QBitmap is a Qt class used for masking/transparency in QPixmap. QBitmap is a class for containing monochrome (that is: each pixel is either on or off) images, instead of the colored Windows bitmaps.
The code below, adapted from Qt example 1: moving a sprite over a background in 2D, shows how to add transparency to a QPixmap.
#include <QGraphicsPixmapItem> struct Sprite : public QGraphicsPixmapItem { Sprite( const std::string& filename, const QColor& transparency_color = QColor(0,255,0)) //Lime green { QPixmap pixmap(filename.c_str()); const QBitmap mask = pixmap.createMaskFromColor(transparency_color); pixmap.setMask(mask); this->setPixmap(pixmap); } };