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< td align = "right" valign = "center" > < img src = "logo32.png" align = "right" width = "64" height = "32" border = "0" > < / td > < / tr > < / table > < h1 align = center > TQLayoutItem Class Reference< / h1 >
< p > The TQLayoutItem class provides an abstract item that a
TQLayout manipulates.
< a href = "#details" > More...< / a >
< p > < tt > #include < < a href = "tqlayout-h.html" > tqlayout.h< / a > > < / tt >
< p > Inherited by < a href = "tqlayout.html" > TQLayout< / a > , < a href = "tqspaceritem.html" > TQSpacerItem< / a > , and < a href = "tqwidgetitem.html" > TQWidgetItem< / a > .
< p > < a href = "tqlayoutitem-members.html" > List of all member functions.< / a >
< h2 > Public Members< / h2 >
< ul >
< li class = fn > < a href = "#TQLayoutItem" > < b > TQLayoutItem< / b > < / a > ( int alignment = 0 )< / li >
< li class = fn > virtual < a href = "#~TQLayoutItem" > < b > ~TQLayoutItem< / b > < / a > ()< / li >
< li class = fn > virtual TQSize < a href = "#sizeHint" > < b > sizeHint< / b > < / a > () const = 0< / li >
< li class = fn > virtual TQSize < a href = "#minimumSize" > < b > minimumSize< / b > < / a > () const = 0< / li >
< li class = fn > virtual TQSize < a href = "#maximumSize" > < b > maximumSize< / b > < / a > () const = 0< / li >
< li class = fn > virtual TQSizePolicy::ExpandData < a href = "#expanding" > < b > expanding< / b > < / a > () const = 0< / li >
< li class = fn > virtual void < a href = "#setGeometry" > < b > setGeometry< / b > < / a > ( const TQRect & r ) = 0< / li >
< li class = fn > virtual TQRect < a href = "#geometry" > < b > geometry< / b > < / a > () const = 0< / li >
< li class = fn > virtual bool < a href = "#isEmpty" > < b > isEmpty< / b > < / a > () const = 0< / li >
< li class = fn > virtual bool < a href = "#hasHeightForWidth" > < b > hasHeightForWidth< / b > < / a > () const< / li >
< li class = fn > virtual int < a href = "#heightForWidth" > < b > heightForWidth< / b > < / a > ( int w ) const< / li >
< li class = fn > virtual void < a href = "#invalidate" > < b > invalidate< / b > < / a > ()< / li >
< li class = fn > virtual TQWidget * < a href = "#widget" > < b > widget< / b > < / a > ()< / li >
< li class = fn > virtual TQLayoutIterator < a href = "#iterator" > < b > iterator< / b > < / a > ()< / li >
< li class = fn > virtual TQLayout * < a href = "#layout" > < b > layout< / b > < / a > ()< / li >
< li class = fn > virtual TQSpacerItem * < a href = "#spacerItem" > < b > spacerItem< / b > < / a > ()< / li >
< li class = fn > int < a href = "#alignment" > < b > alignment< / b > < / a > () const< / li >
< li class = fn > virtual void < a href = "#setAlignment" > < b > setAlignment< / b > < / a > ( int a )< / li >
< / ul >
< hr > < a name = "details" > < / a > < h2 > Detailed Description< / h2 >
The TQLayoutItem class provides an abstract item that a
< a href = "tqlayout.html" > TQLayout< / a > manipulates.
< p > This is used by custom layouts.
< p > Pure virtual functions are provided to return information about
the layout, including, < a href = "#sizeHint" > sizeHint< / a > (), < a href = "#minimumSize" > minimumSize< / a > (), < a href = "#maximumSize" > maximumSize< / a > ()
and < a href = "#expanding" > expanding< / a > ().
< p > The layout's geometry can be set and retrieved with < a href = "#setGeometry" > setGeometry< / a > ()
and < a href = "#geometry" > geometry< / a > (), and its alignment with < a href = "#setAlignment" > setAlignment< / a > () and
< a href = "#alignment" > alignment< / a > ().
< p > < a href = "#isEmpty" > isEmpty< / a > () returns whether the layout is empty. < a href = "#iterator" > iterator< / a > () returns
an iterator for the layout's children. If the concrete item is a
< a href = "tqwidget.html" > TQWidget< / a > , it can be retrieved using < a href = "#widget" > widget< / a > (). Similarly for
< a href = "#layout" > layout< / a > () and < a href = "#spacerItem" > spacerItem< / a > ().
< p > < p > See also < a href = "tqlayout.html" > TQLayout< / a > , < a href = "appearance.html" > Widget Appearance and Style< / a > , and < a href = "geomanagement.html" > Layout Management< / a > .
< hr > < h2 > Member Function Documentation< / h2 >
< h3 class = fn > < a name = "TQLayoutItem" > < / a > TQLayoutItem::TQLayoutItem ( int alignment = 0 )
< / h3 >
< p > Constructs a layout item with an < em > alignment< / em > that is a bitwise OR
of the < a href = "tqt.html#AlignmentFlags-enum" > TQt::AlignmentFlags< / a > . Not all subclasses support
alignment.
