_name backStep cancel click doContextAction doubleClick draw drawAngleText drawAngleText gatherShapes getName getSelectedIDs getShape initialize initializeWithSelection isDrawingCommand isFloatingCommand longPress MgCommand MgCommand mouseHover release touchBegan touchEnded touchMoved twoFingersMove ~MgCommand

backStep() virtual bool MgCommand::backStep ( const MgMotion *  sender ) virtual 回退一步 在 MgCmdSelect, MgCommandDraw, MgCmdDrawLines, MgCmdDrawSplines, MgCmdDrawLine, MgCmdErase, MgCmdDrawFreeLines , 以及 MgCmdDrawRect 内被实现. 函数调用图: