!SineSumBeats:  As noted, changing  omega  resest  A  to 1
!It would be more natural to have the rollover recorded in multiples of
!pi, but drawing the pi might take too much time?

!It might be fast enough if I draw it once, and then capture it as
!a pattern of graphics memory - sort of like a rubber stamp.

!Meanwhile, I was showing the SineSum tool to someone, the most recent linux
!compile, and it broke on me: I set the amplitude A to 1/2, then changed the
!frequency (I think - maybe the phase, but I think it was omega) and presto,
!the amplitude reset itself to 1.

!! File: SineSumBeats
!! May 26, 2003 Hubert Hohn

PUBLIC PCFlag,Mac5Flag,M68KFlag,UnixFlag,xmax,ymax
PUBLIC toolLft,toolRgt,toolBas,toolTop,toolhdr,toolHgt,toolWid  ! tool boundaries
PUBLIC winLft,winRgt,winBas,winTop,winHgt,winWid      ! window
PUBLIC workLft,workRgt,workBas,workTop,workMidx  ! work area
PUBLIC backclr,black,drkgry,drkmid,midgry,litmid,litgry,white
PUBLIC red,yellow,green,cyan,blue,magenta,pink,colorscheme
PUBLIC planeclr,gridclr,rimclr,axisclr,axislabelclr,titleclr,rightsclr
PUBLIC numberlineclr,slotdrkclr,slotlgtclr,slideclr
PUBLIC largefonts, title$, SLUmode

LET toolHgt= 560
LET toolWid= 780
LET window$= "The d'Arbeloff Interactive Math Project"
LET colorscheme= 0

LET title$ = "Sine Sum Beats"

SUB ThisProgram
    CALL SineSumBeats
    CLEAR
END SUB


!! ---------------------------------------------------------
!! ------ Start TB4 Mac Header and Subs ------

!LET M68KFlag = 1
!LIBRARY "MacTools*", "HHLib.trc"
!ASK PIXELS winWid,winHgt
!LET winLft= 0
!LET winTop= 0
!LET winRgt= winWid-1
!LET winBas= winHgt-1
!SET WINDOW 0,winRgt,winBas,0
!CALL Palette
!CLEAR
!
!CALL ToolPanel
!CALL ThisProgram
!
!END
!EXTERNAL
!
!MODULE Mac4Parts
!    SUB SetTextFont(font,size,style$)
!        CALL MacTextFont(font)
!        CALL MacTextSize(size)
!        CALL MacTextFace(style$)
!    END SUB
!
!    SUB StringWidth(sw$,sl)
!        DECLARE DEF MacStringWidth
!        LET sl= MacStringWidth(sw$)
!    END SUB
!
!    SUB SetLineWeight(wgt)
!        CALL MacPenSize(wgt,wgt)
!    END SUB
!
!    SUB BoxDisk(Lft,Rgt,Bas,Top)
!        CALL MacPaintOval(Lft,Rgt,Bas,Top)
!    END SUB
!END MODULE

!! --- End TB4 Mac Header and Subs ---
!!---------------------------------------------------------
!!--- Start TB5 Cross-Platform header and subs ---

LIBRARY "c:\TB Gold 51a\TBLibs\TrueCtrl.trc"     ! windows
LIBRARY "c:\TB Gold 51a\TBLibs\HHLib.trc"
!
!LIBRARY ":TBLibs:TrueCtrl.trc"                   ! macintosh
!LIBRARY "HHLib.trc"
!
PUBLIC WinID
DECLARE PUBLIC OBJM_SET,OBJM_SYSINFO
LET winHgt= toolHgt
LET winWid= toolWid
DIM values(1)

CALL TC_Init

CALL Object(OBJM_SYSINFO,WinID,"MACHINE",system$,values())
IF system$="MAC" then
   LET Mac5Flag= 1
ELSE IF system$="WIN32" then
   LET PCFlag  = 1
END IF

CALL TC_SetUnitsToPixels                         ! 5.1 and up needs this
CALL TC_GetScreenSize(scrnLft,scrnRgt,scrnBas,scrnTop)
LET winLft= int((scrnRgt-scrnLft-winWid)/2)
LET winRgt= winLft+winWid-1
LET winTop= int((scrnBas-scrnTop-winHgt)/2) + 10
LET winBas= winTop+winHgt-1

CALL TC_Win_Create (WinID,"TITLE",winLft,winRgt,winBas,winTop)
LET values(1)= 2
CALL Object(OBJM_SET, WinID, "TYPE", "", values())

