modules/video_filter/alphamask.c

   1 /*****************************************************************************
   2  * alphamask.c : Alpha layer mask video filter for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2007 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Antoine Cellerier <dionoea at videolan tod org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34
  35 #include <vlc_image.h>
  36 #include <vlc_filter.h>
  37 #include <vlc_picture.h>
  38 #include <vlc_url.h>
  39
  40 #define ALPHAMASK_HELP N_( \
  41     "Use an image's alpha channel as a transparency mask." )
  42
  43 #define MASK_TEXT N_("Transparency mask")
  44 #define MASK_LONGTEXT N_( \
  45     "Alpha blending transparency mask. Uses a png alpha channel.")
  46
  47 #define CFG_PREFIX "alphamask-"
  48
  49 /*****************************************************************************
  50  * Local prototypes
  51  *****************************************************************************/
  52 static int  Create      ( vlc_object_t * );
  53 static void Destroy     ( vlc_object_t * );
  54
  55 static picture_t *Filter( filter_t *, picture_t * );
  56 static void LoadMask( filter_t *, const char * );
  57 static int MaskCallback( vlc_object_t *, char const *,
  58                          vlc_value_t, vlc_value_t, void * );
  59
  60 /*****************************************************************************
  61  * Module descriptor
  62  *****************************************************************************/
  63 vlc_module_begin ()
  64     set_description( N_("Alpha mask video filter") )
  65     set_shortname( N_("Alpha mask" ))
  66     set_help( ALPHAMASK_HELP )
  67     set_category( CAT_VIDEO )
  68     set_subcategory( SUBCAT_VIDEO_VFILTER )
  69     set_capability( "video filter", 0 )
  70     add_shortcut( "alphamask", "mask" )
  71     set_callbacks( Create, Destroy )
  72
  73     add_loadfile( CFG_PREFIX "mask", NULL, MASK_TEXT,
  74                 MASK_LONGTEXT, false )
  75 vlc_module_end ()
  76
  77 static const char *const ppsz_filter_options[] = {
  78     "mask", NULL
  79 };
  80
  81 struct filter_sys_t
  82 {
  83     picture_t *p_mask;
  84     vlc_mutex_t mask_lock;
  85 };
  86
  87 static int Create( vlc_object_t *p_this )
  88 {
  89     filter_t *p_filter = (filter_t *)p_this;
  90     filter_sys_t *p_sys;
  91     char *psz_string;
  92
  93     if( p_filter->fmt_in.video.i_chroma != VLC_CODEC_YUVA )
  94     {
  95         msg_Err( p_filter,
  96                  "Unsupported input chroma \"%4.4s\". "
  97                  "Alphamask can only use \"YUVA\".",
  98                  (char*)&p_filter->fmt_in.video.i_chroma );
  99         return VLC_EGENERIC;
 100     }
 101
 102     /* Allocate structure */
 103     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 104     if( p_filter->p_sys == NULL )
 105         return VLC_ENOMEM;
 106     p_sys = p_filter->p_sys;
 107
 108     config_ChainParse( p_filter, CFG_PREFIX, ppsz_filter_options,
 109                        p_filter->p_cfg );
 110
 111     psz_string =
 112         var_CreateGetStringCommand( p_filter, CFG_PREFIX "mask" );
 113     if( psz_string && *psz_string )
 114     {
 115         LoadMask( p_filter, psz_string );
 116         if( !p_sys->p_mask )
 117             msg_Err( p_filter, "Error while loading mask (%s).",
 118                      psz_string );
 119     }
 120     else
 121        p_sys->p_mask = NULL;
 122     free( psz_string );
 123
 124     vlc_mutex_init( &p_sys->mask_lock );
 125     var_AddCallback( p_filter, CFG_PREFIX "mask", MaskCallback,
 126                      p_filter );
