Detailed Description
The QIconSet class provides a set of icons with different
styles and sizes.
A QIconSet can generate smaller, larger, active, and disabled pixmaps
from the set of icons it is given. Such pixmaps are used by
QToolButton, QHeader, QPopupMenu, etc. to show an icon representing a
particular action.
The simplest use of QIconSet is to create one from a QPixmap and then
use it, allowing Qt to work out all the required icon styles and
sizes. For example:
QToolButton *but = new QToolButton( QIconSet( QPixmap("open.xpm") ), ... );
Using whichever pixmaps you specify as a base, QIconSet provides a
set of six icons, each with a Size and a Mode: Small Normal,
Small Disabled, Small Active, Large Normal, Large Disabled, and
Large Active.
An additional set of six icons can be provided for widgets that have
an "On" or "Off" state, like checkable menu items or toggleable
toolbuttons. If you provide pixmaps for the "On" state, but not for
the "Off" state, the QIconSet will provide the "Off" pixmaps. You may
specify icons for both states in you wish.
You can set any of the icons using setPixmap().
When you retrieve a pixmap using pixmap(Size, Mode, State),
QIconSet will return the icon that has been set or previously
generated for that size, mode and state combination. If none is
available, QIconSet will ask the icon factory. If the icon factory
cannot provide any (the default), QIconSet generates a pixmap based
on the pixmaps it has been given and returns it.
The Disabled appearance is computed using an algorithm that
produces results very similar to those used in Microsoft Windows
95. The Active appearance is identical to the Normal
appearance unless you use setPixmap() to set it to something
special.
When scaling icons, QIconSet uses smooth scaling, which can partially blend the color component
of pixmaps. If the results look poor, the best solution
is to supply pixmaps in both large and small sizes.
You can use the static function setIconSize() to set the preferred
size of the generated large/small icons. The default small size is
22 x 22, while the default large size is 32 x 32. These sizes only
affect generated icons.
The isGenerated() function returns TRUE if an icon was generated by
QIconSet or by a factory; clearGenerated() clears all cached
pixmaps.
Making Classes that Use QIconSet
If you write your own widgets that have an option to set a small
pixmap, consider allowing a QIconSet to be set for that pixmap. The
Qt class QToolButton is an example of such a widget.
Provide a method to set a QIconSet, and when you draw the icon, choose
whichever icon is appropriate for the current state of your widget.
For example:
void MyWidget::drawIcon( QPainter* p, QPoint pos )
{
p->drawPixmap( pos, icons->pixmap(
QIconSet::Small,
isEnabled() ? QIconSet::Normal :
QIconSet::Disabled,
isEnabled() ? QIconSet::On :
QIconSet::Off));
}
You might also make use of the Active mode, perhaps making your
widget Active when the mouse is over the widget (see QWidget::enterEvent()), while the mouse is pressed pending the
release that will activate the function, or when it is the currently
selected item. If the widget can be toggled, the "On" mode might be
used to draw a different icon.
See also QIconFactory, QPixmap, QMainWindow::usesBigPixmaps, GUI Design Handbook: Iconic Label, Graphics Classes, Image Processing Classes, and Implicitly and Explicitly Shared Classes.
Member Type Documentation
QIconSet::Mode
This enum type describes the mode for which a pixmap is intended to be
used.
The currently defined modes are:
- QIconSet::Normal -
Display the pixmap when the user is
not interacting with the icon, but the
functionality represented by the icon is available.
- QIconSet::Disabled -
Display the pixmap when the
functionality represented by the icon is not available.
- QIconSet::Active -
Display the pixmap when the
functionality represented by the icon is available and
the user is interacting with the icon, for example, moving the
mouse over it or clicking it.
QIconSet::Size
This enum type describes the size at which a pixmap is intended to be
used.
The currently defined sizes are:
- QIconSet::Automatic - The size of the pixmap is determined from its
pixel size. This is a useful default.
- QIconSet::Small - The pixmap is the smaller of two.
- QIconSet::Large - The pixmap is the larger of two.
If a Small pixmap is not set by QIconSet::setPixmap(), the Large
pixmap will be automatically scaled down to the size of a small pixmap
to generate the Small pixmap when required. Similarly, a Small pixmap
will be automatically scaled up to generate a Large pixmap. The
preferred sizes for large/small generated icons can be set using
setIconSize().
See also setIconSize(), iconSize(), setPixmap(), pixmap(), and QMainWindow::usesBigPixmaps.
