!! File: ConvolutionForeward
!! January 7, 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 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

! DECLARE DEF quitWithin,infoWithin

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

LET title$ = "Convolution: Looking Ahead"

SUB ThisProgram
    CALL Convolution
    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 ------
! -----------------------------------------------------------


! *** Foreward Convolution

SUB Convolution
    DECLARE PUBLIC worklft,workrgt,workbas,worktop,workmid      ! work area
    DECLARE PUBLIC black,drkgry,drkmid,midgry,litmid,litgry,white
    DECLARE PUBLIC red,yellow,green,cyan,blue,magenta,colorscheme
    DECLARE PUBLIC slideclr,axislabelclr,true,false

    DECLARE DEF InfoWithin, QuitWithin


    ! --- remix colors ---

    SET COLOR MIX( 9)  0,.8,0                    ! green
    SET COLOR MIX(10)  0,.8,1                    ! cyan


    ! --- Help Screen Array ---

    DIM  info$(1:1)
    MAT READ info$
    DATA "Information on convolution"


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

    DECLARE DEF clamp,roundn,e


    ! --- Functions and Parameters ---

    LET a  = log(2)
    LET b  = 2
    LET c  = sqr(a^2 + b^2)

    LET a2 = a^2
    LET b2 = b^2
    LET b4 = b2^2
    LET c2 = a^2 + b^2
    LET c4 = c2^2

    LET ra = 1/a
    LET ra2= 1/a2
    LET rb = 1/b
    LET h  = 1/2

    DEF f(t)                                     ! signal
        SELECT CASE signum
        CASE 0
             LET f = 1
        CASE 1
             LET f = e^(-a*t)
        CASE 2
             LET f = 1 + cos(b*t)
        END SELECT
    END DEF

    DEF w(t)                                     ! weight
        SELECT CASE wgtnum
        CASE 0
             LET w = 1
        CASE 1
             LET w = e^(-a*t)
        CASE 2
             LET w = t
        CASE 3
             LET w = ra*(1-e^(-a*t))
        CASE 4
             LET w = t*e^(-a*t)
        END SELECT
    END DEF

    DEF cnv(t)                                   ! t less than u
        SELECT CASE signum
        CASE 0
             SELECT CASE wgtnum
             CASE 0
                  LET cnv = t
             CASE 1
                  LET cnv = ra - ra*e^(-a*t)
             CASE 2
                  LET cnv = t^2/2
             CASE 3
                  LET cnv = -ra2 + ra*t + ra2*e^(-a*t)
             CASE 4
                  LET cnv = ra2 - (ra2 + ra*t) * e^(-a*t)
             END SELECT
        CASE 1
             SELECT CASE wgtnum
             CASE 0
                  LET cnv = ra - ra*e^(-a*t)
             CASE 1
                  LET cnv = t*e^(-a*t)
             CASE 2
                  LET cnv = -ra2 + ra*t + ra2*e^(-a*t)
             CASE 3
                  LET cnv = ra2 - (ra2 + ra*t) * e^(-a*t)
             CASE 4
                  LET cnv = (t^2/2) * e^(-a*t)
             END SELECT
        CASE 2
             SELECT CASE wgtnum
             CASE 0
                  LET cnv = t + (1/b)*sin(b*t)
             CASE 1
                  LET cnv = ra - ((2*a + ra*b2)/c2)*e^(-a*t) + (a/c2)*cos(b*t) + (b/c2)*sin(b*t)
             CASE 2
                  LET cnv = (1/b2) + h*t^2 - (1/b2)*cos(b*t)
             CASE 3
                  LET cnv = -ra2 + ra*t - (1/c2)*cos(b*t) + (a/(b*c2))*sin(b*t) + ((2*a2 + b2)/(c2*a2))*e^(-a*t)
             CASE 4
                  LET cnv = ra2 + ((a2-b2)/c4)*cos(b*t) + (2*a*b/c4)*sin(b*t)  - ((2*a2 + b2 + (b4/a2))/c4)*e^(-a*t) - ((2*a + (b2/a))/c2)*t*e^(-a*t)
             END SELECT
        END SELECT
    END DEF

