qregion.3qt

Qt/Embedded是一个多平台的C++图形用户界面应用程序框架

.TH QRegion 3qt "3 September 2000" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2000 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QRegion \- Clip region for a painter
.SH SYNOPSIS
.br
.PP
\fC#include <qregion.h>\fR
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "enum \fBRegionType\fR { Rectangle, Ellipse }"
.br
.ti -1c
.BI "\fBQRegion\fR () "
.br
.ti -1c
.BI "\fBQRegion\fR ( int " "x" ", int " "y" ", int " "w" ", int " "h" ", RegionType = Rectangle ) "
.br
.ti -1c
.BI "\fBQRegion\fR ( const QRect &, RegionType = Rectangle ) "
.br
.ti -1c
.BI "\fBQRegion\fR ( const QPointArray &, bool " "winding" "=FALSE ) "
.br
.ti -1c
.BI "\fBQRegion\fR ( const QRegion & ) "
.br
.ti -1c
.BI "\fBQRegion\fR ( const QBitmap & ) "
.br
.ti -1c
.BI "\fB~QRegion\fR () "
.br
.ti -1c
.BI "QRegion& \fBoperator=\fR ( const QRegion & ) "
.br
.ti -1c
.BI "bool \fBisNull\fR () const"
.br
.ti -1c
.BI "bool \fBisEmpty\fR () const"
.br
.ti -1c
.BI "bool \fBcontains\fR ( const QPoint & p ) const"
.br
.ti -1c
.BI "bool \fBcontains\fR ( const QRect & r ) const"
.br
.ti -1c
.BI "void \fBtranslate\fR ( int " "dx" ", int dy ) "
.br
.ti -1c
.BI "QRegion \fBunite\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBintersect\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBsubtract\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBeor\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRect \fBboundingRect\fR () const"
.br
.ti -1c
.BI "QArray<QRect> \fBrects\fR () const"
.br
.ti -1c
.BI "void \fBsetRects\fR ( const QRect *, int ) "
.br
.ti -1c
.BI "QRegion \fBoperator|\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBoperator+\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBoperator&\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBoperator-\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion \fBoperator^\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "QRegion& \fBoperator|=\fR ( const QRegion & ) "
.br
.ti -1c
.BI "QRegion& \fBoperator+=\fR ( const QRegion & ) "
.br
.ti -1c
.BI "QRegion& \fBoperator&=\fR ( const QRegion & ) "
.br
.ti -1c
.BI "QRegion& \fBoperator-=\fR ( const QRegion & ) "
.br
.ti -1c
.BI "QRegion& \fBoperator^=\fR ( const QRegion & ) "
.br
.ti -1c
.BI "bool \fBoperator==\fR ( const QRegion & ) const"
.br
.ti -1c
.BI "bool \fBoperator!=\fR ( const QRegion & r ) const"
.br
.in -1c
.SH RELATED FUNCTION DOCUMENTATION
(Note that these are not member functions.)
.in +1c
.ti -1c
.BI "QDataStream & \fBoperator>>\fR (QDataStream & " "s" ", QRegion & " "r" ")"
.br
.ti -1c
.BI "QDataStream & \fBoperator<<\fR (QDataStream & " "s" ", const QRegion & " "r" ")"
.br
.in -1c
.SH DESCRIPTION
The QRegion class specifies a clip region for a painter.
.PP
QRegion is used with QPainter::setClipRegion() to limit the paint area to what needs to be painted. There is also a QWidget::repaint() that takes a QRegion parameter. QRegion is the best tool for reducing flicker.
.PP
A region can be created from a rectangle, an ellipse, a polygon or a bitmap. Complex regions may be created by combining simple regions, using unite(), intersect(), subtract() or eor() (exclusive or). Use translate() to move a region.
.PP
You can test if a region isNull(), isEmpty() or if it contains() a QPoint or QRect. The bounding rectangle is given by boundingRect().
.PP
The function rects() gives a decomposition of the region into rectangles.
.PP
Example of using complex regions:
.PP
.nf
.br
    void MyWidget::paintEvent( QPaintEvent * )
.br
    {
.br
        QPainter p;                             // our painter
.br
        QRegion r1( QRect(100,100,200,80),      // r1 = elliptic region
.br
                    QRegion::Ellipse );
.br
        QRegion r2( QRect(100,120,90,30) );     // r2 = rectangular region
.br
        QRegion r3 = r1.intersect( r2 );        // r3 = intersection
.br
        p.begin( this );                        // start painting widget
.br
        p.setClipRegion( r3 );                  // set clip region
.br
        ...                                     // paint clipped graphics
.br
        p.end();                                // painting done
.br
    }
.fi
.PP
QRegion is an implicitely shared class.
