KeyEvent

[Anonymous]

Is there a possibility to get information about pressed keys in a graphic window, without stop the programm until a key is pressed?

I am using the ms windows version of X11 basic.

[Markus Hoffmann]

Wait! Have you tried the EVENT?() function? It can tell you at least if an event is pending without waiting for it.

[Markus Hoffmann]

Ok, I see what you mean. It is currently not working under WINDOWS. I am working on that. The next release 1.23-22 should have improved EVENT command and EVENT?() function, which together should do the job.

[Anonymous]

Hi,
so is it working now? I cannot get this work on my android device. It is crucial function to me to create program which is doing something and I can interrupt it with a keypress. do you have example code please?

[Yet Another Troll]

Here is something to try. It seems to work on Win32, even though I was mainly investigating some Android quirks having to do with rotating the Android device and getting the program to detect the changed screen parameters and redraw as well as quit on a touch. It does detect and report keypresses.

:::basic
#!/usr/bin/xbasic

Program Sined

 ' Initialize global variables
 Clr ScaleLeft, ScaleTop, ScaleRight, ScaleBottom
 Clr ScaleHM, ScaleHB, ScaleVM, ScaleVB

 '@FlushEvents
 @Main
 '@FlushEvents
End

Procedure Main()
 Local PrevLeft%, PrevTop%, PrevWidth%, PrevHeight%
 Local CurrLeft%, CurrTop%, CurrWidth%, CurrHeight%
 Local QuittingTime%, RedrawNeeded%
 Local EventMask%, EventType%
 Local KEvents%, MEvents%, WEvents%

 ' Cls
 Screen 28 ! 1280x1024x24, no-op on Android?
 Get_ScreenSize PrevLeft%, PrevTop%, PrevWidth%, PrevHeight%
 Print PrevLeft%, PrevTop%, PrevWidth%, PrevHeight%

 ' All no-op on Android?
 OpenW 1
 MoveW 1, 10, 20
 SizeW 1, 800, 480
 TitleW 1, "Sined, Sealed, Delivered"
 ShowPage
 Pause 0.1

 ' Initialize the event loop
 Clr KEvents%, MEvents%, WEvents%
 Clr EventMask%, EventType%
 QuittingTime% = False
 RedrawNeeded% = True

 ' Our very first event pump in X11 BASIC 
 While (EventType% <> 0) Or Not QuittingTime%

  ' Looks like we need to poll for resizes due to device rotations 
  ' or the on screen keyboard being summoned or dismissed
  Get_Geometry 1, CurrLeft%, CurrTop%, CurrWidth%, CurrHeight%
  ' Is the left, top coordinate ever not (0, 0) ?
  If (CurrWidth% <> PrevWidth%) Or (CurrHeight% <> PrevHeight%) Then
   Print "Geometry changed"
   PrevLeft% = CurrLeft%
   PrevTop% = CurrTop%
   PrevWidth% = CurrWidth%
   PrevHeight% = CurrHeight%
   RedrawNeeded% = True
   ' Device rotations also appear to cause spurious kb events?
   ' @FlushEvents
   ' Cls
  EndIf

  If RedrawNeeded% Then
   Print "Redrawing"
   @Redraw()
   RedrawNeeded% = False
  EndIf

  ' Peek at any/all pending events, keyboard/mouse/window
  EventMask% = 1 Or 2 Or 4 Or 8 Or 0x40 Or 0x40000 Or 0x200000
  Print Hex$(EventMask%); " ";
  EventMask% = Event?(EventMask%)
  Print Hex$(EventMask%); " ";

  If EventMask% Then
   ' Fetch a pending event
   Event EventType% ! Lots of fun optional out parameters can go here
   Print EventType%; " ";
  Else
   ' No events are waiting
   EventType% = 0
  EndIf

  Select EventType%
   Case 10, 13
    ' Window moved or resized
    Print "Window"
    Inc WEvents%
    RedrawNeeded% = True
   Case 2, 3
    ' Keyboard key down/up
    Print "Keybd"
    Inc KEvents%
    ' Beware of spurious kb events on Android
    ' QuittingTime% = True
   Case 4, 5, 6
    ' Mouse button down/up, move
    Print "Mouse"
    Inc MEvents%
    QuittingTime% = True
   Default
    ' No news is good news
    Print "Nada"
  EndSelect

  If (EventType% = 0) And Not QuittingTime% Then
   Pause 1
  EndIf 

 Wend

 Print KEvents%; " key, ";  MEvents%; " mouse, "; WEvents%; " window"

Return

Procedure Redraw()
 Local Left%, Top%, Width%, Height%
 Local cX, cY, pX, pY, theta

 OpenW 1
 Get_Geometry 1, Left%, Top%, Width%, Height%
 Print Left%, Top%, Width% - 1, Height% - 1

 ' Sanity check coordinate system

 Color Color_RGB(0, 0, 1, 0.7)
 Draw Left%, Top% To (Left% + Width% - 1), (Top% + Height% - 1)
 ShowPage