    DEF future(t,u)                              ! t greater than u
        LET c0 =  cnv(u)

        SELECT CASE wgtnum
        CASE 0
             LET future = c0
        CASE 1
             LET future = c0 * e^(-a*(t-u))
        CASE 2
             SELECT CASE signum
             CASE 0
                  LET c1 = u
             CASE 1
                  LET c1 = ra - ra*e^(-a*u)
             CASE 2
                  ! LET c1 = u + (1/b)*cos(b*u)
                  LET c1 = u + rb*sin(b*u)
             END SELECT

             LET future = c0 + c1*(t-u)
        CASE 3                                   ! 4th weight function
             SELECT CASE signum
             CASE 0
                  LET c1 = ra - ra*e^(-a*u)
             CASE 1
                  LET c1 = u*e^(-a*u)
             CASE 2
                  LET c1 = ra + (a/c2)*cos(b*u) + (b/c2)*sin(b*u) - ((2*a2+b2)/(a*c2))*e^(-a*u)
             END SELECT

             LET future = c0 + (c1/a)*(1-e^(-a*(t-u)))
        CASE 4
             SELECT CASE signum
             CASE 0
                  LET c1 = u*e^(-a*u)
             CASE 1
                  LET c1 = (u-a*h*u^2) * e^(-a*u)
             CASE 2
                  LET c1 = ((b^3 - a2*b)/c2^2)*sin(b*u) + (2*a*b2/c2^2)*cos(b*u) - (2*a*b2/c4)*e^(-a*u) + ((2*a2 + b2)/c2)*u*e^(-a*u)
             END SELECT

             LET future = (c0+(c1+a*c0)*(t-u)) * e^(-a*(t-u))
        END SELECT
    END DEF


    ! --- Graphing plane parameters and methods

    LET wwid = 480                               ! multiples of 48 (12 / 1/4)
    LET whgt2= 256
    LET whgt1= 120

    ! --- 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 w1wWid,w1wHgt,w1fWid,w1fHgt
    DECLARE PUBLIC w1fxRatio,w1fyRatio,w1wxRatio,w1wyRatio,w1Aspect
    DECLARE PUBLIC w1xPiFlag, w1xMult, w1yPiFlag, w1yMult

    LET w1Flag   = 1
    LET w1xPiFlag= 0
    LET w1yPiFlag= 0

    LET w1Lft = worklft + 55                     ! pixel bounds
    LET w1Rgt = w1Lft + wwid
    LET w1Top = workbas - whgt1 - 50
    LET w1Bas = w1Top + whgt1

    LET w1fLft=  0                               ! function bounds
    LET w1fRgt= 12
    LET w1fTop=  2
    LET w1fBas=  0

    LET w1Xax$= "t"                              ! axis labels
    LET w1Yax$= "y"

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

    LET w1xStik = 0                              ! horizontal axis Tik marks
    LET w1xLtik = 1
    LET w1xLabel= 0
    LET w1xFirst= w1fLft
    LET w1xMult = 1

    LET w1yStik = 0                              ! vertical axis Tik marks
    LET w1yLtik = 0.5
    LET w1yLabel= 0.5
    LET w1yFirst= w1fBas
    LET w1yMult = 1

    ! --- Plane 1 methods ---

    DECLARE DEF w1Fncx,w1Fncy,w1Wndx,w1Wndy      ! window/function transforms
    DECLARE DEF w1wWithin

    CALL w1Variables

    SUB w1ClearPlaneGraph
        CALL BoxArea(w1Lft+1,w1Rgt-1,w1Bas-1,w1Top+1,black)
        SET COLOR 3
        PLOT w1Lft,w1Top; w1Rgt,w1Top; w1Rgt,w1Bas
        SET COLOR 4
        PLOT w1Lft,w1Top; w1Lft,w1Bas; w1Rgt,w1Bas
    END SUB

    SUB w1Init
        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 PlotTextLJ(w1lft-28,w1Top-12,"f(u) g(t-u)",cyan)

