research.m1stereo.tv/gitweb/ - melted/blob - src/modules/vmfx/filter_mono.c

   1 /*
   2  * filter_mono.c -- Arbitrary alpha channel shaping
   3  * Copyright (C) 2005 Visual Media Fx Inc.
   4  * Author: Charles Yates <charles.yates@pandora.be>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include <framework/mlt_filter.h>
  22 #include <string.h>
  23 #include <framework/mlt_factory.h>
  24 #include <framework/mlt_frame.h>
  25 #include <framework/mlt_producer.h>
  26 #include <framework/mlt_geometry.h>
  27
  28 /** Get the images and apply the luminance of the mask to the alpha of the frame.
  29 */
  30
  31 static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  32 {
  33         int use_alpha = mlt_deque_pop_back_int( MLT_FRAME_IMAGE_STACK( this ) );
  34         int midpoint = mlt_deque_pop_back_int( MLT_FRAME_IMAGE_STACK( this ) );
  35         int invert = mlt_deque_pop_back_int( MLT_FRAME_IMAGE_STACK( this ) );
  36
  37         // Render the frame
  38         if ( mlt_frame_get_image( this, image, format, width, height, writable ) == 0 )
  39         {
  40                 uint8_t *p = *image;
  41                 uint8_t A = invert? 235 : 16;
  42                 uint8_t B = invert? 16 : 235;
  43                 int size = *width * *height;
  44
  45                 if ( !use_alpha )
  46                 {
  47                         while( size -- )
  48                         {
  49                                 if ( *p < midpoint )
  50                                         *p ++ = A;
  51                                 else
  52                                         *p ++ = B;
  53                                 *p ++ = 128;
  54                         }
  55                 }
  56                 else
  57                 {
  58                         uint8_t *alpha = mlt_frame_get_alpha_mask( this );
  59                         while( size -- )
  60                         {
  61                                 if ( *alpha ++ < midpoint )
  62                                         *p ++ = A;
  63                                 else
  64                                         *p ++ = B;
  65                                 *p ++ = 128;
  66                         }
  67                 }
  68         }
  69
  70         return 0;
  71 }
  72
  73 /** Filter processing.
  74 */
  75
  76 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  77 {
  78         int midpoint = mlt_properties_get_int( MLT_FILTER_PROPERTIES( this ), "midpoint" );
  79         int use_alpha = mlt_properties_get_int( MLT_FILTER_PROPERTIES( this ), "use_alpha" );
  80         int invert = mlt_properties_get_int( MLT_FILTER_PROPERTIES( this ), "invert" );
  81         mlt_deque_push_back_int( MLT_FRAME_IMAGE_STACK( frame ), invert );
  82         mlt_deque_push_back_int( MLT_FRAME_IMAGE_STACK( frame ), midpoint );
  83         mlt_deque_push_back_int( MLT_FRAME_IMAGE_STACK( frame ), use_alpha );
  84         mlt_frame_push_get_image( frame, filter_get_image );
  85         return frame;
  86 }
  87
  88 /** Constructor for the filter.
  89 */
  90
  91 mlt_filter filter_mono_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
  92 {
  93         mlt_filter this = mlt_filter_new( );
  94         if ( this != NULL )
  95         {
  96                 mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "midpoint", 128 );
  97                 mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "use_alpha", 0 );
  98                 mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "invert", 0 );
  99                 this->process = filter_process;
 100         }
 101         return this;
 102 }
 103