Re: [perl-win32-gui-users] Text size

[Roode, E. <er...@ba...>]

On 17 July 2008, Sean Healy wrote:
>
> ($x, $y) = $Label->GetTextExtentPoint32($string);

Upon further experimentation, there is something not quite right with
that.  The width it returns is too wide.  There seems to be some sort
of per-character skew -- short strings are very accurate; longer
strings get progressively worse.

Here is a sample program to demonstrate the problem.  I have attached
a screenshot of the resulting output.


  use strict;
  use warnings;
  use Win32::GUI();
  
  my $main = Win32::GUI::Window->new (-name => 'Main', -width => 300,
                                      -height => 150);
  
  my $top = 0;
  for my $str ('', 'A', 'AAAAA', 'This is a test')
  {
      # Demonstrate the width as computed
      my $demo = $main->AddLabel(-text => 'dummy', -top => $top,
                                 -left => 150, -background => 0xFF80FF);
      my ($w, $h) = $demo->GetTextExtentPoint32($str);
  
      $demo->Text($str);
      $demo->Width($w);
  
      # Label the demo output
      my $info = $main->AddLabel(-text => "'$str' => w=$w",
                                 -top => $top, -left => 0);
      $top += $info->Height;
  }
  
  $main->Show;
  Win32::GUI::Dialog;
  exit;
  
  sub Main_Terminate { -1; }


Why do the longer fields have a large error in the computed width?

Thanks,
Eric