        CALL w1DrawBackgroundSignal
        CALL w1KeepGridLayer
    END SUB

    ! ------------------------------------------
    ! --- 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 w2wWid,w2wHgt,w2fWid,w2fHgt
    DECLARE PUBLIC w2fxRatio,w2fyRatio,w2wxRatio,w2wyRatio,w2Aspect
    DECLARE PUBLIC w2xPiFlag, w2xMult, w2yPiFlag, w2yMult

    LET w2Flag   = 1
    LET w2xPiFlag= 0
    LET w2yPiFlag= 0

    LET w2Lft = w1lft                            ! pixel bounds
    LET w2Rgt = w2Lft + wwid
    LET w2Top = worktop + 34
    LET w2Bas = w2Top + whgt2

    LET w2fLft= w1fLft                           ! function bounds * pi
    LET w2fRgt= w1fRgt
    LET w2fTop= w1fTop
    LET w2fBas= w1fBas

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

    LET w2xAx$= "t"                              ! axis labels
    LET w2yAx$= "I"

    LET w2xStik = 0                              ! horizontal axis Tik marks
    LET w2xLtik = 1
    LET w2xLabel= 1
    LET w2xFirst= w2fLft
    LET w2xMult = 1

    LET w2yStik = 0                              ! vertical axis Tik marks
    LET w2yLtik = 0.5
    LET w2yLabel= 0.5
    LET w2yFirst= w2fBas
    LET w2yMult = 1

    SUB w2SetBounds(wgtnum)
        SELECT CASE signum
        CASE 0,2
             SELECT CASE wgtnum
             CASE 0
                  LET w2fTop  = 12
                  LET w2yLtik =  1
                  LET w2yLabel=  2
             CASE 1
                  LET w2fTop  =  2
                  LET w2yLtik =  0.5
                  LET w2yLabel=  0.5
             CASE 2
                  LET w2fTop  = 72
                  LET w2yLtik =  6
                  LET w2yLabel= 12
             CASE 3
                  LET w2fTop  = 16
                  LET w2yLtik =  2
                  LET w2yLabel=  4
             CASE 4
                  LET w2fTop  =  3
                  LET w2yLtik =  0.5
                  LET w2yLabel=  1
             END SELECT
        CASE 1
             SELECT CASE wgtnum
             CASE 0
                  LET w2fTop  =  2
                  LET w2yLtik =  0.5
                  LET w2yLabel=  0.5
             CASE 1
                  LET w2fTop  =  0.6
                  LET w2yLtik =  0.1
                  LET w2yLabel=  0.1
             CASE 2
                  LET w2fTop  = 16
                  LET w2yLtik =  2
                  LET w2yLabel=  4
             CASE 3
                  LET w2fTop  =  3
                  LET w2yLtik =  0.5
                  LET w2yLabel=  1
             CASE 4
                  LET w2fTop  =  0.6
                  LET w2yLtik =  0.1
                  LET w2yLabel=  0.1
             END SELECT
        CASE else
        END SELECT
        LET w2fBas  = 0
        LET w2yStik = 0                          ! vertical axis Tik marks
        LET w2yFirst= w2fBas
        CALL w2Variables
    END SUB

    ! --- plane 2 methods ---

    DECLARE DEF w2Fncx, w2Fncy, w2Wndx, w2Wndy   ! window/function transforms
    DECLARE DEF w2wWithin

    CALL w2Variables

    SUB w2Init
        CALL w2DrawPlane(1,1,1)                  ! x axis, y axis, zeroaxes

        CALL SetTextFont(1,12,"bold")
        CALL PlotTextLJ(w2Rgt+8,w2y0+3,w2xAx$,litgry)
        LET txt$= "(f*g)(t)"
        CALL StringWidth(txt$,sw)
        CALL SwapMultiplication(w2Lft-sw/2+1,w2Top-12,txt$,yellow)

        CALL w2DrawBackgroundConvolution
        CALL w2KeepGridLayer
    END SUB

    ! --- plane 3 data ---

    DECLARE PUBLIC w3Lft,w3Rgt,w3Bas,w3Top,w3Midx,w3Midy
    DECLARE PUBLIC w3fLft,w3fRgt,w3fBas,w3fTop,w3x0,w3y0
    DECLARE PUBLIC w3xFirst, w3xStik, w3xLtik, w3xLabel, w3xGridstep
    DECLARE PUBLIC w3yFirst, w3yStik, w3yLtik, w3yLabel, w3yGridstep
    DECLARE PUBLIC w3wWid,w3wHgt,w3fWid,w3fHgt
    DECLARE PUBLIC w3fxRatio,w3fyRatio,w3wxRatio,w3wyRatio,w3Aspect
    DECLARE PUBLIC w3xPiFlag, w3xMult, w3yPiFlag, w3yMult

