DrawFrame - animation sub using DRAW

[dajan]

The DRAW is a cool sub, having it's own sublanguage. But can it be more cool? Sure thing! Let's just encapsulate it by another sub, say DrawFrame, that takes one more parameter - time of the frame to draw - and can process 2 more statements within the drawstring for animation purposes: the "K" statement to define time intervals for animation and the "Q" statement for easy statements sequence repeating.

Here's the mentioned sub's code with a  simple player and a 60 seconds long demo clip$ showcasing most of new statements in simple animations.
Syntax of the new statements is described in code comments at the beginning.
Demo player is controled by arrow keys (time shift, speed), space (pause), R(reverse) and +/- (size).

Code: QB64: [Select]

1. '----------------------------------------------------------------------------------------------------------------------------------------------------
2. ' DrawFrame + DrawPlayer demonstration
3. '
4. ' ver. 1.0.1
5. ' by Daniel Janec, 2020
6. ' DrawFrame sub adds the "K", "V" and "Q" statements to the Draw sub statement set to handle mostly animation
7.  
8. ' Syntax:
9. '    DrawFrame ( sourceString$, frameTime, size )
10. ' Parameters:
11. '    sourceString$ - a string containing Draw statements and new/modified Drawferame statements described bellow
12. '    frameTime - in seconds, specifying the time, in which animated statements are drawed
13. '    size - draw magnifying factor, 1 is original size, 2 is double, 0.5 is half size etc.
14. '
15. ' Syntax of the new or modified DrawFrame statements:
16. ' K [id [ _ idRelativeK ] : ] [+/-] startTime; [+/-] endTime [ [# / *] [repeatCount] ]
17. '    Defines time interval "id" used for grapihical statements animation, starting at strartTime sec, ending at endTime sec,
18. '      optionaly repeating animation repeatCount times (or indefinetly if omitted) by using "*" for straight repeat or "#" for back-and-forth repeat.
19. '    Also sets this interval for next animated statements.
20. '    If "_" is used, the "+" or "-" sign can by used in time definition to set startTime/endTime relatively to another defined K interval "idReativeK".
21. '
22. ' K [id]
23. '    Sets defined interval "id" for next animated statements
24. '    Following statements written in form X [!] x1,y1; [!] x2;y2 (e.g. M 100,100;200;200) will be animated accordingly to the frametime parameter of Drawframe; acquiring x1, y1 values at startTime and x2, y2 at endTime
25. '
26. ' Q [id] [ : startTime [ ; endTime ] ] ]  [ * [repeatCount] ] [ ( commandSequenceString ) ]
27. '    Defines the "id" named sequence of statements commandSequenceString and repeats it repeatCount times.
28. '    If startTime and/or endTime are defined, this sequence does not apply outside of this time interval.
29. '
30. ' V angle
31. '    Turns the draw direction relatively to actual direction by <angle> degrees
32. '
33. ' S size %
34. '    Extends the S statement usage by % option.
35. '    Sets the drawing size relatively to the last absolute size set - to the <size>% of it
36. '
37. ' DrawPlayer controls:
38. '    Left / Right arrow: skip back / forward in time
39. '    Up / Down arrow: increase / decrease playback speed
40. '    Space: pause / play
41. '    R: toggle reverse playback on/off
42. '    + / -: increase / decrease size picture size
43. '
44. '----------------------------------------------------------------------------------------------------------------------------------------------------
45.  
46.  
47. '----------------------------------------------------------------------------------------------------------------------------------------------------
48. ' The Tree string
49. '----------------------------------------------------------------------------------------------------------------------------------------------------
50. leaf1$ = "Q1:17;* (V30 K11:17;17.5 S1%;!40% K11:17.5;19 S!40%;50% V-90 K12 V-10;10 U50 V-800U20 V30U20 V30U20 V20U40 V20U40 V20U50 V100U50 V20U40 V20U40 V20U20 V30U20 V30U20 V-800 K12 U50;47 V180 K12 V10;-10 V90 V-30 S100%)"
51. smallimb2$ = "Q2:7;* (V-90 K22:7;14 S1%;100% U100 K23:40;44 BM+0,+0;-4000,-100 K12:22;22.2# Q1 K23 BM+0,+0;+4000,+100 K22 S1%;100% U200 K23:47;49 BM+0,+0;-4000,-100 K12:22.1;22.3# Q1 K23 BM+0,+0;+4000,+100 K22 S1%;100% U100 V90 U10 V90 V-90 K23:49;51 BM+0,+0;-4000,-100 K12:22.2;22.4# Q1 K23 BM+0,+0;+4000,+100 K22 S1%;100% V90 U200 V-60 K23:49.5;51.5 BM+0,+0;-4000,-100 K12:22.3;22.5# Q1 K23 BM+0,+0;+4000,+100 K22 S1%;100% V60 U200 V-90 S100%)"
52. biglimb3$ = "Q3:4;* (V-88 K31:4.0;11 S1%;100% U250 K32:25;25.4# V30;50 Q2 K32 V-30;-50 K31 S1%;100% U200 V88 K33:25.1;25.5# V-35;-15 Q2 K33 V35;15 V88 K34:25.2;25.6# V-40;-20 Q2 K34 V40;20 K31 S1%;100% U450 V92 V-180 S100%)"
53. trunk4$ = "Q4 (K41:0;10 S1%;100% U500 K42:28.9;29.3# V30;40 Q3 K42 V-30;-40 K41 S1%;100% U400 V88 K43:29;29.4# V0;5 Q3 K43 V0;-5 V88 K41 S1%;100% U200 K44:29.1;29.5# V-30;-20 Q3 K44 V30;20 K41 S1%;100% M+0,+0;-10,-10 K45:17;17.6 M+0,+0;-25,-20 U700 V92 V92 S100%)"
54. cloud5$ = "Q51:17; (Q5*8(U30-V30) S150% V200 Q5*6 S130% V230 Q5*6 S120% V210 Q5*8 S160% V220 Q5*6 S160% V235 Q5*6) S2"
55. clip$ = "S2 BM1200,1000" + leaf1$ + smallimb2$ + biglimb3$ + "K1:0;10#C35;52 L400 K101:24.9;25.3# M-3,-0;+3,+0 " + trunk4$ + " K101 M+3,+0;-3,-0 M910,1000 L400 K102:17;23 BM2500,50;1400,100 TA90 K51:0;0.3# S2;2.05 " + cloud5$ + " TA0 K103:20;30 BM0,0 BM-800,+100;+500,+300 TA90 K51:0;0.3# S3;3.05 Q51"
56.  
57. '----------------------------------------------------------------------------------------------------------------------------------------------------
58. ' Examples of clip strings
59. '----------------------------------------------------------------------------------------------------------------------------------------------------
60. 'clip$ = "BM500,300 Q1*12( U20 V30 )" '1 circle
61. 'clip$ = "B M500,300 Q2*6( BU100 Q1*12( U20 V30 ) BD100 V60 )" '6 circles queued in round
62. 'clip$ = "B M500,300 K1:0;3# V0;360 Q2*6( BU50 Q1*12( U10 V30 ) BD50 V60 )" '6 circles queued in round rotating
63. 'clip$ = "B M500,300 K1:0;3* V0;360 Q2*6( K2:0;2# BU50;200 Q1*12( U10 V30 ) BD50;200 V60 )" '6 circles queued in round rotating and swingigng towards centre
64. 'clip$ = "B M500,300 K2:0;2# K1:0;3* V0;360 Q2*6( K2_2:+0.2;+0.2# BU50;200 Q1*12( U10 V30 ) BD50;200 V60 )" '6 circles queued in round rotating and swingigng towards centre in different phase
65. 'clip$ = "B M500,300 K2:0;1# K1:0;3* V0;360 Q2*6( K2_2:+0.2;+0.2# BU50;200 S100%;300% Q1*12( U10 V30 ) S100% BD50;200 V60 )" '6 circles queued in round rotating and swingigng towards centre in different phase changing size
66.  
67. '----------------------------------------------------------------------------------------------------------------------------------------------------
68. ' The Dog string
69. '----------------------------------------------------------------------------------------------------------------------------------------------------
70. ' Q0 - dog positioning
71. ' Q2 - dog walking
72. ' Q3 - dog head shape, Q31 - head running
73. ' Q4 - dog ear shape, Q41 - ear running
74. ' Q5 - dog tail shape, Q51 - tail running
75. ' Q7 - dog foot shape, Q71 - foot running
76.  
77. 'clip$ = "S2 BM1900,518 L3500 Q0*(K0:0;10 BM1800,400;300,400 TA0)  Q7*(L40 D20 R40 U20)  Q71*(BM+20,+180 K71_71:-0.5;-0.5* K72_71:+0;-0.5# K71 V0;360 BD40 V360;0 K72 V-10;30 Q7) K41:0;0.25#"+_
78. '        "Q4*(L40M+20,-40M+20,40) Q41*(K41_41:+0.05;+0.05# V-35;15 Q4 V35;-15) " + _
79. '        "Q5*(R50 U40 L50 D40) Q51*(K51:0;0.25#  V10;30 BM+100,-40 Q5)" + _
80. '        "Q3*(BM-20,-110 L200D120R200U120 BM-70,+30 R20D20L20U20 BM-120,-20 R30D30L30U30)  Q31*(K32:4;4.5 V0;50 K33_32:+3;+2.8 V!0;-50 K32 BM+0,0;-50,20 K33 BM+0,0;+50,-20 K31:0;0.25# BD-20;10 Q3 BM+140,-30 Q41 BR60 Q41) "+ _
81. '        "Q2(Q0 K21:-0.125;0.125# BU0;40 D150R250U150L250 BM+200,+70 Q51 K71:0;1* Q0 Q71 Q0 Q71 Q0BM+250,0 Q71 Q0BM+250,+0 Q71 Q0 Q31)
82.  
83. '----------------------------------------------------------------------------------------------------------------------------------------------------
84. SCREEN _NEWIMAGE(1920, 1080, 256)
85. _SCREENMOVE (_DESKTOPWIDTH - _WIDTH) / 2, (_DESKTOPHEIGHT - _HEIGHT) / 2
86.  
87. DrawPlayer clip$, 0, 60, 30, _WIDTH / 1920, 1
88.  
89. '----------------------------------------------------------------------------------------------------------------------------------------------------
90. 'Player demonstration
91. '----------------------------------------------------------------------------------------------------------------------------------------------------
92. SUB DrawPlayer (movie$, playfromtime, playtotime, fps, size, speed)
93.     t = playfromtime * fps
94.     dir = 1
95.     DO
96.         CLS
97.         _PRINTSTRING (0, 5), "size:" + STR$(RoundDec(size, 2)) + "   speed:" + STR$(dir * speed) + "x  time:" + STR$(RoundDec(t / fps * speed, 2))
98.         DrawFrame movie$, t / fps * speed, size
99.         IF k = 32 THEN SLEEP: k = _KEYHIT: k = _KEYHIT
100.         IF k = 20480 AND speed > 0.1 THEN speed = speed / 2: t = t * 2
101.         IF k = 18432 AND speed < 100 THEN speed = speed * 2: t = t / 2
102.         IF k = 19200 THEN t = t - 2 * fps
103.         IF k = 19712 THEN t = t + 2 * fps
104.         IF k = 43 THEN size = size + 0.01
105.         IF k = 45 THEN size = size - 0.01
106.         IF k = 114 THEN dir = -dir
107.         t = t + dir
108.         IF size > 10 THEN size = 10
109.         IF size < 0.01 THEN size = 0.01
110.         IF t > playtotime * fps / speed THEN t = playtotime * fps / speed
111.         IF t < 0 THEN t = 0
112.         k = _KEYHIT
113.         _DISPLAY
114.         _LIMIT fps
115.     LOOP UNTIL _KEYDOWN(27)
116. END SUB
117.  
118. '----------------------------------------------------------------------------------------------------------------------------------------------------
119. 'Sub & Function definitions
120. '----------------------------------------------------------------------------------------------------------------------------------------------------
121. SUB DrawFrame (SrcStrOrig AS STRING, frametime AS SINGLE, size AS SINGLE)
122.  
123.     CONST CMD_LEN_MAX = 1000 'max. command sequence length definable using statement Q()
124.  
125.     TYPE TKFset 'Key frame set type
126.         id AS INTEGER
127.         defined AS _BYTE
128.         timestart AS SINGLE
129.         timeend AS SINGLE
130.         repeat AS STRING * 1
131.         repeatcount AS INTEGER
132.     END TYPE
133.  
134.     TYPE TCmdSeq 'Command Sequence
135.         id AS INTEGER
136.         CmdStr AS STRING * CMD_LEN_MAX
137.         defined AS _BYTE
138.         startpos AS LONG
139.         endpos AS LONG
140.         timestart AS SINGLE
141.         timeend AS SINGLE
142.         repeatcount AS INTEGER
143.     END TYPE
144.  
145.     TYPE TDrawState 'global Draw state
146.         SrcLen AS LONG 'Source string length
147.         SrcPos AS LONG 'Source string last read char position
148.         ActKFSetIdx AS INTEGER 'KFset index applied to actual statement if KF enabled
149.         ActTA AS SINGLE 'Actual parameter value of previous TA statement (in degrees)
150.         ActS AS SINGLE 'Actual parameter value of previous "S" statement usage
151.         ErrDsc AS STRING * 50 'Error description
152.     END TYPE
153.  
154.     DIM KFset(0 TO 999) AS TKFset
155.     DIM CmdSeq(0 TO 99) AS TCmdSeq
156.     DIM DS AS TDrawState
157.     DIM char AS STRING * 1
158.     DIM prevchar AS STRING * 1
159.     DIM TrgStr AS STRING
160.     DIM c$, code$, label$, x1$, y1$, x2$, y2$, sgnx1$, sgny1$, rep$, repcnt$, par$, exclfrom$, exclto$, csstart$, percx1$, percx2$
161.     DIM x AS SINGLE, y AS SINGLE, x1 AS SINGLE, y1 AS SINGLE, x2 AS SINGLE, y2 AS SINGLE, kid AS INTEGER, csid AS INTEGER
162.     DIM readstate AS _BYTE
163.     DIM stat$, ParseStatement$ ' Actual statement being read from source draw string
164.     DIM SrcStr AS STRING
165.  
166.     SrcStr = SrcStrOrig
167.     TrgStr = ""
168.     stat$ = ""
169.     prevchar = ""
170.     SrcStr = SrcStr + "&"
171.     DS.SrcLen = LEN(SrcStr)
172.     DS.SrcPos = 0
173.     DS.ActKFSetIdx = 0
174.     DS.ActTA = 0
175.     DS.ActS = 4
176.  
177.     DO 'read statement
178.         DS.SrcPos = DS.SrcPos + 1
179.         char = MID$(SrcStr, DS.SrcPos, 1)
180.         IF (ASC(char) >= 64 AND ASC(char) <= 90 AND NOT (char = "A" AND prevchar = "T")) OR char = "&" THEN
181.             '-------------------------------------------Parser begin-----------------------------------------------------------
182.             stat$ = stat$ + "&"
183.             ParseStatement$ = ""
184.             readstate = 0
185.             KFenabled = 0
186.             omitstate = 0
187.             par$ = "": code$ = "": label$ = "": x1$ = "": y1$ = "": x2$ = "": y2$ = "": sgnx1$ = "": sgny1$ = "": sgnx2$ = ""