IF PCFlag=1 then                                 ! kill dithering
   LET  values(1)= 1
   CALL Object(OBJM_SET, WinID, "SOLID MIX", "", values())
END IF

LET  values(1)= 0
CALL TC_SetRect(WinID,winLft,winRgt,winBas,winTop)
CALL TC_Win_SetTitle(WinID,window$)
CALL TC_Show(WinID)

SET MODE "COLORSTANDARD"

ASK PIXELS winWid,winHgt                         ! must follow set mode
LET winLft= 0
LET winTop= 0
LET winRgt= winWid-1
LET winBas= winHgt-1
SET WINDOW 0,winRgt,winBas,0

CALL Palette

IF PCFlag=1 then
   LET  values(1)= 0                             ! now force solid colors
   CALL Object(OBJM_SET, WinID, "SOLID MIX", "", values())
   CALL TC_Win_RealizePalette(WinID)             ! some PCs need this

   CALL TC_Win_SetFont(WinID,"arial",9,"plain")
   CALL StringWidth("0",sw)
   IF sw>7 then LET largefonts=1 else LET largefonts=0
END IF

CALL TC_Win_Switch(WinID)

CALL ToolPanel
CALL ThisProgram

CALL SetTextFont(1,12,"bold")                    ! now shut down and clean up
LET quit$= "click the mouse or press a key to close..."
CALL PlotTextCJ(workmidx,(workbas+worktop)/2,quit$,yellow)
CALL TC_CleanUp

END
EXTERNAL

MODULE TB5Parts
    SUB StringWidth(sw$,sl)
        DECLARE PUBLIC WinID
        LET sl= StrWidth(WinID,sw$)
    END SUB

    SUB SetLineWeight(wgt)
        DECLARE PUBLIC OBJM_SET
        DECLARE PUBLIC WinID
        DIM values(1)
        LET values(1)= wgt
        CALL Object(OBJM_SET,WinID, "WIDTH", "", values())
    END SUB

    SUB SetTextFont(font,size,style$)
        DECLARE PUBLIC WinID,Mac5Flag,PCFlag,largefonts
        IF Mac5Flag=1 then
           SELECT CASE font
           CASE 4
                LET font$= "Courier"
           CASE 16
                LET font$= "Times"
           CASE else
                LET font$= "Geneva"
           END SELECT
        ELSE IF PCFlag=1 then
           IF largefonts=1 then
              IF size<12 then
                 LET size=  6
              ELSE IF size=14 then
                 LET size= 10
              ELSE IF size=18 then
                 LET size= 12
              ELSE IF size=24 then
                 LET size= 14
              ELSE IF size=12 then
                 LET size=  8
              ELSE
                 LET size= round(72/96 * size * .8)
              END IF
           ELSE
              IF size<12 then
                 LET size=  7
              ELSE IF size=14 then
                 LET size= 12
              ELSE IF size=12 then
                 LET size=  9
              ELSE IF size=18 then
                 LET size= 14
              ELSE IF size=24 then
                 LET size= 18
              ELSE
                 LET size= round(72/96 * size)
              END IF
           END IF
           SELECT CASE font
           CASE 4
                LET font$= "Courier New"
           CASE 16
                LET font$= "Times New Roman"
           CASE else
                LET font$= "Verdana"
           END SELECT
        END IF
        IF style$= "normal" then LET style$= "plain"
        CALL TC_Win_SetFont(WinID,font$,size,style$)
    END SUB

    SUB BoxDisk(Lft,Rgt,Bas,Top)
        BOX DISK Lft,Rgt,Bas,Top
    END SUB
END MODULE

!  --- End TB5 Cross-platform header and subs ---
!! ---------------------------------------------------------

