Appendix: Drawing Faces
 
REM ****************************************
REM ** BBC BASIC procedure to draw a face **
REM ****************************************
DEF PROCdraw_face(Draw%,x%,y%,r%,Fill_colour%,Line_colour%,Line_width%,cheeks,eyes,nose,mouth,RETURN face_boundary%())
LOCAL Word%, Movepath%, Bezierpath%, Closepath%
LOCAL Line_style%, Points%, block%
Word% = 4
Movepath% = 2
Bezierpath% = 6
Closepath% = 5
Points% = 97*Word%
Line_style% = FNdraw_line_style(1,1,1,1,0,0)
REM *Simple function describing a basic line*
r% = r%/2.5
DIM block% Points%
block%!0 = Movepath%
block%!Word% = x%-r%*2
block%!(Word%*2) = y%+r%*2
block%!(Word%*3) = Bezierpath%
block%!(Word%*4) = x%-r%*1.3
block%!(Word%*5) = y%+r%*3.13
block%!(Word%*6) = x%+r%*1.3
block%!(Word%*7) = y%+r%*3.13
block%!(Word%*8) = x%+r%*2
block%!(Word%*9) = y%+r%*2
block%!(Word%*10) = Bezierpath%
block%!(Word%*11) = x%+r%*(2.78+cheeks*2)
block%!(Word%*12) = y%+r%*0.73
block%!(Word%*13) = x%+r%*1.49
block%!(Word%*14) = y%-r%*2
block%!(Word%*15) = x%
block%!(Word%*16) = y%-r%*2
block%!(Word%*17) = Bezierpath%
block%!(Word%*18) = x%-r%*1.49
block%!(Word%*19) = y%-r%*2
block%!(Word%*20) = x%-r%*(2.78+cheeks*2)
block%!(Word%*21) = y%+r%*0.73
block%!(Word%*22) = x%-r%*2
block%!(Word%*23) = y%+r%*2
block%!(Word%*24) = Closepath%
REM left eye
block%!(Word%*25) = Movepath%
block%!(Word%*26) = x%-r%*(7+3*eyes)/8
block%!(Word%*27) = y%+r%*(10-3*eyes)/8
block%!(Word%*28) = Bezierpath%
block%!(Word%*29) = x%-r%*(7+3*eyes)/8
block%!(Word%*30) = y%+r%*(10-3*eyes)/8
block%!(Word%*31) = x%-r%*(5+eyes)/8
block%!(Word%*32) = y%+r%*(9-4*eyes)/8
block%!(Word%*33) = x%-r%/2
block%!(Word%*34) = y%+r%*(10-3*eyes)/8
block%!(Word%*35) = Bezierpath%
block%!(Word%*36) = x%+r%*(2+2*eyes)/8
block%!(Word%*37) = y%+r%*(16-eyes)/8
block%!(Word%*38) = x%-r%*(13+5*eyes)/8
block%!(Word%*39) = y%+r%*(16-eyes)/8
block%!(Word%*40) = x%-r%*(7+3*eyes)/8
block%!(Word%*41) = y%+r%*(10-3*eyes)/8
block%!(Word%*42) = Closepath%
REM right eye
block%!(Word%*43) = Movepath%
block%!(Word%*44) = x%+r%*(7+3*eyes)/8
block%!(Word%*45) = y%+r%*(10-3*eyes)/8
block%!(Word%*46) = Bezierpath%
block%!(Word%*47) = x%+r%*(7+3*eyes)/8
block%!(Word%*48) = y%+r%*(10-3*eyes)/8
block%!(Word%*49) = x%+r%*(5+eyes)/8
block%!(Word%*50) = y%+r%*(9-4*eyes)/8
block%!(Word%*51) = x%+r%/2
block%!(Word%*52) = y%+r%*(10-3*eyes)/8
block%!(Word%*53) = Bezierpath%
block%!(Word%*54) = x%-r%*(2+2*eyes)/8
block%!(Word%*55) = y%+r%*(16-eyes)/8
block%!(Word%*56) = x%+r%*(13+5*eyes)/8