188.             rep$ = "": repcnt$ = "": par$ = "": exclfrom$ = "": exclto$ = "": csstart$ = "": percx1$ = "": percx2$ = "": rel$ = "": krel$ = ""
189.             x = 0: y = 0: x1 = 0: y1 = 0: x2 = 0: y2 = 0: kid = 0: csid = 0
190.  
191.             FOR i = 1 TO LEN(stat$)
192.                 c$ = MID$(stat$, i, 1)
193.                 SELECT CASE readstate
194.                     CASE 0:
195.                         SELECT CASE c$
196.                             CASE "A" TO "Z":
197.                                 code$ = code$ + c$
198.                             CASE "_":
199.                                 label$ = par$: par$ = "": rel$ = c$: readstate = 11
200.                             CASE ":":
201.                                 label$ = par$: par$ = "": readstate = 1
202.                             CASE ",":
203.                                 x1$ = par$: par$ = "": readstate = 2
204.                             CASE ";":
205.                                 x1$ = par$: par$ = "": readstate = 3
206.                                 KFenabled = 1
207.                             CASE "!":
208.                                 exclfrom$ = c$
209.                             CASE "+", "-":
210.                                 par$ = par$ + c$
211.                                 sgnx1$ = c$
212.                             CASE "0" TO "9", ".":
213.                                 par$ = par$ + c$
214.                             CASE "%":
215.                                 percx1$ = percx1$ + c$
216.                             CASE "*":
217.                                 label$ = par$: par$ = "": rep$ = c$: readstate = 5
218.                             CASE "(":
219.                                 label$ = par$: csstart$ = c$: readstate = 10
220.                             CASE "&", ")":
221.                                 x1$ = par$: par$ = "": readstate = 10
222.                             CASE ELSE: readstate = 99
223.                         END SELECT
224.                     CASE 11:
225.                         SELECT CASE c$
226.                             CASE "0" TO "9":
227.                                 par$ = par$ + c$
228.                             CASE ":":
229.                                 krel$ = par$: par$ = "": readstate = 1
230.                             CASE ELSE: readstate = 99
231.                         END SELECT
232.                     CASE 1:
233.                         SELECT CASE c$
234.                             CASE ",":
235.                                 x1$ = par$: par$ = "": readstate = 2
236.                             CASE ";":
237.                                 x1$ = par$: par$ = "": readstate = 3
238.                                 KFenabled = 1
239.                             CASE "!":
240.                                 exclfrom$ = c$
241.                             CASE "+", "-":
242.                                 par$ = par$ + c$
243.                                 sgnx1$ = c$
244.                             CASE "0" TO "9", ".":
245.                                 par$ = par$ + c$
246.                             CASE "%":
247.                                 percx1$ = percx1$ + c$
248.                             CASE "(":
249.                                 x1$ = par$: csstart$ = c$: readstate = 10
250.                             CASE "&", ")":
251.                                 x1$ = par$: par$ = "": readstate = 10
252.                             CASE ELSE: readstate = 99
253.                         END SELECT
254.                     CASE 2:
255.                         SELECT CASE c$
256.                             CASE ";":
257.                                 y1$ = par$: par$ = "": readstate = 3
258.                                 KFenabled = 1
259.                             CASE "+", "-":
260.                                 par$ = par$ + c$
261.                                 sgny1$ = c$
262.                             CASE "0" TO "9", ".":
263.                                 par$ = par$ + c$
264.                             CASE "&", ")":
265.                                 y1$ = par$: par$ = "": readstate = 10
266.                             CASE ELSE: readstate = 99