    LET w3Flag   = 1
    LET w3xPiFlag= 0
    LET w3yPiFlag= 0

    LET w3Lft = worklft + 55                     ! pixel bounds
    LET w3Rgt = w3Lft + wwid
    LET w3Top = w1Bas + 72
    LET w3Bas = w3Top + whgt1

    LET w3fLft=  0                               ! function bounds
    LET w3fRgt= 12
    LET w3fTop=  2
    LET w3fBas=  0

    LET w3Xax$= "t"                              ! axis labels
    LET w3Yax$= "y"

    LET w3xGridstep= 0                           ! horizontal grid intervals
    LET w3yGridstep= 0                           ! vertical grid intervals

    LET w3xStik = 0                              ! horizontal axis Tik marks
    LET w3xLtik = 1
    LET w3xLabel= 1
    LET w3xFirst= w3fLft
    LET w3xMult = 1

    LET w3yStik = 0                              ! vertical axis Tik marks
    LET w3yLtik = 0.5
    LET w3yLabel= 0.5
    LET w3yFirst= w3fBas
    LET w3yMult = 1

    ! --- Plane 1 methods ---

    DECLARE DEF w3Fncx,w3Fncy,w3Wndx,w3Wndy      ! window/function transforms
    DECLARE DEF w3wWithin

    CALL w3Variables

    SUB w3Init
        CALL w3DrawPlane(1,1,1)                  ! x axis, y axis, zeroaxes
        CALL SetTextFont(1,12,"bold")
        CALL PlotTextLJ(w3Rgt+8,w3y0+3,w3Xax$,axislabelclr)     ! axis labels
        CALL PlotTextCJ(w3lft,w3Top-12,"w(t)",litgry)
        CALL w3KeepGridLayer
    END SUB


    ! --- Slider parameters and methods

    ! --- 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

    LET h1PiAxis= 0

    LET h1clr   = litgry
    LET h1name$ = "u"
    LET h1form$ = "--%.###"
    LET h1Mult  = 1
    LET h1Places= 3

    LET h1axis = w1Bas + 22
    LET h1wLft = w1Lft
    LET h1wRgt = w1Rgt
    LET h1fLft = w1fLft
    LET h1fRgt = w1fRgt

    LET h1STik = 0.25                            ! short tick marks
    LET h1LTik = 1                               ! long tick marks
    LET h1Label= 1                               ! labels
    LET h1First= h1fLft                          ! first tick mark
    LET h1Click= 1

    DECLARE DEF h1Within,h1Fncx                  ! window/function transforms

    CALL h1SliderVariables

    SUB h1Iinit
        CALL h1DrawSlider(h1name$,tau)
    END SUB


    ! --- t1 text rectangle - convolution equation  ---

    SUB t1Convolution(lft,ty)
        LET clr= yellow

        CALL FLessEqUT(lft,ty,clr)               ! f_u

        CALL SwapMultiplication(tx,ty,"(t)*g(t) = ",clr)
        CALL StringWidth("(t)*g(t) = ",sw)
        LET  tx= tx + sw + 4

        DRAW IntegralSign(clr) with shift(tx,ty)
        CALL SetTextFont(1,9,"bold")
        CALL PlotTextLJ(tx+4,ty+7,"0",clr)
        CALL PlotTextLJ(tx+5,ty-9,"t",clr)
        LET  tx= tx + 35

        CALL SetTextFont(1,12,"bold")
        CALL FLessEqUT(tx,ty,clr)                ! f_u
        LET  tx= tx +  3
        CALL PlotTextLJ(tx,ty,"(u) g(t-u) dt",clr)
    END SUB

    SUB FLessEqUT(mid,ty,clr)
        CALL StringWidth("f=u(t)",sw)
        LET tx  = mid - sw/2
        CALL PlotTextLJ(tx,ty,"f",clr)

