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Revision as of 09:30, 8 June 2012 by hamishwillee (Talk | contribs)

Archived:Calculating text width in Qt

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Archived.pngArchived: This article is archived because it is not considered relevant for third-party developers creating commercial solutions today. If you think this article is still relevant, let us know by adding the template {{ReviewForRemovalFromArchive|user=~~~~|write your reason here}}.

Qt Quick should be used for all UI development on mobile devices. The approach described in this article (using C++ for the Qt app UI) is deprecated.

Article Metadata
Code ExampleTested with
Devices(s): Nokia 5800 XpressMusic
Compatibility
Platform(s): S60 3rd Edition, FP1, FP2
S60 5th Edition
Symbian
Article
Keywords: QFontMetrics, QFont
Created: tepaa (26 Mar 2009)
Last edited: hamishwillee (08 Jun 2012)

Contents

Overview

This code snippets shows how to use the QFont and QFontMetrics classes to draw a string into the center of the screen and to get the string height and width in pixels.

Preconditions

Source code

  • This source code centers the text and sets the text colour.
void QMyWidget::paintEvent(QPaintEvent*)
{
QPainter painter(this);
 
// Create font
QFont f("Helvetica",20);
// Set current font
painter.setFont(f);
// Set font color
painter.setPen(Qt::white);
// Get QFontMetrics reference
QFontMetrics fm = painter.fontMetrics();
 
QString text = "helloworld";
 
// Calculate text center position into the screen using QFontMetrics class
QPoint center = QPoint( ( width()-fm.width(text))/2,
( height() - fm.height())/2 );
 
// QFontMetrics::width() gives calculated text width with current QFont in QPainter
// QFontMetrics::height() gives text height
 
painter.drawText(center,text);
}


Postconditions

The text is centered on the screen.

The code example can be found at File:HelloworldNew.zip

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