267.                         END SELECT
268.                     CASE 3:
269.                         SELECT CASE c$
270.                             CASE ",":
271.                                 x2$ = par$: par$ = "": readstate = 4
272.                             CASE "#":
273.                                 x2$ = par$: par$ = "": rep$ = c$: readstate = 5
274.                             CASE "*":
275.                                 x2$ = par$: par$ = "": rep$ = c$: readstate = 5
276.                             CASE "!":
277.                                 exclto$ = c$
278.                             CASE "+", "-":
279.                                 par$ = par$ + c$
280.                                 sgnx2$ = c$
281.                             CASE "0" TO "9", ".":
282.                                 par$ = par$ + c$
283.                             CASE "%":
284.                                 percx2$ = percx2$ + c$
285.                             CASE "(":
286.                                 x2$ = par$: csstart$ = c$: readstate = 10
287.                             CASE "&", ")":
288.                                 x2$ = par$: par$ = "": readstate = 10
289.                             CASE ELSE: readstate = 99
290.                         END SELECT
291.                     CASE 4:
292.                         SELECT CASE c$
293.                             CASE "#":
294.                                 y2$ = par$: par$ = "": rep$ = c$: readstate = 5
295.                             CASE "*":
296.                                 y2$ = par$: par$ = "": rep$ = c$: readstate = 5
297.                             CASE "0" TO "9", "+", "-", ".":
298.                                 par$ = par$ + c$
299.                             CASE "&", ")":
300.                                 y2$ = par$: par$ = "": readstate = 10
301.                             CASE ELSE: readstate = 99
302.                         END SELECT
303.                     CASE 5:
304.                         SELECT CASE c$
305.                             CASE "0" TO "9", "+", "-", ".":
306.                                 par$ = par$ + c$
307.                             CASE "(":
308.                                 repcnt$ = par$: par$ = "": csstart$ = c$: readstate = 10
309.                             CASE "&", ")":
310.                                 repcnt$ = par$: par$ = "": readstate = 10
311.                             CASE ELSE: readstate = 99
312.                         END SELECT
313.                 END SELECT
314.             NEXT i
315.  
316.             IF readstate = 99 THEN DS.ErrDsc = "Error in statement: " + LEFT$(stat$, LEN(stat$) - 1) ELSE DS.ErrDsc = ""
317.             IF code$ = "K" THEN
318.                 IF x2$ <> "" THEN ' defining KFset
319.                     tsdelta = 0: tedelta = 0
320.                     kid = VAL(label$)
321.                     KFset(kid).id = kid
322.                     KFset(kid).defined = 1
323.                     IF krel$ <> "" THEN
324.                         krel = VAL(krel$)
325.                         IF sgnx1$ <> "" THEN tsdelta = KFset(krel).timestart
326.                         IF sgnx2$ <> "" THEN tedelta = KFset(krel).timeend
327.                     END IF
328.                     KFset(kid).timestart = VAL(x1$) + tsdelta
329.                     KFset(kid).timeend = VAL(x2$) + tedelta
330.                     KFset(kid).repeat = rep$
331.                     KFset(kid).repeatcount = VAL(repcnt$)
332.                     DS.ActKFSetIdx = kid
333.                 ELSE ' referencing KFset
334.                     IF label$ = "" AND x1$ <> "" THEN label$ = x1$
335.                     kid = VAL(label$)
336.                     DS.ActKFSetIdx = kid
337.                 END IF
338.  
339.             ELSEIF code$ = "Q" THEN
340.                 IF x1$ <> "" OR x2$ <> "" AND label$ <> "" THEN
341.                     csid = VAL(label$)
342.                     CmdSeq(csid).timestart = VAL(x1$)
343.                     CmdSeq(csid).timeend = VAL(x2$)
344.                 END IF
345.                 IF label$ = "" AND x1$ <> "" AND x2$ = "" THEN label$ = x1$
346.                 csid = VAL(label$)
347.                 CmdSeq(csid).id = csid
