Creating text

. Creating text

7.1. Hello World - writing text in an image

To create text the PDB function gimp_text_fontname() may be used. In this function the font is specified in the X11 font conventions.

Here is an example of a script that creates an image containing "Hello world".

  1:  #!/usr/local/bin/perl 
  2:   
  3:  use Gimp ":auto"; 
  4:  use Gimp::Fu; 
  5:   
  6:  sub text1 { 
  7:      my($font, $text) = @_; 
  8:       
  9:      # Create a new image 
 10:      $img = gimp_image_new(350, 100, RGB); 
 11:   
 12:      # Create a new layer and draw it to the image at the top 
 13:      $drw = gimp_layer_new($img, $img->width, $img->height, 
 14:  			  RGB, "BG", 100, NORMAL_MODE); 
 15:      $drw->add_layer(-1); 
 16:      gimp_palette_set_background("black"); 
 17:      gimp_edit_fill($drw, BG_IMAGE_FILL); 
 18:   
 19:   
 20:      # Choose color of text 
 21:      gimp_palette_set_foreground([255,255,0]); 
 22:   
 23:      # Create the text 
 24:      my $border = 10; 
 25:      my $text_layer = gimp_text_fontname($drw,  0, 0, $text, 
 26:  					$border, 1,  
 27:  					xlfd_size($font), $font); 
 28:      gimp_floating_sel_anchor($text_layer); 
 29:       
 30:      return $img; 
 31:  } 
 32:   
 33:  # register the script 
 34:  register "hello_world1", "basic text", "basic text", "Dov", "Dov", 
 35:      "1999-05-14", 
 36:      "<Toolbox>/Xtns/Perl-Fu/Tutorial/Basic text 1",  
 37:      "*", 
 38:      [ 
 39:       [PF_FONT, "font", "font", "-*-utopia-bold-r-*-*-70-*-*-*-*-*-*-*"], 
 40:       [PF_STRING, "text", "text", "Hello world!"] 
 41:      ], 
 42:      \&text1; 
 43:   
 44:  # Handle over control to gimp 
 45:  exit main(); 

The result:  

The script makes use of the function xlfd_size which extracts the size of the font from the X11 font name. This is necessary as the authors of gimp_text_fontname decided that the font size within the fontname is ignored.

One thing to note in this script is that the text that is created on line 24 is a

floating layer, than needs to be anchored to its parent layer. This is done in line 27 through the call to gimp_floating_sel_anchor().

This script suffers from the problem that the image size is unrelated to the text size. This is taken care of in the following more complex example which shows the basic steps for a logo generating script.

• Creation of an image arbitrary size
• Creation of a background drawable of an arbitrary size
• Creation of text layer which exactly fits the text with the command gimp_text_fontname().
• Resizing the image and the background to the size of the text layer.

The result is an image composed of two layers; a transparent text layer on top of a uniform background.

basic-logo

1: #!/usr/local/bin/perl 2: 3: use Gimp ":auto"; 4: use Gimp::Fu; 5: 6: sub basic_logo { 7: my($font, $border, $text, $bgcolor, $fgcolor) = @_; 8: 9: # Create a new image of an arbitrary size with 10: $img = gimp_image_new(100, 100, RGB); 11: 12: # Create a new layer for the background of arbitrary size, and 13: # add it to the image 14: my $background = gimp_layer_new($img, 100, 100, 15: RGB, "Background", 100, 16: NORMAL_MODE); 17: gimp_image_add_layer($background, 1); 18: 19: # Choose color of text 20: gimp_palette_set_foreground($fgcolor); 21: 22: # Create the text layer. Using -1 as the drawable creates a new layer. 23: my $text_layer = gimp_text_fontname($img, -1, 0, 0, $text, 24: $border, 1, xlfd_size($font), $font); 25: 26: # Get size of the text drawable and resize the image and the 27: # background layer to this size. 28: my($width, $height) = ($text_layer->width, $text_layer->height); 29: gimp_image_resize($img, $width, $height, 0, 0); 30: gimp_layer_resize($background, $width, $height, 0, 0); 31: 32: # Fill the background layer now when it has the right size. 33: gimp_palette_set_background($bgcolor); 34: gimp_edit_fill($background, BG_IMAGE_FILL); 35: 36: return $img; 37: } 38: 39: # register the script 40: register "basic_logo", "basic logo", "basic logo", 41: "Dov Grobgeld", "Dov Grobgeld", 42: "1999-06-09", 43: "<Toolbox>/Xtns/Perl-Fu/Tutorial/Basic Logo", 44: "*", 45: [ 46: [PF_FONT, "font", "font", "-*-utopia-bold-r-*-*-70-*-*-*-*-*-*-*"], 47: [PF_INT, "border", "border", "10"], 48: [PF_STRING, "text", "text", "Hello world!"], 49: [PF_COLOR, "bg_color", "Background color", [40,180,160]], 50: [PF_COLOR, "fg_color", "Background color", [255,255,0]], 51: ], 52: \&basic_logo; 53: 54: # Handle over control to gimp 55: exit main();

Note the special syntax of gimp_image_text_fontname() in line 23 in basic-logo with an image specified for a first parameter, and the drawable = -1. This is in contradiction to the rule above that the image should not be specified for PDB functions that take both an image and a drawable as the first two parameters. But since the drawable=-1, which has no image related to it, an image explicitely be provided. The special case drawable=-1 means that instead of creating a floating layer, a new image layer will be created.

The result shown in the following dialog and the resulting image: