Viadeo Twitter Google Bookmarks ! Facebook Digg del.icio.us MySpace Yahoo MyWeb Blinklist Netvouz Reddit Simpy StumbleUpon Bookmarks Windows Live Favorites 
Logo Documentation Qt ·  Page d'accueil  ·  Toutes les classes  ·  Toutes les fonctions  ·  Vues d'ensemble  · 

QPicture Class Reference

The QPicture class is a paint device that records and replays QPainter commands. More...

 #include <QPicture>

Inherits: QPaintDevice.

Inherited by: Q3Picture.

Public Functions

QPicture ( int formatVersion = -1 )
QPicture ( const QPicture & pic )
~QPicture ()
QRect boundingRect () const
const char * data () const
bool isNull () const
bool load ( const QString & fileName, const char * format = 0 )
bool load ( QIODevice * dev, const char * format = 0 )
bool play ( QPainter * painter )
bool save ( const QString & fileName, const char * format = 0 )
bool save ( QIODevice * dev, const char * format = 0 )
void setBoundingRect ( const QRect & r )
virtual void setData ( const char * data, uint size )
uint size () const
QPicture & operator= ( const QPicture & p )

Related Non-Members

QDataStream & operator<< ( QDataStream & s, const QPicture & r )
QDataStream & operator>> ( QDataStream & s, QPicture & r )

Additional Inherited Members

Detailed Description

The QPicture class is a paint device that records and replays QPainter commands.

A picture serializes painter commands to an IO device in a platform-independent format. They are sometimes referred to as meta-files.

Qt pictures use a proprietary binary format. Unlike native picture (meta-file) formats on many window systems, Qt pictures have no limitations regarding their contents. Everything that can be painted on a widget or pixmap (e.g., fonts, pixmaps, regions, transformed graphics, etc.) can also be stored in a picture.

QPicture is resolution independent, i.e. a QPicture can be displayed on different devices (for example svg, pdf, ps, printer and screen) looking the same. This is, for instance, needed for WYSIWYG print preview. QPicture runs in the default system dpi, and scales the painter to match differences in resolution depending on the window system.

Example of how to record a picture:

         QPicture picture;
         QPainter painter;
         painter.begin(&picture);           // paint in picture
         painter.drawEllipse(10,20, 80,70); // draw an ellipse
         painter.end();                     // painting done
         picture.save("drawing.pic");       // save picture

Note that the list of painter commands is reset on each call to the QPainter::begin() function.

Example of how to replay a picture:

         QPicture picture;
         picture.load("drawing.pic");           // load picture
         QPainter painter;
         painter.begin(&myImage);               // paint in myImage
         painter.drawPicture(0, 0, picture);    // draw the picture at (0,0)
         painter.end();                         // painting done

Pictures can also be drawn using play(). Some basic data about a picture is available, for example, size(), isNull() and boundingRect().

See also QMovie.

Member Function Documentation

QPicture::QPicture ( int formatVersion = -1 )

Constructs an empty picture.

The formatVersion parameter may be used to create a QPicture that can be read by applications that are compiled with earlier versions of Qt.

Note that the default formatVersion is -1 which signifies the current release, i.e. for Qt 4.0 a formatVersion of 7 is the same as the default formatVersion of -1.

Reading pictures generated by earlier versions of Qt is not supported in Qt 4.0.

QPicture::QPicture ( const QPicture & pic )

Constructs a copy of pic.

This constructor is fast thanks to implicit sharing.

QPicture::~QPicture ()

Destroys the picture.

QRect QPicture::boundingRect () const

Returns the picture's bounding rectangle or an invalid rectangle if the picture contains no data.

See also setBoundingRect().

const char * QPicture::data () const

Returns a pointer to the picture data. The pointer is only valid until the next non-const function is called on this picture. The returned pointer is 0 if the picture contains no data.

See also setData(), size(), and isNull().

bool QPicture::isNull () const

Returns true if the picture contains no data; otherwise returns false.

bool QPicture::load ( const QString & fileName, const char * format = 0 )

Loads a picture from the file specified by fileName and returns true if successful; otherwise returns false.

