inlink->dst->outputs[0], AV_PERM_WRITE | AV_PERM_NEG_LINESIZES,
                                         FFMAX(inlink->w, pad->w),
                                         FFMAX(inlink->h, pad->h));

         if (!outpicref)
             return AVERROR(ENOMEM);
 

         avfilter_copy_buffer_ref_props(outpicref, inpicref);
     }
 

     outpicref->video->w = pad->w;
     outpicref->video->h = pad->h;
 

     for_next_filter = avfilter_ref_buffer(outpicref, ~0);

     if (!for_next_filter) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     ret = ff_start_frame(inlink->dst->outputs[0], for_next_filter);
     if (ret < 0)
         goto fail;
 
     inlink->dst->outputs[0]->out_buf = outpicref;
     return 0;
 
 fail:
     avfilter_unref_bufferp(&outpicref);
     return ret;

 }
 

 static int draw_send_bar_slice(AVFilterLink *link, int y, int h, int slice_dir, int before_slice)

 {
     PadContext *pad = link->dst->priv;

     int bar_y, bar_h = 0, ret = 0;

 
     if        (slice_dir * before_slice ==  1 && y == pad->y) {
         /* top bar */
         bar_y = 0;
         bar_h = pad->y;
     } else if (slice_dir * before_slice == -1 && (y + h) == (pad->y + pad->in_h)) {
         /* bottom bar */
         bar_y = pad->y + pad->in_h;
         bar_h = pad->h - pad->in_h - pad->y;
     }
 
     if (bar_h) {

         ff_fill_rectangle(&pad->draw, &pad->color,
                           link->dst->outputs[0]->out_buf->data,

                           link->dst->outputs[0]->out_buf->linesize,
                           0, bar_y, pad->w, bar_h);

         ret = ff_draw_slice(link->dst->outputs[0], bar_y, bar_h, slice_dir);

     }

     return ret;

 }
 

 static int draw_slice(AVFilterLink *link, int y, int h, int slice_dir)

 {
     PadContext *pad = link->dst->priv;

     AVFilterBufferRef *outpic = link->dst->outputs[0]->out_buf;

     AVFilterBufferRef *inpic = link->cur_buf;

     int ret;

 
     y += pad->y;
 

     y = ff_draw_round_to_sub(&pad->draw, 1, -1, y);
     h = ff_draw_round_to_sub(&pad->draw, 1, -1, h);

 
     if (!h)

         return 0;

     draw_send_bar_slice(link, y, h, slice_dir, 1);
 
     /* left border */

     ff_fill_rectangle(&pad->draw, &pad->color, outpic->data, outpic->linesize,
                       0, y, pad->x, h);

 
     if(pad->needs_copy){

         ff_copy_rectangle2(&pad->draw,
                            outpic->data, outpic->linesize,
                            inpic ->data, inpic ->linesize,
                            pad->x, y, 0, y - pad->y, inpic->video->w, h);

     }
 

     /* right border */

     ff_fill_rectangle(&pad->draw, &pad->color, outpic->data, outpic->linesize,

                       pad->x + pad->in_w, y, pad->w - pad->x - pad->in_w, h);

     ret = ff_draw_slice(link->dst->outputs[0], y, h, slice_dir);
     if (ret < 0)
         return ret;

     return draw_send_bar_slice(link, y, h, slice_dir, -1);

 }
 
 AVFilter avfilter_vf_pad = {
     .name          = "pad",

     .description   = NULL_IF_CONFIG_SMALL("Pad input image to width:height[:x:y[:color]] (default x and y: 0, default color: black)."),

 
     .priv_size     = sizeof(PadContext),
     .init          = init,
     .query_formats = query_formats,
 

     .inputs    = (const AVFilterPad[]) {{ .name             = "default",
                                           .type             = AVMEDIA_TYPE_VIDEO,
                                           .config_props     = config_input,
                                           .get_video_buffer = get_video_buffer,
                                           .start_frame      = start_frame,

                                           .draw_slice       = draw_slice, },

                                         { .name = NULL}},
 
     .outputs   = (const AVFilterPad[]) {{ .name             = "default",
                                           .type             = AVMEDIA_TYPE_VIDEO,
                                           .config_props     = config_output, },
                                         { .name = NULL}},

 };