qlayoutitem.3qt

tmark1.11:用于生成QT/EMBEDDED应用工程的Markfile文件

.TH QLayoutItem 3qt "6 July 1999" "Troll Tech AS" \" -*- nroff -*-
.\" Copyright 1992-1999 Troll Tech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QLayoutItem \- The abstract items which a QLayout manipulates
.SH SYNOPSIS
.br
.PP
\fC#include <qabstractlayout.h>\fR
.PP
Inherited by QLayout, QSpacerItem and QWidgetItem.
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "\fBQLayoutItem\fR ( int " "alignment" " = 0 )"
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.BI "virtual \fB~QLayoutItem\fR ()"
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.BI "virtual QSize \fBsizeHint\fR () const"
.br
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.BI "virtual QSize \fBminimumSize\fR () const"
.br
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.BI "virtual QSize \fBmaximumSize\fR () const"
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.BI "virtual QSizePolicy::ExpandData \fBexpanding\fR () const"
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.BI "virtual void \fBsetGeometry\fR ( const QRect & )"
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.BI "virtual QRect \fBgeometry\fR () const"
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.BI "virtual bool \fBisEmpty\fR () const"
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.BI "virtual bool \fBhasHeightForWidth\fR () const"
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.BI "virtual int \fBheightForWidth\fR ( int ) const"
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.BI "virtual void \fBinvalidate\fR ()"
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.BI "virtual QWidget* \fBwidget\fR ()"
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.BI "virtual QLayoutIterator \fBiterator\fR ()"
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.BI "virtual QLayout* \fBlayout\fR ()"
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.BI "virtual QSpacerItem* \fBspacerItem\fR ()"
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.BI "int \fBalignment\fR () const"
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.BI "virtual void \fBsetAlignment\fR ( int a )"
.br
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.SH DESCRIPTION
The abstract items which a QLayout manipulates.
.PP
For custom layouts.
.PP
See also: QLayout.
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QLayoutItem::QLayoutItem ( int alignment = 0 )"
Constructs a layout item with alignment \fIalignment.\fR Alignment may not be supported by all subclasses.
.SH "QLayoutItem::~QLayoutItem () \fC[virtual]\fR"
Destructs the QLayoutItem.
.SH "int QLayoutItem::alignment () const"
Returns the alignment of this item.
.SH "QSizePolicy::ExpandData QLayoutItem::expanding() const \fC[virtual]\fR"
Implemented in subclasses to return whether this item "wants" to expand.
.PP
Reimplemented in QWidgetItem, QBoxLayout, QGridLayout, QSpacerItem and QLayout.
.SH "QRect QLayoutItem::geometry () const \fC[virtual]\fR"
Returns the rectangle covered by this layout item.
.PP
Reimplemented in QWidgetItem, QLayout and QSpacerItem.
.SH "bool QLayoutItem::hasHeightForWidth () const \fC[virtual]\fR"
Returns TRUE if this layout's preferred height depends on its width. The default implementation returns FALSE;
.PP
Reimplement this function in layout managers that support height for width.
.PP
See also: heightForWidth() and QWidget::heightForWidth().
.PP
Reimplemented in QBoxLayout, QGridLayout and QWidgetItem.
.SH "int QLayoutItem::heightForWidth ( int ) const \fC[virtual]\fR"
Returns the preferred height for this layout item, given the width \fIw.\fR
.PP
The default implementation returns -1, indicating that the preferred height is independent of the width of the item. Using the function hasHeightForWidth() will typically be much faster than calling this function and testing for -1.
.PP
Reimplement this function in layout managers that support height for width. A typical implementation will look like this:
.PP
.nf
.br
  int MyLayout::heightForWidth( int w ) const
.br
  {
.br
      if ( cache_dirty || cached_width != w ) {
.br
          //Not all C++ compilers support "mutable" yet:
.br
          MyLayout * mthis = (MyLayout*)this;
.br
          int h = calculateHeightForWidth( w );
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          mthis->cached_hfw = h;
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          return h;
.br
      }
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      return cached_hfw;
.br
  }
.fi
.PP
Caching is strongly recommended, without it layout will take exponential time.
.PP
See also: hasHeightForWidth().
.PP
Reimplemented in QWidgetItem, QBoxLayout and QGridLayout.
.SH "void QLayoutItem::invalidate () \fC[virtual]\fR"
Invalidates any cached information in this layout item.
.PP
Reimplemented in QBoxLayout and QGridLayout.
.SH "virtual bool QLayoutItem::isEmpty () const \fC[virtual]\fR"
Implemented in subclasses to return whether this item is empty, i.e. whether it contains any widgets.
.PP
Reimplemented in QWidgetItem, QSpacerItem and QLayout.
.SH "QLayoutIterator QLayoutItem::iterator () \fC[virtual]\fR"
Returns an iterator over this item's QLayoutItem children. The default implementation returns an empty iterator.
.PP
Reimplement this function in subclasses that can have children.
.PP
Reimplemented in QGridLayout and QBoxLayout.
.SH "QLayout * QLayoutItem::layout () \fC[virtual]\fR"
If this item is a QLayout, return it as a QLayout, otherwise return 0. This function provides type-safe casting.
.PP
Reimplemented in QLayout.
.SH "QSize QLayoutItem::maximumSize () const \fC[virtual]\fR"
Implemented in subclasses to return the maximum size of this item.
.PP
Reimplemented in QBoxLayout, QLayout, QSpacerItem, QGridLayout and QWidgetItem.
.SH "QSize QLayoutItem::minimumSize () const \fC[virtual]\fR"
Implemented in subclasses to return the minimum size of this item.
.PP
Reimplemented in QSpacerItem, QLayout, QWidgetItem, QGridLayout and QBoxLayout.
.SH "void QLayoutItem::setAlignment ( int a ) \fC[virtual]\fR"
Sets the alignment of this item to \fIa.\fR
.SH "void QLayoutItem::setGeometry ( const QRect & r ) \fC[virtual]\fR"
Implemented in subclasses to set this item's geometry to \fIr.\fR
.PP
Reimplemented in QLayout, QSpacerItem, QWidgetItem, QBoxLayout and QGridLayout.
.SH "QSize QLayoutItem::sizeHint () const \fC[virtual]\fR"
Implemented in subclasses to return the preferred size of this item.
.PP
Reimplemented in QSpacerItem and QWidgetItem.
.SH "QSpacerItem * QLayoutItem::spacerItem () \fC[virtual]\fR"
If this item is a QSpacerItem, return it as a QSpacerItem, otherwise return 0. This function provides type-safe casting.
.PP
Reimplemented in QSpacerItem.
.SH "QWidget * QLayoutItem::widget () \fC[virtual]\fR"
If this item is a QWidgetItem, the managed widget is returned.
The default implementation returns 0;.
.SH "SEE ALSO"
.BR http://www.troll.no/qt/qlayoutitem.html
.SH COPYRIGHT
Copyright 1992-1999 Troll Tech AS.  See the license file included in
the distribution for a complete license statement.
.SH AUTHOR
Generated automatically from the source code.