AFTERImage example 7: Text rendering

libAfterImage/tutorials/ASText

• NAME

  ASText

• SYNOPSIS

  libAfterImage application for rendering texturized text.
  

• DESCRIPTION

  In this tutorial we will attempt to render arbitrary text in window,
  with optional texturized background and foreground. We shall also
  surround rendered text with beveled frame, creating an illusion of a
  button.
  
  New steps described in this tutorial are :
  ASText.1. Openning and closing fonts.
  ASText.2. Approximating rendered text size.
  ASText.3. Rendering texturized text.
  ASText.4. Merging foreground and background with bevel.
  

• 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.
  Tutorial 4: ASMerge - scaling and blending of arbitrary number of
                        images.
  Tutorial 5: ASGrad  - drawing multipoint linear gradients.
  Tutorial 6: ASFlip  - image rotation.
  

• SOURCE

  
  #include "../afterbase.h"
  #include "../afterimage.h"
  #include "common.h"
  
  /* Usage:  astext [-f font] [-s size] [-t text] [-S 3D_style]
                    [-c text_color] [-b background_color]
                    [-T foreground_texture] [-B background_image]
                    [-r foreground_resize_type] [-R background_resize_type]
   */
  
  #define BEVEL_HI_WIDTH 20
  #define BEVEL_LO_WIDTH 30
  #define BEVEL_ADDON    (BEVEL_HI_WIDTH+BEVEL_LO_WIDTH)
  
  void usage()
  {
      printf( "  Usage:   astext [-h] [-f font] [-s size] [-t text] "
              "[-S 3D_style] \n");
      printf( "                  [-c text_color] [-b background_color]\n");
      printf( "                  [-T foreground_texture] "
              "[-B background_image]\n");
      printf( "                  [-r foreground_resize_type] "
              "[-R background_resize_type]\n");
      printf( "                  [-m ]\n");
      printf( "  Where: font - TrueType font's filename or X font spec or "
              "alias;\n");
      printf( "         size - size in points for TrueType fonts;\n");
      printf( "         text - text to be drawn;\n");
      printf( "         3D_style - 3D style of text. "
              "One of the following:\n");
      printf( "             0 - plain 2D tetx, 1 - embossed, 2 - sunken, "
              "3 - shade above,\n");
      printf( "             4 - shade below, 5 - embossed thick, "
              "6 - sunken thick.\n");
      printf( "             7 - ouline above, 8 - ouline below, "
              "9 - full ouline.\n");
      printf( "         resize_type - tells how texture/image should be "
              "transformed to fit\n");
      printf( "         the text size. Could be: scale or tile." 
              "Default is tile\n");
      printf( "         -m make font monospaced. \n");
  
  
  }
  
  int main(int argc, char* argv[])
  {
      Display *dpy = NULL;
      ASVisual *asv = NULL ;
      int screen = 0, depth = 0;
      char *font_name = "test.ttf";
      int size = 32 ;
  #if 0
      char *text = "　　还没有";  /* chinese */ 
  #else
      char *text = "Smart Brown Dog jumps\nOver The Lazy Fox,\n"
                   "and falls into the ditch.";
  #endif
      ARGB32 text_color = ARGB32_White, back_color = ARGB32_Black;
      char *text_color_name = "#FFFFFFFF", *back_color_name = "#FF000000";
      char *fore_image_file = "fore.xpm" ;
      char *back_image_file = "back.xpm" ;
      Bool scale_fore_image = False, scale_back_image = False ;
      ASImage *fore_im = NULL, *back_im = NULL;
      ASImage *text_im = NULL ;
      struct ASFontManager *fontman = NULL;
      struct ASFont  *font = NULL;
      unsigned int width, height ;
      int i ;
      int text_margin = size/2 ;
      Bool monospaced = False ;
      char * font_path = NULL;
      ASTextAttributes attr = {ASTA_VERSION_1, ASTA_UseTabStops, 
                               AST_ShadeBelow, ASCT_UTF8, 8, 0, 
                               NULL, 0, ARGB32_White };
      
