research.m1stereo.tv/gitweb/ - melted/blob - src/modules/gtk2/producer_pango.c

   1 /*
   2  * producer_pango.c -- a pango-based titler
   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 "producer_pango.h"
  22 #include <framework/mlt_frame.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <gdk-pixbuf/gdk-pixbuf.h>
  26 #include <pango/pangoft2.h>
  27 #include <freetype/freetype.h>
  28 #include <iconv.h>
  29
  30 struct producer_pango_s
  31 {
  32         struct mlt_producer_s parent;
  33         int width;
  34         int height;
  35         uint8_t *image;
  36         uint8_t *alpha;
  37         char *fgcolor;
  38         char *bgcolor;
  39         int   align;
  40         int   pad;
  41         char *markup;
  42         char *text;
  43         char *font;
  44         int weight;
  45 };
  46
  47 // special color type used by internal pango routines
  48 typedef struct
  49 {
  50         uint8_t r, g, b, a;
  51 } rgba_color;
  52
  53 // Forward declarations
  54 static int producer_get_frame( mlt_producer parent, mlt_frame_ptr frame, int index );
  55 static void producer_close( mlt_producer parent );
  56 static void pango_draw_background( GdkPixbuf *pixbuf, rgba_color bg );
  57 static GdkPixbuf *pango_get_pixbuf( const char *markup, const char *text, const char *font,
  58         rgba_color fg, rgba_color bg, int pad, int align, int weight, int size );
  59
  60 /** Return nonzero if the two strings are equal, ignoring case, up to
  61     the first n characters.
  62 */
  63 int strncaseeq(const char *s1, const char *s2, size_t n)
  64 {
  65         for ( ; n > 0; n--)
  66         {
  67                 if (tolower(*s1++) != tolower(*s2++))
  68                         return 0;
  69         }
  70         return 1;
  71 }
  72
  73 /** Parse the alignment property.
  74 */
  75
  76 static int alignment_parse( char* align )
  77 {
  78         int ret = pango_align_left;
  79
  80         if ( align == NULL );
  81         else if ( isdigit( align[ 0 ] ) )
  82                 ret = atoi( align );
  83         else if ( align[ 0 ] == 'c' || align[ 0 ] == 'm' )
  84                 ret = pango_align_center;
  85         else if ( align[ 0 ] == 'r' )
  86                 ret = pango_align_right;
  87
  88         return ret;
  89 }
  90
  91 static PangoFT2FontMap *fontmap = NULL;
  92
  93 mlt_producer producer_pango_init( const char *filename )
  94 {
  95         producer_pango this = calloc( sizeof( struct producer_pango_s ), 1 );
  96         if ( this != NULL && mlt_producer_init( &this->parent, this ) == 0 )
  97         {
  98                 mlt_producer producer = &this->parent;
  99
 100                 // THIS SHOULD BE MUTEXED...
 101                 if ( fontmap == NULL )
 102                         fontmap = (PangoFT2FontMap*) pango_ft2_font_map_new();
 103
 104                 producer->get_frame = producer_get_frame;
 105                 producer->close = ( mlt_destructor )producer_close;
 106
 107                 // This is required to initialise gdk-pixbuf
 108                 g_type_init();
 109
 110                 // Get the properties interface
 111                 mlt_properties properties = MLT_PRODUCER_PROPERTIES( &this->parent );
 112
 113                 // Set the default properties
 114                 mlt_properties_set( properties, "fgcolour", "0xffffffff" );
 115                 mlt_properties_set( properties, "bgcolour", "0x00000000" );
 116                 mlt_properties_set_int( properties, "align", pango_align_left );
 117                 mlt_properties_set_int( properties, "pad", 0 );
 118                 mlt_properties_set( properties, "text", "" );
 119                 mlt_properties_set( properties, "font", "Sans 48" );
 120                 mlt_properties_set( properties, "encoding", "UTF-8" );
 121                 mlt_properties_set_int( properties, "weight", PANGO_WEIGHT_NORMAL );
 122
 123                 if ( filename == NULL )
 124                 {
 125                         mlt_properties_set( properties, "markup", "" );
 126                 }
 127                 else if ( filename[ 0 ] == '+' || strstr( filename, "/+" ) )
 128                 {
 129                         char *copy = strdup( filename + 1 );
 130                         char *markup = copy;
 131                         if ( strstr( markup, "/+" ) )
