基于QT的磁性套索工具实现，在图上选择想要的区域，闭合以后可以裁剪出来，选则的边错误可以回退。-Implementation based on QT magnetic lasso tool and the desired area on the map. After the closure can be cut out, selection errors in edge can regress.

使用自定义QGraphicsItem，实现拼图游戏,拼图游戏的底图来源于资源文件(Use a custom QGraphicsItem implementation, jigsaw puzzle, jigsaw puzzle map from the resource file)