.PP
See also QPainter::setClipRegion() and QPainter::setClipRect().
.SS "Member Type Documentation"
.SH "QRegion::RegionType"
Determines the shape of the region to be created.
.TP
\fCRectangle\fR - the region covers the entire rectangle
.TP
\fCEllipse\fR - the region is an ellipse inside the rectangle
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QRegion::QRegion ()"
Constructs a null region.
.PP
See also isNull().
.SH "QRegion::QRegion ( const QBitmap & bm )"
Constructs a region from the bitmap \fIbm.\fR
.PP
The resulting region consists of the pixels in \fIbm\fR that are \fCcolor1,\fR as if each pixel was a 1 by 1 rectangle.
.PP
This constructor may create complex regions that will slow down painting when used. Note that drawing masked pixmaps can be done much faster using QPixmap::setMask().
.SH "QRegion::QRegion ( const QPointArray & a, bool winding=FALSE )"
Constructs a polygon region from the point array \fIa.\fR
.PP
If \fIwinding\fR is TRUE, the polygon region is filled using the winding algorithm, otherwise the default even-odd fill algorithm is used.
.PP
This constructor may create complex regions that will slow down painting when used.
.SH "QRegion::QRegion ( const QRegion & r )"
Constructs a new region which is equal to \fIr.\fR
.SH "QRegion::QRegion ( int x, int y, int w, int h, RegionType t = Rectangle )"
Constructs a rectangular or elliptic region.
.PP
If \fIt\fR is \fCRectangle,\fR the region is the filled rectangle (\fIx, y, w, h).\fR If \fIt\fR is \fCEllipse,\fR the region is the filled ellipse ellipse with center at (\fIx\fR + \fIw\fR / 2, \fIy\fR + \fIh\fR / 2) and size (\fIw\fR ,\fIh\fR ).
.SH "QRegion::QRegion ( const QRect & r, RegionType t = Rectangle )"
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
.SH "QRegion::~QRegion ()"
Destructs the region.
.SH "QRect QRegion::boundingRect () const"
Returns the bounding rectangle of this region. An empty region gives a rectangle that is QRect::isNull().
.SH "bool QRegion::contains ( const QPoint & p ) const"
Returns TRUE if the region contains the point \fIp,\fR or FALSE if \fIp\fR is outside the region.
.SH "bool QRegion::contains ( const QRect & r ) const"
Returns TRUE if the region overlaps the rectangle \fIr,\fR or FALSE if \fIr\fR is completely outside the region.
.SH "QRegion QRegion::eor ( const QRegion & r ) const"
Returns a region which is the exclusive or (XOR) of this region and \fIr.\fR
.PP
<img src=rxor.png>
.PP
The figure shows the exclusive or of two elliptical regions.
.SH "QRegion QRegion::intersect ( const QRegion & r ) const"
Returns a region which is the intersection of this region and \fIr.\fR
.PP
<img src=rintersect.png>
.PP
The figure shows the intersection of two elliptical regions.
.SH "bool QRegion::isEmpty () const"
Returns TRUE if the region is empty, or FALSE if it is non-empty. An empty region is a region that contains no points.
.PP
Example:
.PP
.nf
.br
    QRegion r1( 10, 10, 20, 20 );
.br
    QRegion r2( 40, 40, 20, 20 );
.br
    QRegion r3;
.br
    r1.isNull();                // FALSE
.br
    r1.isEmpty();               // FALSE
.br
    r3.isNull();                // TRUE
.br
    r3.isEmpty();               // TRUE
.br
    r3 = r1.intersect( r2 );    // r3 = intersection of r1 and r2
.br
    r3.isNull();                // FALSE
.br
    r3.isEmpty();               // TRUE
.br
    r3 = r1.unite( r2 );        // r3 = union of r1 and r2
.br
    r3.isNull();                // FALSE
.br
    r3.isEmpty();               // FALSE
.fi
.PP
See also isNull().
.SH "bool QRegion::isNull () const"
Returns TRUE if the region is a null region, otherwise FALSE.
.PP
A null region is a region that has not been initialized. A null region is always empty.
