/*

  * Copyright (c) 2007 Bobby Bingham

  *
  * 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 vertical flip filter
  */
 

 #include "libavutil/pixdesc.h"

 #include "avfilter.h"
 
 typedef struct {
     int vsub;   ///< vertical chroma subsampling
 } FlipContext;
 
 static int config_input(AVFilterLink *link)
 {
     FlipContext *flip = link->dst->priv;
 

     flip->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;

 
     return 0;
 }
 

 static AVFilterBufferRef *get_video_buffer(AVFilterLink *link, int perms,

                                         int w, int h)
 {
     FlipContext *flip = link->dst->priv;

     AVFilterBufferRef *picref;

     int i;
 

     if (!(perms & AV_PERM_NEG_LINESIZES))
         return avfilter_default_get_video_buffer(link, perms, w, h);

     picref = avfilter_get_video_buffer(link->dst->outputs[0], perms, w, h);

     for (i = 0; i < 4; i ++) {
         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
 

         if (picref->data[i]) {

             picref->data[i] += ((h >> vsub)-1) * picref->linesize[i];

             picref->linesize[i] = -picref->linesize[i];
         }
     }
 
     return picref;
 }
 

 static void start_frame(AVFilterLink *link, AVFilterBufferRef *inpicref)

 {
     FlipContext *flip = link->dst->priv;

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

     int i;
 

     for (i = 0; i < 4; i ++) {
         int vsub = i == 1 || i == 2 ? flip->vsub : 0;
 

         if (outpicref->data[i]) {
             outpicref->data[i] += ((link->h >> vsub)-1) * outpicref->linesize[i];
             outpicref->linesize[i] = -outpicref->linesize[i];

         }
     }
 

     avfilter_start_frame(link->dst->outputs[0], outpicref);

 }
 

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

 {
     AVFilterContext *ctx = link->dst;
 

     avfilter_draw_slice(ctx->outputs[0], link->h - (y+h), h, -1 * slice_dir);

 }
 
 AVFilter avfilter_vf_vflip = {
     .name      = "vflip",

     .description = NULL_IF_CONFIG_SMALL("Flip the input video vertically."),
 

     .priv_size = sizeof(FlipContext),
 
     .inputs    = (AVFilterPad[]) {{ .name             = "default",

                                     .type             = AVMEDIA_TYPE_VIDEO,

                                     .get_video_buffer = get_video_buffer,
                                     .start_frame      = start_frame,
                                     .draw_slice       = draw_slice,
                                     .config_props     = config_input, },
                                   { .name = NULL}},
     .outputs   = (AVFilterPad[]) {{ .name             = "default",

                                     .type             = AVMEDIA_TYPE_VIDEO, },

                                   { .name = NULL}},
 };