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 the default palette of the current style (returned by QApplication::palette()) and modify that as necessary. This is done by Qt's widgets when they are drawn.

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: window(), windowText(), 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 Window, 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 Window.

Selected (marked) items have two roles:

There are two color roles related to hyperlinks:

Note that we do not use the Link and LinkVisited roles when rendering rich text in Qt, and that we recommend that you use CSS and the QTextDocument::setDefaultStyleSheet() function to alter the appearance of links. For example:

     QTextBrowser browser;
     QColor linkColor(Qt::red);
     QString sheet = QString::fromLatin1("a { text-decoration: underline; color: %1 }").arg(linkColor.name());
     browser.document()->setDefaultStyleSheet(sheet);

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. Window 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. Window will be the button color as well.

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

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

QPalette::QPalette ( const QBrush & windowText, const QBrush & button, const QBrush & light, const QBrush & dark, const QBrush & mid, const QBrush & text, const QBrush & bright_text, const QBrush & base, const QBrush & window )

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

See also QBrush.

QPalette::QPalette ( const QPalette & p )

Constructs a copy of p.

This constructor is fast thanks to 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::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 group, ColorRole role ) const

Returns the brush in the specified color group, used for the given color role.

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

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

This is an overloaded member function, provided for convenience.

Returns the brush that has been set for the given color role 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().

qint64 QPalette::cacheKey () const

Returns a number that identifies the contents of this QPalette object. Distinct QPalette objects can have the same key if they refer to the same contents.

The cacheKey() will change when the palette is altered.

const QColor & QPalette::color ( ColorGroup group, ColorRole role ) const

Returns the color in the specified color group, used for the given color role.

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

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

This is an overloaded member function, provided for convenience.

Returns the color that has been set for the given color role 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::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::isBrushSet ( ColorGroup cg, ColorRole cr ) const

Returns true if the ColorGroup cg and ColorRole cr has been set previously on this palette; otherwise returns false.

This function was introduced in Qt 4.2.

See also setBrush().

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.

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

Sets the brush for the given color role to the specified brush for all groups in the palette.

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

void QPalette::setBrush ( ColorGroup group, ColorRole role, const QBrush & brush )

This is an overloaded member function, provided for convenience.

Sets the brush in the specified color group, used for the given color role, to brush.

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

void QPalette::setColor ( ColorGroup group, ColorRole role, const QColor & color )

Sets the brush in the specified color group, used for the given color role, to the specified solid color.

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

void QPalette::setColor ( ColorRole role, const QColor & color )

This is an overloaded member function, provided for convenience.

Sets the color used for the given color role, in all color groups, to the specified solid color.

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

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

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

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().

const QBrush & QPalette::window () const

Returns the window (general background) brush of the current color group.

See also ColorRole and brush().

const QBrush & QPalette::windowText () const

Returns the window text (general 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 thanks to 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.

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.

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.