path: root/doc/man/man3/tqregion.3qt

'\" t
.TH TQRegion 3qt "2 February 2007" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2007 Trolltech ASA.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
TQRegion \- Clip region for a painter
.SH SYNOPSIS
\fC#include <tqregion.h>\fR
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "enum \fBRegionType\fR { Rectangle, Ellipse }"
.br
.ti -1c
.BI "\fBTQRegion\fR ()"
.br
.ti -1c
.BI "\fBTQRegion\fR ( int x, int y, int w, int h, RegionType t = Rectangle )"
.br
.ti -1c
.BI "\fBTQRegion\fR ( const TQRect & r, RegionType t = Rectangle )"
.br
.ti -1c
.BI "\fBTQRegion\fR ( const TQPointArray & a, bool winding = FALSE )"
.br
.ti -1c
.BI "\fBTQRegion\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "\fBTQRegion\fR ( const TQBitmap & bm )"
.br
.ti -1c
.BI "\fB~TQRegion\fR ()"
.br
.ti -1c
.BI "TQRegion & \fBoperator=\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "bool \fBisNull\fR () const"
.br
.ti -1c
.BI "bool \fBisEmpty\fR () const"
.br
.ti -1c
.BI "bool \fBcontains\fR ( const TQPoint & p ) const"
.br
.ti -1c
.BI "bool \fBcontains\fR ( const TQRect & r ) const"
.br
.ti -1c
.BI "void \fBtranslate\fR ( int dx, int dy )"
.br
.ti -1c
.BI "TQRegion \fBunite\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "TQRegion \fBintersect\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "TQRegion \fBsubtract\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "TQRegion \fBeor\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "TQRect \fBboundingRect\fR () const"
.br
.ti -1c
.BI "TQMemArray<TQRect> \fBrects\fR () const"
.br
.ti -1c
.BI "const TQRegion \fBoperator|\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "const TQRegion \fBoperator+\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "const TQRegion \fBoperator&\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "const TQRegion \fBoperator-\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "const TQRegion \fBoperator^\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "TQRegion & \fBoperator|=\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "TQRegion & \fBoperator+=\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "TQRegion & \fBoperator&=\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "TQRegion & \fBoperator-=\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "TQRegion & \fBoperator^=\fR ( const TQRegion & r )"
.br
.ti -1c
.BI "bool \fBoperator==\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "bool \fBoperator!=\fR ( const TQRegion & r ) const"
.br
.ti -1c
.BI "HRGN \fBhandle\fR () const"
.br
.in -1c
.SH RELATED FUNCTION DOCUMENTATION
.in +1c
.ti -1c
.BI "TQDataStream & \fBoperator<<\fR ( TQDataStream & s, const TQRegion & r )"
.br
.ti -1c
.BI "TQDataStream & \fBoperator>>\fR ( TQDataStream & s, TQRegion & r )"
.br
.in -1c
.SH DESCRIPTION
The TQRegion class specifies a clip region for a painter.
.PP
TQRegion is used with TQPainter::setClipRegion() to limit the paint area to what needs to be painted. There is also a TQWidget::repaint() that takes a TQRegion parameter. TQRegion 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). You can move a region using translate().
.PP
You can test whether a region isNull(), isEmpty() or if it contains() a TQPoint or TQRect. 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( TQPaintEvent * )
.br
        {
.br
            TQPainter p;                         // our painter
.br
            TQRegion r1( TQRect(100,100,200,80),  // r1 = elliptic region
.br
                        TQRegion::Ellipse );
.br
            TQRegion r2( TQRect(100,120,90,30) ); // r2 = rectangular region
.br
            TQRegion 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
        }
.br
.fi
.PP
TQRegion is an implicitly shared class.
.PP
\fBWarning:\fR Due to window system limitations, the whole coordinate space for a region is limited to the points between -32767 and 32767 on Mac OS X and Windows 95/98/ME.
.PP
See also TQPainter::setClipRegion(), TQPainter::setClipRect(), Graphics Classes, and Image Processing Classes.
.SS "Member Type Documentation"
.SH "TQRegion::RegionType"
Specifies the shape of the region to be created.
.TP
\fCTQRegion::Rectangle\fR - the region covers the entire rectangle.
.TP
\fCTQRegion::Ellipse\fR - the region is an ellipse inside the rectangle.
.SH MEMBER FUNCTION DOCUMENTATION
.SH "TQRegion::TQRegion ()"
Constructs a null region.
.PP
See also isNull().
.SH "TQRegion::TQRegion ( int x, int y, int w, int h, RegionType t = Rectangle )"
Constructs a rectangular or elliptic region.
.PP
If \fIt\fR is Rectangle, the region is the filled rectangle (\fIx\fR, \fIy\fR, \fIw\fR, \fIh\fR). If \fIt\fR is Ellipse, the region is the filled ellipse with center at (\fIx\fR + \fIw\fR / 2, \fIy\fR + \fIh\fR / 2) and size (\fIw\fR ,\fIh\fR ).
.SH "TQRegion::TQRegion ( const TQRect & r, RegionType t = Rectangle )"
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
.PP
Create a region based on the rectange \fIr\fR with region type \fIt\fR.
.PP
If the rectangle is invalid a null region will be created.
.PP
See also TQRegion::RegionType.
.SH "TQRegion::TQRegion ( const TQPointArray & 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 "TQRegion::TQRegion ( const TQRegion & r )"
Constructs a new region which is equal to region \fIr\fR.
.SH "TQRegion::TQRegion ( const TQBitmap & bm )"
Constructs a region from the bitmap \fIbm\fR.
.PP
The resulting region consists of the pixels in bitmap \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 TQPixmap::setMask().
.SH "TQRegion::~TQRegion ()"
Destroys the region.
.SH "TQRect TQRegion::boundingRect () const"
Returns the bounding rectangle of this region. An empty region gives a rectangle that is TQRect::isNull().
.SH "bool TQRegion::contains ( const TQPoint & p ) const"
Returns TRUE if the region contains the point \fIp\fR; otherwise returns FALSE.
.SH "bool TQRegion::contains ( const TQRect & r ) const"
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
.PP
Returns TRUE if the region overlaps the rectangle \fIr\fR; otherwise returns FALSE.
.SH "TQRegion TQRegion::eor ( const TQRegion & r ) const"
Returns a region which is the exclusive or (XOR) of this region and \fIr\fR.
.PP
<center>
.ce 1
.B "[Image Omitted]"
.PP
</center>
.PP
The figure shows the exclusive or of two elliptical regions.
.SH "HRGN TQRegion::handle () const"
Returns the region's handle.
.SH "TQRegion TQRegion::intersect ( const TQRegion & r ) const"
Returns a region which is the intersection of this region and \fIr\fR.
.PP
<center>
.ce 1
.B "[Image Omitted]"
.PP
</center>
.PP
The figure shows the intersection of two elliptical regions.
.SH "bool TQRegion::isEmpty () const"
Returns TRUE if the region is empty; otherwise returns FALSE. An empty region is a region that contains no points.
.PP
Example:
.PP
.nf
.br
        TQRegion r1( 10, 10, 20, 20 );
.br
        TQRegion r2( 40, 40, 20, 20 );
.br
        TQRegion 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
.br
.fi
.PP
See also isNull().
.SH "bool TQRegion::isNull () const"
Returns TRUE if the region is a null region; otherwise returns 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 TQRegion::operator!= ( const TQRegion & r ) const"
Returns TRUE if the region is different from \fIr\fR; otherwise returns FALSE.
.SH "const TQRegion TQRegion::operator& ( const TQRegion & r ) const"
Applies the intersect() function to this region and \fIr\fR. \fCr1&r2\fR is equivalent to \fCr1.intersect(r2)\fR
.PP
See also intersect().
.SH "TQRegion & TQRegion::operator&= ( const TQRegion & r )"
Applies the intersect() function to this region and \fIr\fR and assigns the result to this region. \fCr1&=r2\fR is equivalent to \fCr1=r1.intersect(r2)\fR
.PP
See also intersect().
