Manipulating and combining existing graphs programatically

//   Removes unwanted controls from the recreation string.
//   GrepList(x, y, 1, "\r") means include all items in x where y is NOT true.
//   ^\t(x|y|y) means starting with (^) a tabulator (\t) followed by either x, y or z.
 
WinRecreationString=GrepList(WinRecreationString, "^\t(DefineGuide|ControlBar|SetWindow|Cursor|ListBox|CheckBox|PopupMenu|ValDisplay|SetVariable|Button|ModifyGraph margin|NewPanel|ModifyPanel|RenameWindow|SetActiveSubwindow|ShowInfo)", 1, "\r")

Function CreateWindow()
//  Creates a graph
String ActiveWindow="MyWindow"
 
    //  Creates some dummy waves to display
    Make/O/N=20 root:Peter/WAVE=Peter
    Make/O/N=100 root:Paul/WAVE=Paul
    Make/O/N=500 root:Mary/WAVE=Mary
    
    NewDataFolder/O root:Grimm
    DFREF GrimmFolder=root:Grimm
 
    Make/O/N=200 GrimmFolder:Hansel/WAVE=Hansel
    Make/O/N=10 GrimmFolder:Gretel/WAVE=Gretel
 
    NewDataFolder/O root:EmptyFolder
        
    Peter=p+10
    Paul=exp(p/100)-p
    Mary=2*p^4+3*p^3-p+5
    Hansel=sin(p/20)-0.01*p
    Gretel=cos(p)
    
    SetScale /P x, 1, 2, "", Peter
    SetScale /P x, 1, -2, "", Paul
    SetScale /P x, 100, 0.1, "", Mary
    SetScale /P x, 0, 0.1, "", Hansel
    SetScale /P x, 0, -0.1, "", Gretel
 
    //  Creates the folder to hold all the permanent waves, used for different bureaucratic purposes, such as listboxes, displaying waves, etc...
    NewDataFolder/O root:Programming
    DFREF ProgramFolder=root:Programming
 
    //  Kills MyWindow if it exists
    DoWindow /K $ActiveWindow   
 
    //  Creates an empty wave to display
    Make/O/N=0 ProgramFolder:DataWave/WAVE=DataWave
    
    //  Creates the graph
    Display /W=(250, 150, 800, 500) /K=1 /N=$ActiveWindow DataWave
    ModifyGraph /W=$ActiveWindow margin(top)=80
    
    //  Selects the active data folder
    PopupMenu DataFolderPopUp bodyWidth=250, mode=1, pos={235, 5}, proc=PopUpFolderProc, value=PopUpFolderList(), win=$ActiveWindow
 
    //  Popup menu to select the spectrum to display
    PopupMenu DisplayedWavePopUp bodyWidth=250, mode=1, pos={235,30}, proc=PopUpWaveProc, value=PopUpWaveList(), win=$ActiveWindow
    
    //  Runs the update function
    UpdateMyWindow()
end
 
 
 
Function/S PopUpFolderList()
//  Returns a semicolon separated string list of the full paths to all datafolders
 
    String FolderName=""
    DFREF ParentFolder=root:
    DFREF ChildFolder=root:
    DFREF ExcludeFolder=root:Programming
    
    //  Creates a wave to hold the names of all existing folders. If more than 4000 folders exist, something will happen....
    Make/FREE/O/DF/N=4000 ListOfFolders
    ListOfFolders[0]=root:
    
    //  Returns a list of the data folders in root:
    String ListString=GetDataFolder(1, root:)+";"
 
    //  Counts through the list of folders
    Variable n=0, i=0, a=0, b=1, c=0
    for (a=0; a<b; a+=1)
    
        //  Finds the number of additional folders in the active folder
        ParentFolder=ListOfFolders[a]
        n=CountObjectsDFR(ParentFolder, 4)
        
        
        //  Adds the additional folders to the list of folders, excluding ExcludeFolder
        for (i=0; i<n; i+=1)
            FolderName=GetIndexedObjNameDFR(ParentFolder, 4, i)
            ChildFolder=ParentFolder:$FolderName
            if (DataFolderRefsEqual(ChildFolder, ExcludeFolder))
                c+=1
            else
                ListOfFolders[b+i-c]=ChildFolder
                ListString+=GetDataFolder(1, ChildFolder)+";"
            endif
        endfor
        
        //  Increases the number of folders by the number of additonal folders
        b+=n-c
        