< h3 class = fn > < a name = "~TQLayoutItem" > < / a > TQLayoutItem::~TQLayoutItem ()< tt > [virtual]< / tt >
< / h3 >
Destroys the TQLayoutItem.
< h3 class = fn > int < a name = "alignment" > < / a > TQLayoutItem::alignment () const
< / h3 >
< p > Returns the alignment of this item.
< h3 class = fn > < a href = "tqsizepolicy.html#ExpandData-enum" > TQSizePolicy::ExpandData< / a > < a name = "expanding" > < / a > TQLayoutItem::expanding () const< tt > [pure virtual]< / tt >
< / h3 >
< p > Implemented in subclasses to return the direction(s) this item
"wants" to expand in (if any).
< p > Reimplemented in < a href = "tqlayout.html#expanding" > TQLayout< / a > , < a href = "tqspaceritem.html#expanding" > TQSpacerItem< / a > , and < a href = "tqwidgetitem.html#expanding" > TQWidgetItem< / a > .
< h3 class = fn > < a href = "tqrect.html" > TQRect< / a > < a name = "geometry" > < / a > TQLayoutItem::geometry () const< tt > [pure virtual]< / tt >
< / h3 >
< p > Returns the rectangle covered by this layout item.
< p > Example: < a href = "customlayout-example.html#x1495" > customlayout/border.cpp< / a > .
< h3 class = fn > bool < a name = "hasHeightForWidth" > < / a > TQLayoutItem::hasHeightForWidth () const< tt > [virtual]< / tt >
< / h3 >
Returns TRUE if this layout's preferred height depends on its
width; otherwise returns FALSE. The default implementation returns
FALSE.
< p > Reimplement this function in layout managers that support height
for width.
< p > < p > See also < a href = "#heightForWidth" > heightForWidth< / a > () and < a href = "tqwidget.html#heightForWidth" > TQWidget::heightForWidth< / a > ().
< p > Examples: < a href = "customlayout-example.html#x1496" > customlayout/border.cpp< / a > and < a href = "customlayout-example.html#x1472" > customlayout/flow.cpp< / a > .
< p > Reimplemented in < a href = "tqgridlayout.html#hasHeightForWidth" > TQGridLayout< / a > and < a href = "tqboxlayout.html#hasHeightForWidth" > TQBoxLayout< / a > .
< h3 class = fn > int < a name = "heightForWidth" > < / a > TQLayoutItem::heightForWidth ( int w ) const< tt > [virtual]< / tt >
< / h3 >
Returns the preferred height for this layout item, given the width
< em > w< / em > .
< p > The default implementation returns -1, indicating that the
preferred height is independent of the width of the item. Using
the function < a href = "#hasHeightForWidth" > hasHeightForWidth< / a > () will typically be much faster
than calling this function and testing for -1.
< p > Reimplement this function in layout managers that support height
for width. A typical implementation will look like this:
< pre >
int MyLayout::heightForWidth( int w ) const
{
if ( cache_dirty || cached_width != w ) {
// not all C++ compilers support "mutable"
MyLayout *that = (MyLayout*)this;
int h = calculateHeightForWidth( w );
that-> cached_hfw = h;
return h;
}
return cached_hfw;
}
< / pre >
< p > Caching is strongly recommended; without it layout will take
exponential time.
< p > < p > See also < a href = "#hasHeightForWidth" > hasHeightForWidth< / a > ().
< p > Example: < a href = "customlayout-example.html#x1473" > customlayout/flow.cpp< / a > .
< p > Reimplemented in < a href = "tqgridlayout.html#heightForWidth" > TQGridLayout< / a > and < a href = "tqboxlayout.html#heightForWidth" > TQBoxLayout< / a > .
< h3 class = fn > void < a name = "invalidate" > < / a > TQLayoutItem::invalidate ()< tt > [virtual]< / tt >
< / h3 >
Invalidates any cached information in this layout item.
< p > Reimplemented in < a href = "tqlayout.html#invalidate" > TQLayout< / a > .
< h3 class = fn > bool < a name = "isEmpty" > < / a > TQLayoutItem::isEmpty () const< tt > [pure virtual]< / tt >
< / h3 >
< p > Implemented in subclasses to return whether this item is empty,
i.e. whether it contains any widgets.
< p > Reimplemented in < a href = "tqlayout.html#isEmpty" > TQLayout< / a > , < a href = "tqspaceritem.html#isEmpty" > TQSpacerItem< / a > , and < a href = "tqwidgetitem.html#isEmpty" > TQWidgetItem< / a > .
< h3 class = fn > < a href = "tqlayoutiterator.html" > TQLayoutIterator< / a > < a name = "iterator" > < / a > TQLayoutItem::iterator ()< tt > [virtual]< / tt >
< / h3 >
Returns an iterator over this item's TQLayoutItem children. The
default implementation returns an empty iterator.
< p > Reimplement this function in subclasses that can have children.