 132                                 markup = strstr( markup, "/+" ) + 2;
 133                         ( *strrchr( markup, '.' ) ) = '\0';
 134                         while ( strchr( markup, '~' ) )
 135                                 ( *strchr( markup, '~' ) ) = '\n';
 136                         mlt_properties_set( properties, "resource", ( char * )filename );
 137                         mlt_properties_set( properties, "markup", markup );
 138                         free( copy );
 139                 }
 140                 else
 141                 {
 142                         FILE *f = fopen( filename, "r" );
 143                         if ( f != NULL )
 144                         {
 145                                 char line[81];
 146                                 char *markup = NULL;
 147                                 size_t size = 0;
 148                                 line[80] = '\0';
 149
 150                                 while ( fgets( line, 80, f ) )
 151                                 {
 152                                         size += strlen( line ) + 1;
 153                                         if ( markup )
 154                                         {
 155                                                 markup = realloc( markup, size );
 156                                                 strcat( markup, line );
 157                                         }
 158                                         else
 159                                         {
 160                                                 markup = strdup( line );
 161                                         }
 162                                 }
 163                                 fclose( f );
 164
 165                                 if ( markup[ strlen( markup ) - 1 ] == '\n' )
 166                                         markup[ strlen( markup ) - 1 ] = '\0';
 167
 168                                 mlt_properties_set( properties, "resource", ( char * ) filename );
 169                                 mlt_properties_set( properties, "markup", ( char * ) ( markup == NULL ? "" : markup ) );
 170                                 free( markup );
 171                         }
 172                         else
 173                         {
 174                                 mlt_properties_set( properties, "markup", "" );
 175                         }
 176                 }
 177
 178                 return producer;
 179         }
 180         free( this );
 181         return NULL;
 182 }
 183
 184 static void set_string( char **string, char *value, char *fallback )
 185 {
 186         if ( value != NULL )
 187         {
 188                 free( *string );
 189                 *string = strdup( value );
 190         }
 191         else if ( *string == NULL && fallback != NULL )
 192         {
 193                 *string = strdup( fallback );
 194         }
 195         else if ( *string != NULL && fallback == NULL )
 196         {
 197                 free( *string );
 198                 *string = NULL;
 199         }
 200 }
 201
 202 rgba_color parse_color( char *color )
 203 {
 204         rgba_color result = { 0xff, 0xff, 0xff, 0xff };
 205
 206         if ( !strncmp( color, "0x", 2 ) )
 207         {
 208                 unsigned int temp = 0;
 209                 sscanf( color + 2, "%x", &temp );
 210                 result.r = ( temp >> 24 ) & 0xff;
 211                 result.g = ( temp >> 16 ) & 0xff;
 212                 result.b = ( temp >> 8 ) & 0xff;
 213                 result.a = ( temp ) & 0xff;
 214         }
 215         else if ( !strcmp( color, "red" ) )
 216         {
 217                 result.r = 0xff;
 218                 result.g = 0x00;
 219                 result.b = 0x00;
 220         }
 221         else if ( !strcmp( color, "green" ) )
 222         {
 223                 result.r = 0x00;
 224                 result.g = 0xff;
 225                 result.b = 0x00;
 226         }
 227         else if ( !strcmp( color, "blue" ) )
 228         {
 229                 result.r = 0x00;
 230                 result.g = 0x00;
 231                 result.b = 0xff;
 232         }
 233         else
 234         {
 235                 unsigned int temp = 0;
 236                 sscanf( color, "%d", &temp );
 237                 result.r = ( temp >> 24 ) & 0xff;