!! --- Start Unix Header and Subs ---

!library "HHLib.unix"
!LET UnixFlag= 1
!ASK PIXELS winWid,winHgt
!LET winLft= 0
!LET winTop= 0
!LET winRgt= winWid-1
!LET winBas= winHgt-1
!SET WINDOW 0,winRgt,winBas,0
!CALL Palette
!
!CALL ToolPanel
!CALL ThisProgram
!
!END
!EXTERNAL
!
!MODULE UnixParts
!    SHARE CharWidth
!
!    SUB SetTextFont(font,size,style$)
!        LET font$= "-adobe-courier-"
!        IF style$= "normal" then
!           LET style$= "medium-r-normal--"
!        ELSE
!           LET style$= "bold-r-normal--"
!        END IF
!        IF size=9 then
!           LET size$= str$(10)
!        ELSE
!           LET size$= str$(size)
!        END IF
!        LET test= SetFont(font$&style$&size$&"*")
!
!        IF size=9 then
!           LET CharWidth=  6
!        ELSE IF size=12 then  ! numeric output - axis labels
!           LET CharWidth=  7
!        ELSE IF size=14 then  ! rare
!           LET CharWidth=  8
!        ELSE IF size=18 then  ! rare
!           LET CharWidth= 10
!        END IF
!    END SUB
!
!    SUB StringWidth(sw$,sl)                      ! string width in pixels
!        ! LET sl= StrWidth(sw$)
!        LET chars= len(sw$)
!        LET sl   = chars*CharWidth
!    END SUB
!
!    SUB SetLineWeight(wgt)
!        ! CALL PenSize(wgt,wgt)
!    END SUB
!
!    SUB BoxDisk(Lft,Rgt,Bas,Top)
!        CALL Fill_Circle(Lft,Rgt,Bas,Top)
!    END SUB
!END MODULE

!! ------ End of TB Unix Header and Subs ------
! -----------------------------------------------------------


! ***

SUB SineSumBeats
    DECLARE PUBLIC black,drkgry,drkmid,midgry,litmid,litgry,white
    DECLARE PUBLIC red,yellow,green,cyan,blue,magenta,colorscheme
    DECLARE PUBLIC planeclr,gridclr,rimclr,axisclr,axislabelclr,slideclr
    DECLARE PUBLIC workLft,workRgt,workBas,workTop,workMidx
    DECLARE PUBLIC true,false

    DECLARE DEF quitWithin, infoWithin

    ! --- help screen array ---

    DIM  info$(1:1)
    MAT READ info$
    DATA "Information on beats and resonance"

    ! ---------- Utility functions ---

    DECLARE DEF clamp,roundn,e

    ! --- functions and parameters

    DEF pi2  = 2*pi

    DEF f(x) = sin(x)                            ! fixed wave

    DEF g(x) = a * sin(w*x - p)                  ! adjustable wave

    DEF env(x)
        IF w>0.5 and w<1.5 then
           LET env= (1+a) * cos(0.5*((1-w)*x + p))    ! envelope for w near 1
        ELSE IF w<0.5 then
           LET env= a + g(x)                     ! envelope for w near 1
        END IF
    END DEF

    ! ---------- Graphing plane parameters and methods ----------

    LET wwid  = 600
    LET whgt  = 128
    LET frgt  = 200
    LET orange=   9

    ! ------------------------------------------
    ! --- plane 2 data ---

    DECLARE PUBLIC w2Lft,w2Rgt,w2Bas,w2Top,w2Midx,w2Midy
    DECLARE PUBLIC w2fLft,w2fRgt,w2fBas,w2fTop,w2x0,w2y0
    DECLARE PUBLIC w2xFirst, w2xSTik, w2xLTik, w2xLabel, w2xGridstep
    DECLARE PUBLIC w2yFirst, w2ySTik, w2yLTik, w2yLabel, w2yGridstep
    DECLARE PUBLIC w2xPiFlag, w2xMult, w2yPiFlag, w2yMult
    DECLARE PUBLIC w2wWid, w2fWid, w2wHgt, w2fHgt, w2Aspect

    LET w2Flag   = 1
    LET w2xPiFlag= 1
    LET w2yPiFlag= 0
    LET w2xMult  = pi
    LET w2yMult  = 1

    LET w2clr    = green

    LET w2Lft = worklft+90                       ! pixel window bounds
    LET w2Rgt = w2Lft+wwid
    LET w2Top = workTop+40
    LET w2Bas = w2Top+whgt

    LET w2fLft=  0                               ! function bounds * pi
    LET w2fRgt= 60
    LET w2fTop=  2                               ! function bounds
    LET w2fBas= -2

    LET w2xGridstep= 0                           ! horizontal grid intervals
    LET w2yGridstep= 0                           ! vertical grid intervals

    LET w2xAx$= "t"                              ! axis labels
    LET w2yAx$= "f(t) + g(t)"

    LET w2xSTik  =  0                            ! horizontal axis Tik marks
    LET w2xLTik  =  2
    LET w2xLabel = 10
    LET w2xFirst = w2fLft

    LET w2ySTik  = 0                             ! vertical axis Tik marks
    LET w2yLTik  = 1
    LET w2yLabel = 1
    LET w2yFirst = w2fBas

    ! --- plane 2 methods ---

    DECLARE DEF w2fncx, w2fncy, w2wndx, w2wndy   ! window/function transforms
    DECLARE DEF w2wWithin