      /* see ASView.1 : */
      set_application_name( argv[0] );
  #if (HAVE_AFTERBASE_FLAG==1)
      set_output_threshold(OUTPUT_LEVEL_DEBUG);
  #endif
  
      if( argc == 1 )
          usage();
      else for( i = 1 ; i < argc ; i++ )
      {
          if( strncmp( argv[i], "-h", 2 ) == 0 )
          {
              usage();
              return 0;
          }
          if( strncmp( argv[i], "-m", 2 ) == 0 )
          {
              monospaced = True ;
          }else if( i+1 < argc )
          {
              if( strncmp( argv[i], "-f", 2 ) == 0 )
                  font_name = argv[i+1] ;
              else if( strncmp( argv[i], "-s", 2 ) == 0 )
              {
                  size = atoi(argv[i+1]);
                  text_margin = size/2 ;
              }else if( strncmp( argv[i], "-t", 2 ) == 0 )
                  text = argv[i+1] ;
              else if( strncmp( argv[i], "-S", 2 ) == 0 )
              {
                  attr.type = atoi(argv[i+1]);
                  if( attr.type >= AST_3DTypes )
                  {
                      show_error( "3D type is wrong. "
                                  "Using 2D Plain instead.");
                      attr.type = AST_Plain ;
                  }
  
              }else if( strncmp( argv[i], "-c", 2 ) == 0 )
                  text_color_name = argv[i+1] ;
              else if( strncmp( argv[i], "-b", 2 ) == 0 )
                  back_color_name = argv[i+1] ;
              else if( strncmp( argv[i], "-T", 2 ) == 0 )
                  fore_image_file = argv[i+1] ;
              else if( strncmp( argv[i], "-B", 2 ) == 0 )
                  back_image_file = argv[i+1] ;
              else if( strncmp( argv[i], "-r", 2 ) == 0 )
                  scale_fore_image = (strcmp( argv[i+1], "scale") == 0);
              else if( strncmp( argv[i], "-R", 2 ) == 0 )
                  scale_back_image = (strcmp( argv[i+1], "scale") == 0);
          }
      }
  
  
  #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 ASText.1 : */
      if( getenv("FONT_PATH") != NULL ) 
      {
          font_path = safemalloc( strlen(getenv("FONT_PATH"))+1+2+1);
          sprintf( font_path, "%s:./", getenv("FONT_PATH") );
          
      }    
      if( (fontman = create_font_manager( dpy, font_path, NULL )) != NULL )
          font = get_asfont( fontman, font_name, 0, size, 
                             ASF_GuessWho|(monospaced?ASF_Monospaced:0) );
  
      if( font == NULL )
      {
          show_error( "unable to load requested font \"%s\". "
                      "Falling back to \"fixed\".", font_name );
          font = get_asfont( fontman, "fixed", 0, size, ASF_GuessWho );
          if( font == NULL )
          {
              show_error("font \"fixed\" is not available either. Aborting.");
              return 1;
          }
      }
  
      /*for( i = 0 ; i < 128 ; ++i ) 
          print_asglyph( stderr, font, i); */
  
      parse_argb_color( text_color_name, &text_color );
      parse_argb_color( back_color_name, &back_color );
  
      attr.fore_color = text_color ;
      if( attr.type >= AST_OutlineAbove ) 
          fore_image_file = NULL ;
  
      /* see ASView.3 : */
      asv = create_asvisual( dpy, screen, depth, NULL );
  
