/*
  * drawtext.c: print text over the screen

  ******************************************************************************

  * Options:

  * -f <filename>    font filename (MANDATORY!!!)
  * -s <pixel_size>  font size in pixels [default 16]

  * -b               print background
  * -o               outline glyphs (use the bg color)

  * -x <pos>         x position ( >= 0) [default 0]
  * -y <pos>         y position ( >= 0) [default 0]

  * -t <text>        text to print (will be passed to strftime())

  *                  MANDATORY: will be used even when -T is used.
  *                  in this case, -t will be used if some error

  *                  occurs
  * -T <filename>    file with the text (re-read every frame)
  * -c <#RRGGBB>     foreground color ('internet' way) [default #ffffff]
  * -C <#RRGGBB>     background color ('internet' way) [default #000000]

  *

  ******************************************************************************
  * Features:
  * - True Type, Type1 and others via FreeType2 library
  * - Font kerning (better output)
  * - Line Wrap (if the text doesn't fit, the next char go to the next line)
  * - Background box
  * - Outline
  ******************************************************************************

  * Author: Gustavo Sverzut Barbieri <gsbarbieri@yahoo.com.br>
  *

  * 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

  */

 
 #define MAXSIZE_TEXT 1024
 

 #include "libavformat/framehook.h"

 #include <stdio.h>
 #include <stdlib.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <string.h>
 #include <unistd.h>

 #undef time

 #include <sys/time.h>
 #include <time.h>
 
 #include <ft2build.h>
 #include FT_FREETYPE_H

 #include FT_GLYPH_H

 #define SCALEBITS 10
 #define ONE_HALF  (1 << (SCALEBITS - 1))
 #define FIX(x)    ((int) ((x) * (1<<SCALEBITS) + 0.5))
 
 #define RGB_TO_YUV(rgb_color, yuv_color) do { \
   yuv_color[0] = (FIX(0.29900)    * rgb_color[0] + FIX(0.58700) * rgb_color[1] + FIX(0.11400) * rgb_color[2] + ONE_HALF) >> SCALEBITS; \
   yuv_color[2] = ((FIX(0.50000)   * rgb_color[0] - FIX(0.41869) * rgb_color[1] - FIX(0.08131) * rgb_color[2] + ONE_HALF - 1) >> SCALEBITS) + 128; \
   yuv_color[1] = ((- FIX(0.16874) * rgb_color[0] - FIX(0.33126) * rgb_color[1] + FIX(0.50000) * rgb_color[2] + ONE_HALF - 1) >> SCALEBITS) + 128; \
 } while (0)

 
 #define COPY_3(dst,src) { \
     dst[0]=src[0]; \
     dst[1]=src[1]; \
     dst[2]=src[2]; \
 }
 
 
 
 #define SET_PIXEL(picture, yuv_color, x, y) { \
     picture->data[0][ (x) + (y)*picture->linesize[0] ] = yuv_color[0]; \
     picture->data[1][ ((x/2) + (y/2)*picture->linesize[1]) ] = yuv_color[1]; \
     picture->data[2][ ((x/2) + (y/2)*picture->linesize[2]) ] = yuv_color[2]; \
 }
 
 #define GET_PIXEL(picture, yuv_color, x, y) { \
     yuv_color[0] = picture->data[0][ (x) + (y)*picture->linesize[0] ]; \
     yuv_color[1] = picture->data[1][ (x/2) + (y/2)*picture->linesize[1] ]; \
     yuv_color[2] = picture->data[2][ (x/2) + (y/2)*picture->linesize[2] ]; \
 }
 
 
 typedef struct {

   unsigned char *text;

   char *file;

   unsigned int x;
   unsigned int y;
   int bg;
   int outline;
   unsigned char bgcolor[3]; /* YUV */
   unsigned char fgcolor[3]; /* YUV */

   FT_Library library;
   FT_Face    face;

   FT_Glyph   glyphs[ 255 ];

   FT_Bitmap  bitmaps[ 255 ];
   int        advance[ 255 ];
   int        bitmap_left[ 255 ];
   int        bitmap_top[ 255 ];
   unsigned int glyphs_index[ 255 ];
   int        text_height;
   int        baseline;
   int use_kerning;