    CALL w2Variables

    SUB w2InitPlane
        CALL w2DrawPlane(1,1,1)                  ! xaxis, yaxis, zeroaxes
        CALL SetTextFont(1,12,"bold")
        CALL PlotTextLJ(w2Rgt+8,w2y0+3,w2xAx$,axislabelclr)     ! axis labels
        CALL PlotTextCJ(w2x0,w2Top-12,w2yAx$,w2clr)
        CALL w2KeepGridLayer
    END SUB

    ! --- plane 1 data ---

    DECLARE PUBLIC w1Lft, w1Rgt, w1Bas, w1Top, w1Midx, w1Midy
    DECLARE PUBLIC w1fLft, w1fRgt, w1fBas, w1fTop, w1x0, w1y0
    DECLARE PUBLIC w1xFirst, w1xSTik, w1xLTik, w1xLabel, w1xGridstep
    DECLARE PUBLIC w1yFirst, w1ySTik, w1yLTik, w1yLabel, w1yGridstep
    DECLARE PUBLIC w1xPiFlag, w1xMult, w1yPiFlag, w1yMult
    DECLARE PUBLIC w1wWid, w1fWid, w1wHgt, w1fHgt, w1Aspect

    LET w1Flag   = 1                             ! pixel window visibility
    LET w1xPiFlag= 1                             ! pi switch for x axis
    LET w1yPiFlag= 0                             ! pi switch for y axis
    LET w1xMult  = pi
    LET w1yMult  = 1

    LET w1clr = red
    LET w3clr = yellow

    LET w1Lft = workLft+90                       ! pixel window bounds
    LET w1Rgt = w1Lft+wwid
    LET w1Top = w2Bas + 70
    LET w1Bas = w1Top+whgt

    LET w1fLft=  0                               ! function bounds
    LET w1fRgt= w2fRgt
    LET w1fTop=  2
    LET w1fBas= -2

    LET w1xAx$= "t"                              ! axis labels
    LET w1yAx$= "f(t) = sin(t)"
    LET w3yAx$= "g(t) = A sin(wt+phi)"

    LET w1xGridstep= 0                           ! horizontal grid intervals
    LET w1yGridstep= 0                           ! vertical grid intervals

    LET w1xSTik =  0                             ! horizontal axis Tik marks
    LET w1xLTik =  2
    LET w1xLabel= 10
    LET w1xFirst= w1fLft

    LET w1ySTik = 0                              ! vertical axis Tik marks
    LET w1yLTik = 1
    LET w1yLabel= 1
    LET w1yFirst= w1fBas

    ! --- Plane 1 methods ---

    DECLARE DEF w1fncx,w1fncy,w1wndx,w1wndy      ! window/function transforms
    DECLARE DEF w1wWithin

    CALL w1Variables

    SUB w1InitPlane
        CALL w1DrawPlane(1,1,1)                  ! x axis, y axis, zeroaxes
        CALL SetTextFont(1,12,"bold")
        CALL PlotTextLJ(w1Rgt+8,w1y0+3,w1xAx$,axislabelclr)     ! axis labels

        CALL PlotTextRJ(w1x0,w1Top-30,"f(t) = ",red)
        CALL PlotTextLJ(w1x0,w1Top-30,"sin(t)",red)

        CALL PlotTextRJ(w1x0,w1Top-12,"g(t) = ",w3Clr)
        CALL StringWidth("A sin(w",sw)
        CALL SwapOmega(w1x0,w1Top-12,"A sin(w","w",w3Clr)
        CALL SwapPhi(w1x0+sw+2,w1Top-12,"t + p)","p",w3Clr)

        CALL w1KeepGridLayer
    END SUB


    ! ----------- horizontal sliders ------------

    LET slideWidth= 100

    ! --- horizontal slider 1 ---

    DECLARE PUBLIC h1axis,h1wLft,h1wRgt,h1wBas,h1wTop,h1fLft,h1fRgt
    DECLARE PUBLIC h1name$,h1form$,h1clr,h1First,h1STik,h1LTik,h1Label
    DECLARE PUBLIC h1PiAxis,h1Mult,h1fMin,h1fMax

    DECLARE DEF  h1Within                        ! window/function transforms

    LET h1PiAxis= 0
    LET h1Mult  = 1

    LET h1clr   = white
    LET h1name$ = "A"
    LET h1form$ = "%.##"
    LET h1Places= 2

