qbitmap.3qt

Trolltech公司发布的基于C++图形开发环境

'\" t
.TH QBitmap 3qt "24 January 2005" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2001 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QBitmap \- Monochrome (1 bit depth) pixmaps
.br
.PP
\fC#include <qbitmap.h>\fR
.PP
Inherits QPixmap.
.PP
.SS "Public Members"
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.BI "\fBQBitmap\fR () "
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.BI "\fBQBitmap\fR ( int " "w" ", int " "h" ", bool " "clear" " = FALSE, QPixmap::Optimization = QPixmap::DefaultOptim ) "
.br
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.BI "\fBQBitmap\fR ( const QSize &, bool " "clear" " = FALSE, QPixmap::Optimization = QPixmap::DefaultOptim ) "
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.BI "\fBQBitmap\fR ( int " "w" ", int " "h" ", const uchar * " "bits" ", bool " "isXbitmap" "=FALSE ) "
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.BI "\fBQBitmap\fR ( const QSize &, const uchar * " "bits" ", bool " "isXbitmap" "=FALSE ) "
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.BI "\fBQBitmap\fR ( const QBitmap & ) "
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.BI "\fBQBitmap\fR ( const QString & " "fileName" ", const char * " "format" "=0 ) "
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.BI "QBitmap& \fBoperator=\fR ( const QBitmap & ) "
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.BI "QBitmap& \fBoperator=\fR ( const QPixmap & ) "
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.BI "QBitmap& \fBoperator=\fR ( const QImage & ) "
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.BI "QBitmap \fBxForm\fR ( const QWMatrix & ) const"
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.SH DESCRIPTION
The QBitmap class provides monochrome (1 bit depth) pixmaps.
.PP
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.
.PP
A QBitmap is a QPixmap with a QPixmap::depth() of 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 QPixmap::isNull() (has depth 0).
.PP
When drawing in a QBitmap (or QPixmap with depth 1), we recommend using the QColor objects \fCQt::color0\fR and \fCQt::color1.\fR Painting with \fCcolor0\fR sets the bitmap bits to 0, and painting with \fCcolor1\fR sets the bits to 1. For a bitmap, 0-bits indicate background (or white) and 1-bits indicate foreground (or black). Using the \fCblack\fR and \fCwhite\fR QColor objects make no sense, because the QColor::pixel() value is not necessarily 0 for black and 1 for white.
.PP
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.
.PP
See also QPixmap, QPainter::drawPixmap(), bitBlt() and Shared Classes
.PP
Examples:
.(l
cursor/cursor.cpp
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.SH MEMBER FUNCTION DOCUMENTATION
.SH "QBitmap::QBitmap ()"
Constructs a null bitmap.
.PP
See also QPixmap::isNull().
.SH "QBitmap::QBitmap ( const QString & fileName, const char * format=0 )"
Constructs a pixmap from the file \fIfileName.\fR If the file does not exist, or is of an unknown format, the pixmap becomes a null pixmap.
.PP
The parameters are passed on to QPixmap::load(). Dithering will be performed if the file format uses more than 1 bit per pixel.
.PP
See also QPixmap::isNull(), QPixmap::load(), QPixmap::loadFromData(), QPixmap::save() and QPixmap::imageFormat().
.SH "QBitmap::QBitmap ( const QBitmap & bitmap )"
Constructs a bitmap which is a copy of \fIbitmap.\fR
.SH "QBitmap::QBitmap ( int w, int h, bool clear = FALSE, QPixmap::Optimization optimization = QPixmap::DefaultOptim )"
Constructs a bitmap with \fIw\fR width and \fIh\fR height.
.PP
The contents of the bitmap is uninitialized if \fIclear\fR is FALSE, otherwise it is filled with pixel value 0 (the QColor \fCQt::color0).\fR
.PP
The optional \fIoptimization\fR 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.
.PP
See also QPixmap::setOptimization() and QPixmap::setDefaultOptimization().
.SH "QBitmap::QBitmap ( int w, int h, const uchar * bits, bool isXbitmap=FALSE )"
Constructs a bitmap with \fIw\fR width and \fIh\fR height and sets the contents to \fIbits.\fR
.PP
The \fIisXbitmap\fR should be TRUE if \fIbits\fR was generated by the X11 bitmap program. The X bitmap bit order is little endian. The QImage documentation discusses bit order of monochrome images.
.PP
Example (creates an arrow bitmap):
.PP
.nf
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    uchar arrow_bits[] = { 0x3f, 0x1f, 0x0f, 0x1f, 0x3b, 0x71, 0xe0, 0xc0 };
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    QBitmap bm( 8, 8, arrow_bits, TRUE );
.fi
.SH "QBitmap::QBitmap ( const QSize & size, bool clear = FALSE, QPixmap::Optimization optimization = QPixmap::DefaultOptim )"
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
.SH "QBitmap::QBitmap ( const QSize & size, const uchar * bits, bool isXbitmap=FALSE )"
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
.SH "QBitmap & QBitmap::operator= ( const QImage & image )"
Converts the image \fIimage\fR to a bitmap and assigns the result to this bitmap. Returns a reference to the bitmap.
.PP
Dithering will be performed if the image has a QImage::depth() greater than 1.
.SH "QBitmap & QBitmap::operator= ( const QPixmap & pixmap )"
Assigns the pixmap \fIpixmap\fR to this bitmap and returns a reference to this bitmap.
.PP
Dithering will be performed if the pixmap has a QPixmap::depth() greater than 1.
.SH "QBitmap & QBitmap::operator= ( const QBitmap & bitmap )"
Assigns the bitmap \fIbitmap\fR to this bitmap and returns a reference to this bitmap.
.SH "QBitmap QBitmap::xForm ( const QWMatrix & matrix ) const"
Returns a transformed copy of this bitmap, using \fImatrix.\fR
.PP
This function does exactly the same as QPixmap::xForm(), except that it returns a QBitmap instead of a QPixmap.
.PP
See also  QPixmap::xForm().
.SH "SEE ALSO"
.BR http://doc.trolltech.com/qbitmap.html
.BR http://www.trolltech.com/faq/tech.html
.SH COPYRIGHT
Copyright 1992-2001 Trolltech AS, http://www.trolltech.com.  See the
license file included in the distribution for a complete license
statement.
.SH AUTHOR
Generated automatically from the source code.
.SH BUGS
If you find a bug in Qt, please report it as described in
.BR http://doc.trolltech.com/bughowto.html .
Good bug reports make our job much simpler. Thank you.
.P
In case of content or formattting problems with this manual page, please
report them to
.BR [e-mail] .
Please include the name of the manual page (qbitmap.3qt) and the Qt
version (2.3.10).