撤消框架

Qt's undo framework is an implementation of the Command pattern, which provides advanced undo/redo functionality.

To show the abilities of the framework, we have implemented a small diagram application in which the diagram items are geometric primitives. You can edit the diagram in the following ways: add, move, change the color of, and delete the items.

文件：

• tools/undo/commands.cpp
• tools/undo/commands.h
• tools/undo/document.cpp
• tools/undo/document.h
• tools/undo/mainwindow.cpp
• tools/undo/mainwindow.h
• tools/undo/mainwindow.ui
• tools/undo/main.cpp
• tools/undo/undo.pro
• tools/undo/undo.qrc