QPainterfillRect

QPainterfillRect refers to the fillRect member function of the QPainter class in the Qt framework. It fills a rectangular area on the current paint device using a brush or color, rather than drawing a border. The function is commonly used to paint solid colors, gradients, textures, or patterns as the interior of a rectangle.

Overloads and signatures include variants that accept either integer coordinates and size or QRect and QRectF objects, with an accompanying brush or color. Typical forms are void fillRect(const QRect & rect, const QBrush & brush), void fillRect(int x, int y, int w, int h, const QBrush & brush), and their counterparts that take a QColor for convenience. The color variants internally convert the color to a brush before filling the area.

Usage and behavior: fillRect respects the painter’s current transform, clipping region, and compositing mode, as well as its opacity setting. The function fills only the interior of the specified rectangle; it does not draw an outline. The appearance of the fill is determined by the brush, which may specify solid colors, gradients, textures, or patterns. If a texture or gradient brush is used, the fill can adapt to the painter’s coordinate system and transformations.

Common use cases include painting widget backgrounds, custom UI elements, or any area requiring a filled rectangular region. In contrast to drawRect, which outlines the rectangle, fillRect focuses on filling the interior.

See also: QPainter, QBrush, QColor, QRect, QRectF, setBrush, setOpacity, setCompositionMode, and rendering hints for anti-aliasing.