Tk: Set text size in a widget


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Tk: Set text size in a widget

by GrandFather (Saint)

on Nov 13, 2005 at 03:02 UTC ( [id://508059]=CUFP: print w/replies, xml )

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This sub takes a single line Tk text widget reference (such as a Label) and a string then sets the font size in the widget to maximise the size of the text without clipping.

Place this in the resize handler for a widget to resize the text when the widget size changes.

sub SetBigText {
my ($widget, $text) = @_;

my $font =     $widget->Font ();
my $widthF =   $widget->fontMeasure ($font, $text);
my $heightF =  $widget->fontMetrics($font, -linespace);
my $xRatio =   $widget->width / $widthF;
my $yRatio =   $widget->height / $heightF;
my $minRatio = $xRatio < $yRatio ? $xRatio : $yRatio;
my $fontSize = $widget->fontActual ($font, -size);
my $newSize =  $minRatio * $fontSize;

$font->configure   (-size => $newSize);
$widget->configure (-text => $text);
$widget->configure (-font => $font);
}
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Re: Tk: Set text size in a widget
by rcseege (Pilgrim) on Nov 13, 2005 at 08:28 UTC

The posted code was interesting (++) - thanks for posting it. I played with it for a bit, and tried a few different things. It serves as a convenient way to highlight some minor issues with Tk's Font handling. As the snippet is written right now, I wouldn't suggest using it as an event handler. If it is called whenever Label is resized, it will introduce a small memory leak.

The code in this post was only tested on a Windows installation. I'd be interested to hear if it works differently on other platforms.