        CALL StringWidth("f",sw)
        LET tx  = tx+sw+1
        LET ysub= ty+3
        DRAW LessEql9(clr) with shift(tx,ysub)
        CALL PlotTextLJ(tx+7,ysub,"u",clr)

        LET tx = tx + 15
    END SUB


    ! ----- menu 1: signal -----

    DECLARE PUBLIC m1Lft, m1Rgt, m1Bas, m1Top, m1Equation, m1Prefix$, m1Menu1$()
    DECLARE PUBLIC m1tClr, m1Name$

    MAT redim m1Menu1$(1:3)
    MAT READ m1Menu1$
    DATA "1"
    DATA "e^[-at]"
    DATA "1 + cos(bt)"

    LET m1Prefix$ = "f(t) = "
    LET m1Lft     = w1Rgt + 40
    LET m1Top     = w2Bas - 90
    LET m1tClr    = green
    LET m1Equation= 1
    LET m1Name$   = "Signal"

    SUB m1Init
        CALL m1ResetMenu(m1State)
    END SUB

    ! ----- menu 2: weight -----

    DECLARE PUBLIC m2Lft, m2Rgt, m2Bas, m2Top, m2Equation, m2Prefix$, m2Menu1$()
    DECLARE PUBLIC m2tClr, m2Name$

    MAT redim m2Menu1$(1:5)
    MAT READ m2Menu1$
    DATA "1"
    DATA "e^[-at]"
    DATA "t"
    DATA "(1/a)(1-e^[-at])"
    DATA "t e^[-at]"

    LET m2Prefix$ = "g(t) = "
    LET m2Lft     = m1Lft
    LET m2Top     = w1Top                        ! m1Top + 115
    LET m2tClr    = white
    LET m2Equation= 1
    LET m2Name$   = "Weight"

    SUB m2Init
        CALL m2ResetMenu(m2State)
    END SUB


    ! --- Radio Buttons ---

    DECLARE PUBLIC r1cnt,r1stp,r1siz
    DECLARE PUBLIC r1lft,r1rgt,r1bas,r1top,r1Name$,r1NameClr
    DECLARE PUBLIC r1NameList$(),r1ColorList()

    MAT redim r1NameList$(1:3)
    MAT READ r1NameList$
    DATA "1/2","1/4","1/8"

    MAT redim r1ColorList(1:3)
    MAT READ r1ColorList
    DATA 5,5,5

    LET r1cnt    = 3
    LET r1Lft    = w1Rgt + 40
    LET r1Top    = w2Top + 50
    LET r1Name$  = "step size"
    LET r1NameClr= 5
    LET r1TxtClr = 5

    DECLARE DEF r1Within
    CALL r1SetVars


    ! --- Set Default Parameters and Draw screen ---

    LET tau,oldtau= 0
    LET maxtau    = 0
    LET signum    = m1Equation-1
    LET wgtnum    = m2Equation-1
    LET r1num     = 1
    LET skip      = 1/2
    LET m1State   = 0
    LET m2State   = 0


    ! ------ Initialize the screen ------

    CALL InitScreen
    CALL m1InitMenu1
    CALL m2InitMenu1
    CALL SetTimer

    SUB InitScreen
        BOX CLEAR workLft,workRgt,workBas,workTop
        CALL w2SetBounds(wgtnum)

        CALL w1Init
        CALL w2Init
        ! CALL w3Init

        CALL m1Init
        CALL m2Init

        CALL r1DrawCheckBoxes
        CALL r1SetCheckBox(r1num)

        CALL h1Iinit

        CALL w2DrawFuture(tau,cyan)
        CALL w2DrawConvolution(tau)
        CALL w1DrawGraphs(tau,cyan)
        CALL w1DrawWeight

