Referencia de la Clase QBitmap

The QBitmap class provides monochrome (1-bit depth) pixmaps. Más...

#include <qbitmap.h>

Diagrama de herencias de QBitmap

Lista de todos los miembros.

Métodos públicos
	QBitmap ()
	QBitmap (int w, int h, bool clear=FALSE, QPixmap::Optimization=QPixmap::DefaultOptim)
	QBitmap (const QSize &, bool clear=FALSE, QPixmap::Optimization=QPixmap::DefaultOptim)
	QBitmap (int w, int h, const uchar *bits, bool isXbitmap=FALSE)
	QBitmap (const QSize &, const uchar *bits, bool isXbitmap=FALSE)
	QBitmap (const QBitmap &)
	QBitmap (const QString &fileName, const char *format=0)
QBitmap &	operator= (const QBitmap &)
QBitmap &	operator= (const QPixmap &)
QBitmap &	operator= (const QImage &)
QBitmap	xForm (const QWMatrix &) const
	QBitmap ()
	QBitmap (int w, int h, bool clear=FALSE, QPixmap::Optimization=QPixmap::DefaultOptim)
	QBitmap (const QSize &, bool clear=FALSE, QPixmap::Optimization=QPixmap::DefaultOptim)
	QBitmap (int w, int h, const uchar *bits, bool isXbitmap=FALSE)
	QBitmap (const QSize &, const uchar *bits, bool isXbitmap=FALSE)
	QBitmap (const QBitmap &)
	QBitmap (const QString &fileName, const char *format=0)
QBitmap &	operator= (const QBitmap &)
QBitmap &	operator= (const QPixmap &)
QBitmap &	operator= (const QImage &)
QBitmap	xForm (const QWMatrix &) const

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Descripción detallada

The QBitmap class provides monochrome (1-bit depth) pixmaps.

The QBitmap class is a monochrome off-screen paint device used mainly for creating custom QCursor and QBrush objects, in QPixmap::setMask() and for QRegion.

A QBitmap is a QPixmap with a depth of 1. If a pixmap with a depth greater than 1 is assigned to a bitmap, the bitmap will be dithered automatically. A QBitmap is guaranteed to always have the depth 1, unless it is QPixmap::isNull() which has depth 0.

When drawing in a QBitmap (or QPixmap with depth 1), we recommend using the QColor objects Qt::color0 and Qt::color1. Painting with color0 sets the bitmap bits to 0, and painting with color1 sets the bits to 1. For a bitmap, 0-bits indicate background (or transparent) and 1-bits indicate foreground (or opaque). Using the black and white QColor objects make no sense because the QColor::pixel() value is not necessarily 0 for black and 1 for white.

The QBitmap can be transformed (translated, scaled, sheared or rotated) using xForm().

Just like the QPixmap class, QBitmap is optimized by the use of implicit sharing, so it is very efficient to pass QBitmap objects as arguments.

Ver también:

QPixmap, QPainter::drawPixmap(), bitBlt(), Shared Classes

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Documentación del constructor y destructor

QBitmap::QBitmap

(

)

Constructs a null bitmap.

Ver también:

QPixmap::isNull()

QBitmap::QBitmap	(	int	w,
		int	h,
		bool	clear = FALSE,
		QPixmap::Optimization	optimization = QPixmap::DefaultOptim
	)

Constructs a bitmap with width w and height h.

The contents of the bitmap is uninitialized if clear is FALSE; otherwise it is filled with pixel value 0 (the QColor Qt::color0).

The optional optimization argument specifies the optimization setting for the bitmap. The default optimization should be used in most cases. Games and other pixmap-intensive applications may benefit from setting this argument; see {QPixmap::Optimization}.

Ver también:

QPixmap::setOptimization(), QPixmap::setDefaultOptimization()

QBitmap::QBitmap	(	const QSize &	size,
		bool	clear = FALSE,
		QPixmap::Optimization	optimization = QPixmap::DefaultOptim
	)

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Constructs a bitmap with the size size.

The contents of the bitmap is uninitialized if clear is FALSE; otherwise it is filled with pixel value 0 (the QColor Qt::color0).

The optional optimization argument specifies the optimization setting for the bitmap. The default optimization should be used in most cases. Games and other pixmap-intensive applications may benefit from setting this argument; see {QPixmap::Optimization}.

QBitmap::QBitmap	(	int	w,
		int	h,
		const uchar *	bits,
		bool	isXbitmap = FALSE
	)

Constructs a bitmap with width w and height h and sets the contents to bits.

The isXbitmap flag should be TRUE if bits was generated by the X11 bitmap program. The X bitmap bit order is little endian. The QImage documentation discusses bit order of monochrome images.

Example (creates an arrow bitmap):

        uchar arrow_bits[] = { 0x3f, 0x1f, 0x0f, 0x1f, 0x3b, 0x71, 0xe0, 0xc0 };
        QBitmap bm( 8, 8, arrow_bits, TRUE );

QBitmap::QBitmap	(	const QSize &	size,
		const uchar *	bits,
		bool	isXbitmap = FALSE
	)

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Constructs a bitmap with the size size and sets the contents to bits.

The isXbitmap flag should be TRUE if bits was generated by the X11 bitmap program. The X bitmap bit order is little endian. The QImage documentation discusses bit order of monochrome images.

QBitmap::QBitmap

(

const QBitmap &

bitmap

)

Constructs a bitmap that is a copy of bitmap.

QBitmap::QBitmap	(	const QString &	fileName,
		const char *	format = 0
	)

Constructs a bitmap from the file fileName. If the file does not exist or is of an unknown format, the bitmap becomes a null bitmap.