    LET h1axis = workbas - 25
    LET h1wLft = w1Lft
    LET h1wRgt = h1wLft+100

    LET h1fLft = 0
    LET h1fRgt = 1

    LET h1STik = 0.1                             ! short tick marks
    LET h1LTik = 0.5                             ! long tick marks
    LET h1Label= 0.5                             ! labels
    LET h1First= h1fLft                          ! first tick mark
    LET h1Click= 1/2

    SUB h1InitSlider
        CALL h1SliderVariables
        CALL h1DrawSlider(h1name$,a)
    END SUB

    ! --- horizontal slider 2 ---

    DECLARE PUBLIC h2axis,h2wLft,h2wRgt,h2wBas,h2wTop,h2fLft,h2fRgt
    DECLARE PUBLIC h2name$,h2form$,h2clr,h2First,h2STik,h2LTik,h2Label
    DECLARE PUBLIC h2PiAxis,h2Mult,h2fMin,h2fMax

    DECLARE DEF h2Within                         ! window/function transforms

    LET h2PiAxis= 0
    LET h2Mult  = 1

    LET h2clr   = white
    LET h2name$ = ""                             ! omega
    LET h2form$ = "%.###"
    LET h2Places= 3

    LET h2axis = h1axis - 45
    LET h2wLft = w1Lft
    LET h2wRgt = h2wLft + 600

    LET h2fLft = 0
    LET h2fRgt = 2

    LET h2STik = 0.05                            ! short tick marks
    LET h2LTik = 0.1                             ! long tick marks
    LET h2Label= 0.5                             ! labels
    LET h2First= h2fLft                          ! first tick mark
    LET h2Click= 0.05

    DECLARE DEF h2LstpWithin , h2RstpWithin
    DECLARE DEF h2LmoveWithin, h2RmoveWithin

    LET h2AnimStep= 0.001
    LET h2MoveStep= 0.002

    SUB h2InitSlider
        CALL h2SliderVariables
        CALL h2DrawSlider(h2name$,w)
        CALL SwapOmega(h2wLft-16,h2wbas-2,"w","w",white)
        CALL h2MoveButtons
    END SUB

    ! --- horizontal slider 3 ---

    DECLARE DEF h3Within                         ! window/function transforms

    DECLARE PUBLIC h3axis,h3wLft,h3wRgt,h3wBas,h3wTop,h3fLft,h3fRgt
    DECLARE PUBLIC h3name$,h3form$,h3clr,h3First,h3STik,h3LTik,h3Label
    DECLARE PUBLIC h3PiAxis,h3Mult,h3fMin,h3fMax

    LET h3piAxis= 1
    LET h3Mult  = pi

    LET h3clr   = white
    LET h3name$ = ""
    LET h3form$ = "%.##"
    LET h3Places= 2

    LET h3axis = h1axis
    LET h3wLft = h1wRgt + 100
    LET h3wRgt = h3wLft + 100

    LET h3fLft = 0
    LET h3fRgt = 2

    LET h3STik = 0                               ! short tick marks
    LET h3LTik = 0.5                             ! long tick marks
    LET h3Label= 1                               ! labels
    LET h3First= h3fLft                          ! first tick mark
    LET h3Click= pi/2

    SUB h3InitSlider
        CALL h3SliderVariables
        CALL h3DrawSlider(h3name$,p)
        CALL SwapPhi(h3wLft-15,h3wbas-2,"p","p",white)
    END SUB

    ! ---------- Text Output Rects ----------

    ! --- text rectangle 1 ---

    LET t1BasLn = w1Bas + 40
    LET t1Lft   = w1Lft
    LET t1Rgt   = t1Lft + 150
    LET t1Bas   = t1BasLn +  5
    LET t1Top   = t1BasLn - 15
    LET t1Label$= "_[tone] = "
    LET t1Eqx   = t1lft + 55
    LET t1vBasLn= t1BasLn + 20
    LET t1vBas  = t1vBasLn +  5
    LET t1vTop  = t1vBasLn - 15
    LET t1clr   = green

    SUB t1Label
        CALL SetTextFont(1,9,"bold")
        CALL StringWidth("tone",sw9)
        CALL SetTextFont(1,12,"bold")
        CALL StringWidth(" = ",sw12)
        LET sw= sw9+sw12

        CALL SuperSubScriptRJ(t1Eqx,t1BasLn,t1Label$,t1Clr)
        CALL DrawLam(t1Eqx-sw-10,t1BasLn,t1Clr)
        CALL PlotTextRJ(t1Eqx,t1vBasLn,"= ",t1Clr)
    END SUB