 238                 result.g = ( temp >> 16 ) & 0xff;
 239                 result.b = ( temp >> 8 ) & 0xff;
 240                 result.a = ( temp ) & 0xff;
 241         }
 242
 243         return result;
 244 }
 245
 246 /** Convert a string property to UTF-8
 247 */
 248 static int iconv_utf8( mlt_properties properties, char *prop_name, const char* encoding )
 249 {
 250         char *text = mlt_properties_get( properties, prop_name );
 251         int result = -1;
 252
 253         iconv_t cd = iconv_open( "UTF-8", encoding );
 254         if ( cd != ( iconv_t )-1 )
 255         {
 256                 char *inbuf_p = text;
 257                 size_t inbuf_n = strlen( text );
 258                 size_t outbuf_n = inbuf_n * 6;
 259                 char *outbuf = mlt_pool_alloc( outbuf_n );
 260                 char *outbuf_p = outbuf;
 261
 262                 memset( outbuf, 0, outbuf_n );
 263
 264                 if ( text != NULL && strcmp( text, "" ) && iconv( cd, &inbuf_p, &inbuf_n, &outbuf_p, &outbuf_n ) != -1 )
 265                         mlt_properties_set( properties, prop_name, outbuf );
 266                 else
 267                         mlt_properties_set( properties, prop_name, "" );
 268
 269                 mlt_pool_release( outbuf );
 270                 iconv_close( cd );
 271                 result = 0;
 272         }
 273         return result;
 274 }
 275
 276 static void refresh_image( mlt_frame frame, int width, int height )
 277 {
 278         // Pixbuf
 279         GdkPixbuf *pixbuf = NULL;
 280
 281         // Obtain properties of frame
 282         mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
 283
 284         // Obtain the producer pango for this frame
 285         producer_pango this = mlt_properties_get_data( properties, "producer_pango", NULL );
 286
 287         // Obtain the producer
 288         mlt_producer producer = &this->parent;
 289
 290         // Obtain the producer properties
 291         mlt_properties producer_props = MLT_PRODUCER_PROPERTIES( producer );
 292
 293         // Get producer properties
 294         char *fg = mlt_properties_get( producer_props, "fgcolour" );
 295         char *bg = mlt_properties_get( producer_props, "bgcolour" );
 296         int align = alignment_parse( mlt_properties_get( producer_props, "align" ) );
 297         int pad = mlt_properties_get_int( producer_props, "pad" );
 298         char *markup = mlt_properties_get( producer_props, "markup" );
 299         char *text = mlt_properties_get( producer_props, "text" );
 300         char *font = mlt_properties_get( producer_props, "font" );
 301         char *encoding = mlt_properties_get( producer_props, "encoding" );
 302         int weight = mlt_properties_get_int( producer_props, "weight" );
 303         int size = mlt_properties_get_int( producer_props, "size" );
 304
 305         // See if any properties changed
 306         int property_changed = ( align != this->align );
 307         property_changed = property_changed || ( this->fgcolor == NULL || ( fg && strcmp( fg, this->fgcolor ) ) );
 308         property_changed = property_changed || ( this->bgcolor == NULL || ( bg && strcmp( bg, this->bgcolor ) ) );
 309         property_changed = property_changed || ( pad != this->pad );
 310         property_changed = property_changed || ( markup && this->markup && strcmp( markup, this->markup ) );
 311         property_changed = property_changed || ( text && this->text && strcmp( text, this->text ) );
 312         property_changed = property_changed || ( font && this->font && strcmp( font, this->font ) );
 313         property_changed = property_changed || ( weight != this->weight );
 314
 315         // Save the properties for next comparison
 316         this->align = align;
 317         this->pad = pad;
 318         set_string( &this->fgcolor, fg, "0xffffffff" );
 319         set_string( &this->bgcolor, bg, "0x00000000" );
 320         set_string( &this->markup, markup, NULL );
 321         set_string( &this->text, text, NULL );
 322         set_string( &this->font, font, "Sans 48" );
 323         this->weight = weight;
 324
 325         if ( property_changed )
 326         {
 327                 rgba_color fgcolor = parse_color( this->fgcolor );
 328                 rgba_color bgcolor = parse_color( this->bgcolor );
 329
