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QBitmap Class Reference

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

#include <qbitmap.h>

Inherits QPixmap.

List of all member functions.

Public Members

Detailed Description

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

The QBitmap class is a monochrome off-screen paint device, used mainly for creating custom mouse cursors or brushes.

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

When drawing in a QBitmap (or QPixmap with depth 1), we recommend using the global color0 and color1 QColor objects. 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 white) and 1-bits indicate foreground (or black). Using the black and white QColor objects make no sense, because the pixel value is not necessarily 0 for black and 1 for white.

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.

See also: QPixmap, QPainter::drawPixmap(), bitBlt() and Shared Classes

Examples: cursor/cursor.cpp

Member Function Documentation


Constructs a null bitmap.

See also: QPixmap::isNull().

QBitmap::QBitmap(constQSize&size, constuchar*bits, boolisXbitmap=FALSE)

Overloaded constructor; takes a QSize parameter instead of (w,h).

QBitmap::QBitmap(constQString&fileName, constchar*format=0)

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

The parameters are passed on to QPixmap::load().

See also: QPixmap::isNull(), QPixmap::load(), QPixmap::loadFromData(), QPixmap::save() and QPixmap::imageFormat().


Constructs a bitmap which is a copy of bitmap.

QBitmap::QBitmap(intw, inth, boolclear=FALSE, QPixmap::Optimizationoptimization=QPixmap::DefaultOptim)

Constructs a bitmap with w width and h height.

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 also: QPixmap::setOptimization() and QPixmap::setDefaultOptimization().

QBitmap::QBitmap(intw, inth, constuchar*bits, boolisXbitmap=FALSE)

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

The isXbitmap 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(constQSize&size, boolclear=FALSE, QPixmap::Optimizationoptimization=QPixmap::DefaultOptim)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.


Converts the image image to a bitmap that is assigned to this bitmap. Returns a reference to the bitmap.

Dithering will be performed if the image has a depth greater than 1.


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

Dithering will be performed if the pixmap has a depth greater than 1.


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


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

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

See also: QPixmap::xForm().

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Qt version 2.0.2