348.                 IF repcnt$ <> "" THEN CmdSeq(csid).repeatcount = VAL(repcnt$)
349.  
350.                 ipos = 0
351.                 IF csstart$ = "(" THEN ' defining command sequence
352.                     parcnt = 1: c$ = ""
353.                     DO ' Find corresponding right parenthes in the source string
354.                         ipos = ipos + 1
355.                         c$ = MID$(SrcStr$, DS.SrcPos + ipos, 1)
356.                         IF c$ = "(" THEN parcnt = parcnt + 1
357.                         IF c$ = ")" THEN parcnt = parcnt - 1
358.                     LOOP UNTIL (c$ = ")" AND parcnt = 0) OR DS.SrcPos + ipos >= DS.SrcLen OR ipos >= CMD_LEN_MAX
359.                     IF (c$ = ")" AND parcnt = 0) THEN
360.                         CmdSeq(csid).CmdStr = MID$(SrcStr, DS.SrcPos, ipos)
361.                         CmdSeq(csid).defined = 1
362.                     ELSE
363.                         CmdSeq(csid).defined = 0
364.                     END IF
365.                 ELSE 'Referencing command sequence
366.                 END IF
367.  
368.                 IF CmdSeq(csid).defined = 1 THEN 'modify source string if command sequence defined
369.                     IF CmdSeq(csid).repeatcount > 0 THEN
370.                         rpt = CmdSeq(csid).repeatcount
371.                     ELSEIF rep$ = "*" THEN
372.                         rpt = 0
373.                     ELSE
374.                         rpt = 1
375.                     END IF
376.                     IF CmdSeq(csid).timeend <> 0 AND (frametime < CmdSeq(csid).timestart OR frametime > CmdSeq(csid).timeend) THEN rpt = 0
377.                     IF frametime < CmdSeq(csid).timestart THEN rpt = 0
378.                     cmdrpt$ = ""
379.                     FOR i = 1 TO rpt: cmdrpt$ = cmdrpt$ + RTRIM$(CmdSeq(csid).CmdStr): NEXT i
380.                     SrcStr = RTRIM$(cmdrpt$) + RIGHT$(SrcStr, DS.SrcLen - DS.SrcPos - ipos + 1)
381.                     DS.SrcLen = LEN(SrcStr)
382.                     DS.SrcPos = 0
383.                     char = ""
384.                 END IF
385.  
386.             ELSE 'do for other graphics statements
387.                 x1 = VAL(x1$): y1 = VAL(y1$): x2 = VAL(x2$): y2 = VAL(y2$)
388.                 kid = DS.ActKFSetIdx
389.                 IF KFenabled = 1 AND KFset(kid).defined = 1 THEN 'change parameters if statement is keyframed
390.                     fk = (frametime - KFset(kid).timestart) / (KFset(kid).timeend - KFset(kid).timestart)
391.                     IF (frametime >= KFset(kid).timestart AND frametime <= KFset(kid).timeend) THEN
392.                         IF x1$ <> "" THEN x1 = x1 + (x2 - x1) * fk
393.                         IF y1$ <> "" THEN y1 = y1 + (y2 - y1) * fk
394.                     ELSEIF (frametime > KFset(kid).timeend AND exclto$ <> "!") THEN
395.                         period = INT((frametime - KFset(kid).timestart) / (KFset(kid).timeend - KFset(kid).timestart))
396.                         IF (KFset(kid).repeat = "*" OR KFset(kid).repeat = "#") AND (period < KFset(kid).repeatcount OR KFset(kid).repeatcount = 0) THEN
397.                             IF KFset(kid).repeat = "#" AND period MOD 2 = 1 THEN
398.                                 fk = (KFset(kid).timeend - frametime + period * (KFset(kid).timeend - KFset(kid).timestart)) / (KFset(kid).timeend - KFset(kid).timestart)
399.                             ELSE
400.                                 fk = (frametime - KFset(kid).timestart - period * (KFset(kid).timeend - KFset(kid).timestart)) / (KFset(kid).timeend - KFset(kid).timestart)
401.                             END IF
402.                             IF x1$ <> "" THEN x1 = x1 + (x2 - x1) * fk
403.                             IF y1$ <> "" THEN y1 = y1 + (y2 - y1) * fk
404.                         ELSE
405.                             IF KFset(kid).repeat = "#" AND KFset(kid).repeatcount MOD 2 = 0 THEN
406.                                 IF x1$ <> "" THEN x1 = x1
407.                                 IF y1$ <> "" THEN y1 = y1
408.                             ELSE
409.                                 IF x1$ <> "" THEN x1 = x2
410.                                 IF y1$ <> "" THEN y1 = y2
411.                             END IF
412.                         END IF
