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227 lines
8.0 KiB
227 lines
8.0 KiB
'\" t
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.TH TQLayoutItem 3qt "2 February 2007" "Trolltech AS" \" -*- nroff -*-
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.\" Copyright 1992-2007 Trolltech ASA. All rights reserved. See the
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.\" license file included in the distribution for a complete license
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.\" statement.
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.\"
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.ad l
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.nh
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.SH NAME
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TQLayoutItem \- Abstract item that a TQLayout manipulates
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.SH SYNOPSIS
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\fC#include <tqlayout.h>\fR
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.PP
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Inherited by TQLayout, TQSpacerItem, and TQWidgetItem.
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.PP
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.SS "Public Members"
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.in +1c
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.ti -1c
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.BI "\fBTQLayoutItem\fR ( int alignment = 0 )"
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.br
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.ti -1c
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.BI "virtual \fB~TQLayoutItem\fR ()"
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.br
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.ti -1c
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.BI "virtual TQSize \fBsizeHint\fR () const = 0"
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.br
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.ti -1c
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.BI "virtual TQSize \fBminimumSize\fR () const = 0"
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.br
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.ti -1c
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.BI "virtual TQSize \fBmaximumSize\fR () const = 0"
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.br
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.ti -1c
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.BI "virtual TQSizePolicy::ExpandData \fBexpanding\fR () const = 0"
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.br
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.ti -1c
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.BI "virtual void \fBsetGeometry\fR ( const TQRect & r ) = 0"
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.br
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.ti -1c
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.BI "virtual TQRect \fBgeometry\fR () const = 0"
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.br
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.ti -1c
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.BI "virtual bool \fBisEmpty\fR () const = 0"
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.br
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.ti -1c
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.BI "virtual bool \fBhasHeightForWidth\fR () const"
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.br
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.ti -1c
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.BI "virtual int \fBheightForWidth\fR ( int w ) const"
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.br
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.ti -1c
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.BI "virtual void \fBinvalidate\fR ()"
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.br
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.ti -1c
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.BI "virtual TQWidget * \fBwidget\fR ()"
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.br
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.ti -1c
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.BI "virtual TQLayoutIterator \fBiterator\fR ()"
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.br
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.ti -1c
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.BI "virtual TQLayout * \fBlayout\fR ()"
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.br
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.ti -1c
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.BI "virtual TQSpacerItem * \fBspacerItem\fR ()"
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.br
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.ti -1c
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.BI "int \fBalignment\fR () const"
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.br
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.ti -1c
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.BI "virtual void \fBsetAlignment\fR ( int a )"
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.br
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.in -1c
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.SH DESCRIPTION
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The TQLayoutItem class provides an abstract item that a TQLayout manipulates.
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.PP
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This is used by custom layouts.
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.PP
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Pure virtual functions are provided to return information about the layout, including, sizeHint(), minimumSize(), maximumSize() and expanding().
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.PP
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The layout's geometry can be set and retrieved with setGeometry() and geometry(), and its alignment with setAlignment() and alignment().
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.PP
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isEmpty() returns whether the layout is empty. iterator() returns an iterator for the layout's children. If the concrete item is a TQWidget, it can be retrieved using widget(). Similarly for layout() and spacerItem().
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.PP
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See also TQLayout, Widget Appearance and Style, and Layout Management.
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.SH MEMBER FUNCTION DOCUMENTATION
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.SH "TQLayoutItem::TQLayoutItem ( int alignment = 0 )"
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Constructs a layout item with an \fIalignment\fR that is a bitwise OR of the TQt::AlignmentFlags. Not all subclasses support alignment.
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.SH "TQLayoutItem::~TQLayoutItem ()\fC [virtual]\fR"
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Destroys the TQLayoutItem.
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.SH "int TQLayoutItem::alignment () const"
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Returns the alignment of this item.
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.SH "TQSizePolicy::ExpandData TQLayoutItem::expanding () const\fC [pure virtual]\fR"
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Implemented in subclasses to return the direction(s) this item" wants" to expand in (if any).
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.PP
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Reimplemented in TQLayout, TQSpacerItem, and TQWidgetItem.
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.SH "TQRect TQLayoutItem::geometry () const\fC [pure virtual]\fR"
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Returns the rectangle covered by this layout item.
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.PP
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Example: customlayout/border.cpp.
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.SH "bool TQLayoutItem::hasHeightForWidth () const\fC [virtual]\fR"
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Returns TRUE if this layout's preferred height depends on its width; otherwise returns FALSE. The default implementation returns FALSE.
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.PP
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Reimplement this function in layout managers that support height for width.
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.PP
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See also heightForWidth() and TQWidget::heightForWidth().
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.PP
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Examples:
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.)l customlayout/border.cpp and customlayout/flow.cpp.
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.PP
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Reimplemented in TQGridLayout and TQBoxLayout.
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.SH "int TQLayoutItem::heightForWidth ( int w ) const\fC [virtual]\fR"
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Returns the preferred height for this layout item, given the width \fIw\fR.
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.PP
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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.
