'ARC_PLAY.BAS
 'The objective is to plot simple circular gauges from 0 to -90 and 0 to +90 degrees
 'The line "CASE -1 to 1" seems to be required - The code below works.
 
 dim integer I
 Const X_Hzt = MM.Hres/2
 const Y_Hzt = MM.VRES/2
 
 cls  
 
 for I = -100 to 100 step 1  'Just to confirm it works beyond 90deg
   select case I
     case <-90
       ARC X_Hzt, Y_Hzt, 40,50 , 270, 360, RGB(red)      'Red for port = left
     case -90 to -1  '0  If this is changed to 0 AND the line "CASE -1 to 1" commented out it fails
       ARC X_Hzt, Y_Hzt, 40,50 , 360+I, 360, RGB(red)  'B
     case -1 to 1  'with this in it works, with this commented out AND the line "CASE -90 to 0" it fails
       'Do nothing - is there any better way than this?
     case 1 to 90
       ARC X_Hzt, Y_Hzt, 40,50 , 360, 360+I, RGB(Green)  'Green for starboard = right
     case > 90
       ARC X_Hzt, Y_Hzt, 40,50 , 0, 90, RGB(Green)
     case Else
       text 400,520,"Else", CM, 1,1,rgb(Green)   'Just to check all options covered
       pause 1000
       text 400,520,"               ", CM, 1,1,rgb(Black)
   end select
   text 400,500,"               ", CM, 1,1,rgb(Black)  'Blank out old text
   text 400,500,str$(I), CM, 1,1,rgb(Green)            'Text new angle
   
   pause 200   'Just to see what is happening
   ARC X_Hzt, Y_Hzt, 40,50 , 270, 90, RGB(black) 'Blank out the old arc
 Next I
 
do:loop while inkey$ = ""
End

' Test code to show tacho
cls

'... some global variables needed by the subs below
'  ... some of these could be moved into locals in
'      the subroutines
dim t_x%=400 ' gauge centre
dim t_y%=240
dim t_r%=118 ' radius
dim w_start%=-150 ' white start
dim g_start%=-50  ' green  "
dim y_start%r=50  ' yellow   "
dim r_start%=80   ' red      "
dim b_start%=150  ' black -the non-display section
dim x%
dim y%
dim radius%
dim lastx1%,lastx2%,lastx3%
dim lasty1%,lasty2%,lasty3%
dim angle%
dim rpm%
dim col%=rgb(150,150,150) ' needle colour

' sample code to show tacho working
InitTacho
do
rpm% = int(rnd()*3000)
UpDateTacho
pause 2000
loop

end
'Tacho - code based on examples from Geoff, Peter
'  and other backshedders - thanks.
 ' Sub Routine to initialise tacho gauge
 ' - this is not GUI so needs to be re-painted after any GUI
 '    that overlays it. eg. setup
Sub InitTacho
 Local ticks%
 ' background to create the outer bezel
 Circle t_x%, t_y%,  t_r%+42,3,, RGB(150,150,150),-1
 Circle t_x%, t_y%,  t_r%+41,3,, RGB(220,220,220),-1
 Circle t_x%, t_y%,  t_r%+40,3,, RGB(white),-1
 Circle t_x%, t_y%,  t_r%+39,3,, RGB(220,220,220),-1
 Circle t_x%, t_y%,  t_r%+38,3,, RGB(180,180,180),-1
 Circle t_x%, t_y%,  t_r%+37,3,, RGB(150,150,150),RGB(60,60,60)
 segment(t_x%, t_y%, t_r%, w_start%, g_start%, RGB(white), 0)
 segment(t_x%, t_y%, t_r%, g_start%, y_start%, RGB(0,180,0), 0)
 segment(t_x%, t_y%, t_r%, y_start%, r_start%, RGB(200,200,0), 0)
 segment(t_x%, t_y%, t_r%, r_start%, b_start%, RGB(red), 0)
 segment(t_x%, t_y%, t_r%, b_start%, w_start%+360,RGB(60,60,60), 0)
 For ticks%=w_start% To b_start% Step 20
   segment(t_x%, t_y%, t_r%, ticks%, ticks%, 0, (t_r%*19)\20)
 Next ticks%
 ' now for inner circle which determines how wide the colour bands are
 Circle t_x%,t_y%,t_r%-20,0,,RGB(0,0,0),RGB(60,60,60)'(t_r%*4)\5,0,,0,0
 Text t_x%, t_y%+75,"RPM x100",C,1,1,RGB(white),RGB(60,60,60)' string centred in black segment
 Text t_x%,t_y%+100,"Engine Hrs",C,1,1,RGB(white),RGB(60,60,60)
 Font 4
 RBox t_x%-42,t_y%+118,84,28,5,RGB(white),RGB(100,100,150)
 Font 2
 ' the following is all for use by needle display
 x%=t_x%
 y%=t_y%
 radius%=t_r%
 lastx1%=t_x%
 lastx2%=t_x%+2
 lastx3%=t_x%+2
 lasty1%=t_y%
 lasty2%=t_y%+2
 lasty3%=t_y%+2
End Sub
 '
 ' Routine to draw a segment of a circle
 ' Parameters are:
 ' x-coordinate of centre of circle
 ' y-coordinate of centre of circle
 ' radius of circle
 ' start radial of segment to be drawn (0-360 degrees)
 ' end radial of segment to be drawn (0-360 degrees)
 ' colour to draw segment
 ' inner radius for drawing radial lines, leave blank or set to zero if not required
 ' NB if start radial and end radial are the same a line will be drawn
Sub segment(x%, y%, outsize%, startradial%, endradial%, col%, insize%)
 Local integer i,j, x1, x2, y1, y2, sr, er, xx0, yy0, xx1, yy1, xx2, yy2, tcol
 Local INTEGER xtxt,ytxt,txtradial
 Local stepsize% = 1
 If startradial%=endradial% Then
   x2=Sin(Rad(startradial%))*outsize% + x%
   y2=-Cos(Rad(startradial%))*outsize% + y%
   x1=Sin(Rad(startradial%))*insize% + x% 'insize is 0 if not specified so a complete line from the centre is drawn
   y1=-Cos(Rad(startradial%))*insize% + y%
   Line x1,y1,x2,y2,,col%
   ' now put in values outside rim
   txtradial = (startradial% + 150)/10 ' adjust degrees to 0 to 2400 rpm
   xtxt=Sin(Rad(startradial%))*(outsize% + 20 ) + x%
   ytxt=-Cos(Rad(startradial%))*(outsize% + 20) + y%
   Font 2
   Text xtxt-12,ytxt-10,Str$(txtradial,2),L,2,1,RGB(white),RGB(60,60,60) ' character positioning offset applied
 Else
   If startradial% < endradial% Then
     sr=startradial%
     er=endradial%
   Else
     er=startradial%
     sr=endradial%
   EndIf
   For i%=sr+stepsize% To er Step stepsize%
     x2=Sin(Rad(i%))*outsize% + x%
     y2=-Cos(Rad(i%))*outsize% + y%
     x1=Sin(Rad(i%-stepsize%))*outsize% + x%
     y1=-Cos(Rad(i%-stepsize%))*outsize% + y%
     xx0=x%
     yy0=y%
     xx1=x1
     yy1=y1
     xx2=x2
     yy2=y2
     tcol=col%
     Triangle xx0,yy0,xx1,yy1,xx2,yy2,tcol,tcol
   Next i%
 EndIf
End Sub
 '
 ' Routine to draw a pointer
 ' Parameters are:
 ' radial of pointer to be drawn (0-360 degrees)
 ' colour to draw pointer
 ' value to be drawn as a number in lower area of dial
Sub needle(angle%, col%)
 Local integer x1,y1,x2,y2,x3,y3,j, xx1,yy1,xx2,yy2,xx3,yy3, tcol, size
 size= radius%\5*4-1
 x1=Sin(Rad(angle%-90))*size/10 + x%
 y1=-Cos(Rad(angle%-90))*size/10 + y%
 x2=Sin(Rad(angle%))*size + x%
 y2=-Cos(Rad(angle%))*size + y%
 x3=Sin(Rad(angle%+90))*size/10 + x%
 y3=-Cos(Rad(angle%+90))*size/10 + y%
 ' overwrite last needle position
 xx1=lastx1%
 yy1=lasty1%
 xx2=lastx2%
 yy2=lasty2%
 xx3=lastx3%
 yy3=lasty3%
 tcol = 0
 Triangle xx1, yy1, xx2, yy2, xx3, yy3,RGB(60,60,60),RGB(60,60,60)
 ' now setup to write new needle position
 xx1=x1
 yy1=y1
 xx2=x2
 yy2=y2
 xx3=x3
 yy3=y3
 tcol=col%
 Triangle xx1, yy1, xx2, yy2, xx3, yy3,RGB(gray),RGB(white)
 ' write out needle centre pin
 Circle x%, y%, size\10, 0, , col%, col%)
 Circle x%, y%, size\15, 0, , 0, 0
 Circle x%, y%, size\20, 0, , RGB(gray), RGB(gray)
 ' save the current needle position as last needle position for next write
 lastx1%=x1
 lastx2%=x2
 lastx3%=x3
 lasty1%=y1
 lasty2%=y2
 lasty3%=y3
End Sub
 '
 ' Update tacho RPM needle position
Sub UpdateTacho
 ' convert rpm value of 0 to 3000 into angle for needle display
 angle% = (rpm%-1500)\10
 needle(angle%,RGB(white))
 Print ""; ' needed to stop needle memory error
End Sub ' End of tacho subroutines

'ARC_PLAY.BAS
'The objective is to plot simple circular gauges from 0 to -90 and 0 to +90 degrees
'The line "CASE -1 to 1" seems to be required - The code below works.

dim integer I
Const X_Hzt = MM.Hres/2
const Y_Hzt = MM.VRES/2

cls  

for I = -120 to 120 step 1  'Just to confirm it works beyond 90deg

  ARC X_Hzt, Y_Hzt, 40,50 , 240, 120, RGB(black) 'Blank out the old arc
'   CIRCLE X_Hzt, Y_Hzt, 50, 10, 1, RGB(Black)  ' Blank out the old arc - which method is better?

  if I < 0 then
    ARC X_Hzt, Y_Hzt, 40,50 , I+360, 0, RGB(Red)
  elseif I > 0 then
    ARC X_Hzt, Y_Hzt, 40,50 , 0, I, RGB(Green)
  else    ' special case when I = 0
    line X_Hzt, Y_Hzt-41, X_Hzt, Y_Hzt-50, 1, RGB(Yellow)
  endif    

'   text 400,500,"               ", CM, 1,1,rgb(Black)      'Blank out old text
  text X_Hzt,Y_Hzt,"  "+str$(I)+"  ", CM, 1,1,rgb(Green)  'Text new angle
 
  pause 20   'Just to see what is happening
Next I

do:loop while inkey$ = ""
End