413.                     ELSEIF (frametime < KFset(kid).timestart AND exclfrom$ <> "!") THEN
414.                         omitstate = 0
415.                     ELSE
416.                         omitstate = 1
417.                     END IF
418.                 END IF
419.                 IF omitstate = 0 THEN
420.                     SELECT CASE code$
421.                         CASE "T", "TA":
422.                             x1 = RoundDec(x1, 6)
423.                             DS.ActTA = x1
424.                             IF (DS.ActTA > 360) OR (DS.ActTA < -360) THEN DS.ActTA = DS.ActTA + (DS.ActTA > 0) * 360
425.                         CASE "V":
426.                             DS.ActTA = DS.ActTA + RoundDec(x1, 6)
427.                             IF (DS.ActTA > 360) OR (DS.ActTA < -360) THEN DS.ActTA = DS.ActTA + (DS.ActTA > 0) * 360
428.                             code$ = "TA"
429.                             x1 = RoundDec(DS.ActTA, 6)
430.                         CASE "C":
431.                             x1 = _ROUND(x1)
432.                         CASE "M", "D", "E", "F", "G", "H", "L", "R", "U":
433.                             x1 = RoundDec(x1 * size, 4)
434.                             y1 = RoundDec(y1 * size, 4)
435.                         CASE "S":
436.                             IF percx1$ <> "" OR percx2$ <> "" THEN
437.                                 x1 = RoundDec(x1 * DS.ActS / 100, 5)
438.                                 IF x1 > 8 THEN x1 = 8
439.                             ELSE
440.                                 DS.ActS = x1
441.                             END IF
442.                     END SELECT
443.                     IF sgnx1$ <> "" AND x1 < 0 THEN sgnx1$ = ""
444.                     IF sgnx1$ <> "" AND x1 > 0 THEN sgnx1$ = "+"
445.                     IF sgny1$ <> "" AND y1 < 0 THEN sgny1$ = ""
446.                     IF sgny1$ <> "" AND y1 > 0 THEN sgny1$ = "+"
447.                     ParseStatement$ = code$
448.                     IF x1$ <> "" THEN
449.                         ParseStatement$ = ParseStatement$ + sgnx1$ + LTRIM$(STR$(x1))
450.                         IF y1$ <> "" THEN ParseStatement$ = ParseStatement$ + "," + sgny1$ + LTRIM$(STR$(y1))
451.                     END IF
452.                 ELSE
453.                     ParseStatement$ = ""
454.                 END IF
455.             END IF
456.  
457.             ''---DEBUG BEGIN-----------
458.             'IF CmdSeq(csid).defined = 1 THEN cmd$ = RTRIM$(CmdSeq(csid).CmdStr) ELSE cmd$ = ""
459.             'PRINT
460.             'PRINT stat$ + " > ", , code$ + "/" + label$ + "/" + x1$ + "/" + y1$ + "/" + x2$ + "/" + y2$ + "/" + exclfrom$ + "/" + exclto$ + "/" + rep$ + "/" + repcnt$
461.             'PRINT "TrgStr: "; TrgStr
462.             'PRINT "SrcStr: "; SrcStr
463.             'PRINT "cmd$: ", cmd$
464.             'PRINT "DS.Srcpos", DS.SrcPos
465.             'PRINT "ParseStatement$: ", ParseStatement$
466.             'IF stat$ = "Q1*(&" OR stat$ = "Q1(&" THEN stopable = 1
467.             'IF stopable THEN
468.             '    DO
469.             '    LOOP UNTIL _KEYHIT = 32
470.             'END IF
471.             ''---DEBUG END-------------
472.  
473.             '-------------------------------------------Parser end-----------------------------------------------------------
474.             TrgStr = TrgStr + ParseStatement$
475.             IF LTRIM$(DS.ErrDsc) <> "" THEN PRINT RTRIM$(DS.ErrDsc) + " at position:" + STR$(DS.SrcPos - LEN(stat$))
476.             stat$ = ""
477.         END IF
478.         IF char <> " " THEN
479.             stat$ = stat$ + char
480.         END IF
481.         prevchar = char
482.     LOOP WHILE DS.SrcPos < DS.SrcLen
483.  
484.     DRAW TrgStr
485.  
486.     'PRINT SrcStr '---DEBUG code----
487.     'PRINT TrgStr '---DEBUG code----
488. END SUB
489.  
490. '----------------------------------------------------------------------------------------------------------------------------------------------------
491. FUNCTION RoundDec (x AS SINGLE, n AS INTEGER)
492.     RoundDec = _ROUND(x * 10 ^ n) / (10 ^ n)
493. END FUNCTION
494.  
495. '----------------------------------------------------------------------------------------------------------------------------------------------------
496.  