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.PP
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Reimplement this function in layout managers that support height for width. A typical implementation will look like this:
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.PP
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.nf
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.br
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int MyLayout::heightForWidth( int w ) const
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.br
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{
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.br
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if ( cache_dirty || cached_width != w ) {
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.br
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// not all C++ compilers support "mutable"
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.br
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MyLayout *that = (MyLayout*)this;
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.br
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int h = calculateHeightForWidth( w );
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.br
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that->cached_hfw = h;
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.br
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return h;
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.br
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}
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.br
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return cached_hfw;
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.br
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}
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.br
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.fi
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.PP
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Caching is strongly recommended; without it layout will take exponential time.
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.PP
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See also hasHeightForWidth().
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.PP
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Example: customlayout/flow.cpp.
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.PP
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Reimplemented in TQGridLayout and TQBoxLayout.
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.SH "void TQLayoutItem::invalidate ()\fC [virtual]\fR"
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Invalidates any cached information in this layout item.
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.PP
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Reimplemented in TQLayout.
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.SH "bool TQLayoutItem::isEmpty () const\fC [pure virtual]\fR"
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Implemented in subclasses to return whether this item is empty, i.e. whether it contains any widgets.
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.PP
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Reimplemented in TQLayout, TQSpacerItem, and TQWidgetItem.
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.SH "TQLayoutIterator TQLayoutItem::iterator ()\fC [virtual]\fR"
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Returns an iterator over this item's TQLayoutItem children. The default implementation returns an empty iterator.
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.PP
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Reimplement this function in subclasses that can have children.
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.PP
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Reimplemented in TQLayout.
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.SH "TQLayout * TQLayoutItem::layout ()\fC [virtual]\fR"
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If this item is a TQLayout, it is returned as a TQLayout; otherwise 0 is returned. This function provides type-safe casting.
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.SH "TQSize TQLayoutItem::maximumSize () const\fC [pure virtual]\fR"
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Implemented in subclasses to return the maximum size of this item.
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.PP
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Reimplemented in TQLayout, TQSpacerItem, and TQWidgetItem.
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.SH "TQSize TQLayoutItem::minimumSize () const\fC [pure virtual]\fR"
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Implemented in subclasses to return the minimum size of this item.
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.PP
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Examples:
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.)l customlayout/border.cpp, customlayout/card.cpp, and customlayout/flow.cpp.
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.PP
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Reimplemented in TQLayout, TQSpacerItem, and TQWidgetItem.
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.SH "void TQLayoutItem::setAlignment ( int a )\fC [virtual]\fR"
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Sets the alignment of this item to \fIa\fR, which is a bitwise OR of the TQt::AlignmentFlags. Not all subclasses support alignment.
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.PP
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Example: chart/optionsform.cpp.
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.SH "void TQLayoutItem::setGeometry ( const TQRect & r )\fC [pure virtual]\fR"
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Implemented in subclasses to set this item's geometry to \fIr\fR.
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.PP
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Examples:
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.)l customlayout/border.cpp, customlayout/card.cpp, and customlayout/flow.cpp.
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.PP
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Reimplemented in TQLayout, TQSpacerItem, and TQWidgetItem.
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.SH "TQSize TQLayoutItem::sizeHint () const\fC [pure virtual]\fR"
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Implemented in subclasses to return the preferred size of this item.
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.PP
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Examples:
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.)l customlayout/border.cpp, customlayout/card.cpp, and customlayout/flow.cpp.
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.PP
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Reimplemented in TQSpacerItem, TQWidgetItem, TQGridLayout, and TQBoxLayout.
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.SH "TQSpacerItem * TQLayoutItem::spacerItem ()\fC [virtual]\fR"
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If this item is a TQSpacerItem, it is returned as a TQSpacerItem; otherwise 0 is returned. This function provides type-safe casting.
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.SH "TQWidget * TQLayoutItem::widget ()\fC [virtual]\fR"
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If this item is a TQWidget, it is returned as a TQWidget; otherwise 0 is returned. This function provides type-safe casting.
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.PP
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Reimplemented in TQWidgetItem.
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.SH "SEE ALSO"
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.BR http://doc.trolltech.com/tqlayoutitem.html
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.BR http://www.trolltech.com/faq/tech.html
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.SH COPYRIGHT
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Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
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license file included in the distribution for a complete license
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statement.
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.SH AUTHOR
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Generated automatically from the source code.
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.SH BUGS
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If you find a bug in Qt, please report it as described in
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.BR http://doc.trolltech.com/bughowto.html .
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Good bug reports help us to help you. Thank you.
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.P
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The definitive TQt documentation is provided in HTML format; it is
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located at $TQTDIR/doc/html and can be read using TQt Assistant or with
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a web browser. This man page is provided as a convenience for those
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users who prefer man pages, although this format is not officially
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supported by Trolltech.
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.P
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If you find errors in this manual page, please report them to
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.BR qt-bugs@trolltech.com .
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Please include the name of the manual page (tqlayoutitem.3qt) and the Qt
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version (3.3.8).
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