QIconSet::State
This enum describes the state for which a pixmap is intended to be
used. The state can be:
- QIconSet::Off - Display the pixmap when the widget is in an "off" state
- QIconSet::On - Display the pixmap when the widget is in an "on" state
See also setPixmap() and pixmap().
Member Function Documentation
QIconSet::QIconSet ()
Constructs a null icon set.
See also setPixmap() and reset().
QIconSet::QIconSet ( const QPixmap & pixmap, Size size = Automatic )
Constructs an icon set for which the Normal pixmap is pixmap,
which is assumed to be of size size.
The default for size is Automatic, which means that QIconSet
will determine whether the pixmap is Small or Large from its pixel
size. Pixmaps less than the width of a small generated icon are
considered to be Small. You can use setIconSize() to set the
preferred size of a generated icon.
See also setIconSize() and reset().
QIconSet::QIconSet ( const QPixmap & smallPix, const QPixmap & largePix )
Creates an iconset which uses the pixmap smallPix for for
displaying a small icon, and the pixmap largePix for displaying a
large icon.
QIconSet::QIconSet ( const QIconSet & other )
Constructs a copy of other. This is very fast.
QIconSet::~QIconSet () [virtual]
Destroys the icon set and frees any allocated resources.
void QIconSet::clearGenerated ()
Clears all cached pixmaps, including those obtained from an
eventual QIconFactory.
void QIconSet::detach ()
Detaches this icon set from others with which it may share data.
You will never need to call this function; other QIconSet functions
call it as necessary.
const QSize & QIconSet::iconSize ( Size which ) [static]
If which is Small, returns the preferred size of a small
generated icon; if which is Large, returns the preferred size
of a large generated icon.
See also setIconSize().
void QIconSet::installIconFactory ( QIconFactory * factory )
Installs factory as the icon factory for this iconset. The
icon factory is used to generates pixmaps not set by the user.
If no icon factory is installed, QIconFactory::defaultFactory()
is used.
bool QIconSet::isGenerated ( Size size, Mode mode, State state = Off ) const
Returns TRUE if the pixmap with size size, mode mode and
state state is generated from other pixmaps; otherwise returns
FALSE.
A pixmap obtained from a QIconFactory is considered non-generated.
bool QIconSet::isNull () const
Returns TRUE if the icon set is empty; otherwise returns FALSE.
QIconSet & QIconSet::operator= ( const QIconSet & other )
Assigns other to this icon set and returns a reference to this
icon set.
See also detach().
QPixmap QIconSet::pixmap ( Size size, Mode mode, State state = Off ) const
Returns a pixmap with size size, mode mode and state state, generating one if necessary. Generated pixmaps are cached.
QPixmap QIconSet::pixmap ( Size size, bool enabled, State state = Off ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.
This is the same as pixmap(size, enabled, state).
QPixmap QIconSet::pixmap () const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns the pixmap originally provided to the constructor or to
reset(). This is the Normal pixmap of unspecified Size.
See also reset().
void QIconSet::reset ( const QPixmap & pixmap, Size size )
Sets this icon set to use pixmap pixmap for the Normal pixmap,
assuming it to be of size size.
This is equivalent to assigning QIconSet(pixmap, size) to this
icon set.
This function does nothing if pixmap is a null pixmap.
void QIconSet::setIconSize ( Size which, const QSize & size ) [static]
Set the preferred size for all small or large icons that are
generated after this call. If which is Small, sets the preferred
size of small generated icons to size. Similarly, if which is
Large, sets the preferred size of large generated icons to size.
Note that cached icons will not be regenerated, so it is recommended
that you set the preferred icon sizes before generating any icon sets.
Also note that the preferred icon sizes will be ignored for icon sets
that have been created using both small and large pixmaps.
See also iconSize().
void QIconSet::setPixmap ( const QPixmap & pixmap, Size size, Mode mode = Normal, State state = Off ) [virtual]
Sets this icon set to provide pixmap pixmap for size size, mode mode and state state. The icon set may also use pixmap for
generating other pixmaps if they are not explicitly set.
The size can be one of Automatic, Large or Small. If Automatic is
used, QIconSet will determine if the pixmap is Small or Large from its
pixel size.
Pixmaps less than the width of a small generated icon are
considered to be Small. You can use setIconSize() to set the preferred
size of a generated icon.
This function does nothing if pixmap is a null pixmap.
See also reset().
void QIconSet::setPixmap ( const QString & fileName, Size size, Mode mode = Normal, State state = Off ) [virtual]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
The pixmap is loaded from fileName when it becomes necessary.
This file is part of the Qt toolkit.
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