Please note that the format parameter has been deprecated and will have no effect.

See also save().

bool QPicture::load ( QIODevice * dev, const char * format = 0 )

This is an overloaded function.

dev is the device to use for loading.

bool QPicture::play ( QPainter * painter )

Replays the picture using painter, and returns true if successful; otherwise returns false.

This function does exactly the same as QPainter::drawPicture() with (x, y) = (0, 0).

bool QPicture::save ( const QString & fileName, const char * format = 0 )

Saves a picture to the file specified by fileName and returns true if successful; otherwise returns false.

Please note that the format parameter has been deprecated and will have no effect.

See also load().

bool QPicture::save ( QIODevice * dev, const char * format = 0 )

This is an overloaded function.

dev is the device to use for saving.

void QPicture::setBoundingRect ( const QRect & r )

Sets the picture's bounding rectangle to r. The automatically calculated value is overridden.

See also boundingRect().

void QPicture::setData ( const char * data, uint size ) [virtual]

Sets the picture data directly from data and size. This function copies the input data.

See also data() and size().

uint QPicture::size () const

Returns the size of the picture data.

See also data().

QPicture & QPicture::operator= ( const QPicture & p )

Assigns picture p to this picture and returns a reference to this picture.

Related Non-Members

QDataStream & operator<< ( QDataStream & s, const QPicture & r )

Writes picture r to the stream s and returns a reference to the stream.

QDataStream & operator>> ( QDataStream & s, QPicture & r )

Reads a picture from the stream s into picture r and returns a reference to the stream.

Publicité

Best Of

Actualités les plus lues

Semaine
Mois
Année
  1. « Quelque chose ne va vraiment pas avec les développeurs "modernes" », un développeur à "l'ancienne" critique la multiplication des bibliothèques 53
  2. Les développeurs ignorent-ils trop les failles découvertes dans leur code ? Prenez-vous en compte les remarques des autres ? 17
  3. BlackBerry 10 : premières images du prochain OS de RIM qui devrait intégrer des widgets et des tuiles inspirées de Windows Phone 0
  4. Apercevoir la troisième dimension ou l'utilisation multithreadée d'OpenGL dans Qt, un article des Qt Quarterly traduit par Guillaume Belz 0
  5. Quelles nouveautés de C++11 Visual C++ doit-il rapidement intégrer ? Donnez-nous votre avis 10
  6. Adieu qmake, bienvenue qbs : Qt Building Suite, un outil déclaratif et extensible pour la compilation de projets Qt 17
  7. La rubrique Qt a besoin de vous ! 1
Page suivante

Le blog Digia au hasard

Logo

Déploiement d'applications Qt Commercial sur les tablettes Windows 8

Le blog Digia est l'endroit privilégié pour la communication sur l'édition commerciale de Qt, où des réponses publiques sont apportées aux questions les plus posées au support. Lire l'article.

Communauté

Ressources

Liens utiles

Contact

  • Vous souhaitez rejoindre la rédaction ou proposer un tutoriel, une traduction, une question... ? Postez dans le forum Contribuez ou contactez-nous par MP ou par email (voir en bas de page).

Qt dans le magazine

Cette page est une traduction d'une page de la documentation de Qt, écrite par Nokia Corporation and/or its subsidiary(-ies). Les éventuels problèmes résultant d'une mauvaise traduction ne sont pas imputables à Nokia. Qt 4.7
Copyright © 2012 Developpez LLC. Tous droits réservés Developpez LLC. Aucune reproduction, même partielle, ne peut être faite de ce site et de l'ensemble de son contenu : textes, documents et images sans l'autorisation expresse de Developpez LLC. Sinon, vous encourez selon la loi jusqu'à 3 ans de prison et jusqu'à 300 000 E de dommages et intérêts. Cette page est déposée à la SACD.
Vous avez déniché une erreur ? Un bug ? Une redirection cassée ? Ou tout autre problème, quel qu'il soit ? Ou bien vous désirez participer à ce projet de traduction ? N'hésitez pas à nous contacter ou par MP !
 
 
 
 
Partenaires

Hébergement Web