Using mousewheel in GUI (listicongadget)

[Shardik]

Not wanting to sound annoying, but is there a simple way of just detecting the the mouse wheel was scrolled, without binding it to gadgets?

I don't think that there is a simpler way. I would strongly advise to bind the mouse wheel event to the ListIconGadget because otherwise you would also react to wheel scrolling when the cursor is outside of your ListIconGadget. But please take a look into the modified example below: it should be at least simpler for you to implement because I have declared the two additional event types

#PB_EventType_MouseWheel_Down
#PB_EventType_MouseWheel_Up

and all 3 callbacks now use PostEvent() to place these new event types in your standard event loop so that you may evaluate the mouse wheel events there:

Code: Select all

    Case #PB_Event_Gadget
      If EventGadget() = #ListIcon
        Select EventType()
          Case #PB_EventType_MouseWheel_Down
            Debug "Mouse wheel moved down"
          Case #PB_EventType_MouseWheel_Up
            Debug "Mouse wheel moved up"
        EndSelect
      EndIf

By the way I also optimized the MacOS part by defining an EventTapCallback (thank you for one of your invaluable examples demonstrating that callback, Wilbert!) instead of calling the procedure ScanVerticalMouseWheel() inside the event loop:

Code: Select all

EnableExplicit

#ListIcon = 0
#Window = 0

Enumeration 
  #PB_EventType_MouseWheel_Down = #PB_EventType_FirstCustomValue
  #PB_EventType_MouseWheel_Up
EndEnumeration

CompilerSelect #PB_Compiler_OS
  CompilerCase #PB_OS_Linux ; --------------------------------------------------
    ProcedureC MouseWheelCallback(*Event.GdkEventScroll, *UserData)
      Protected *ListView.GtkWidget = GadgetID(#ListIcon)
     
      If *ListView\window = gdk_window_get_parent_(*Event\window)
        If *Event\type = #GDK_SCROLL
          Select *Event\direction
            Case #GDK_SCROLL_UP
              PostEvent(#PB_Event_Gadget, #Window, #ListIcon,
                #PB_EventType_MouseWheel_Up)
            Case #GDK_SCROLL_DOWN
              PostEvent(#PB_Event_Gadget, #Window, #ListIcon,
                #PB_EventType_MouseWheel_Down)
          EndSelect
        EndIf
      EndIf
     
      gtk_main_do_event_(*Event)
    EndProcedure
  CompilerCase #PB_OS_MacOS ; --------------------------------------------------
    #kCGEventTapOptionListenOnly = 1
    #kCGHeadInsertEventTap = 0
    #NX_SCROLLWHEELMOVED = 22
    #NX_SCROLLWHEELMOVEDMASK = 1 << #NX_SCROLLWHEELMOVED

    ImportC ""
      CGEventTapCreateForPSN(*ProcessSerialNumber, CGEventTapPlacement.I,
        CGEventTapOptions.I, CGEventMask.Q, CGEventTapCallback.I, *UserData)
      GetCurrentProcess(*ProcessSerialNumber)
    EndImport

    ProcedureC MouseWheelCallback(CGEventTapProxy.I, CGEventType.I, CGEvent.I,
      *UserData)
      Protected DeltaY.CGFloat
      Protected NSEvent.I
      Protected Point.NSPoint
      
      NSEvent = CocoaMessage(0, 0, "NSEvent eventWithCGEvent:", CGEvent)
      CocoaMessage(@Point, NSEvent, "locationInWindow")
      
      If CocoaMessage(0, CocoaMessage(0, WindowID(#Window), "contentView"),
        "hitTest:@", @Point) = GadgetID(#ListIcon)
        CocoaMessage(@DeltaY, NSEvent, "deltaY")
        
        If DeltaY < 0.0
          PostEvent(#PB_Event_Gadget, #Window, #ListIcon,
            #PB_EventType_MouseWheel_Down)
        Else
          PostEvent(#PB_Event_Gadget, #Window, #ListIcon,
            #PB_EventType_MouseWheel_Up)
        EndIf
      EndIf
    EndProcedure
  CompilerCase #PB_OS_Windows ; ------------------------------------------------
    Define DefaultListIconCallback.I

    Procedure CustomListIconCallback(WindowHandle.I, Msg.I, WParam.I, LParam.I)
      Shared DefaultListIconCallback.I

      If Msg = #WM_MOUSEWHEEL
        If (WParam >> 16) & $8000
          PostEvent(#PB_Event_Gadget, #Window, #ListIcon,
            #PB_EventType_MouseWheel_Down)
        Else         
          PostEvent(#PB_Event_Gadget, #Window, #ListIcon,
            #PB_EventType_MouseWheel_Up)
        EndIf
      EndIf

      ProcedureReturn CallWindowProc_(DefaultListIconCallback, WindowHandle,
        Msg, WParam, LParam)
   EndProcedure
CompilerEndSelect

Define i.I

OpenWindow(0, 200, 100, 300, 140, "Detect mouse wheel scrolling")
ListIconGadget(#ListIcon, 10, 10, 280, 120, "Column 1", 100)

For i = 1 To 20
  AddGadgetItem(0, -1, "Line " + Str(i))
Next i

CompilerSelect #PB_Compiler_OS
  CompilerCase #PB_OS_Linux
    gdk_event_handler_set_(@MouseWheelCallback(), 0, 0)
  CompilerCase #PB_OS_MacOS
    Define MachPort.I
    Define ProcessSerialNumber.Q

    GetCurrentProcess(@ProcessSerialNumber)
    MachPort = CGEventTapCreateForPSN(@ProcessSerialNumber,
      #kCGHeadInsertEventTap, #kCGEventTapOptionListenOnly,
      #NX_SCROLLWHEELMOVEDMASK, @MouseWheelCallback(), 0)

    If MachPort
      CocoaMessage(0, CocoaMessage(0, 0, "NSRunLoop currentRunLoop"),
      "addPort:", MachPort,
      "forMode:$", @"kCFRunLoopCommonModes")
    EndIf
  CompilerCase #PB_OS_Windows
    DefaultListIconCallback = GetWindowLongPtr_(GadgetID(#ListIcon),
      #GWL_WNDPROC)
    SetWindowLongPtr_(GadgetID(#ListIcon), #GWL_WNDPROC,
      @CustomListIconCallback())
CompilerEndSelect

SetActiveGadget(#ListIcon)

Repeat
  Select WaitWindowEvent()
    Case #PB_Event_CloseWindow
      CompilerSelect #PB_Compiler_OS
        CompilerCase #PB_OS_Linux
          gdk_event_handler_set_(0, 0, 0)
        CompilerCase #PB_OS_MacOS
          CFRelease_(MachPort)
      CompilerEndSelect
      Break
    Case #PB_Event_Gadget
      If EventGadget() = #ListIcon
        Select EventType()
          Case #PB_EventType_MouseWheel_Down
            Debug "Mouse wheel moved down"
          Case #PB_EventType_MouseWheel_Up
            Debug "Mouse wheel moved up"
        EndSelect
      EndIf
  EndSelect
ForEver

[marcoagpinto]

Thanks for all the help!!!!!