 127     p_filter->pf_video_filter = Filter;
 128
 129     return VLC_SUCCESS;
 130 }
 131
 132 static void Destroy( vlc_object_t *p_this )
 133 {
 134     filter_t *p_filter = (filter_t *)p_this;
 135     filter_sys_t *p_sys = p_filter->p_sys;
 136
 137     var_DelCallback( p_filter, CFG_PREFIX "mask", MaskCallback,
 138                      p_filter );
 139
 140     vlc_mutex_destroy( &p_sys->mask_lock );
 141     if( p_sys->p_mask )
 142         picture_Release( p_sys->p_mask );
 143
 144     free( p_sys );
 145 }
 146
 147 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 148 {
 149     filter_sys_t *p_sys = p_filter->p_sys;
 150
 151     vlc_mutex_lock( &p_sys->mask_lock );
 152     plane_t *p_mask = p_sys->p_mask->p+A_PLANE;
 153     plane_t *p_apic = p_pic->p+A_PLANE;
 154     if(    p_mask->i_visible_pitch
 155         != p_apic->i_visible_pitch
 156         || p_mask->i_visible_lines
 157         != p_apic->i_visible_lines )
 158     {
 159         msg_Err( p_filter,
 160                   "Mask size (%d x %d) and image size (%d x %d) "
 161                   "don't match. The mask will not be applied.",
 162                   p_mask->i_visible_pitch,
 163                   p_mask->i_visible_lines,
 164                   p_apic->i_visible_pitch,
 165                   p_apic->i_visible_lines );
 166     }
 167     else
 168     {
 169         plane_CopyPixels( p_apic, p_mask );
 170     }
 171     vlc_mutex_unlock( &p_sys->mask_lock );
 172     return p_pic;
 173 }
 174
 175 /* copied from video_filters/erase.c . Gruik ? */
 176 static void LoadMask( filter_t *p_filter, const char *psz_filename )
 177 {
 178     image_handler_t *p_image;
 179     video_format_t fmt_in, fmt_out;
 180     video_format_Init( &fmt_in, 0 );
 181     video_format_Init( &fmt_out, VLC_CODEC_YUVA );
 182     if( p_filter->p_sys->p_mask )
 183         picture_Release( p_filter->p_sys->p_mask );
 184     p_image = image_HandlerCreate( p_filter );
 185     char *psz_url = vlc_path2uri( psz_filename, NULL );
 186     p_filter->p_sys->p_mask =
 187         image_ReadUrl( p_image, psz_url, &fmt_in, &fmt_out );
 188     free( psz_url );
 189     video_format_Clean( &fmt_in );
 190     video_format_Clean( &fmt_out );
 191     image_HandlerDelete( p_image );
 192 }
 193
 194 /*****************************************************************************
 195 * Callback to update params on the fly
 196 *****************************************************************************/
 197 static int MaskCallback( vlc_object_t *p_this, char const *psz_var,
 198                          vlc_value_t oldval, vlc_value_t newval,
 199                          void *p_data )
 200 {
 201     VLC_UNUSED(p_this); VLC_UNUSED(oldval);
 202     filter_t *p_filter = (filter_t *)p_data;
 203     filter_sys_t *p_sys = p_filter->p_sys;
 204     int i_ret = VLC_SUCCESS;
 205
 206 #define VAR_IS( a ) !strcmp( psz_var, CFG_PREFIX a )
 207     if( VAR_IS( "mask" ) )
 208     {
 209         vlc_mutex_lock( &p_sys->mask_lock );
 210         if( newval.psz_string && *newval.psz_string )
 211         {
 212             LoadMask( p_filter, newval.psz_string );
 213             if( !p_sys->p_mask )
 214             {
 215                 msg_Err( p_filter, "Error while loading mask (%s).",
 216                          newval.psz_string );
 217                 i_ret = VLC_EGENERIC;
 218             }
 219         }
 220         else if( p_sys->p_mask )
 221         {
 222             picture_Release( p_sys->p_mask );
 223             p_sys->p_mask = NULL;
 224         }
 225         vlc_mutex_unlock( &p_sys->mask_lock );
 226     }
 227 #undef VAR_IS
 228
 229     return i_ret;
 230 }