For those interested in handling new commands, here's a quick tutorial, based on uncommenting corresponding line code "clip$=" in the part "Examples of clip strings".
Let's start simple and develop the string gradualy to something more complex.


1 circle

clip$ = "BM500,300 Q1*12( U20 V30 )"

Q statement defines sequence "U20 V30" as sequence "1" and repeats it 12 times -  line up (U20) , turn 30 degrees relative (V30), effectively drawing a circle (12*30=360).


6 circles queued in round

clip$ = "B M500,300 Q2*6( BU100 Q1*12( U20 V30 ) BD100 V60 )"

Q1 is nested into Q2 command sequence, together with additional movement before drawing the circle Q1 and movement + turning after drawing the circle.


6 circles queued in round rotating

clip$ = "B M500,300 K1:0;3# V0;360 Q2*6( BU50 Q1*12( U10 V30 ) BD50 V60 )"

K statement defines keyframes interval "1", begining at time 0s, ending at 3s. The # means the animation, the interval "1" is set before, will be repeated back and forth indefinetly.
Next command V is animated with KF interval "1" set, thus turning the direction from 0 degrees at 0 s to 360 degrees at 2 s and then backwards.


6 circles queued in round rotating and swingigng towards centre

clip$ = "B M500,300 K1:0;3* V0;360 Q2*6( K2:0;2# BU50;200 Q1*12( U10 V30 ) BD50;200 V60 )"

Another KF interval "2" is added and set before modified D50, that is thus animated acquiring values  from 50 to 200 in time 0s to 2s.


6 circles queued in round rotating and swingigng towards centre in different phase

clip$ = "B M500,300 K2:0;2# K1:0;3* V0;360 Q2*6( K2_2:+0.2;+0.2# BU50;200 Q1*12( U10 V30 ) BD50;200 V60 )"

This one is bit tricky. KF interval "2" (K2) is now initialy defined outside the Q2 sequence, so that it could be later redefined within the Q2, using relative start and end time (+0.2s) to current itself's definition (K2_2).


6 circles queued in round rotating and swingigng towards centre in different phase while changing size

clip$ = "B M500,300 K2:0;1# K1:0;3* V0;360 Q2*6( K2_2:+0.2;+0.2# BU50;200 S100%;300% Q1*12( U10 V30 ) S100% BD50;200 V60 )"

This one demonstrates relative size change. Before drawing the circle (Q1) there is animated S statement, with animation drived by the last previous KF set (K2).
Immediately after the Q1 circle is drawed, size has to be reset to 100% of absolute size. The advantage of setting the size relatively inside definition is that you can scale the whole sequence (say object) by setting absolute size before it.

Edit1: I'll be updating this post to the the most recent code version; now for v.1.0.1 - mostly bugs fixes, TA works with decimals now

[RhoSigma]

That's truely impressive work and a cool demo. It's always interesting to see what's possible with simple statements, if somebody really takes the time to investigate how it can be used effectively and builts a useful framework around it.

[johnno56]

Very nicely done indeed!! To quote Darth Vader (Star Wars IV: A new Hope: 1977), "Impressive. