#includeIn this code, we create a QGraphicsRectItem and a QColor object. We then set the red, green, and blue color components of the QColor object to 1, 0, and 0 respectively, effectively setting the color to bright red. Finally, we set the brush of the QGraphicsRectItem to the QColor object, which sets its fill color. Package library: This method is part of the Qt library, which is a popular C++ GUI application development framework.#include QGraphicsRectItem *rectItem = new QGraphicsRectItem; QColor color; color.setRgbF(1, 0, 0); // Set the color to bright red rectItem->setBrush(color);