 } ContextInfo;
 
 
 void Release(void *ctx)
 {
     if (ctx)
         av_free(ctx);
 }
 
 

 static int ParseColor(char *text, unsigned char yuv_color[3])

 {
   char tmp[3];
   unsigned char rgb_color[3];
   int i;
 
   tmp[2] = '\0';
 
   if ((!text) || (strlen(text) != 7) || (text[0] != '#') )
     return -1;
 
   for (i=0; i < 3; i++)
     {
       tmp[0] = text[i*2+1];
       tmp[1] = text[i*2+2];
 
       rgb_color[i] = strtol(tmp, NULL, 16);
     }
 
   RGB_TO_YUV(rgb_color, yuv_color);
 
   return 0;
 }
 
 int Configure(void **ctxp, int argc, char *argv[])
 {
     int c;
     int error;
     ContextInfo *ci=NULL;
     char *font=NULL;
     unsigned int size=16;

     FT_BBox bbox;
     int yMax, yMin;

     *ctxp = av_mallocz(sizeof(ContextInfo));
     ci = (ContextInfo *) *ctxp;
 
     /* configure Context Info */
     ci->text = NULL;

     ci->file = NULL;

     ci->x = ci->y = 0;
     ci->fgcolor[0]=255;
     ci->fgcolor[1]=128;
     ci->fgcolor[2]=128;
     ci->bgcolor[0]=0;
     ci->fgcolor[1]=128;
     ci->fgcolor[2]=128;
     ci->bg = 0;
     ci->outline = 0;

     ci->text_height = 0;

     optind = 1;

     while ((c = getopt(argc, argv, "f:t:T:x:y:s:c:C:bo")) > 0) {

       switch (c) {
       case 'f':

         font = optarg;
         break;

       case 't':

         ci->text = av_strdup(optarg);
         break;

       case 'T':

         ci->file = av_strdup(optarg);
         break;

       case 'x':

         ci->x = (unsigned int) atoi(optarg);
         break;

       case 'y':

         ci->y = (unsigned int) atoi(optarg);
         break;

       case 's':

         size = (unsigned int) atoi(optarg);
         break;

       case 'c':

         if (ParseColor(optarg, ci->fgcolor) == -1)
           {

             av_log(NULL, AV_LOG_ERROR, "Invalid foreground color: '%s'. You must specify the color in the internet way(packaged hex): #RRGGBB, ie: -c #ffffff (for white foreground)\n", optarg);

             return -1;
           }
         break;

       case 'C':

         if (ParseColor(optarg, ci->bgcolor) == -1)
           {

             av_log(NULL, AV_LOG_ERROR, "Invalid background color: '%s'. You must specify the color in the internet way(packaged hex): #RRGGBB, ie: -C #ffffff (for white background)\n", optarg);

             return -1;
           }
         break;

       case 'b':

         ci->bg=1;
         break;

       case 'o':

         ci->outline=1;
         break;

       case '?':

         av_log(NULL, AV_LOG_ERROR, "Unrecognized argument '%s'\n", argv[optind]);

         return -1;

       }
     }
 

     if (!ci->text)

       {

         av_log(NULL, AV_LOG_ERROR, "No text provided (-t text)\n");

         return -1;

       }
 

     if (ci->file)
       {

         FILE *fp;
         if ((fp=fopen(ci->file, "r")) == NULL)
           {

             av_log(NULL, AV_LOG_INFO, "WARNING: The file could not be opened. Using text provided with -t switch: %s", strerror(errno));

           }
         else
           {
             fclose(fp);
           }

       }
 

     if (!font)
       {

         av_log(NULL, AV_LOG_ERROR, "No font file provided! (-f filename)\n");

         return -1;

       }
 

     if ((error = FT_Init_FreeType(&(ci->library))) != 0)

       {

         av_log(NULL, AV_LOG_ERROR, "Could not load FreeType (error# %d).\n", error);

         return -1;

       }
 

     if ((error = FT_New_Face( ci->library, font, 0, &(ci->face) )) != 0)

       {

         av_log(NULL, AV_LOG_ERROR, "Could not load face: %s  (error# %d).\n", font, error);

         return -1;

