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How to get maximum Font Size in Qt to fit text into Widget

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Article Metadata
Tested with
Devices(s): Emulator / desktop / device
Compatibility
Platform(s): All Qt Supported
Symbian
Article
Keywords: QWidget, QFont, QFontMetrics
Created: Avis (30 Nov 2010)
Last edited: hamishwillee (11 Oct 2012)


Basic Idea

This article shows how you can calculate the maximum font size of text in a QWidget using the font attributes QFont and QFontMetrics. See also Archived:Calculating text width in Qt


And here is contrary task: set font size to maximally fit into widget's size. Simple loop will help.

// Function gets aFont with initialized Font Family, and aText - which size is calculated
void TextWidget::calcFontSize(const QString aText, QFont& aFont)
{
// get widget's width
int wd_width = size().width();
// get widget's height
int wd_hgt = size().height();
int fontPointSize;
// calculating loop
for (int i = 0; i < 200; i++)
{
aFont.setPointSize(i);
// create FontMetrics for resized font
QFontMetrics fm(aFont);
// get text width for current font size
int x = fm.width(aText);
// get text height for current font size
int y = fm.height();
// check if text fits widget
if ((x > wd_width) || (y > wd_hgt))
{
// saving maximum possible size of font
fontPointSize = i-1;
break;
}
}
aFont.setPointSize(fontPointSize);
// as a result - we get already resized aFont
}

--Avis 8:29, 30 November 2010 (UTC)

This page was last modified on 11 October 2012, at 04:17.
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