        ! CALL t1Convolution(w2Midx-80,w2Top-16) ! show equation

        CALL w1KeepGraphLayer
        CALL w2KeepGraphLayer

    END SUB


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

    DO
       LET clearflag= 0
       SET COLOR litgry
       LET oldmx= -999
       DO
          GET MOUSE: mx,my,ms
          IF w1wWithin(mx,my)=1 or w2wWithin(mx,my)=1 then
             LET x = w1Fncx(mx)
             LET x = roundn(x,skip)
             LET mx= w1Wndx(x)
             IF mx<>oldmx then
                CALL RollOver
                LET oldmx= mx
             END IF
          ELSE IF clearflag=1 then
             CALL w1ShowGraphLayer
             CALL w2ShowGraphLayer
             LET clearflag= 0
          END IF
       LOOP until ms=2

       IF w1wWithin(mx,my)=1 or w2wWithin(mx,my)=1 then
          ! temp areas while mouse button is down
          LET temptau= w1Fncx(mx)
          LET temptau= roundn(temptau,skip)
          LET wtau   = w1Wndx(temptau)

          CALL w1ShowGridLayer
          CALL PlotLine( wtau,w1Bas-1, wtau,w1Top+1, litmid)
          CALL w1FillGraph(temptau,cyan)

          SET COLOR yellow
          FOR wx= w2Lft to wtau                  ! convolution graph
              LET t= w2Fncx(wx)
              LET y= cnv(t)
              PLOT wx,w2Wndy(y);
          NEXT wx
          PLOT
          CALL w2FillGraph(temptau,cyan)

          CALL MouseUp(mx,my,ms)                 ! wait for mouse up
          CALL w1ShowGraphLayer
          CALL w2ShowGraphLayer

       ELSE IF h1Within(mx,my)=1 then
          IF my<h1axis then
             CALL h1ClickMouse(mx,my,tau)
          ELSE
             CALL h1DragMouse(mx,my,tau)
          END IF

       ELSE IF mx>m1Lft and mx<m1Rgt and my>m1Top and my<m1Bas then  ! menu 1
          CALL MouseButtonUp(m1Lft,m1Rgt,m1Bas,m1Top,ms)
          CALL m1ReadMenu
          LET signum= m1Equation-1
          CALL MenuEvent
       ELSE IF mx>m2Lft and mx<m2Rgt and my>m2Top and my<m2Bas then  ! menu 2
          CALL MouseButtonUp(m2Lft,m2Rgt,m2Bas,m2Top,ms)
          CALL m2ReadMenu
          LET wgtnum= m2Equation-1
          CALL MenuEvent

       ELSE IF r1Within(mx,my)=1 then
          CALL MouseUp(mx,my,ms)
          LET r1num= int((my-r1Top)/r1Stp) + 1
          CALL r1SetCheckBox(r1num)
          CALL ReSetSkip(r1num)

       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

    ! --- rollover ---

    SUB RollOver
        CALL w1ShowGraphLayer
        CALL w2ShowGraphLayer

        SET COLOR 4                              ! draw vertical rules
        PLOT mx,w1Bas-1; mx,w1Top+1
        PLOT mx,w2Bas-1; mx,w2Top+1
        LET clearflag= 1
    END SUB

    ! --- radio button event ---

    SUB ReSetSkip(r1num)
        SELECT CASE r1num
        CASE 1
             LET skip= 1/2
        CASE 2
             LET skip= 1/4
        CASE 3
             LET skip= 1/8
        END SELECT
        CALL w1ShowGridLayer
        CALL w2ShowGridLayer

        CALL w1KeepGraphLayer
        CALL w2KeepGraphLayer

        LET tau   = 0                            !skip
        LET maxtau= 0
        LET oldtau= 0
        CALL h1Mark(tau)
    END SUB

    ! --- menu event ---

    SUB MenuEvent
        LET tau   = 0
        LET maxtau= 0
        LET oldtau= 0
        CALL w2SetBounds(wgtnum)
        CALL w2Init
        CALL ChangeEquation
    END SUB

    ! --- menu action ---

    SUB ChangeEquation
        CALL h1Mark(tau)
        CALL w1ClearPlaneGraph
        CALL w1DrawBackgroundSignal
        CALL w2DrawFuture(tau,cyan)
        CALL w1DrawGraphs(tau,cyan)
        CALL w1DrawWeight
        CALL w1KeepGraphLayer
        CALL w2KeepGraphLayer
    END SUB