       }

     if ((error = FT_Set_Pixel_Sizes( ci->face, 0, size)) != 0)

       {

         av_log(NULL, AV_LOG_ERROR, "Could not set font size to %d pixels (error# %d).\n", size, error);

         return -1;

       }

 
     ci->use_kerning = FT_HAS_KERNING(ci->face);
 
     /* load and cache glyphs */
     yMax = -32000;
     yMin =  32000;
     for (c=0; c < 256; c++)
       {

         /* Load char */
         error = FT_Load_Char( ci->face, (unsigned char) c, FT_LOAD_RENDER | FT_LOAD_MONOCHROME );
         if (error) continue;  /* ignore errors */
 
         /* Save bitmap */
         ci->bitmaps[c] = ci->face->glyph->bitmap;
         /* Save bitmap left */
         ci->bitmap_left[c] = ci->face->glyph->bitmap_left;
         /* Save bitmap top */
         ci->bitmap_top[c] = ci->face->glyph->bitmap_top;
 
         /* Save advance */
         ci->advance[c] = ci->face->glyph->advance.x >> 6;
 
         /* Save glyph */
         error = FT_Get_Glyph( ci->face->glyph, &(ci->glyphs[c]) );
         /* Save glyph index */
         ci->glyphs_index[c] = FT_Get_Char_Index( ci->face, (unsigned char) c );
 
         /* Measure text height to calculate text_height (or the maximum text height) */
         FT_Glyph_Get_CBox( ci->glyphs[ c ], ft_glyph_bbox_pixels, &bbox );
         if (bbox.yMax > yMax)
           yMax = bbox.yMax;
         if (bbox.yMin < yMin)
           yMin = bbox.yMin;

       }
 
     ci->text_height = yMax - yMin;
     ci->baseline = yMax;
 

     return 0;
 }
 
 

 static inline void draw_glyph(AVPicture *picture, FT_Bitmap *bitmap, unsigned int x, unsigned int y, unsigned int width, unsigned int height, unsigned char yuv_fgcolor[3], unsigned char yuv_bgcolor[3], int outline)

 {
   int r, c;
   int spixel, dpixel[3], in_glyph=0;
 
   if (bitmap->pixel_mode == ft_pixel_mode_mono)
     {
       in_glyph = 0;
       for (r=0; (r < bitmap->rows) && (r+y < height); r++)

         {
           for (c=0; (c < bitmap->width) && (c+x < width); c++)
             {
               /* pixel in the picture (destination) */
               GET_PIXEL(picture, dpixel, (c+x), (y+r));
 
               /* pixel in the glyph bitmap (source) */
               spixel = bitmap->buffer[r*bitmap->pitch +c/8] & (0x80>>(c%8));
 
               if (spixel)
                 COPY_3(dpixel, yuv_fgcolor);
 
               if (outline)
                 {
                   /* border detection: */
                   if ( (!in_glyph) && (spixel) )
                     /* left border detected */
                     {
                       in_glyph = 1;
                       /* draw left pixel border */
                       if (c-1 >= 0)
                         SET_PIXEL(picture, yuv_bgcolor, (c+x-1), (y+r));
                     }
                   else if ( (in_glyph) && (!spixel) )
                     /* right border detected */
                     {
                       in_glyph = 0;
                       /* 'draw' right pixel border */
                       COPY_3(dpixel, yuv_bgcolor);
                     }
 
                   if (in_glyph)
                     /* see if we have a top/bottom border */
                     {
                       /* top */
                       if ( (r-1 >= 0) && (! bitmap->buffer[(r-1)*bitmap->pitch +c/8] & (0x80>>(c%8))) )
                         /* we have a top border */
                         SET_PIXEL(picture, yuv_bgcolor, (c+x), (y+r-1));
 
                       /* bottom */
                       if ( (r+1 < height) && (! bitmap->buffer[(r+1)*bitmap->pitch +c/8] & (0x80>>(c%8))) )
                         /* we have a bottom border */
                         SET_PIXEL(picture, yuv_bgcolor, (c+x), (y+r+1));
 
