Insert dragable and resizeable subgraphs into a graph window

#pragma TextEncoding = "UTF-8"
#pragma rtGlobals=3
#pragma DefaultTab={3,20,4}

function TestAppendSubGraph(string mainGName, wave plotThis)
    GetWindow $mainGName, expand
    variable gExpand = V_value; gExpand = gExpand == 0 ? 1 : gExpand    // pixel conversion and expansion factor
    variable pixConv = ScreenResolution/72*gExpand
   
    GetWindow $mainGName psizeDC        // define an initial size
    variable size = max(min((V_bottom-V_top)/4,(V_right-V_left)/5),subMinSize)/pixConv
    variable wL = (V_left+20)/pixConv, wT = (V_top+20)/pixConv, wR = wL+size*1.2, wB = wT+size
   
    NewPanel/HOST=$mainGName/N=floatPanel/W=(wL,wT,wR,wB)
    Display/HOST=#/FG=(FL,FT,FR,FB) plotThis
    ModifyGraph frameStyle=1        // edges are easier to see with a frame
    SetActiveSubwindow $mainGName
    SetWindow $mainGName hook(DragUpdate)=DragHookFunction
end

function TestRemoveHook(string gName)
    string subWinList = ChildWindowList(gName)
    int i
    for (i=0; i<ItemsInList(subWinList); i++)
        SetWindow $gName userdata($StringFromList(i,subWinList))=""     // remove user data from graph
    endfor
    SetWindow $gName userdata(dragInfo)=""
    SetWindow $gName hook(DragUpdate)=$""
end

// ##################

static Constant subMinSize = 100
static Constant edgeDetect = 15

function DragHookFunction(STRUCT WMWinHookStruct &s)
    string gName = StringFromList(0,s.winName,"#")
    string sName = StringFromList(1,s.winName,"#")
    string dragInfo = "", floatStruct = ""
    int i, hookTakeOver = 0
   
    GetWindow $gName, expand
    variable gExpand = V_value; gExpand = gExpand == 0 ? 1 : gExpand    // pixel conversion and expansion factor
    variable pixConv = ScreenResolution/72*gExpand
    variable winEdge = 0, dragEdge = 0
    STRUCT DragStruct d
    STRUCT rect tempRect
   
    if (WhichListItem(s.eventName, "mousedown;mousemoved;mouseup;")>-1 && CmpStr(s.winName, gName))     // mouse events on the sub-graph
        GetWindow $s.winName psizeDC
        tempRect.top    = v_top
        tempRect.left   = v_left
        tempRect.right  = v_right
        tempRect.bottom = v_bottom
        if (!CheckPointInRect(s.mouseLoc,tempRect))     // mouse is not in plot area
            GetWindow $s.winName gsizeDC;    winEdge = 1            // encode sub-window mouse edge detection into winEdge
            winEdge = abs(s.mouseloc.h-v_left) <edgeDetect && abs(s.mouseloc.v-v_top)   <edgeDetect ? 2 : winEdge   // LT
            winEdge = abs(s.mouseloc.h-v_right)<edgeDetect && abs(s.mouseloc.v-v_top)   <edgeDetect ? 3 : winEdge   // RT
            winEdge = abs(s.mouseloc.h-v_left) <edgeDetect && abs(s.mouseloc.v-v_bottom)<edgeDetect ? 4 : winEdge   // LB
            winEdge = abs(s.mouseloc.h-v_right)<edgeDetect && abs(s.mouseloc.v-v_bottom)<edgeDetect ? 5 : winEdge   // RB
        endif
    endif
   
    StrSwitch(s.eventName)
        case "mousedown":
            if (CmpStr(s.winName, gName) && s.eventMod==1)
                if (CheckPointInRect(s.mouseLoc,tempRect))
                    break
                endif
                GetWindow $gName gsizeDC
                d.graphRect.top    = v_top
                d.graphRect.left   = v_left
                d.graphRect.bottom = v_bottom
                d.graphRect.right  = v_right
                d.mouse_init = s.mouseloc
                d.subwinRect = s.winrect
                StructPut/S d, floatStruct
                SetWindow $gName userdata($sName)=floatStruct           // save info for the current subwindow
                SetWindow $gName userdata(dragInfo)=num2str(winEdge)+";"+sName+";"      // a list of the edge to drag and the dragged subwindow name
                hookTakeOver = 1
            endif
        break
        case "mouseup":
            if (str2num(GetUserData(gName, "", "dragInfo")))
                SetActiveSubwindow $gName
                SetWindow $gName userdata(dragInfo)=""
            endif
        break
        case "mousemoved":
            if (winEdge)
                s.cursorCode = str2num(StringFromList(winEdge,"0;8;4;11;10;7;"))
                s.doSetCursor = 1   // change mouse cursor
            endif
            dragInfo = GetUserData(gName, "", "dragInfo")
            dragEdge = str2num(StringFromList(0,dragInfo))
            dragEdge = numtype(dragEdge) != 0 ? 0 : dragEdge
            if (dragEdge)
                GetMouse/W=$gName
                if (!(V_flag & 1))  // mouse button released? => maybe we missed a mouse-up event?
                    SetWindow $gName userdata(dragInfo)=""
                    dragEdge = 0
                endif
            else
                break
            endif
           