< p > Reimplemented in < a href = "tqlayout.html#iterator" > TQLayout< / a > .
< h3 class = fn > < a href = "tqlayout.html" > TQLayout< / a > * < a name = "layout" > < / a > TQLayoutItem::layout ()< tt > [virtual]< / tt >
< / h3 >
If this item is a < a href = "tqlayout.html" > TQLayout< / a > , it is returned as a TQLayout; otherwise
0 is returned. This function provides type-safe casting.
< h3 class = fn > < a href = "tqsize.html" > TQSize< / a > < a name = "maximumSize" > < / a > TQLayoutItem::maximumSize () const< tt > [pure virtual]< / tt >
< / h3 >
< p > Implemented in subclasses to return the maximum size of this item.
< p > Reimplemented in < a href = "tqlayout.html#maximumSize" > TQLayout< / a > , < a href = "tqspaceritem.html#maximumSize" > TQSpacerItem< / a > , and < a href = "tqwidgetitem.html#maximumSize" > TQWidgetItem< / a > .
< h3 class = fn > < a href = "tqsize.html" > TQSize< / a > < a name = "minimumSize" > < / a > TQLayoutItem::minimumSize () const< tt > [pure virtual]< / tt >
< / h3 >
< p > Implemented in subclasses to return the minimum size of this item.
< p > Examples: < a href = "customlayout-example.html#x1497" > customlayout/border.cpp< / a > , < a href = "customlayout-example.html#x1515" > customlayout/card.cpp< / a > , and < a href = "customlayout-example.html#x1474" > customlayout/flow.cpp< / a > .
< p > Reimplemented in < a href = "tqlayout.html#minimumSize" > TQLayout< / a > , < a href = "tqspaceritem.html#minimumSize" > TQSpacerItem< / a > , and < a href = "tqwidgetitem.html#minimumSize" > TQWidgetItem< / a > .
< h3 class = fn > void < a name = "setAlignment" > < / a > TQLayoutItem::setAlignment ( int a )< tt > [virtual]< / tt >
< / h3 >
Sets the alignment of this item to < em > a< / em > , which is a bitwise OR of
the < a href = "tqt.html#AlignmentFlags-enum" > TQt::AlignmentFlags< / a > . Not all subclasses support alignment.
< p > Example: < a href = "tutorial2-09.html#x2644" > chart/optionsform.cpp< / a > .
< h3 class = fn > void < a name = "setGeometry" > < / a > TQLayoutItem::setGeometry ( const < a href = "tqrect.html" > TQRect< / a > & r )< tt > [pure virtual]< / tt >
< / h3 >
< p > Implemented in subclasses to set this item's geometry to < em > r< / em > .
< p > Examples: < a href = "customlayout-example.html#x1498" > customlayout/border.cpp< / a > , < a href = "customlayout-example.html#x1516" > customlayout/card.cpp< / a > , and < a href = "customlayout-example.html#x1475" > customlayout/flow.cpp< / a > .
< p > Reimplemented in < a href = "tqlayout.html#setGeometry" > TQLayout< / a > , < a href = "tqspaceritem.html#setGeometry" > TQSpacerItem< / a > , and < a href = "tqwidgetitem.html#setGeometry" > TQWidgetItem< / a > .
< h3 class = fn > < a href = "tqsize.html" > TQSize< / a > < a name = "sizeHint" > < / a > TQLayoutItem::sizeHint () const< tt > [pure virtual]< / tt >
< / h3 >
< p > Implemented in subclasses to return the preferred size of this item.
< p > Examples: < a href = "customlayout-example.html#x1499" > customlayout/border.cpp< / a > , < a href = "customlayout-example.html#x1517" > customlayout/card.cpp< / a > , and < a href = "customlayout-example.html#x1476" > customlayout/flow.cpp< / a > .
< p > Reimplemented in < a href = "tqspaceritem.html#sizeHint" > TQSpacerItem< / a > , < a href = "tqwidgetitem.html#sizeHint" > TQWidgetItem< / a > , < a href = "tqgridlayout.html#sizeHint" > TQGridLayout< / a > , and < a href = "tqboxlayout.html#sizeHint" > TQBoxLayout< / a > .
< h3 class = fn > < a href = "tqspaceritem.html" > TQSpacerItem< / a > * < a name = "spacerItem" > < / a > TQLayoutItem::spacerItem ()< tt > [virtual]< / tt >
< / h3 >
If this item is a < a href = "tqspaceritem.html" > TQSpacerItem< / a > , it is returned as a TQSpacerItem;
otherwise 0 is returned. This function provides type-safe casting.
< h3 class = fn > < a href = "tqwidget.html" > TQWidget< / a > * < a name = "widget" > < / a > TQLayoutItem::widget ()< tt > [virtual]< / tt >
< / h3 >
If this item is a < a href = "tqwidget.html" > TQWidget< / a > , it is returned as a TQWidget; otherwise
0 is returned. This function provides type-safe casting.
< p > Reimplemented in < a href = "tqwidgetitem.html#widget" > TQWidgetItem< / a > .
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