QPalette Class Reference
^{[QtGui module]}

Detailed Description

The QPalette class contains color groups for each widget state.

A palette consists of three color groups: Active, Disabled, and Inactive. All widgets in Qt contain a palette and use their palette to draw themselves. This makes the user interface easily configurable and easier to keep consistent.

If you create a new widget we strongly recommend that you use the colors in the palette rather than hard-coding specific colors.

The color groups:

• The Active group is used for the window that has keyboard focus.
• The Inactive group is used for other windows.
• The Disabled group is used for widgets (not windows) that are disabled for some reason.

Both active and inactive windows can contain disabled widgets. (Disabled widgets are often called inaccessible or grayed out.)

In most styles, Active and Inactive look the same.

Colors and brushes can be set for particular roles in any of a palette's color groups with setColor() and setBrush(). A color group contains a group of colors used by widgets for drawing themselves. We recommend that widgets use color group roles from the palette such as "foreground" and "base" rather than literal colors like "red" or "turquoise". The color roles are enumerated and defined in the ColorRole documentation.

We strongly recommend that you use a system-supplied color group and modify that as necessary.

To modify a color group you call the functions setColor() and setBrush(), depending on whether you want a pure color or a pixmap pattern.

There are also corresponding color() and brush() getters, and a commonly used convenience function to get the ColorRole for the current ColorGroup: background(), foreground(), base(), etc.

You can copy a palette using the copy constructor and test to see if two palettes are identical using isCopyOf().

QPalette is optimized by the use of implicit sharing, so it is very efficient to pass QPalette objects as arguments.

See also QApplication::setPalette(), QWidget::setPalette(), and QColor.

Member Type Documentation

enum QPalette::ColorGroup

enum QPalette::ColorRole

The ColorRole enum defines the different symbolic color roles used in current GUIs.

The central roles are:

There are some color roles used mostly for 3D bevel and shadow effects. All of these are normally derived from Background, and used in ways that depend on that relationship. For example, buttons depend on it to make the bevels look attractive, and Motif scroll bars depend on Mid to be slightly different from Background.

Selected (marked) items have two roles:

Finally, there is a special role for text that needs to be drawn where Text or Foreground would give poor contrast, such as on pressed push buttons. Note that text colors can be used for things other than just words; text colors are usually used for text, but it's quite common to use the text color roles for lines, icons, etc.

This image shows most of the color roles in use:

Member Function Documentation

QPalette::QPalette ()

Constructs a palette object that uses the application's default palette.

See also QApplication::setPalette() and QApplication::palette().

QPalette::QPalette ( const QColor & button )

Constructs a palette from the button color. The other colors are automatically calculated, based on this color. Background will be the button color as well.

QPalette::QPalette ( Qt::GlobalColor button )

Constructs a palette from the button color. The other colors are automatically calculated, based on this color. Background will be the button color as well.

QPalette::QPalette ( const QColor & button, const QColor & background )

Constructs a palette from a button color and a background. The other colors are automatically calculated, based on these colors.

QPalette::QPalette ( const QBrush & foreground, const QBrush & button, const QBrush & light, const QBrush & dark, const QBrush & mid, const QBrush & text, const QBrush & bright_text, const QBrush & base, const QBrush & background )

Constructs a palette. You can pass either brushes, pixmaps or plain colors for foreground, button, light, dark, mid, text, bright_text, base and background.

See also QBrush.

QPalette::QPalette ( const QPalette & p )

Constructs a copy of p.

This constructor is fast because of implicit sharing.

QPalette::~QPalette ()

Destroys the palette.

const QBrush & QPalette::alternateBase () const

Returns the alternate base brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::background () const

Returns the background brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::base () const

Returns the base brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::brightText () const

Returns the bright text foreground brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::brush ( ColorGroup gr, ColorRole cr ) const

Returns the brush in color group gr, used for color role cr.

See also color(), setBrush(), and ColorRole.

const QBrush & QPalette::brush ( ColorRole r ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns the brush that has been set for color role r in the current ColorGroup.

See also color(), setBrush(), and ColorRole.

const QBrush & QPalette::button () const

Returns the button brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::buttonText () const

Returns the button text foreground brush of the current color group.

