use strict;
use warnings;
use Tk;
use Tk::JPEG;
use GD;

my $file = $ARGV[0];
my $mw  = MainWindow->new();
my $ww = $mw->screenwidth;
my $wh = $mw->screenheight;

my $imgd = GD::Image->newFromJpeg($file);
my ($iw, $ih) = $imgd->getBounds();
my $imtk;
if ($iw > $ww or $ih > $wh) {
    my $wratio = $ww / $iw;
    my $ratio  = $wh / $ih;
    $ratio = $wratio if $wratio < $ratio;
    $imgd->copyResampled($imgd, 0, 0, 0, 0, $iw * $ratio, $ih * $ratio
+, $iw, $ih);
    $imtk = $mw->Photo(-data => $imgd->jpeg(), -format => 'jpeg');
} else {
    $imtk = $mw->Photo(-file => $file,         -format => 'jpeg');
}

$mw->Label(-image => $imtk)->pack(-expand => 1, -fill => 'both');
$mw->update;
MainLoop;

[download]

This code works when used on a file smaller than the screen. On a larger file, it fails with the error

couldn't recognize image data at C:/Strawberry/perl/site/lib/Tk/Image.
+pm line 21.

[download]

Note that this is a reference to the Tk::Image module, not my code. Putting in print statements identifies the failing line as line 20 of my code, i.e. the line before the } else {. I cannot find anything in the Tk or GD docs to indicate what I'm doing wrong.

Regards,

John Davies

In reply to [Solved] Tk not recognising GD image by davies

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.