.PP
See also isEmpty().
.SH "bool QRegion::operator!= ( const QRegion & r ) const"
Returns TRUE if the region is different from \fIr,\fR or FALSE if the regions are equal.
.SH "QRegion QRegion::operator& ( const QRegion & r ) const"
\fCr1&r2\fR is equivalent to \fCr1.intersect(r2)\fR
.PP
See also intersect().
.SH "QRegion& QRegion::operator&= ( const QRegion & r )"
\fCr1&=r2\fR is equivalent to \fCr1=r1.intersect(r2)\fR
.PP
See also intersect().
.SH "QRegion QRegion::operator+ ( const QRegion & r ) const"
\fCr1+r2\fR is equivalent to \fCr1.unite(r2)\fR
.PP
See also unite() and operator|().
.SH "QRegion& QRegion::operator+= ( const QRegion & r )"
\fCr1+=r2\fR is equivalent to \fCr1=r1.unite(r2)\fR
.PP
See also intersect().
.SH "QRegion QRegion::operator- ( const QRegion & r ) const"
\fCr1-r2\fR is equivalent to \fCr1.subtract(r2)\fR
.PP
See also subtract().
.SH "QRegion& QRegion::operator-= ( const QRegion & r )"
\fCr1-=r2\fR is equivalent to \fCr1=r1.subtract(r2)\fR
.PP
See also subtract().
.SH "QRegion & QRegion::operator= ( const QRegion & r )"
Assigns \fIr\fR to this region and returns a reference to the region.
.SH "bool QRegion::operator== ( const QRegion & r ) const"
Returns TRUE if the region is equal to \fIr,\fR or FALSE if the regions are different.
.SH "QRegion QRegion::operator^ ( const QRegion & r ) const"
\fCr1^r2\fR is equivalent to \fCr1.eor(r2)\fR
.PP
See also eor().
.SH "QRegion& QRegion::operator^= ( const QRegion & r )"
\fCr1^=r2\fR is equivalent to \fCr1=r1.eor(r2)\fR
.PP
See also eor().
.SH "QRegion QRegion::operator| ( const QRegion & r ) const"
\fCr1|r2\fR is equivalent to \fCr1.unite(r2)\fR
.PP
See also unite() and operator+().
.SH "QRegion& QRegion::operator|= ( const QRegion & r )"
\fCr1|=r2\fR is equivalent to \fCr1=r1.unite(r2)\fR
.PP
See also unite().
.SH "QArray<QRect> QRegion::rects () const"
Returns an array of non-overlapping rectangles that make up the region.
.PP
The union of all the rectangles is equal to the original region.
.SH "void QRegion::setRects ( const QRect * rects, int num )"
Sets the region to be the given set of rectangles. The rectangles \fImust\fR be optimal Y-X sorted bands as follows:
.TP
The rectangles must not intersect
.TP
All rectangles with a given top coordinate must have the same height.
.TP
No two rectangles may abut horizontally (they should be combined into a single wider rectangle in that case).
.TP
The rectangles must be sorted ascendingly by Y as the major sort key and X as the minor sort key.
.SH "QRegion QRegion::subtract ( const QRegion & r ) const"
Returns a region which is \fIr\fR subtracted from this region.
.PP
<img src=rsubtract.png>
.PP
The figure shows the result when the ellipse on the right is subtracted from the ellipse on the left. (\fCleft-right\fR ).
.SH "void QRegion::translate ( int dx, int dy )"
Translates (moves) the region \fIdx\fR along the X axis and \fIdy\fR along the Y axis.
.SH "QRegion QRegion::unite ( const QRegion & r ) const"
Returns a region which is the union of this region and \fIr.\fR
.PP
<img src=runion.png>
.PP
The figure shows the union of two elliptical regions.
.SH RELATED FUNCTION DOCUMENTATION
.SH "QDataStream & operator>> (QDataStream & s, QRegion & r)"
Reads a region from the stream \fIs\fR into \fIr\fR and returns a reference to the stream.
.PP
See also Format of the QDataStream operators
.SH "QDataStream & operator<< (QDataStream & s, const QRegion & r)"
Writes the region \fIr\fR to the stream \fIs\fR and returns a reference to the stream.
.PP
See also  Format of the QDataStream operators
.SH "SEE ALSO"
.BR http://doc.trolltech.com/qregion.html
.SH COPYRIGHT
Copyright 1992-2000 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.