      /* see ASText.2 : */
      /*set_asfont_glyph_spacing( font, 10, 40 );*/
      /*Simple way:get_text_size( text, font, attr.type, &width, &height ); */
      /*Fancy way : */
      get_fancy_text_size( text, font, &attr, &width, &height, 0, NULL );
  /* show_progress( "extimated text size = %dx%d", width, height ); */
      
      if( fore_image_file )
      {
          ASImage *tmp = file2ASImage( fore_image_file, 0xFFFFFFFF,
                                       SCREEN_GAMMA, 0, getenv("IMAGE_PATH"), NULL );
          if( tmp )
          {
              if( tmp->width != width || tmp->height != height )
              {   /* see ASScale.2 : */
                  if( scale_fore_image )
                      fore_im = scale_asimage( asv, tmp, width, height,
                                               ASA_ASImage, 0, 
                                               ASIMAGE_QUALITY_DEFAULT );
                  else
                      fore_im = tile_asimage( asv, tmp, 0, 0, 
                                              width, height, 0,
                                              ASA_ASImage, 0, 
                                              ASIMAGE_QUALITY_DEFAULT );
                  destroy_asimage( &tmp );
              }else
                  fore_im = tmp ;
          }else
              fore_im = NULL ;
      }
      width  += text_margin*2 + BEVEL_ADDON;
      height += text_margin*2 + BEVEL_ADDON;
      if( back_image_file )
      { /* see ASView.2 : */
          ASImage *tmp = file2ASImage( back_image_file, 0xFFFFFFFF,
                                      SCREEN_GAMMA, 0, getenv("IMAGE_PATH"), NULL );
          if( tmp )
          {
              if( scale_back_image && 
                  (tmp->width != width || tmp->height != height) )
              {   /* see ASScale.2 : */
                  back_im = scale_asimage( asv, tmp, width, height,
                                           ASA_ASImage, 0, 
                                           ASIMAGE_QUALITY_DEFAULT );
                  destroy_asimage( &tmp );
              }else
                  back_im = tmp ;
          }else
              back_im = NULL ;
      }
  
      /* see ASText.3 : */
      /* simple way : text_im = draw_text( text, font, attr.type, 0 ); */
      text_im = draw_fancy_text( text, font, &attr, 0, 0 );
      if( fore_im )
      {
          move_asimage_channel( fore_im, IC_ALPHA, text_im, IC_ALPHA );
          destroy_asimage( &text_im );
      }else
          fore_im = text_im ;
  
      /* see ASText.1 : */
      release_font( font );
      destroy_font_manager( fontman, False );
  
      if( fore_im )
      {
          ASImage *rendered_im ;
          ASImageLayer layers[2] ;
          ASImageBevel bevel = {0/*BEVEL_SOLID_INLINE*/, 0xFFDDDDDD, 
                                0xFF555555, 0xFFFFFFFF, 
                                0xFF777777, 0xFF222222,
                                BEVEL_HI_WIDTH, BEVEL_HI_WIDTH,
                                BEVEL_LO_WIDTH, BEVEL_LO_WIDTH,
                                BEVEL_HI_WIDTH, BEVEL_HI_WIDTH,
                                BEVEL_LO_WIDTH, BEVEL_LO_WIDTH } ;
  
          /* see ASText.4 : */
          init_image_layers( &(layers[0]), 2 );
          if( back_im )
              back_im->back_color = back_color ;
          if( fore_im ) 
              fore_im->back_color = text_color ;
          layers[0].im = back_im ;
          layers[0].dst_x = 0 ;
          layers[0].dst_y = 0 ;
          layers[0].clip_width = width ;
          layers[0].clip_height = height ;
          layers[0].bevel = &bevel ;
          layers[1].im = fore_im ;
          layers[1].dst_x = text_margin+BEVEL_HI_WIDTH*2 ;
          layers[1].dst_y = text_margin+
                              MIN( (int)text_margin,
                                  ((int)font->max_height-
                                   (int)font->max_ascend))/2+
                                   BEVEL_HI_WIDTH*2;
          if( fore_im ) 
          {   
              layers[1].clip_width = fore_im->width ;
              layers[1].clip_height = fore_im->height ;
          }
          rendered_im = merge_layers( asv, &(layers[0]), 2,
                                      width+BEVEL_ADDON, height+BEVEL_ADDON,
  #ifndef X_DISPLAY_MISSING
                                      ASA_XImage,
  #else
                                      ASA_ASImage,
  #endif
                                      0, ASIMAGE_QUALITY_DEFAULT);
          destroy_asimage( &fore_im );
          destroy_asimage( &back_im );
  
