research.m1stereo.tv/gitweb/ - melted/blob - src/modules/core/transition_composite.c

   1 /*
   2  * transition_composite.c -- compose one image over another using alpha channel
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Dan Dennedy <dan@dennedy.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU 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 General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU 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 "transition_composite.h"
  22 #include <framework/mlt_frame.h>
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26
  27 /** Composition class.
  28 */
  29
  30 typedef struct
  31 {
  32         struct mlt_transition_s parent;
  33 }
  34 transition_composite;
  35
  36 /** Get the image.
  37 */
  38
  39 static int transition_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  40 {
  41         // Get the properties of the a frame
  42         mlt_properties a_props = mlt_frame_properties( this );
  43
  44         // Get the b frame from the stack
  45         mlt_frame b_frame = mlt_frame_pop_frame( this );
  46
  47         // Get the properties of the b frame
  48         mlt_properties b_props = mlt_frame_properties( b_frame );
  49
  50         // Arbitrary composite defaults
  51         int x = 50;
  52         int y = 50;
  53         double weight = 1.0;
  54
  55         // Override from b frame properties if provided
  56         if ( mlt_properties_get( b_props, "x" ) != NULL )
  57                 x = mlt_properties_get_int( b_props, "x" );
  58         if ( mlt_properties_get( b_props, "y" ) != NULL )
  59                 y = mlt_properties_get_int( b_props, "y" );
  60         if ( mlt_properties_get( b_props, "weight" ) != NULL )
  61                 weight = mlt_properties_get_double( b_props, "weight" );
  62
  63         // Composite the b_frame on the a_frame
  64         mlt_frame_composite_yuv( this, b_frame, x, y, weight );
  65
  66         // Extract the a_frame image info
  67         *width = mlt_properties_get_int( a_props, "width" );
  68         *height = mlt_properties_get_int( a_props, "height" );
  69         *image = mlt_properties_get_data( a_props, "image", NULL );
  70
  71         // Close the b_frame
  72         mlt_frame_close( b_frame );
  73
  74         return 0;
  75 }
  76
  77 /** Composition transition processing.
  78 */
  79
  80 static mlt_frame composite_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
  81 {
  82         mlt_frame_push_get_image( a_frame, transition_get_image );
  83         mlt_frame_push_frame( a_frame, b_frame );
  84         return a_frame;
  85 }
  86
  87 /** Constructor for the filter.
  88 */
  89
  90 mlt_transition transition_composite_init( void *arg )
  91 {
  92         transition_composite *this = calloc( sizeof( transition_composite ), 1 );
  93         if ( this != NULL )
  94         {
  95                 mlt_transition transition = &this->parent;
  96                 mlt_transition_init( transition, this );
  97                 transition->process = composite_process;
  98                 return &this->parent;
  99         }
 100         return NULL;
 101 }
 102