                     }
                 }
 
               SET_PIXEL(picture, dpixel, (c+x), (y+r));
             }
         }

     }
 }
 
 

 static inline void draw_box(AVPicture *picture, unsigned int x, unsigned int y, unsigned int width, unsigned int height, unsigned char yuv_color[3])

 {
   int i, j;
 
   for (j = 0; (j < height); j++)

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

         SET_PIXEL(picture, yuv_color, (i+x), (y+j));

       }

 }
 
 
 
 

 void Process(void *ctx, AVPicture *picture, enum PixelFormat pix_fmt, int width, int height, int64_t pts)

 {
   ContextInfo *ci = (ContextInfo *) ctx;

   FT_Face face = ci->face;

   FT_GlyphSlot  slot = face->glyph;

   unsigned char *text = ci->text;
   unsigned char c;
   int x = 0, y = 0, i=0, size=0;
   unsigned char buff[MAXSIZE_TEXT];
   unsigned char tbuff[MAXSIZE_TEXT];

   time_t now = time(0);

   int str_w, str_w_max;

   FT_Vector pos[MAXSIZE_TEXT];

   FT_Vector delta;
 

   if (ci->file)

     {
       int fd = open(ci->file, O_RDONLY);

 
       if (fd < 0)

         {
           text = ci->text;

           av_log(NULL, AV_LOG_INFO, "WARNING: The file could not be opened. Using text provided with -t switch: %s", strerror(errno));

         }

       else

         {
           int l = read(fd, tbuff, sizeof(tbuff) - 1);
 
           if (l >= 0)
             {
               tbuff[l] = 0;
               text = tbuff;
             }
           else
             {
               text = ci->text;

               av_log(NULL, AV_LOG_INFO, "WARNING: The file could not be read. Using text provided with -t switch: %s", strerror(errno));

             }
           close(fd);
         }

     }
   else
     {
       text = ci->text;
     }

 
   strftime(buff, sizeof(buff), text, localtime(&now));
 
   text = buff;
 
   size = strlen(text);

 
   /* measure string size and save glyphs position*/
   str_w = str_w_max = 0;

   x = ci->x;

   y = ci->y;

   for (i=0; i < size; i++)
     {

       c = text[i];

       /* kerning */
       if ( (ci->use_kerning) && (i > 0) && (ci->glyphs_index[c]) )

         {
           FT_Get_Kerning( ci->face,
                           ci->glyphs_index[ text[i-1] ],
                           ci->glyphs_index[c],
                           ft_kerning_default,
                           &delta );

           x += delta.x >> 6;
         }

       if (( (x + ci->advance[ c ]) >= width ) || ( c == '\n' ))

         {
           str_w = width - ci->x - 1;

           y += ci->text_height;
           x = ci->x;
         }

 
 
       /* save position */
       pos[i].x = x + ci->bitmap_left[c];
       pos[i].y = y - ci->bitmap_top[c] + ci->baseline;
 
 
       x += ci->advance[c];
 
 
       if (str_w > str_w_max)

         str_w_max = str_w;

 
     }
 

 
 
   if (ci->bg)
     {
       /* Check if it doesn't pass the limits */
       if ( str_w_max + ci->x >= width )

         str_w_max = width - ci->x - 1;

       if ( y >= height )

         y = height - 1 - 2*ci->y;

 
       /* Draw Background */

       draw_box( picture, ci->x, ci->y, str_w_max, y - ci->y, ci->bgcolor );

     }
 
 
 
   /* Draw Glyphs */
   for (i=0; i < size; i++)
     {

       c = text[i];
 
       if (

           ( (c == '_') && (text == ci->text) ) || /* skip '_' (consider as space)
                                                      IF text was specified in cmd line

                                                      (which doesn't like nested quotes)  */

           ( c == '\n' ) /* Skip new line char, just go to new line */
           )
         continue;
 
         /* now, draw to our target surface */
         draw_glyph( picture,
                     &(ci->bitmaps[ c ]),
                     pos[i].x,
                     pos[i].y,
                     width,
                     height,
                     ci->fgcolor,
                     ci->bgcolor,
                     ci->outline );

       /* increment pen position */
       x += slot->advance.x >> 6;
     }
 
 
 }