Provided by: libafterimage-dev_2.2.12-6_amd64 bug

NAME

       asmerge -     demonstrates     blending     of     multiple     image    using    different    algorithms
       libAfterImage/tutorials/ASMerge

NAMEASMerge

SYNOPSIS

       Scaling and blending of arbitrary number of images using libAfterImage.

DESCRIPTION

       We will attempt to interpret command line arguments  as  sequence  of  image  filenames,  geometries  and
       blending types. We'll then try and load all the images, scaling first one to requested size, and blending
       others at specifyed locations of the first image.  We then display the result in  simple  window.   After
       that we would want to wait, until user closes our window.

       New  steps  described  in  this  tutorial  are : Step 1. Layers.  Step 2. Merging methods.  Step 3. Layer
       parameters.  Step 4. Actual blending of the set of images.

SEE ALSO

       Tutorial 1: ASView  - explanation of basic steps needed to use
                             libAfterImage and some other simple things.  Tutorial 2: ASScale  -  image  scaling
       basics.  Tutorial 3: ASTile  - image tiling and tinting

SOURCE

           #include "../afterbase.h" #include "../afterimage.h" #include "common.h"

           char *burning_rose[] = {
               "asmerge",
               "rose512.jpg",
               "add",
               "back.xpm:512x386",
               "hue",
               "fore.xpm:512x386" };

           void usage() {
               printf( "Usage: asmerge [-h]|[image op1 image1 [op2 image2 [...]]]\n");
               printf( "Where: image  - is background image filename\n");
               printf( "       image1 - is first overlay's filename\n");
               printf( "       op1,op2,... - overlay operation."
                       " Supported operations are :\n");
               list_scanline_merging( stdout,
                       "         %-15.15s- %s\n"); }

           int main(int argc, char* argv[]) {
               Display *dpy = NULL;
               ASVisual *asv ;
               int screen = 0, depth = 0;
               int to_width = 1, to_height = 1;
               ASImageLayer *layers ;
               int layers_num = 0, i;
               ASImage *merged_im ;

               /* see ASView.1 : */
               set_application_name( argv[0] ); #if (HAVE_AFTERBASE_FLAG==1)
               set_output_threshold(OUTPUT_LEVEL_DEBUG); #endif
               if( argc == 2 && strncmp(argv[1],"-h", 2) == 0 )
               {
                   usage();
                   return 0;
               }
               if( argc <= 3 )
               {
                   show_error( "not enough arguments, please see usage:%s", " ");
                   usage() ;
                   printf( "Using the default, \"The Burning Rose\", composition :\n");
                   printf( "\n\trose512.jpg add back.xpm:512x386 hue "
                           "fore.xpm:512x386\n");
                   argv = &(burning_rose[0]) ;
                   argc = 6;
               }

           #ifndef X_DISPLAY_MISSING
               dpy = XOpenDisplay(NULL);
               _XA_WM_DELETE_WINDOW = XInternAtom( dpy, "WM_DELETE_WINDOW", False);
               screen = DefaultScreen(dpy);
               depth = DefaultDepth( dpy, screen ); #endif
               /* see ASView.3 : */
               asv = create_asvisual( dpy, screen, depth, NULL );

               /* see ASMerge.1 : */
               layers = safecalloc( argc/2, sizeof(ASImageLayer) );

               for( i = 1 ; i < argc ; i++ )
               {
                   int x = 0, y = 0;
                   unsigned int width, height ;
                   int geom_flags = 0 ;
                   char *separator;
                   char *filename ;
                   /* see ASMerge.2 */
                   if( i > 1 )
                   {
                       /* see blend_scanlines_name2func() : */
                       if((layers[layers_num].merge_scanlines =
                            blend_scanlines_name2func( argv[i] )) == NULL )
                           continue ;
                       if( ++i >= argc )
                           break;
                   }
                   if( (separator = strchr( argv[i], ':' )) != NULL )
                   {   /* see ASTile.1 : */
                       geom_flags = XParseGeometry( separator+1,
                                                    &x, &y, &width, &height);
                       filename = mystrndup( argv[i], separator-argv[i] );
                   }else
                       filename = argv[i] ;
                   layers[layers_num].im = file2ASImage( filename, 0xFFFFFFFF,
                                                         SCREEN_GAMMA, 100, getenv("IMAGE_PATH"), NULL );
                   if( filename != argv[i] )
                       free( filename );
                   if( layers[layers_num].im != NULL )
                   {
                       if( !get_flags(geom_flags, WidthValue) )
                           width = layers[layers_num].im->width  ;
                       if( !get_flags(geom_flags, HeightValue) )
                           height = layers[layers_num].im->height ;
                       /* see ASMerge.3 : */
                       if( layers[layers_num].merge_scanlines == NULL )
                           layers[layers_num].merge_scanlines =
                               alphablend_scanlines ;
                       layers[layers_num].clip_width = width ;
                       layers[layers_num].clip_height = height ;
                       if( layers_num > 0 )
                       {
                           layers[layers_num].dst_x = x ;
                           layers[layers_num].dst_y = y ;
                       }else
                       {
                           to_width = width ;
                           to_height = height ;
                           if( width != layers[layers_num].im->width ||
                               height != layers[layers_num].im->height )
                           {
                               ASImage *scaled_bottom ;
                               /* see ASScale.2 : */
                               scaled_bottom = scale_asimage( asv,
                                                              layers[layers_num].im,
                                                              width, height,
                                                              False, 100,
                                                           ASIMAGE_QUALITY_DEFAULT );
                               destroy_asimage( &(layers[layers_num].im) );
                               layers[layers_num].im = scaled_bottom ;
                           }
                       }
                       ++layers_num ;
                   }
               }

               if( layers_num <= 0 )
               {
                   show_error( "there is no images to merge. Aborting");
                   return 2;
               }

               /* see ASMerge.4 */
               merged_im = merge_layers( asv, layers, layers_num,
                                         to_width, to_height, #ifndef X_DISPLAY_MISSING
                                         ASA_XImage, #else
                                         ASA_ASImage, #endif
                                         0, ASIMAGE_QUALITY_DEFAULT );
               while( --layers_num >= 0 )
                   destroy_asimage( &(layers[layers_num].im) );
               free( layers );

               if( merged_im )
               { #ifndef X_DISPLAY_MISSING
               /* see ASView.4 : */
                   Window w = create_top_level_window( asv, DefaultRootWindow(dpy),
                                                       32, 32,
                                                       to_width, to_height,
                                                       1, 0, NULL,
                                                       "ASMerge", NULL );
                   if( w != None )
                   {
                       Pixmap p ;

                       XMapRaised   (dpy, w);
                       /* see ASView.5 : */
                       p = asimage2pixmap( asv, DefaultRootWindow(dpy), merged_im,
                                       NULL, True );

                       destroy_asimage( &merged_im );
                       /* see common.c: set_window_background_and_free() : */
                       p = set_window_background_and_free( w, p );
                       /* see common.c: wait_closedown() : */
                   }
                   wait_closedown(w);
                   dpy = NULL; #else
                   /* writing result into the file */
                   ASImage2file( merged_im, NULL, "asmerge.jpg", ASIT_Jpeg, NULL );
                   destroy_asimage( &merged_im ); #endif
               } #ifdef DEBUG_ALLOCS
               build_xpm_colormap(NULL);
               print_unfreed_mem(); #endif
               return 0 ; }

       libAfterImage/tutorials/ASMerge.1 [4.1]

SYNOPSIS

       Step 1. Layers.

DESCRIPTION

       libAfterImage  performs  blending/merging  of  different images, using arrays of ASImageLayer structures,
       with first element representing  the  bottommost  image.  Each  structure  specifies  exact  position  on
       resulting image where overlay should be blended to, tint of the overlay, size, to which overlay should be
       tiled, overlay's origin, and overlay's background color. Arbitrary number of layers can be merged whithin
       single run.

       Accordingly all that is needed to merge bunch of images is to create array of ASImageLayer structures and
       fill it up appropriately.

EXAMPLE

           layers = safecalloc( argc/2, sizeof(ASImageLayer) );
       libAfterImage/tutorials/ASMerge.2 [4.2]

SYNOPSIS

       Step 2. Merging methods.

DESCRIPTION

       Each layer can be merged in using its own method. There are about 15  different  methods  implemented  in
       libAfterImage,  and user app can implement other methods of its own. To specify method all that is needed
       is to set merge_scanlines member of ASImageLayer  to  pointer  to  the  function,  implementing  specific
       method.

       libAfterImage  provides  facility to parse method name strings into actuall function pointers. That could
       be used to simplifi scripting, etc.

EXAMPLE

              if((layers[layers_num].merge_scanlines =
                  blend_scanlines_name2func( argv[i] )) == NULL )
                  continue ; NOTE All layers MUST have valid merge_scanlines pointer, even the bottommost layer,
       despite  the  fact  that it has nothing to be merged with. If merge_scanlines is set to NULL - this layer
       will be ignored.  That could be used to turn on/off particular layers.
       libAfterImage/tutorials/ASMerge.3 [4.3]

SYNOPSIS

       Step 3. Layer parameters.

DESCRIPTION

       Several ASImageLayer members are mandatory and cannot be set to 0.  Such as : im - image  to  be  merged;
       clip_width, clip_height - this will be used to tile the image; merge_scanlines - must be set to a pointer
       to the function implementing merging method. If any of this is set to 0  - then layer  will  be  ignored.
       The rest of the parameters are optional. Note thou that tint parameter will tint overlay's RGB components
       and alpha component, as the result it could be used to make opaque images - semitransparent.

EXAMPLE

           if( layers[layers_num].merge_scanlines == NULL )
               layers[layers_num].merge_scanlines =
                   alphablend_scanlines ;
           layers[layers_num].clip_width = width ;
           layers[layers_num].clip_height = height ;
           if( layers_num > 0 )
           {
               layers[layers_num].dst_x = x ;
               layers[layers_num].dst_y = y ;
           }
       libAfterImage/tutorials/ASMerge.4 [4.4]

SYNOPSIS

       Step 4. Actual blending of the set of images.

DESCRIPTION

       After set of layers has been prepared - it can be passed to merge_layers() function, that will create new
       ASImage of specifyed size, and then blend all the layers together to fill this image.

EXAMPLE

               merged_im = merge_layers( asv, layers, layers_num,
                                         to_width, to_height,
                                         ASA_ASImage, 0,
                                         ASIMAGE_QUALITY_DEFAULT );
               while( --layers_num >= 0 )
                   destroy_asimage( &(layers[layers_num].im) );
               free( layers );

NOTES

       After  we've  blended  layers  -  we no longer need ASImageLayer array.  So proceeding to clean it up, by
       destroying overlay AsImages first, and then freeing array itself.

SEE ALSO

       merge_asimage().