QtGlobalColor

QtGlobalColor, formally exposed as Qt::GlobalColor, is a legacy enumeration in the Qt framework used to reference a small set of predefined, global colors. It is part of the public API in the QtGui module and provides a convenient way to specify colors without composing explicit RGB values. Programs can convert these constants to color values when creating QColors or when setting colors in palettes.

The enumeration includes a collection of common colors such as white, black, red, green, blue, cyan, magenta, yellow, gray, darkGray, and lightGray. These constants can be used with APIs that accept a QColor, because there is a constructor in QColor that takes a Qt::GlobalColor, enabling straightforward conversion from a global color to a QColor.

Usage examples are straightforward: you can create a QColor from a global color, or pass a global color to APIs that ultimately require a QColor. For instance, a palette color can be set by constructing a QColor from Qt::white and applying it to a QPalette role. This mechanism helps achieve simple theming in a cross-platform manner.

In modern Qt development, explicit RGB values, hex literals, or stylesheet-based styling are more commonly used. Qt::GlobalColor remains available primarily for backward compatibility with older codebases and simple, name-based color references. It is predominantly of historical interest in contemporary Qt applications, where more flexible color specification is preferred.