PDF::API2 : re-sizing the mediabox once drawn/ crop pdf to actual content

aegidel has asked for the wisdom of the Perl Monks concerning the following question:

Hello all, i'm trying to create a label-sized pdf printout (brother ql 580n, 62mm media endless paper) under debian 2.6.39-bpo.2-686-pae with perl v5.10.1 (*) built for i486-linux-gnu-thread-multi that dynamically adjusts the page height based on content. So far i have

#!/usr/bin/perl

use strict;
use warnings;

use PDF::API2;
use PDF::TextBlock;

use constant mm => 25.4 / 72;
use constant in => 1 / 72;
use constant pt => 1;

my ( $paragraph1, $paragraph2) = ('Headertext', 'Testtext zur Ausgabe 
+in einem selbstgebauten PDF mit den richtigen Maßen. Mal sehen, was d
+as gibt! ÄÜÖüäößéèàá');

my $pdf = PDF::API2->new( -file => "./test.pdf" );
my $page = $pdf->page;

$page->mediabox (62/mm, 100/mm);
#$page->cropbox  (2/mm, 4/mm, 60/mm, 92/mm); # printable area

my %font = (
  Helvetica => {
    Bold   => $pdf->corefont( 'Helvetica-Bold',    -encoding => 'latin
+1' ),
  },
  Times => {
    Roman  => $pdf->corefont( 'Times',        -encoding => 'latin1' ),
  },
);

# do some umlaut conversions here .... (snipped)

my $tb = PDF::TextBlock->new({
  pdf => $pdf,
  page => $page,
  fonts => {
    b => PDF::TextBlock::Font->new({
      pdf => $pdf,
      font => $font{'Helvetica'}{'Bold'},
      size => 16/pt,
      fillcolor => '#000000',
    }),
    p => PDF::TextBlock::Font->new({
      pdf => $pdf,
      font => $font{'Times'}{'Roman'},
      size => 14/pt,
      fillcolor => '#000000',
    }),
  },
});

$tb->text(
  "<b>$paragraph1</b>\n\n<p>$paragraph2</p>"
);

# set the start of the paragraph and maxwidth/ height
$tb->x(7/mm);
$tb->y(82/mm);
$tb->w(50/mm);
$tb->h(95/mm);

my ($endw, $ypos) = $tb->apply;

$pdf->save;
$pdf->end;
[download]

All my tries (recalling mediabox, trimbox etc after $tb->apply etc) so far have ended up cropping the top part of the pdf (due to 0.0 origin at bottom left i suppose) or resizing to letter.. However, calculating a cut-off region by doing

my $cutAt = ($ypos + 20) / 2.45;
[download]

i would like to resize the PDF to the width=62 mm (as defined, doesn't change) and height=$cutAt (e.g. 60mm) FROM THE TOP. I've been trying without success, any ideas on how this can be achieved? Thanks!

Comment on PDF::API2 : re-sizing the mediabox once drawn/ crop pdf to actual content Select or Download Code

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Re: PDF::API2 : re-sizing the mediabox once drawn/ crop pdf to actual content by Eliya (Vicar) on Dec 14, 2011 at 17:51 UTC
A PDF MediaBox is represented by four parameters: x,y of the lower left corner, and x,y of the upper right corner (with 0,0 being located at the bottom left of the page). And `$page->mediabox(62/mm, 100/mm)` is a short form of saying `$page->mediabox(0, 0, 62/mm, 100/mm)`. If you need to reduce the MediaBox at its bottom end, you don't want the lower left corner to be 0,0, so you have to use the four argument version of `$page->mediabox()`. `62mm,100mm --------------------- \| \| \| This is your \| \| \| \| textblock \| \| \| \| foo bar baz \| \| \| \| end. \| \| \| 0,$ypos\|.....................\| \| \| \| \| \| \| \| \| --------------------- 0,0` [download] In other words, if I'm understanding your requirements correctly, all you need is `... my ($endw, $ypos) = $tb->apply; $page->mediabox(0, $ypos, 62/mm, 100/mm); # <--- $pdf->save; $pdf->end;` [download] (AFAICT, `$ypos` - as returned by `$tb->apply()` - is the current y-position (cursor) after the block has been rendered, i.e. your y-coordinate of the lower left corner.) Update: just tested it, and it works fine for me.	[reply] [d/l] [select]
Re^2: PDF::API2 : re-sizing the mediabox once drawn/ crop pdf to actual content by aegidel (Initiate) on Dec 14, 2011 at 21:15 UTC
Elyia, thanks so much. Exactly what i was looking for and well explained to a PDF newb. Now i just have to figure out why the brother ql-580n won't honour the custom media sizes i define with brpapertool/lpoptions and keeps printing out 100mm of paper every time though pdfinfo shows the pdf is correctly defined. Oh well.. Again: thanks for your input!	[reply]