          if( rendered_im )
          {
  #ifndef X_DISPLAY_MISSING
              Window w;
              /* see ASView.4 : */
              w = create_top_level_window( asv, DefaultRootWindow(dpy), 
                                           32, 32,
                                           width+BEVEL_ADDON, 
                                           height+BEVEL_ADDON,
                                           1, 0, NULL,
                                           "ASText", text );
              if( w != None )
              {
                  Pixmap p ;
  
                  XMapRaised   (dpy, w);
  
                  /* see ASView.5 : */
                  p = asimage2pixmap( asv, DefaultRootWindow(dpy), 
                                      rendered_im, NULL, True );
                  destroy_asimage( &rendered_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( rendered_im, NULL, "astext.jpg", ASIT_Jpeg, 
                            NULL );
              destroy_asimage( &rendered_im );
  #endif
          }
      }
      return 0 ;
  }
  

  
  

libAfterImage/tutorials/ASText.1 [7.1]

• SYNOPSIS

  Step 1. Openning and closing fonts.
  

• DESCRIPTION

  Before any text can be rendered using libAfterImage - desired font
  has to be opened for use. Font opening process is two-step. At first
  we need to create font manager ( ASFontManager ). That is done once,
  and same font manager can be used throughout entire application. It
  contains information about used external libraries, hash of opened
  fonts, and some other info.
  
  When ASFontManager is created it could be used to obtain actuall fonts.
  get_asfont() call is used to query cahce of the ASFontManager, to see
  if the font has been loaded already, and if not - then it will load
  the font and prepare it for drawing.
  
  

• EXAMPLE

      if( (fontman = create_font_manager( dpy, NULL, NULL )) != NULL )
          font = get_asfont( fontman, font_name, 0, size, ASF_GuessWho);
      if( font == NULL )
      {
          font = get_asfont( fontman, "fixed", 0, size, ASF_GuessWho );
          if( font == NULL )
          {
              show_error( "font \"fixed\" is not available either. 
                              Aborting.");
              return 1;
          }
      }
      ...
      destroy_font( font );
      destroy_font_manager( fontman, False );
  

• SEE ALSO

  create_font_manager(), get_asfont(), destroy_font(),
  destroy_font_manager()
  

libAfterImage/tutorials/ASText.2 [7.2]

• SYNOPSIS

  Step 2. Approximating rendered text size.
  

• DESCRIPTION

  Prior to actually drawing the text it is useful to estimate the size
  of the image, that rendered text will occupy, So that window can be
  created of appropriate size, and othe interface elements laid out
  accordingly. get_text_size() could be used to obtain rendered text
  size without actually drawing it.
  

• EXAMPLE

      get_text_size( text, font, type_3d, &width, &height );
      if( fore_image_file )
      {
          ASImage *tmp = file2ASImage( fore_image_file, 0xFFFFFFFF,
                                       SCREEN_GAMMA, 0, NULL );
          if( tmp )
          {
              if( tmp->width != width || tmp->height != height )
              {
                  if( scale_fore_image )
                      fore_im = scale_asimage( asv, tmp, width, height,
                                               ASA_ASImage, 0,
                                               ASIMAGE_QUALITY_DEFAULT );
                  else
                      fore_im = tile_asimage( asv, tmp, 0, 0,
                                              width, height, 0,
                                              ASA_ASImage, 0,
                                              ASIMAGE_QUALITY_DEFAULT );
                  destroy_asimage( &tmp );
              }else
                  fore_im = tmp ;
          }
      }
  

• NOTES

  In this particular example we either tile or scale foreground texture
  to fit the text. In order to texturize the text  - we need to use
  rendered text as an alpha channel on texture image. That can easily
  be done only if both images are the same size.
  