See also ColorRole and brush().

const QColor & QPalette::color ( ColorGroup gr, ColorRole r ) const

Returns the color in color group gr, used for color role r.

See also brush(), setColor(), and ColorRole.

const QColor & QPalette::color ( ColorRole r ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Returns the color that has been set for color role r in the current ColorGroup.

See also brush() and ColorRole.

ColorGroup QPalette::currentColorGroup () const

Returns the palette's current color group.

See also setCurrentColorGroup().

const QBrush & QPalette::dark () const

Returns the dark brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::foreground () const

Returns the foreground brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::highlight () const

Returns the highlight brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::highlightedText () const

Returns the highlighted text brush of the current color group.

See also ColorRole and brush().

bool QPalette::isCopyOf ( const QPalette & p ) const

Returns true if this palette and p are copies of each other, i.e. one of them was created as a copy of the other and neither was subsequently modified; otherwise returns false. This is much stricter than equality.

See also operator=() and operator==().

bool QPalette::isEqual ( ColorGroup cg1, ColorGroup cg2 ) const

Returns true (usually quickly) if color group cg1 is equal to cg2; otherwise returns false.

const QBrush & QPalette::light () const

Returns the light brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::link () const

Returns the unvisited link text brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::linkVisited () const

Returns the visited link text brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::mid () const

Returns the mid brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::midlight () const

Returns the midlight brush of the current color group.

See also ColorRole and brush().

QPalette QPalette::resolve ( const QPalette & other ) const

Returns a new QPalette that has attributes copied from other.

int QPalette::serialNumber () const

Returns a number that uniquely identifies this QPalette object. The serial number is intended for caching. Its value may not be used for anything other than equality testing.

Note that QPalette uses implicit sharing, and the serial number changes during the lazy copy operation (when the palette is actually modified), not during a shallow copy (copy constructor or assignment).

See also QPixmap, QPixmapCache, and QCache.

void QPalette::setBrush ( ColorRole cr, const QBrush & brush )

Sets the brush used to color role cr and brush brush.

See also brush(), setColor(), and ColorRole.

void QPalette::setBrush ( ColorGroup cg, ColorRole cr, const QBrush & b )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Sets the brush in color group cg, used for color role cr, to b.

See also brush(), setColor(), and ColorRole.

void QPalette::setColor ( ColorGroup gr, ColorRole r, const QColor & c )

Sets the brush in color group gr, used for color role r, to the solid color c.

See also setBrush(), color(), and ColorRole.

void QPalette::setColor ( ColorRole r, const QColor & c )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Sets the brush used for color role r in the current ColorGroup to a solid color c.

See also brush(), setColor(), and ColorRole.

void QPalette::setColorGroup ( ColorGroup cg, const QBrush & foreground, const QBrush & button, const QBrush & light, const QBrush & dark, const QBrush & mid, const QBrush & text, const QBrush & bright_text, const QBrush & base, const QBrush & background )

Sets a the group at cg. You can pass either brushes, pixmaps or plain colors for foreground, button, light, dark, mid, text, bright_text, base and background.

See also QBrush.

void QPalette::setCurrentColorGroup ( ColorGroup cg )

Set the palette's current color group to cg.

See also currentColorGroup().

const QBrush & QPalette::shadow () const

Returns the shadow brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::text () const

Returns the text foreground brush of the current color group.

See also ColorRole and brush().

QPalette::operator QVariant () const

Returns the palette as a QVariant

bool QPalette::operator!= ( const QPalette & p ) const

Returns true (slowly) if this palette is different from p; otherwise returns false (usually quickly).

QPalette & QPalette::operator= ( const QPalette & p )

Assigns p to this palette and returns a reference to this palette.

This operation is fast because of implicit sharing.

bool QPalette::operator== ( const QPalette & p ) const

Returns true (usually quickly) if this palette is equal to p; otherwise returns false (slowly).

Related Non-Members

QDataStream & operator<< ( QDataStream & s, const QPalette & p )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Writes the palette, p to the stream s and returns a reference to the stream.

See also Format of the QDataStream operators.

QDataStream & operator>> ( QDataStream & s, QPalette & p )

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Reads a palette from the stream, s into the palette p, and returns a reference to the stream.

See also Format of the QDataStream operators.