The parameters fileName and format are passed on to QPixmap::load(). Dithering will be performed if the file format uses more than 1 bit per pixel.

Ver también:

QPixmap::isNull(), QPixmap::load(), QPixmap::loadFromData(), QPixmap::save(), QPixmap::imageFormat()

QBitmap::QBitmap

(

)

QBitmap::QBitmap	(	int	w,
		int	h,
		bool	clear = FALSE,
		QPixmap::Optimization	= QPixmap::DefaultOptim
	)

QBitmap::QBitmap	(	const QSize &	,
		bool	clear = FALSE,
		QPixmap::Optimization	= QPixmap::DefaultOptim
	)

QBitmap::QBitmap	(	int	w,
		int	h,
		const uchar *	bits,
		bool	isXbitmap = FALSE
	)

QBitmap::QBitmap	(	const QSize &	,
		const uchar *	bits,
		bool	isXbitmap = FALSE
	)

QBitmap::QBitmap

(

const QBitmap &

)

QBitmap::QBitmap	(	const QString &	fileName,
		const char *	format = 0
	)

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Documentación de las funciones miembro

QBitmap & QBitmap::operator=

(

const QBitmap &

bitmap

)

Assigns the bitmap bitmap to this bitmap and returns a reference to this bitmap.

QBitmap & QBitmap::operator=

(

const QPixmap &

pixmap

)

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Assigns the pixmap pixmap to this bitmap and returns a reference to this bitmap.

Dithering will be performed if the pixmap has a QPixmap::depth() greater than 1.

Reimplementado de QPixmap.

QBitmap& QBitmap::operator=

(

const QImage &

image

)

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Converts the image image to a pixmap that is assigned to this pixmap. Returns a reference to the pixmap.

Ver también:

convertFromImage().

Reimplementado de QPixmap.

QBitmap& QBitmap::operator=

(

const QPixmap &

pixmap

)

Assigns the pixmap pixmap to this pixmap and returns a reference to this pixmap.

Reimplementado de QPixmap.

QBitmap& QBitmap::operator=

(

const QBitmap &

)

QBitmap & QBitmap::operator=

(

const QImage &

image

)

Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Converts the image image to a bitmap and assigns the result to this bitmap. Returns a reference to the bitmap.

Dithering will be performed if the image has a QImage::depth() greater than 1.

Reimplementado de QPixmap.

QBitmap QBitmap::xForm

(

const QWMatrix &

matrix

)

const

Returns a transformed copy of this bitmap by using matrix.

This function does exactly the same as QPixmap::xForm(), except that it returns a QBitmap instead of a QPixmap.

Ver también:

QPixmap::xForm()

Reimplementado de QPixmap.

QBitmap QBitmap::xForm

(

const QWMatrix &

matrix

)

const

Returns a copy of the pixmap that is transformed using matrix.

Qt uses this function to implement rotated text on window systems that do not support such complex features.

Example of how to manually draw a rotated text at (100,200) in a widget:

    char    *str = "Trolls R Qt"; // text to be drawn
    QFont    f( "Charter", 24 ); // use Charter 24pt font
    QPixmap  pm( 8, 8 );
    QPainter p;
    QRect    r;    // text bounding rectangle
    QPoint   bl;   // text baseline position

    p.begin( &pm );   // first get the bounding
    p.setFont( f );   //   text rectangle
    r = p.fontMetrics().boundingRect(str);
    bl = -r.topLeft();   // get baseline position
    p.end();

    pm.resize( r.size() );  // resize to fit the text
    pm.fill( white );   // fills pm with white
    p.begin( &pm );   // begin painting pm
    p.setFont( f );   // set the font
    p.setPen( blue );   // set blue text color
    p.drawText( bl, str );  // draw the text
    p.end();    // painting done

    QWMatrix m;    // transformation matrix
    m.rotate( -33.4 );   // rotate coordinate system
    QPixmap rp = pm.xForm( m );  // rp is rotated pixmap

    QWMatrix t = QPixmap::trueMatrix( m, pm.width(), pm.height() );
    int x, y;
    t.map( bl.x(),bl.y(), &x,&y ); // get pm's baseline pos in rp

    bitBlt( myWidget, 100-x, 200-y, // blt rp into a widget
     &rp, 0, 0, -1, -1 );

This example outlines how Qt implements rotated text under X11. The font calculation is the most tedious part. The rotation itself is only 3 lines of code.

If you want to draw rotated text, you do not have to implement all the code above. The code below does exactly the same thing as the example above, except that it uses a QPainter.

    char    *str = "Trolls R Qt"; // text to be drawn
    QFont    f( "Charter", 24 ); // use Charter 24pt font
    QPainter p;

    p.begin( myWidget );
    p.translate( 100, 200 );  // translates coord system
    p.rotate( -33.4 );   // rotates it counterclockwise
    p.setFont( f );
    p.drawText( 0, 0, str );
    p.end();

Bug:

2 and 4 bits pixmaps are not supported.

Ver también:

trueMatrix(), QWMatrix, QPainter::setWorldMatrix()

Returns a copy of the pixmap that is transformed using matrix. The original pixmap is not changed.

The transformation matrix is internally adjusted to compensate for unwanted translation, i.e. xForm() returns the smallest image that contains all the transformed points of the original image.

This function is slow because it involves transformation to a QImage, non-trivial computations and a transformation back to a QPixmap.

Ver también:

trueMatrix(), QWMatrix, QPainter::setWorldMatrix() QImage::xForm()

Reimplementado de QPixmap.

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La documentación para esta clase fue generada a partir de los siguientes ficheros:

• src/qt/include/qbitmap.h
• src/qt/src/kernel/qbitmap.h
• src/qt/src/kernel/qbitmap.cpp