Perl Graphics Programming

The PostScript::TextBlock Module

The TextBlock module is an object that may be used to construct a block of text in PostScript. It is meant to be a simple, abstract interface for generating PostScript code from Perl scripts or CGI scripts, as in the example in the previous section. Example 11-3 introduces the TextBlock module.

Example 11-3. Using the TextBlock module

use PostScript::TextBlock;
my $tb = new PostScript::TextBlock;
$tb->addText( text => "Hullabalo in Hoosick Falls.\n",
              font => 'CenturySchL-Ital',
              size => 24,
              leading => 26
            );
$tb->addText( text => "by Charba Gaspee.\n",
              font => 'URWGothicL-Demi',
              size => 12,
              leading => 14
            );
print 'There are '.$tb->numElements.' elements in this object.';
open OUT, '>psoutput.ps' or die "Couldn't open psoutput.ps: $!";
my ($code, $remainder) = $tb->Write(572, 752, 20, 772);
print OUT $code;

As you can see, the TextBlock module allows the web programmer to create printable documents without any knowledge of PostScript. The PostScript code generated by this script looks like this:

0 setgray 20 746 moveto
/CenturySchL-Ital findfont
24 scalefont setfont
(Hullabalo in Hoosick Falls.) show
0 setgray 20 732 moveto
/URWGothicL-Demi findfont
12 scalefont setfont
(by Charba Gaspee.) show

By itself, the TextBlock object can print only on a single page. In many cases, your project will require a multi-page PostScript document. The TextBlock::Write( ) method returns the code and a TextBlock representing the text that doesn’t fit in the region passed ...