@ These are some drawing functions for handbell signs. (The circle is a
@ general function also present in the circles file.)

heading "" 

@ This function draws a circle. It must be called with four values on
@ the stack: the thickness of the line, the radius, and the coordinates 
@ of the centre. For example:
@   heading draw 0.4 20 24 0 circle
@ The variables xx1 - xx4 are used as local variables.

draw circle
  moveto 1.414 div 
  dup 0.6 mul /xx1 exch def dup 1.4 mul /xx2 exch def
  dup 0.5 mul /xx3 exch def dup 2.0 mul /xx4 exch def
  neg dup rmoveto
  xx1 xx3 neg xx2 xx3 neg xx4 0 rcurveto
  xx1 xx1 xx1 xx2 0 xx4 rcurveto
  xx1 neg xx3 xx2 neg xx3 xx4 neg 0 rcurveto
  xx1 neg xx1 neg xx1 neg xx2 neg 0 xx4 neg rcurveto
  setlinewidth stroke
enddraw    

@ Damp Sign:
@ Three arguments: x and y position of the centre, and the
@ scale, which is the length from the centre to the end of
@ the cross arms.

draw dampsign
  /s exch def                 @ s is the scale
  translate
  0 s moveto 0 s 2 mul neg rlineto
  s 0 moveto s 2 mul neg 0 rlineto
  0.3 setlinewidth stroke
  0.3 s 0.66 mul 0 0 draw circle
  0.3 s 0.33 mul 0 0 draw circle
enddraw

@ Echo:
@ Eight arguments: x and y position of the centre of the semicirle, the
@ radius of the semicircle, the length of the left-hand extension, the
@ length of the right-hand extension, the width of the arrow, the
@ length of the arrow, and the width of the line.

draw echo
  /w exch def                                    @ line width
  /al exch def                                   @ arrow length
  /aw exch 0.5 mul def                           @ 1/2 arrow width
  /rl exch def                                   @ right extension
  /ll exch def                                   @ left extension   
  /r exch def                                    @ radius
   
  translate                                      @ to centre of semicircle
  r neg 0 moveto 0 ll rlineto                    @ draw left extension
  r 0 moveto 0 rl rlineto currentpoint           @ draw right extension
  w setlinewidth stroke                          @ vertical lines
   
  moveto aw 0 rlineto aw neg al rlineto          @ triangle
  aw neg al neg rlineto fill 
  
  r neg 0 moveto                                 @ curved bit
  0 r 1.4 mul neg r 2 mul r 1.4 mul neg 
  r 2 mul 0 rcurveto stroke
enddraw  

@ Gyro:
@ Three arguments: x and y position of the centre of the cirle, and the
@ scale, which is the radius of the semicircle.

draw gyro
  /r exch def 
  /t r 0.2 mul def 
  translate
  0.3 r 0 0 draw circle
  
  currentgray
  currentlinewidth 
  0 r moveto
  r 0.25 mul neg   0
  r 0.4 mul neg   r 0.03 mul neg
 
  r 0.8 mul neg r 0.4 mul neg rcurveto 
  
  1 setgray
  1 setlinewidth 
  stroke 
  setlinewidth 
  setgray 
  
  0 r 0.99 mul t sub moveto
  0 t 2 mul rlineto
  t 2.5 neg t neg rlineto
  t 2.5 t neg rlineto
  fill    
enddraw    

@ Martellato:
@ Three arguments: x and y position of the tip, plus a scale value,
@ which is half the width of the triangle.

draw mart
  /s exch def
  translate 
  0 0 moveto s s 3 mul rlineto s 2 mul neg 0 rlineto fill
enddraw


@ Macro to call signs with default positioning

*define ds(24,6)    [draw 3 &&1 &&2 dampsign] 

@ Eight arguments: x and y position of the centre of the semicirle, the
@ radius of the semicircle, the length of the left-hand extension, the
@ length of the right-hand extension, the width of the arrow, the
@ length of the arrow, and the width of the line.


@ Macro argument gives vertical position                      
*define echo(24)    [draw 3 &&1 1.6 2 8.5 3 3 0.3 echo]
@                         |  |   |  |  |  | |  |
@                         |  |   |  |  |  | |  -> width of line
@                         |  |   |  |  |  | ----> length of arrow
@                         |  |   |  |  |  ------> width of arrow
@                         |  |   |  |  ---------> right-hand length
@                         |  |   |  ------------> left-hand length
@                         |  |   ---------------> radius
@                         |  -------------------> y coordinate
@                         ----------------------> x coordinate

*define gyro(24,5)  [draw 3 &&1 &&2 gyro]
*define mart(24,2)  [draw 3 &&1 &&2 mart]


@ Testing...

Magnification 1.5

[stave 1 treble 1]
g &ds g &ds g &echo g | &echo(4) q 
&gyro g &mart gg |
[endstave]