 Color Color_RGB(0, 1, 0, 0.7)
 Draw (Left% + Width% - 100), Top%  To Left%, Top%
 Draw To Left%, (Top% + Height% - 1)
 Draw To (Left% + Width% - 1), (Top% + Height% - 1)
 Draw To (Left% + Width% - 1), Top%
 ShowPage

 ' Reject screen's reality and substitute our own
 @SetScale(-10, 10, -2, 2)

 ' Set up our axes
 Color Color_RGB(1, 1, 1)
 @ScaleLine(-10, 0, 10, 0)
 @ScaleLine(0, 2, 0, -2)
 For cY = 0 To ScaleTop Step 0.25
  @ScaleLine(-0.1, cY, 0.1, cY)
  @ScaleLine(-0.1, -cY, 0.1, -cY)
 Next cY
 For cY = 0 To ScaleTop
  @ScaleLine(-0.25, cY, 0.25, cY)
  @ScaleLine(-0.25, -cY, 0.25, -cY)
 Next cY
 For cX = 0 To ScaleRight Step (Pi / 4)
  @ScaleLine(cX, 0.025, cX, -0.025)
  @ScaleLine(-cX, 0.025, -cX, -0.025)
 Next cX
 For cX = 0 To ScaleRight Step (Pi / 2)
  @ScaleLine(cX, 0.05, cX, -0.05)
  @ScaleLine(-cX, 0.05, -cX, -0.05)
 Next cX
 For cX = 0 To ScaleRight Step Pi
  @ScaleLine(cX, 0.1, cX, -0.1)
  @ScaleLine(-cX, 0.1, -cX, -0.1)
 Next cX
 ShowPage

 ' Plot f(x)
 Color Color_RGB(1, 0, 0)
 Clr pX, pY, cX, cY
 pX = 1e200
 For theta = ScaleLeft To ScaleRight Step (Pi / 100)
  cX = theta
  cY = @f(theta)
  If (ScaleLeft <= pX) And (pX <= ScaleRight) Then
   @ScaleLine(pX, pY, cX, cY)
  EndIf
  pX = cX
  pY = cY
 Next theta
 ShowPage
Return

DefFn f(x) = (Sin(x) + (Cos(5*x)/2))

Procedure SetScale(NewLeft, NewRight, NewBottom, NewTop)
 Local Left%, Top%, Width%, Height%

 Get_Geometry 1, Left%, Top%, Width%, Height%
 Print Left%, Top%, Width% - 1, Height% - 1

 ScaleLeft = NewLeft
 ScaleTop = NewTop
 ScaleRight = NewRight
 ScaleBottom = NewBottom

 ScaleHM = (Width% - 1) / (NewRight - NewLeft)
 ScaleHB = Left% - ((Width% - 1) / (NewRight - NewLeft)) * NewLeft
 ScaleVM = (Height% - 1) / (NewBottom - NewTop)
 ScaleVB = Top% - ((Height% - 1) / (NewBottom - NewTop)) * NewTop

 Print ScaleLeft, ScaleRight, ScaleBottom, ScaleTop
 Print ScaleHM, ScaleHB, ScaleVM, ScaleVB
Return

Procedure ScaleLine(x0, y0, x1, y1)
 Draw ScaleHM * x0 + ScaleHB, ScaleVM * y0 + ScaleVB \
   To ScaleHM * x1 + ScaleHB, ScaleVM * y1 + ScaleVB
Return

' Android appears to allow events to accumulate between runs
Procedure FlushEvents()
 Local EventMask%, EventType%
 Clr EventMask%, EventType%
 Print "FlushEvents ";
 Repeat
  ' Are any events clogging the queue?
  ' Peek at any/all pending events, keyboard/mouse/window
  EventMask% = 1 Or 2 Or 4 Or 8 Or 0x40 Or 0x40000 Or 0x200000
  EventMask% = Event?(EventMask%)
  If EventMask% Then
   ' Catch and kill pending event
   Event EventType%
  Else
   ' No events are waiting
   EventType% = 0
  EndIf
  Print EventType%; " ";
 Until EventType% = 0
 Print ""
Return

' Stolen from http://x11-basic.sourceforge.net/FAQ.html
Function ChrW$(Unicode%)
 If Unicode% < 0x80 Then
  Return Chr$(Unicode%)
 Else If Unicode% < 0x2000 Then
  Return Chr$(0xc0 Or ((Unicode% Div 64) And 0x1f)) \ 
       + Chr$(0x80 Or (Unicode% And 0x3f))
 Else
  Return Chr$(0xe0 Or ((Unicode% Div (64 * 64)) And 0xf)) \
       + Chr$(0x80 Or ((Unicode% Div 64) And 0x3f))       \
       + Chr$(0x80 Or (Unicode% And 0x3f))
 EndIf
EndFunction