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

QBitmap ()
QBitmap ( int w, int h, bool clear = FALSE )
QBitmap ( const QSize &, bool clear = FALSE )
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 char * fileName, const char * format=0 )
QBitmap& operator= ( const QBitmap & )
QBitmap& operator= ( const QPixmap & )
QBitmap& operator= ( const QImage & )
QBitmap xForm ( const QWMatrix & ) const

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

QBitmap::QBitmap ()

Constructs a null bitmap.

QBitmap::QBitmap ( const QSize & size, bool clear = FALSE )

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

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

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

QBitmap::QBitmap ( const QBitmap & bitmap )

Constructs a bitmap which is a copy of bitmap.

QBitmap::QBitmap ( const char * fileName, const char * 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().

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

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 color0).

QBitmap::QBitmap ( int w, int h, const uchar * bits, bool isXbitmap=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::operator= ( const QImage & image )

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.

QBitmap & QBitmap::operator= ( const QPixmap & pixmap )

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.

QBitmap & QBitmap::operator= ( const QBitmap & bitmap )

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

QBitmap QBitmap::xForm ( const QWMatrix & matrix ) const

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.