    SUB t1Set
        IF (a+w)<>0 then
           LET t1$= "(4/(w_[n]+w))"
           CALL SuperSubScriptOmegaLJ(t1Eqx,t1BasLn,t1$,"w",t1Clr)
           LET t1$= "(4/(wn+w))"
           CALL StringWidth(t1$,sw)
           BOX SHOW t1pi$ at t1Eqx+sw+4,t1BasLn
        ELSE

        END IF
        CALL t1vSet
    END SUB

    SUB t1vSet
        CALL t1vClear
        IF (a+w)<>0 then
           LET t1$= trim$(using$("---%.##",4/(a+w)))
           CALL PlotTextLJ(t1Eqx,t1vBasLn,t1$,t1Clr)
           CALL StringWidth(t1$,sw)
           BOX SHOW t1pi$ at t1Eqx+sw+4,t1vBasLn
        ELSE
           CALL SwapInf(t1Eqx+2,t1vBasLn,"8","8",t1Clr)
        END IF
    END SUB

    SUB t1Clear
        BOX CLEAR t1Lft-2,t1Rgt,t1Bas,t1Top
    END SUB

    SUB t1vClear
        BOX CLEAR t1Eqx-2,t1Rgt,t1vBas,t1vTop
    END SUB

    SUB t1Init
        CALL t1Label
        CALL t1Set
    END SUB


    ! --- text rectangle 2 ---

    LET t2BasLn = t1BasLn
    LET t2Lft   = w2Rgt - 165
    LET t2Rgt   = w2Rgt + 20
    LET t2Bas   = t2BasLn +  5
    LET t2Top   = t2BasLn - 15
    LET t2Label$= "_[packet] = "
    LET t2Eqx   = t2Lft + 75
    LET t2vBasLn= t2BasLn + 20
    LET t2vBas  = t2vBasLn +  5
    LET t2vTop  = t2vBasLn - 15
    LET t2Clr   = cyan

    SUB t2Label
        CALL SetTextFont(1,9,"bold")
        CALL StringWidth("packet",sw9)
        CALL SetTextFont(1,12,"bold")
        CALL StringWidth(" = ",sw12)
        LET sw= sw9+sw12

        CALL SuperSubScriptRJ(t2Eqx,t2BasLn,t2Label$,t2Clr)
        CALL DrawLam(t2Eqx-sw-10,t2BasLn,t2Clr)
        CALL PlotTextRJ(t2Eqx,t2vBasLn,"= ",t2Clr)
    END SUB

    SUB t2Set
        LOCAL z$
        IF a-w<>0 then
           CALL SetTextFont(1,12,"bold")
           LET t2$= "(2/|w_[n]-w|)"
           CALL SuperSubScriptOmegaLJ(t2Eqx,t2BasLn,t2$,"w",t2Clr)
           LET t2$= "(2/|wn-w|)"
           CALL StringWidth(t2$,sw)
           BOX SHOW t2pi$ at t2Eqx+sw+4,t2BasLn
        ELSE

        END IF
        CALL t2vSet
    END SUB

    SUB t2vSet
        CALL t2vClear
        CALL SetTextFont(1,12,"bold")
        LET t2a= 1
        IF t2a-w<>0 then
           LET t2$= trim$(using$("----%.##",2/abs(t2a-w)))
           CALL PlotTextLJ(t2Eqx,t2vBasLn,t2$,t2Clr)
           CALL StringWidth(t2$,sw)
           BOX SHOW t2pi$ at t2Eqx+sw+4,t2vBasLn
        ELSE
           CALL SwapInf(t2Eqx+2,t2vBasLn,"8","8",t2Clr)
        END IF
    END SUB

    SUB t2vClear
        BOX CLEAR t2Eqx-2,t2Rgt,t2vBas,t2vTop
    END SUB

    SUB t2Init
        CALL t2Label
        CALL t2Set
    END SUB


    ! --- Rollover parameters and cleanup ---

    LET rolft  = w2Lft - 25
    LET rorgt  = w2Rgt + 40
    LET robasln= w2Top - 27
    LET robas  = robasln+ 5
    LET rotop  = robasln-10

    SUB ClearRollText
        BOX CLEAR rolft,rorgt,robas,rotop
    END SUB

    SUB ClearRollover
        CALL w1ShowGraphLayer
        CALL w2ShowGraphLayer
        CALL ClearRollText
        LET clearflag= 0
    END SUB


    ! --- Buttons ---

    LET elft= w2Rgt - 78
    LET ergt= elft  + 78
    LET etop= w2Bas + 25
    LET ebas= etop  + 18