    ! --- slider action ---

    SUB h1ClickMouse(mx,my,tau)
        CALL h1GetClickVal(ms,h1Click,tau)
        CALL h1action
        CALL w1KeepGraphLayer
        CALL w2KeepGraphLayer
    END SUB
    SUB h1DragMouse(mx,my,tau)
        DO
           GET MOUSE: mx,my,ms
           LET mx= clamp(mx,h1wLft,h1wRgt)
           LET x = roundn(h1Fncx(mx),skip)
           IF x<>oldx then
              CALL h1Mark(x)
              LET oldx= x
           END IF
        LOOP until ms=3
        LET tau= x
        CALL h1action
        CALL w1KeepGraphLayer
        CALL w2KeepGraphLayer
    END SUB

    SUB h1action
        IF tau<>oldtau then
           IF tau=0 then
              CALL w1DrawWeight
              CALL w2ShowGridLayer
           ELSE
              LET maxtau= roundn(maxtau,skip)
              LET oldtau= tau
              CALL h1Mark(tau)

              IF tau>maxtau then                 ! new drawing to right
                 IF tau-maxtau>=skip then
                    FOR i= maxtau+skip to tau+.1 step skip      ! for each step
                        SET COLOR yellow
                        IF maxtau>skip then
                           LET start= maxtau-skip
                        ELSE
                           LET start= 0
                        END IF
                        FOR wx= w2Wndx(start) to w2Wndx(i)      ! draw the curve
                            LET t= w2Fncx(wx)
                            LET y= cnv(t)
                            PLOT wx,w2Wndy(y);
                        NEXT wx
                        PLOT
                        CALL Delay(1/100)
                        CALL w1DrawGraphs(i,cyan)
                        CALL w2DrawFuture(i,cyan)
                    NEXT i
                 END IF
              ELSE IF tau<maxtau then            ! clear drawing to left
                 IF maxtau-tau>=skip then
                    FOR i= maxtau to tau-.1 step -skip
                        LET i1,i2= roundn(i,skip)
                        IF i<maxtau then CALL w1DrawGraphs(i2,cyan)
                        CALL w2DrawFuture(i1,black)
                    NEXT i
                    IF tau>0 or wgtnum=2 then CALL w2DrawFuture(tau,cyan)      ! touch up
                 END IF
              END IF

              LET maxtau= tau
           END IF
        END IF
    END SUB


    ! --- Tool specific drawing and typesetting routines ---

    ! --------- w1 plane - show weight function ---------

    SUB w1DrawWeight
        ! display weight function in the bottom plane
        CALL w1ShowGridLayer
        SET COLOR litgry
        FOR wx= w1Lft to w1Rgt
            LET t = w1Fncx(wx)
            LET y = w(t)
            LET wy= w1Wndy(y)
            IF wy>w1Top and wy<w1Bas then
               PLOT wx,wy;
            ELSE
               PLOT
            END IF
        NEXT wx
        PLOT
    END SUB

    ! --- w1 plane - product plane ---

    SUB w1DrawBackgroundSignal
        ! signal curve ghost in product plane
        SET COLOR drkmid
        FOR wx= w1Lft+1 to w1Rgt-1
            LET u = w1Fncx(wx)
            LET y1= f(u)
            LET wy= round(w1Wndy(y1))
            IF wy>w1Top and wy<w1Bas then
               PLOT wx,wy;
            ELSE
               PLOT
            END IF
        NEXT wx
        PLOT
        CALL w1KeepGridLayer
    END SUB

    SUB w1DrawGraphs(w1tau,clr)
        ! response to h1 slider and equation change
        CALL w1ShowGridLayer
        LET wlft= w1Wndx(w1tau)
        IF w1tau>0 then
           ! draw signal from left to tau in plane 1
           SET COLOR green
           FOR wx= w1Lft to wlft
               LET u = w1Fncx(wx)
               LET y= f(u)
               LET wy= round(w1Wndy(y))
               IF wy>w1Top and wy<w1Bas then
                  PLOT wx,wy;
               ELSE
                  PLOT
               END IF
           NEXT wx
           PLOT