 330                 mlt_pool_release( this->image );
 331                 mlt_pool_release( this->alpha );
 332                 this->image = NULL;
 333                 this->alpha = NULL;
 334
 335                 // Convert from specified encoding to UTF-8
 336                 if ( encoding != NULL && !strncaseeq( encoding, "utf-8", 5 ) && !strncaseeq( encoding, "utf8", 4 ) )
 337                 {
 338                         if ( markup != NULL && iconv_utf8( producer_props, "markup", encoding ) != -1 )
 339                         {
 340                                 markup = mlt_properties_get( producer_props, "markup" );
 341                                 set_string( &this->markup, markup, NULL );
 342                         }
 343                         if ( text != NULL && iconv_utf8( producer_props, "text", encoding ) != -1 )
 344                         {
 345                                 text = mlt_properties_get( producer_props, "text" );
 346                                 set_string( &this->text, text, NULL );
 347                         }
 348                 }
 349
 350                 // Render the title
 351                 pixbuf = pango_get_pixbuf( markup, text, font, fgcolor, bgcolor, pad, align, weight, size );
 352
 353                 if ( pixbuf != NULL )
 354                 {
 355                         // Register this pixbuf for destruction and reuse
 356                         mlt_properties_set_data( producer_props, "pixbuf", pixbuf, 0, ( mlt_destructor )g_object_unref, NULL );
 357
 358                         mlt_properties_set_int( producer_props, "real_width", gdk_pixbuf_get_width( pixbuf ) );
 359                         mlt_properties_set_int( producer_props, "real_height", gdk_pixbuf_get_height( pixbuf ) );
 360
 361                         // Store the width/height of the pixbuf temporarily
 362                         this->width = gdk_pixbuf_get_width( pixbuf );
 363                         this->height = gdk_pixbuf_get_height( pixbuf );
 364                 }
 365         }
 366         else if ( width > 0 && ( this->image == NULL || width != this->width || height != this->height ) )
 367         {
 368                 mlt_pool_release( this->image );
 369                 mlt_pool_release( this->alpha );
 370                 this->image = NULL;
 371                 this->alpha = NULL;
 372
 373                 pixbuf = mlt_properties_get_data( producer_props, "pixbuf", NULL );
 374         }
 375
 376         // If we have a pixbuf and a valid width
 377         if ( pixbuf && width > 0 )
 378         {
 379                 char *interps = mlt_properties_get( properties, "rescale.interp" );
 380                 int interp = GDK_INTERP_BILINEAR;
 381
 382                 if ( strcmp( interps, "nearest" ) == 0 )
 383                         interp = GDK_INTERP_NEAREST;
 384                 else if ( strcmp( interps, "tiles" ) == 0 )
 385                         interp = GDK_INTERP_TILES;
 386                 else if ( strcmp( interps, "hyper" ) == 0 )
 387                         interp = GDK_INTERP_HYPER;
 388
 389 //              fprintf( stderr, "SCALING PANGO from %dx%d to %dx%d was %dx%d\n", gdk_pixbuf_get_width( pixbuf ), gdk_pixbuf_get_height( pixbuf ), width, height, this->width, this->height );
 390
 391                 // Note - the original pixbuf is already safe and ready for destruction
 392                 pixbuf = gdk_pixbuf_scale_simple( pixbuf, width, height, interp );
 393
 394                 // Store width and height
 395                 this->width = width;
 396                 this->height = height;
 397
 398                 // Allocate/define image
 399                 this->image = mlt_pool_alloc( width * ( height + 1 ) * 2 );
 400                 this->alpha = mlt_pool_alloc( this->width * this->height );
 401
 402                 // Convert the image
 403                 mlt_convert_rgb24a_to_yuv422( gdk_pixbuf_get_pixels( pixbuf ),
 404                                                                           this->width, this->height,
 405                                                                           gdk_pixbuf_get_rowstride( pixbuf ),
 406                                                                           this->image, this->alpha );
 407
 408                 // Finished with pixbuf now