            sName = StringFromList(1,dragInfo)         
            StructGet/S d, GetUserData(gName, "", sName)
            variable deltah = s.mouseloc.h - d.mouse_init.h
            variable deltav = s.mouseloc.v - d.mouse_init.v
            tempRect = d.subwinRect
            tempRect.top    += deltav * (dragEdge == 1 || dragEdge == 2 || dragEdge == 3)
            tempRect.left   += deltah * (dragEdge == 1 || dragEdge == 2 || dragEdge == 4)
            tempRect.right  += deltah * (dragEdge == 1 || dragEdge == 5 || dragEdge == 3)
            tempRect.bottom += deltav * (dragEdge == 1 || dragEdge == 5 || dragEdge == 4)
           
            string subWin = gName + "#" + sName
            if (CheckRectPosAndSize(tempRect, d.graphRect) && WinType(subWin))
                MoveSubwindow/W=$subWin fnum=(tempRect.left/pixConv, tempRect.top/pixConv, tempRect.right/pixConv, tempRect.bottom/pixConv)
                d.subwinRect = tempRect
            endif
            d.mouse_init = s.mouseloc
            StructPut/S d, floatStruct
            SetWindow $gName userdata($sName)=floatStruct
        break
        case "resize":
            string subWinList = ChildWindowList(gName)
            if (!ItemsInList(subWinList))
                break
            endif
           
            GetWindow $gName wsizeDC
            int isHostMinW = abs(v_right-v_left) <= subMinSize
            int isHostMinH = abs(v_bottom-v_top) <= subMinSize
            for (i=0; i<ItemsInList(subWinList); i++)
                sName = StringFromList(i, subWinList)
                GetWindow $(gName+"#"+sName) wsizeDC
                variable subW = abs(v_right-v_left)
                variable subH = abs(v_bottom-v_top)
               
                variable dW = isHostMinW ? 0 : subMinSize - subW    // check if the panel width is smaller than the minimum
                variable dH = isHostMinH ? 0 : subMinSize - subH
                if (dW <= 0 && dH <= 0)
                    continue
                endif
               
                dragInfo = GetUserData(gName, "", sName)
                if (strlen(dragInfo))
                    StructGet/S d, dragInfo
                    subW = abs(d.subwinRect.right -d.subwinRect.left)
                    subH = abs(d.subwinRect.bottom-d.subwinRect.top)
                endif
               
                tempRect.top    = v_top  - dH*(dH>0)
                tempRect.bottom = v_top  - dH*(dH>0) + subH
                tempRect.left   = v_left - dW*(dW>0)
                tempRect.right  = v_left - dW*(dW>0) + subW
                MoveSubwindow/W=$(gName+"#"+sName) fnum=(tempRect.left/pixConv, tempRect.top/pixConv, tempRect.right/pixConv, tempRect.bottom/pixConv)
            endfor
        break
    endswitch
    return hookTakeOver
end

// ++++++++++++

static structure DragStruct
    STRUCT point mouse_init
    STRUCT Rect subwinRect
    STRUCT Rect graphRect
endstructure

static function CheckRectPosAndSize(STRUCT rect &in, STRUCT rect &ref)
    int isInside  = (in.left>ref.left && in.top>ref.top && in.right<ref.right && in.bottom<ref.bottom)
    int isMinSize = abs(in.right-in.left) >= subMinSize && abs(in.bottom-in.top) >= subMinSize
    return isInside && isMinSize
end

static function CheckPointInRect(STRUCT point &pnt, STRUCT rect &ref)
    return ( pnt.h>ref.left && pnt.h<ref.right && pnt.v>ref.top && pnt.v<ref.bottom )
end