           ! draw vertical at tau in plane 1?
           IF wgtnum>1 then
              CALL PlotLine( wlft,w1y0-1, wlft,wy, green)
           ELSE
              CALL PlotLine( wlft,w1y0-1, wlft,wy, cyan)
           END IF

           ! draw product curve from tau to right in plane 1
           SET COLOR clr
           FOR wx= wlft to w1Rgt-1
               LET t = w1Fncx(wx)
               LET y = w(t-w1tau)*f(w1tau)
               LET wy= round(w1Wndy(y))
               IF wy>w1Top and wy<w1Bas then
                  PLOT wx,wy;
               ELSE
                  PLOT
               END IF
           NEXT wx
           PLOT
        END IF
    END SUB

    SUB w1FillGraph(tau,clr)                     ! lower product plane
        LET wLft= round(w1Wndx(tau))

        ! draws green signal curve from left to tau
        SET COLOR green
        FOR wx= w1Lft+1 to wLft
            LET u = w1Fncx(wx)
            LET y = f(u)
            LET wy= w1Wndy(y)
            PLOT wx,wy;
        NEXT wx
        PLOT

        ! draws filled area under product from tau to right
        IF tau>0 then
           SET COLOR clr
           FOR wx= wLft+1 to w1Rgt-1             ! graph in plane 1
               LET t = w1Fncx(wx)
               LET y = w(t-tau)*f(tau)
               LET wy= max(w1Wndy(y),w1Top)
               PLOT wx,wy; wx,w1y0-1
           NEXT wx
           PLOT
        END IF
    END SUB

    ! --- w2 plane - upper convolution ---

    SUB w2DrawBackgroundConvolution              ! fixed integral curve
        ! draws gray convolution curve on background
        SET COLOR 3                              ! gray convolution ghost
        FOR wx= w2Lft to w2Rgt
            LET t = w2Fncx(wx)
            LET y = cnv(t)
            LET wy= w2Wndy(y)
            PLOT wx,wy;
        NEXT wx
        PLOT
        CALL w2KeepGridLayer
    END SUB

    SUB w2DrawConvolution(tau)
        ! draws yellow convolution curve in upper plane
        SET COLOR yellow
        FOR wx= w2Lft to w2Wndx(tau)
            LET t = w2Fncx(wx)
            LET y = cnv(t)
            LET wy= w2Wndy(y)
            PLOT wx,wy;
        NEXT wx
        PLOT
    END SUB

    SUB w2DrawFuture(tau2,clr)                   ! graph in upper plane 2
        ! removes yellow convolution curve back to tau
        IF clr=black then                        ! restore convolution ghost
           SET COLOR drkmid
           LET wtaux= max(int(w2Wndx(tau2)),w2Lft)
           FOR wx= wtaux to w2Rgt-1
               LET t = w2Fncx(wx)
               LET y = cnv(t)
               LET wy= w2Wndy(y)
               PLOT wx,wy;
           NEXT wx
           PLOT
        END IF

        IF clr=cyan or tau2>tau then
           ! draws if cyan, erases if black
           LET wtaux= int(w2Wndx(tau2))
           SET COLOR clr
           FOR wx= wtaux to w2Rgt-1              ! y is decay from convolve
               LET t = w2Fncx(wx)
               LET y = future(t,tau2)
               LET wy= round(w2Wndy(y))
               IF wy<w2Bas then
                  PLOT wx,wy;
               ELSE
                  PLOT
               END IF
           NEXT wx
           PLOT
        END IF
    END SUB

    SUB w2FillGraph(tau,clr)
        ! filled area between graphs in plane 2 - upper plane
        IF tau>0 then
           LET tau0 = tau - skip
           LET wtaux= int(w2Wndx(tau)) + 1
           LET wbasx= w2y0 - 1

           SET COLOR clr
           FOR wx= wtaux to w2Rgt-1              ! y is decay from convolve
               LET t  = w2Fncx(wx)

               LET y  = future(t,tau)
               LET wy = min(w2Wndy(y),wbasx)

               LET y0 = future(t,tau0)
               LET wy0= min(w2Wndy(y0),wbasx)

               PLOT wx,wy; wx,wy0
           NEXT wx
           PLOT
        END IF
    END SUB
END SUB

! ----- end of convolution code ------