 409                 g_object_unref( pixbuf );
 410         }
 411
 412         // Set width/height
 413         mlt_properties_set_int( properties, "width", this->width );
 414         mlt_properties_set_int( properties, "height", this->height );
 415         mlt_properties_set_int( properties, "real_width", mlt_properties_get_int( producer_props, "real_width" ) );
 416         mlt_properties_set_int( properties, "real_height", mlt_properties_get_int( producer_props, "real_height" ) );
 417
 418         // pass the image data without destructor
 419         mlt_properties_set_data( properties, "image", this->image, this->width * ( this->height + 1 ) * 2, NULL, NULL );
 420         mlt_properties_set_data( properties, "alpha", this->alpha, this->width * this->height, NULL, NULL );
 421 }
 422
 423 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
 424 {
 425         // Obtain properties of frame
 426         mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
 427
 428         *width = mlt_properties_get_int( properties, "rescale_width" );
 429         *height = mlt_properties_get_int( properties, "rescale_height" );
 430
 431         // Refresh the image
 432         refresh_image( frame, *width, *height );
 433
 434         // Determine format
 435         //mlt_producer this = mlt_properties_get_data( properties, "producer_pango", NULL );
 436         //*format = ( mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( this ), "bpp" ) == 4 ) ? mlt_image_rgb24a : mlt_image_rgb24;
 437
 438         // May need to know the size of the image to clone it
 439         int size = 0;
 440
 441         // Get the image
 442         uint8_t *image = mlt_properties_get_data( properties, "image", &size );
 443
 444         // Get width and height
 445         *width = mlt_properties_get_int( properties, "width" );
 446         *height = mlt_properties_get_int( properties, "height" );
 447
 448         // Clone if necessary
 449         if ( writable )
 450         {
 451                 // Clone our image
 452                 uint8_t *copy = mlt_pool_alloc( size );
 453                 if ( copy != NULL && image != NULL )
 454                         memcpy( copy, image, size );
 455
 456                 // We're going to pass the copy on
 457                 image = copy;
 458
 459                 // Now update properties so we free the copy after
 460                 mlt_properties_set_data( properties, "image", copy, size, ( mlt_destructor )mlt_pool_release, NULL );
 461         }
 462
 463         // Pass on the image
 464         *buffer = image;
 465
 466         return 0;
 467 }
 468
 469 static uint8_t *producer_get_alpha_mask( mlt_frame this )
 470 {
 471         // Obtain properties of frame
 472         mlt_properties properties = MLT_FRAME_PROPERTIES( this );
 473
 474         // Return the alpha mask
 475         return mlt_properties_get_data( properties, "alpha", NULL );
 476 }
 477
 478 static int producer_get_frame( mlt_producer producer, mlt_frame_ptr frame, int index )
 479 {
 480         producer_pango this = producer->child;
 481
 482         // Generate a frame
 483         *frame = mlt_frame_init( );
 484
 485         // Obtain properties of frame and producer
 486         mlt_properties properties = MLT_FRAME_PROPERTIES( *frame );
 487
 488         // Set the producer on the frame properties
 489         mlt_properties_set_data( properties, "producer_pango", this, 0, NULL, NULL );
 490
 491         // Refresh the pango image
 492         refresh_image( *frame, 0, 0 );
 493
 494         // Set producer-specific frame properties
 495         mlt_properties_set_int( properties, "progressive", 1 );
 496         mlt_properties_set_double( properties, "aspect_ratio", 0 );
 497
 498         // Set alpha call back
 499         ( *frame )->get_alpha_mask = producer_get_alpha_mask;
 500
 501         // Stack the get image callback
 502         mlt_frame_push_get_image( *frame, producer_get_image );
 503
 504         // Update timecode on the frame we're creating
 505         mlt_frame_set_position( *frame, mlt_producer_position( producer ) );
 506
 507         // Calculate the next timecode
 508         mlt_producer_prepare_next( producer );
 509
 510         return 0;
 511 }
 512
 513 static void producer_close( mlt_producer parent )
 514 {
 515         producer_pango this = parent->child;
 516         mlt_pool_release( this->image );
 517         mlt_pool_release( this->alpha );
 518         free( this->fgcolor );
 519         free( this->bgcolor );
 520         free( this->markup );
 521         free( this->text );
 522         free( this->font );
 523         parent->close = NULL;
 524         mlt_producer_close( parent );
 525         free( this );
 526 }
 527
 528 static void pango_draw_background( GdkPixbuf *pixbuf, rgba_color bg )
 529 {
 530         int ww = gdk_pixbuf_get_width( pixbuf );
 531         int hh = gdk_pixbuf_get_height( pixbuf );
 532         uint8_t *p = gdk_pixbuf_get_pixels( pixbuf );
 533         int i, j;
 534
 535         for ( j = 0; j < hh; j++ )
 536         {
 537                 for ( i = 0; i < ww; i++ )
 538                 {
 539                         *p++ = bg.r;
 540                         *p++ = bg.g;
 541                         *p++ = bg.b;
 542                         *p++ = bg.a;
 543                 }
 544         }
 545 }
 546
 547 static GdkPixbuf *pango_get_pixbuf( const char *markup, const char *text, const char *font, rgba_color fg, rgba_color bg, int pad, int align, int weight, int size )
 548 {
 549         PangoContext *context = pango_ft2_font_map_create_context( fontmap );
 550         PangoLayout *layout = pango_layout_new( context );
 551         int w, h, x;
 552         int i, j;
 553         GdkPixbuf *pixbuf = NULL;
 554         FT_Bitmap bitmap;
 555         uint8_t *src = NULL;
 556         uint8_t* dest = NULL;
 557         uint8_t *d, *s, a;
 558         int stride;
 559         PangoFontDescription *desc = pango_font_description_from_string( font );
 560
 561         pango_ft2_font_map_set_resolution( fontmap, 72, 72 );
 562         pango_layout_set_width( layout, -1 ); // set wrapping constraints
 563         pango_font_description_set_weight( desc, ( PangoWeight ) weight  );
 564         if ( size != 0 )
 565                 pango_font_description_set_size( desc, PANGO_SCALE * size );
 566         pango_layout_set_font_description( layout, desc );
 567 //      pango_layout_set_spacing( layout, space );
 568         pango_layout_set_alignment( layout, ( PangoAlignment ) align  );
 569         if ( markup != NULL && strcmp( markup, "" ) != 0 )
 570                 pango_layout_set_markup( layout, markup, strlen( markup ) );
 571         else if ( text != NULL && strcmp( text, "" ) != 0 )
 572                 pango_layout_set_text( layout, text, strlen( text ) );
 573         else
 574                 pango_layout_set_text( layout, "  ", 2 );
 575         pango_layout_get_pixel_size( layout, &w, &h );
 576
 577         pixbuf = gdk_pixbuf_new( GDK_COLORSPACE_RGB, TRUE /* has alpha */, 8, w + 2 * pad, h + 2 * pad );
 578         pango_draw_background( pixbuf, bg );
 579
 580         stride = gdk_pixbuf_get_rowstride( pixbuf );
 581
 582         bitmap.width     = w;
 583         bitmap.pitch     = 32 * ( ( w + 31 ) / 31 );
 584         bitmap.rows      = h;
 585         bitmap.buffer    = mlt_pool_alloc( h * bitmap.pitch );
 586         bitmap.num_grays = 256;
 587         bitmap.pixel_mode = ft_pixel_mode_grays;
 588
 589         memset( bitmap.buffer, 0, h * bitmap.pitch );
 590
 591         pango_ft2_render_layout( &bitmap, layout, 0, 0 );
 592
 593         src = bitmap.buffer;
 594         x = ( gdk_pixbuf_get_width( pixbuf ) - w - 2 * pad ) * align / 2 + pad;
 595         dest = gdk_pixbuf_get_pixels( pixbuf ) + 4 * x + pad * stride;
 596         j = h;
 597
 598         while( j -- )
 599         {
 600                 d = dest;
 601                 s = src;
 602                 i = w;
 603                 while( i -- )
 604                 {
 605                         a = *s ++;
 606                         *d++ = ( a * fg.r + ( 255 - a ) * bg.r ) >> 8;
 607                         *d++ = ( a * fg.g + ( 255 - a ) * bg.g ) >> 8;
 608                         *d++ = ( a * fg.b + ( 255 - a ) * bg.b ) >> 8;
 609                         *d++ = ( a * fg.a + ( 255 - a ) * bg.a ) >> 8;
 610                 }
 611                 dest += stride;
 612                 src += bitmap.pitch;
 613         }
 614         mlt_pool_release( bitmap.buffer );
 615         pango_font_description_free( desc );
 616         g_object_unref( layout );
 617         g_object_unref( context );
 618
 619         return pixbuf;
 620 }