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QPalette Class Reference

The QPalette class contains color groups for each widget state. More...

#include <QPalette>

List of all members.

Public Types

Public Functions

Related Non-Members


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 contain a palette, and all widgets in Qt 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:

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

In Motif style, Active and Inactive look the same. In Windows 2000 style and Macintosh Platinum style, the two styles look slightly different.

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 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.

You modify a color group by calling the access 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 each ColorRole: background(), foreground(), base(), etc.

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

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


Member Type Documentation

enum QPalette::ColorGroup

QPalette::Disabled 
QPalette::Active 
QPalette::Inactive 
QPalette::Normalsynonym for Active

enum QPalette::ColorRole

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

The central roles are:

QPalette::BackgroundA general background color.
QPalette::ForegroundA general foreground color.
QPalette::BaseUsed as the background color for text entry widgets; usually white or another light color.
QPalette::TextThe foreground color used with Base. This is usually the same as the Foreground, in which case it must provide good contrast with Background and Base.
QPalette::ButtonThe general button background color in which buttons need a background that is different from Background, as in the Macintosh style.
QPalette::ButtonTextA foreground color used with the Button color.

There are some color roles used mostly for 3D bevel and shadow effects:

QPalette::LightLighter than Button color.
QPalette::MidlightBetween Button and Light.
QPalette::DarkDarker than Button.
QPalette::MidBetween Button and Dark.
QPalette::ShadowA very dark color. By default, the shadow color is Qt::black.

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:

QPalette::HighlightA color to indicate a selected item or the current item. By default, the highlight color is Qt::darkBlue.
QPalette::HighlightedTextA text color that contrasts with Highlight. By default, the highlighted text color is Qt::white.

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:

QPalette::BrightTextA text color that is very different from Foreground, and contrasts well with e.g. Dark.
QPalette::LinkA text color used for unvisited hyperlinks. By default, the link color is Qt::blue.
QPalette::LinkVisitedA text color used for already visited hyperlinks. By default, the linkvisited color is Qt::magenta.

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:

Color Roles


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 QColor & foreground, const QColor & background, const QColor & light, const QColor & dark, const QColor & mid, const QColor & text, const QColor & base )

This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.

Constructs a palette with the specified foreground, background, light, dark, mid, text, and base colors. The button color will be set to the background color.

QPalette::QPalette ( const QPalette & p )

Constructs a copy of p.

This constructor is fast (it uses copy-on-write).

QPalette::~QPalette ()

Destroys the palette.

const QBrush & QPalette::background () const

Returns the background color of the current color group.

See also ColorRole.

const QBrush & QPalette::base () const

Returns the base color of the current color group.

See also ColorRole.

const QBrush & QPalette::brightText () const

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

See also ColorRole.

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 color of the current color group.

See also ColorRole.

const QBrush & QPalette::buttonText () const

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

See also ColorRole.

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.

const QBrush & QPalette::dark () const

Returns the dark color of the current color group.

See also ColorRole.

const QBrush & QPalette::foreground () const

Returns the foreground color of the current color group.

See also ColorRole.

const QBrush & QPalette::highlight () const

Returns the highlight color of the current color group.

See also ColorRole.

const QBrush & QPalette::highlightedText () const

Returns the highlighted text color of the current color group.

See also ColorRole.

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 color of the current color group.

See also ColorRole.

const QBrush & QPalette::link () const

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

See also ColorRole.

const QBrush & QPalette::linkVisited () const

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

See also ColorRole.

const QBrush & QPalette::mid () const

Returns the mid color of the current color group.

See also ColorRole.

const QBrush & QPalette::midlight () const

Returns the midlight color of the current color group.

See also ColorRole.

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 copy-on-write, and the serial number changes during the lazy copy operation (detach()), 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.

const QBrush & QPalette::shadow () const

Returns the shadow color of the current color group.

See also ColorRole.

const QBrush & QPalette::text () const

Returns the text foreground color of the current color group.

See also ColorRole.

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 is fast (it uses copy-on-write).

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.


Copyright © 2004 Trolltech. Trademarks
Qt 4.0.0-tp1