block%!(Word%*57) = y%+r%*(16-eyes)/8
block%!(Word%*58) = x%+r%*(7+3*eyes)/8
block%!(Word%*59) = y%+r%*(10-3*eyes)/8
block%!(Word%*60) = Closepath%
REM nose
block%!(Word%*61) = Movepath%
block%!(Word%*62) = x%
block%!(Word%*63) = y%+r%
block%!(Word%*64) = Bezierpath%
block%!(Word%*65) = x%
block%!(Word%*66) = y%+r%
block%!(Word%*67) = x%-r%*(1.1+nose*2/3)
block%!(Word%*68) = y%
block%!(Word%*69) = x%
block%!(Word%*70) = y%
block%!(Word%*71) = Bezierpath%
block%!(Word%*72) = x%+r%*(1.1+nose*2/3)
block%!(Word%*73) = y%
block%!(Word%*74) = x%
block%!(Word%*75) = y%+r%
block%!(Word%*76) = x%
block%!(Word%*77) = y%+r%
block%!(Word%*78) = Closepath%
REM mouth
block%!(Word%*79) = Movepath%
block%!(Word%*80) = x%-r%*0.8
block%!(Word%*81) = y%+r%*(mouth/4-0.75)
block%!(Word%*82) = Bezierpath%
block%!(Word%*83) = x%-r%*0.8
block%!(Word%*84) = y%+r%*(mouth/4-0.75)
block%!(Word%*85) = x%
block%!(Word%*86) = y%-r%*(8+mouth*6)/8
block%!(Word%*87) = x%+r%*0.8
block%!(Word%*88) = y%+r%*(mouth/4-0.75)
block%!(Word%*89) = Bezierpath%
block%!(Word%*90) = x%+r%*0.8*(5-mouth)/8
block%!(Word%*91) = y%-r%*(9+mouth*7)/8
block%!(Word%*92) = x%-r%*0.8/2
block%!(Word%*93) = y%-r%*(8+mouth*8)/8
block%!(Word%*94) = x%-r%*0.8
block%!(Word%*95) = y%+r%*(mouth/4-0.75)
block%!(Word%*96) = Closepath%
PROCdraw_path_object(Draw%,Fill_colour%,Line_colour%,Line_width%,Line_style
|%,block%,Points%,face_boundary%())
ENDPROC
REM *****************************************
DEF PROCdraw_path_object(Draw%,Fill_colour%,Line_colour%,Line_width%,Line_s
|tyle%,Pointer%,Points%,RETURN parent_boundary%())
LOCAL pointer%, Path%, Endpath%, tag%, Word%, boundary%(), point%
Path% = 2
Endpath% = 0
Word% = 4
DIM boundary%(4)
boundary%()=0,2^30,2^30,-(2^30),-(2^30)
pointer% = FNdraw_start_object(Path%)
PROCdraw_word(Fill_colour%)
PROCdraw_word(Line_colour%)
PROCdraw_word(Line_width%)
PROCdraw_word(Line_style%)
point%=0
REPEAT
tag%=Pointer%!point%
PROCdraw_word(tag%)
point% += Word%
CASE tag% OF
WHEN 2,8
PROCdraw_coords(Pointer%!point%,Pointer%!(point%+Word%),boundary%())
point% += 2*Word%
WHEN 6
PROCdraw_coords(Pointer%!point%,Pointer%!(point%+Word%),boundary%())
point% += 2*Word%
PROCdraw_coords(Pointer%!point%,Pointer%!(point%+Word%),boundary%())
point% += 2*Word%
PROCdraw_coords(Pointer%!point%,Pointer%!(point%+Word%),boundary%())
point% += 2*Word%
ENDCASE
UNTIL point% = Points%
PROCdraw_word(Endpath%)
PROCdraw_end_object(pointer%, boundary%())
PROCdraw_extend_boundary(parent_boundary%(), boundary%())
ENDPROC