    SUB EnvButton(state)
        LET EnvBtnFlag= state
        IF state=1 then
           CALL SetTextFont(1,12,"Bold")
           CALL DrawButton(elft,ergt,ebas,etop,5,"Envelope")
        ELSE
           BOX CLEAR elft,ergt,ebas,etop
           LET envelopeFlag= 0
        END IF
    END SUB


    ! --- Default Parameters ---

    LET a,olda= 1
    LET w,oldw= 1.05
    LET p,oldp= 0
    CALL InitPi(worklft+1,worktop+10,green,t1pi$)
    CALL InitPi(worklft+1,worktop+10,cyan,t2pi$)
    CALL InitPi(worklft+1,worktop+10,white,w1pi$)
    LET envelopeFlag= 0
    IF a=1 then LET EnvBtnFlag= 1

    ! --- Draw the screen ---

    CALL InitScreen

    SUB InitScreen
        BOX CLEAR worklft,workrgt,workbas,worktop
        CALL w1InitPlane
        CALL w2InitPlane

        CALL h1InitSlider
        CALL h2InitSlider
        CALL h3InitSlider

        CALL EnvButton(EnvBtnFlag)
        CALL w1DrawGraph
        CALL w1KeepGridLayer
        CALL DrawGraphs(1)

        CALL t1Init
        CALL t2Init
    END SUB


    ! ----------------- Event manager -----------------

    DO
       LET clearflag=  0
       LET oldmx    = -99999
       CALL SetTextFont(1,12,"Bold")
       DO
          GET MOUSE: mx,my,ms
          IF mx>w1Lft and mx<w1Rgt and my>w2Top and my<w1Bas then
             CALL Rollover
          ELSE IF clearflag=true then
             CALL ClearRollover
          END IF
       LOOP until ms=2
       IF clearflag=1 then CALL ClearRollover

       IF h1Within(mx,my)=true then
          IF my<h1axis then
             CALL h1MouseClick
          ELSE
             CALL h1MouseDrag
          END IF
       ELSE IF h2Within(mx,my)=true then
          IF my<h2axis then
             CALL h2MouseClick
          ELSE
             CALL h2MouseDrag
          END IF
       ELSE IF h3Within(mx,my)=true then
          IF my<h3axis then
             CALL h3MouseClick
          ELSE
             CALL h3MouseDrag
          END IF

       ELSE IF h2LstpWithin(mx,my)=true then
          CALL h2LstpButtonUp(ms)
          CALL h2LeftStep(w,h2AnimStep)
          CALL h2MouseAction(1)
       ELSE IF h2RstpWithin(mx,my)=true then
          CALL h2RstpButtonUp(ms)
          CALL h2RightStep(w,h2AnimStep)
          CALL h2MouseAction(1)

       ELSE IF h2LmoveWithin(mx,my)=true then
          CALL h2LmoveButtonDown
          DO
             GET MOUSE: mx,my,ms
             CALL h2LeftStep(w,h2MoveStep)
             IF w>h2fLft and w<h2fRgt then
                CALL h2MouseAction(1)
             END IF
          LOOP until ms=3
          CALL h2LmoveButtonUp
       ELSE IF h2RmoveWithin(mx,my)=true then
          CALL h2RmoveButtonDown
          DO
             GET MOUSE: mx,my,ms
             CALL h2RightStep(w,h2MoveStep)
             IF w>h2fLft and w<h2fRgt then
                CALL h2MouseAction(1)
             END IF
          LOOP until ms=3
          CALL h2RmoveButtonUp

       ELSE IF EnvBtnFlag=true and mx>eLft and mx<eRgt and my>eTop and my<eBas then
          CALL MouseButtonUp(eLft,eRgt,eBas,eTop,ms)
          LET envelopeFlag= 1-envelopeFlag
          CALL DrawGraphs(1)

       ELSE IF infoWithin(mx,my,ms)=true then
          CALL infoButtonUp(ms)
          CALL InfoPage(Info$)
          CALL InitScreen
       ELSE IF quitWithin(mx,my,ms)=true then
          CALL quitButtonUp(ms)
          EXIT SUB
       ELSE
          CALL MouseUp(mx,my,ms)
       END IF
    LOOP


    ! --- graph window rollover events ---

    SUB Rollover
        IF mx<>oldmx then
           LET oldmx= mx
           SET COLOR litgry

           CALL w1ShowGraphLayer
           PLOT mx,w1Bas-1; mx,w1Top+1
           CALL w2ShowGraphLayer
           PLOT mx,w2Bas-1; mx,w2Top+1