        //  Resets the exclude counter
        c=0
    endfor
    
    //  Returns the case-insensitive alphanumerically sorted list of data folders
    Return SortList(ListString, ";", 16)
end
 
 
 
Function/S PopUpWaveList()
//  Returns a list of all one-dimensional waves in the selected data folder
String ListOfWaves=""
 
    //  Finds the selected folder
    ControlInfo /W=MyWindow DataFolderPopUp
    String FolderName=S_Value
    DFREF Folder=$FolderName
    
    if (DataFolderRefStatus(Folder)==0)
 
        //  Returns data folder does not exist, if the data folder does not exist       
        ListOfWaves="Data folder does not exist;"
    else
 
        //  Saves the active data folder
        DFREF CurrentFolder=GetDataFolderDFR()
 
        //  Changes the active folder to Folder
        SetDataFolder Folder
    
        //  Returns a semi-colon seperated list of one-dimensional numeric waves in the active folder
        ListOfWaves=WaveList("*", ";", "DIMS:1,DF:0,CMPLX:0,TEXT:0,WAVE:0")
    
        //  Returns the active folder to the original folder
        SetDataFolder CurrentFolder
 
        //  Sorts the list alphabetically, using a case-insensitive alphanumeric sort that sorts wave0 and wave9 before wave10
        ListOfWaves=SortList(ListOfWaves, ";", 16)
    
        //  If the list is empty "No waves in folder" is added
        if (StrLen(ListOfWaves)==0)
            ListOfWaves="No waves in folder;"
        endif
    endif
    
    //  Returns the list of waves
    Return ListOfWaves
end
 
 
 
Function PopUpFolderProc(PU_Struct) : PopupMenuControl
//  Runs the update function if the data folder selection is changed
STRUCT WMPopupAction &PU_Struct
 
    //  If the selection was changed
    if  (PU_Struct.eventCode==2)
    
        //  Ignores further calls to the popup menu procedure until this one has finished
        PU_Struct.blockReentry=1
        
        //  Finds the selected folder
        String FolderName=PU_Struct.popStr
        DFREF Folder=$FolderName
    
        //  Changes the displayed wave selection to the first item in the list and updates the list
        PopupMenu DisplayedWavePopUp mode=1, win=$PU_Struct.win
 
        //  Runs the update function
        UpdateMyWindow()        
        
        //  If the user scrolls through the items in the list too fast, the selection will change before the update has finished, and the selection will not match the displayed data. This will prevent that
        PopupMenu $PU_Struct.ctrlName popmatch=PU_Struct.popStr, win=$PU_Struct.win
    endif
end
 
 
 
Function PopUpWaveProc(PU_Struct) : PopupMenuControl
//  Runs the update function if the wave selection is changed
STRUCT WMPopupAction &PU_Struct
 
    //  If the selection was changed
    if  (PU_Struct.eventCode==2)
    
        //  Ignores further calls to the popup menu procedure until this one has finished
        PU_Struct.blockReentry=1
        
        //  Runs the update function
        UpdateMyWindow()
        
        //  If the user scrolls through the items in the list too fast, the selection will change before the update has finished, and the selection will not match the displayed data. This will prevent that
        PopupMenu $PU_Struct.ctrlName popmatch=PU_Struct.popStr, win=$PU_Struct.win
    endif
end
 
 
 
Function UpdateMyWindow()
//  Displays the selected wave in MyWindow
 
    DFREF ProgramFolder=root:Programming
 
    //  Finds the selected folder
    ControlInfo /W=MyWindow DataFolderPopUp
    String FolderName=S_Value
    DFREF Folder=$FolderName
    
    if (DataFolderRefStatus(Folder)==0)
 
        //  Creates an empty wave to display if the datafolder selection is invalid
        Make/O/N=0 ProgramFolder:DataWave
    else
 
        //  Finds the selected wave
        ControlInfo /W=MyWindow DisplayedWavePopUp
        String DisplayedWaveName=S_Value
        Wave/Z DisplayedWave=Folder:$DisplayedWaveName
 
        if (WaveExists(DisplayedWave))
        
            //  Displays the selected wave
            Duplicate/O DisplayedWave, ProgramFolder:DataWave
        else
 
            //  Creates an empty wave to display if the wave selection is invalid
            Make/O/N=0 ProgramFolder:DataWave   
        endif   
    endif
end