Although we won't talk about the technical details of how a camera works, the overview of the implementation of a camera in Qt will be covered. Support for a camera is included in Qt Multimedia, which is a module that provides a rich set of QML types and C++ classes to handle multimedia content. Things such as audio playback, camera, and radio functionality are shown. To complement this, the Qt Multimedia Widgets module provides widget-based multimedia classes to make the work easier.

There are some classes to help us deal with the camera. For instance, viewfinder lets a user look through the camera to compose, and in many cases focus, the picture. In Qt/C++, you can use QGraphicsView along with QGraphicsVideoItem to do this job. QGraphicsView provides a widget to display the contents of QGraphicsScene. In this case, QGraphicsVideoItem is an item of the scene. This view-scene-item is the Graphics View Framework. For details on this concept, visit http://doc.qt.io...