           CALL ClearRollText
           LET x = w1Fncx(mx)/pi
           LET n$= trim$(using$("---%.##",x))
           CALL StringWidth(n$,sw)
           LET nrgt= mx+sw/2+2
           CALL PlotTextCJ(mx,robasln,n$,white)
           BOX SHOW w1pi$ at nrgt,robasln
           LET clearflag= 1
        END IF
    END SUB

    ! --- h1 slider events ---

    SUB h1MouseClick
        CALL h1GetClickVal(ms,h1Click,a)
        CALL h1MouseAction(1)
    END SUB
    SUB h1MouseDrag
        DO
           CALL h1GetDragVal(ms,h1Places,a)
           CALL h1MouseAction(2)
        LOOP until ms=3
        CALL DrawGraphs(1)
    END SUB
    SUB h1MouseAction(drawstep)
        IF a<>olda then
           IF a=1 and olda<>1 then
              CALL EnvButton(1)
           ELSE IF a<>1 and olda=1 then
              CALL EnvButton(0)
           END IF
           LET olda= a
           CALL DrawGraphs(drawstep)
        END IF
    END SUB

    ! --- h2 slider events ---

    SUB h2MouseClick
        CALL h2GetClickVal(ms,h2Click,w)
        CALL h2MouseAction(1)
    END SUB
    SUB h2MouseDrag
        DO
           CALL h2GetDragVal(ms,h2Places,w)
           CALL h2MouseAction(2)
        LOOP until ms=3
        CALL DrawGraphs(1)
    END SUB
    SUB h2MouseAction(drawstep)
        IF w<>oldw then
           CALL DrawGraphs(drawstep)
           CALL t1vSet
           CALL t2vSet
           LET oldw= w
        END IF
    END SUB

    ! --- h3 slider events

    SUB h3MouseClick
        CALL h3GetClickVal(ms,h3Click,p)
        CALL h3MouseAction(1)
    END SUB
    SUB h3MouseDrag
        DO
           CALL h3GetDragVal(ms,h3Places,p)
           CALL h3MouseAction(2)
        LOOP until ms=3
        CALL DrawGraphs(1)
    END SUB
    SUB h3MouseAction(drawstep)
        IF p<>oldp then
           LET oldp= p
           CALL DrawGraphs(drawstep)
        END IF
    END SUB

    ! --- graph drawing routines ---

    SUB w1DrawGraph                              ! addend waves
        CALL w1ShowGridLayer
        SET COLOR w1clr
        FOR wx= w1lft to w1rgt
            LET x = w1Fncx(wx)
            LET y1= f(x)
            LET wy= w1Wndy(y1)
            PLOT wx,wy;
        NEXT wx
        PLOT
        CALL w1KeepGraphLayer
    END SUB

    SUB DrawEnvelope(estp)
        IF w<>1 then
           SET COLOR cyan
           FOR wx= w2lft to w2rgt step estp
               LET x = w2Fncx(wx)
               LET y1= env(x)
               LET wy= w2Wndy(y1)
               PLOT wx,wy
               IF w>0.5 and w<1.5 then
                  LET y1= -y1
                  LET wy= w2Wndy(y1)
                  PLOT wx,wy
               ELSE IF w<0.5 then
                  LET y1= y1-2*a
                  LET wy= w2Wndy(y1)
                  PLOT wx,wy
               END IF
           NEXT wx
           PLOT
        END IF
    END SUB

    SUB DrawGraphs(stp)
        ! stp>1 means animation

        CALL w2ShowGridLayer                     ! sum curve (beats- upper plane)
        IF envelopeFlag=1 then CALL DrawEnvelope(stp/2)
        SET COLOR w2clr
        FOR wx= w2lft to w2rgt step stp
            LET x = w2Fncx(wx)
            LET y1= g(x)+f(x)
            LET wy= w2Wndy(y1)
            PLOT wx,wy;
        NEXT wx
        PLOT

        CALL w1ShowGridLayer                     ! addend curve (lower plane)
        SET COLOR w3clr
        FOR wx= w1lft to w1rgt step stp
            LET x = w1Fncx(wx)
            LET y2= g(x)
            LET wy= w1Wndy(y2)
            PLOT wx,wy;
        NEXT wx
        PLOT

        IF stp=1 then                            ! keep for rollover
           CALL w1KeepGraphLayer
           CALL w2KeepGraphLayer
        END IF
    END SUB
END SUB

! --- end of Sine sum beats code -------------------