.SH "const TQRegion TQRegion::operator+ ( const TQRegion & r ) const"
Applies the unite() function to this region and \fIr\fR. \fCr1+r2\fR is equivalent to \fCr1.unite(r2)\fR
.PP
See also unite() and operator|().
.SH "TQRegion & TQRegion::operator+= ( const TQRegion & r )"
Applies the unite() function to this region and \fIr\fR and assigns the result to this region. \fCr1+=r2\fR is equivalent to \fCr1=r1.unite(r2)\fR
.PP
See also intersect().
.SH "const TQRegion TQRegion::operator- ( const TQRegion & r ) const"
Applies the subtract() function to this region and \fIr\fR. \fCr1-r2\fR is equivalent to \fCr1.subtract(r2)\fR
.PP
See also subtract().
.SH "TQRegion & TQRegion::operator-= ( const TQRegion & r )"
Applies the subtract() function to this region and \fIr\fR and assigns the result to this region. \fCr1-=r2\fR is equivalent to \fCr1=r1.subtract(r2)\fR
.PP
See also subtract().
.SH "TQRegion & TQRegion::operator= ( const TQRegion & r )"
Assigns \fIr\fR to this region and returns a reference to the region.
.SH "bool TQRegion::operator== ( const TQRegion & r ) const"
Returns TRUE if the region is equal to \fIr\fR; otherwise returns FALSE.
.SH "const TQRegion TQRegion::operator^ ( const TQRegion & r ) const"
Applies the eor() function to this region and \fIr\fR. \fCr1^r2\fR is equivalent to \fCr1.eor(r2)\fR
.PP
See also eor().
.SH "TQRegion & TQRegion::operator^= ( const TQRegion & r )"
Applies the eor() function to this region and \fIr\fR and assigns the result to this region. \fCr1^=r2\fR is equivalent to \fCr1=r1.eor(r2)\fR
.PP
See also eor().
.SH "const TQRegion TQRegion::operator| ( const TQRegion & r ) const"
Applies the unite() function to this region and \fIr\fR. \fCr1|r2\fR is equivalent to \fCr1.unite(r2)\fR
.PP
See also unite() and operator+().
.SH "TQRegion & TQRegion::operator|= ( const TQRegion & r )"
Applies the unite() function to this region and \fIr\fR and assigns the result to this region. \fCr1|=r2\fR is equivalent to \fCr1=r1.unite(r2)\fR
.PP
See also unite().
.SH "TQMemArray<TQRect> TQRegion::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 "TQRegion TQRegion::subtract ( const TQRegion & r ) const"
Returns a region which is \fIr\fR subtracted from this region.
.PP
<center>
.ce 1
.B "[Image Omitted]"
.PP
</center>
.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 TQRegion::translate ( int dx, int dy )"
Translates (moves) the region \fIdx\fR along the X axis and \fIdy\fR along the Y axis.
.SH "TQRegion TQRegion::unite ( const TQRegion & r ) const"
Returns a region which is the union of this region and \fIr\fR.
.PP
<center>
.ce 1
.B "[Image Omitted]"
.PP
</center>
.PP
The figure shows the union of two elliptical regions.
.SH RELATED FUNCTION DOCUMENTATION
.SH "TQDataStream & operator<< ( TQDataStream & s, const TQRegion & r )"
Writes the region \fIr\fR to the stream \fIs\fR and returns a reference to the stream.
.PP
See also Format of the TQDataStream operators.
.SH "TQDataStream & operator>> ( TQDataStream & s, TQRegion & 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 TQDataStream operators.

.SH "SEE ALSO"
.BR http://doc.trolltech.com/tqregion.html
.BR http://www.trolltech.com/faq/tech.html
.SH COPYRIGHT
Copyright 1992-2007 Trolltech ASA, 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 help us to help you. Thank you.
.P
The definitive TQt documentation is provided in HTML format; it is
located at $TQTDIR/doc/html and can be read using TQt Assistant or with
a web browser. This man page is provided as a convenience for those
users who prefer man pages, although this format is not officially
supported by Trolltech. 
.P
If you find errors in this manual page, please report them to
.BR [email protected] .
Please include the name of the manual page (tqregion.3qt) and the Qt
version (3.3.8).