- Qt 5.15
- Qt Widgets
- C++ Classes
- QApplication
- Qt 5.15.18 Reference Documentation

# Obsolete Members for QApplication

The following members of class QApplication are obsolete. They are provided to keep old source code working. We strongly advise against using them in new code.

## Public Types

`(obsolete)` enum | ColorSpec { NormalColor, CustomColor, ManyColor }

## Properties

- `(obsolete)` globalStrut : QSize

## Static Public Members

`(obsolete)` int | colorSpec()
`(obsolete)` QDesktopWidget * | desktop()
`(obsolete)` QSize | globalStrut()
`(obsolete)` bool | keypadNavigationEnabled()
`(obsolete)` void | setColorSpec(int spec)
`(obsolete)` void | setGlobalStrut(const QSize &)
`(obsolete)` void | setKeypadNavigationEnabled(bool enable)

## Member Type Documentation

### enum QApplication::ColorSpec

This enum is obsolete.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

Constant | Value | Description
--- | --- | ---
`QApplication::NormalColor` | `0` | the default color allocation policy
`QApplication::CustomColor` | `1` | the same as NormalColor for X11; allocates colors to a palette on demand under Windows
`QApplication::ManyColor` | `2` | the right choice for applications that use thousands of colors

See setColorSpec() for full details.

## Property Documentation

### globalStrut : QSize

This property is obsolete.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

This property holds the minimum size that any GUI element that the user can interact with should have

For example, no button should be resized to be smaller than the global strut size. The strut size should be considered when reimplementing GUI controls that may be used on touch-screens or similar I/O devices.

Example:

     QSize MyWidget::sizeHint() const
     {
         return QSize(80, 25);
     }

By default, this property contains a QSize object with zero width and height.

Access functions:

QSize | globalStrut()
void | setGlobalStrut(const QSize &)

## Member Function Documentation

### `[static]` int QApplication::colorSpec()

This function is obsolete.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

Returns the color specification.

See also QApplication::setColorSpec().

### `[static]` QDesktopWidget *QApplication::desktop()

This function is obsolete.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

Returns the desktop widget (also called the root window).

The desktop may be composed of multiple screens, so it would be incorrect, for example, to attempt to center some widget in the desktop's geometry. QDesktopWidget has various functions for obtaining useful geometries upon the desktop, such as QDesktopWidget::screenGeometry() and QDesktopWidget::availableGeometry().

### `[static]` bool QApplication::keypadNavigationEnabled()

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

Returns `true` if Qt is set to use keypad navigation; otherwise returns false. The default value is false.

This feature is available in Qt for Embedded Linux, and Windows CE only.

Note: On Windows CE this feature is disabled by default for touch device mkspecs. To enable keypad navigation, build Qt with QT_KEYPAD_NAVIGATION defined.

See also setKeypadNavigationEnabled() and navigationMode().

### `[static]` void QApplication::setColorSpec(int spec)

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

Sets the color specification for the application to spec.

This call has no effect.

The color specification controls how the application allocates colors when run on a display with a limited amount of colors, e.g. 8 bit / 256 color displays.

The color specification must be set before you create the QApplication object.

The options are:

- QApplication::NormalColor. This is the default color allocation strategy. Use this option if your application uses buttons, menus, texts and pixmaps with few colors. With this option, the application uses system global colors. This works fine for most applications under X11, but on the Windows platform, it may cause dithering of non-standard colors.
- QApplication::CustomColor. Use this option if your application needs a small number of custom colors. On X11, this option is the same as NormalColor. On Windows, Qt creates a Windows palette, and allocates colors to it on demand.
- QApplication::ManyColor. Use this option if your application is very color hungry, e.g., it requires thousands of colors.
  Under X11 the effect is:
  - For 256-color displays which have at best a 256 color true color visual, the default visual is used, and colors are allocated from a color cube. The color cube is the 6x6x6 (216 color) "Web palette" (the red, green, and blue components always have one of the following values: 0x00, 0x33, 0x66, 0x99, 0xCC, or 0xFF), but the number of colors can be changed by the -ncols option. The user can force the application to use the true color visual with the -visual option.
  - For 256-color displays which have a true color visual with more than 256 colors, use that visual. Silicon Graphics X servers this feature, for example. They provide an 8 bit visual by default but can deliver true color when asked.

  On Windows, Qt creates a Windows palette, and fills it with a color cube.

Be aware that the CustomColor and ManyColor choices may lead to colormap flashing: The foreground application gets (most) of the available colors, while the background windows will look less attractive.

Example:

     int main(int argc, char *argv[])
     {
         QApplication::setColorSpec(QApplication::ManyColor);
         QApplication app(argc, argv);
         ...
         return app.exec();
     }

See also colorSpec().

### `[static]` void QApplication::setKeypadNavigationEnabled(bool enable)

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

Sets whether Qt should use focus navigation suitable for use with a minimal keypad.

This feature is available in Qt for Embedded Linux, and Windows CE only.

Note: On Windows CE this feature is disabled by default for touch device mkspecs. To enable keypad navigation, build Qt with QT_KEYPAD_NAVIGATION defined.

See also keypadNavigationEnabled() and setNavigationMode().