• SEE ALSO

  get_text_size(), scale_asimage(), tile_asimage(), ASText.3
  

libAfterImage/tutorials/ASText.3 [7.3]

• SYNOPSIS

  Step 3. Rendering texturized text.
  

• DESCRIPTION

  The most effective text texturization technique provided by
  libAfterImage consists of substitution of the alpha channel of the
  texture, with rendered text. That is possible since all the text is
  rendered into alpha channel only. move_asimage_channel() call is used
  to accomplish this operation. This call actually removes channel
  data from the original image and stores it in destination image. If
  there was something in destination image's channel  already - it will
  be destroyed.
  All kinds of nifty things could be done using this call, actually.
  Like, for example, rendered text can be moved into green channel of
  the texture, creating funky effect.
  

• EXAMPLE

      text_im = draw_text( text, font, 0 );
      if( fore_im )
      {
          move_asimage_channel( fore_im, IC_ALPHA, text_im, IC_ALPHA );
          destroy_asimage( &text_im );
      }else
          fore_im = text_im ;
  

• NOTES

  move_asimage_channel() will only work if both images have exactly the
  same size. It will do nothing otherwise.
  

• SEE ALSO

  draw_text(), move_asimage_channel()
  

libAfterImage/tutorials/ASText.4 [7.4]

• SYNOPSIS

  Step 4. Merging foreground and background with bevel.
  

• DESCRIPTION

  On this step we have 2 images ready for us - background and texturized
  text. At this point we need to merge them together by alpha-blending
  text over background (remeber - text is alpha-channel of foreground
  texture). At the same time we would like to add some nice bevel border
  around entire image. To accomplish that task all we have to do is setup
  ASImageLayer structure for both background and foreground, and apply
  merge_layers on them. When it is done - we no longer need original
  images and we destroy them to free up some memory.
  

• EXAMPLE

      ASImageLayer layers[2] ;
      ASImageBevel bevel = {0, 0xFFDDDDDD, 0xFF555555,
                               0xFFFFFFFF, 0xFF777777, 0xFF444444,
                            BEVEL_HI_WIDTH, BEVEL_HI_WIDTH,
                            BEVEL_LO_WIDTH, BEVEL_LO_WIDTH,
                            BEVEL_HI_WIDTH, BEVEL_HI_WIDTH,
                            BEVEL_LO_WIDTH, BEVEL_LO_WIDTH } ;
      memset( &(layers[0]), 0x00, sizeof(layers) );
      layers[0].im = back_im ;
      layers[0].clip_width = width ;
      layers[0].clip_height = height ;
      layers[0].merge_scanlines = alphablend_scanlines ;
      layers[0].bevel = &bevel ;
      layers[1].im = fore_im ;
      layers[1].dst_x = TEXT_MARGIN ;
      layers[1].dst_y = TEXT_MARGIN ;
      layers[1].clip_width = fore_im->width ;
      layers[1].clip_height = fore_im->height ;
      layers[1].back_color = text_color ;
      layers[1].merge_scanlines = alphablend_scanlines ;
      rendered_im = merge_layers( asv, &(layers[0]), 2,
                                  width+BEVEL_ADDON, height+BEVEL_ADDON,
                                  ASA_XImage, 0, ASIMAGE_QUALITY_DEFAULT);
      destroy_asimage( &fore_im );
      destroy_asimage( &back_im );
  

• NOTES

  We have to remember that outside bevel border will addup to the image
  size, hence we have to use width+BEVEL_ADDON , height+BEVEL_ADDON as
  desired image size.
  

• SEE ALSO

  ASImageLayer, ASImageBevel, merge_layers()
  

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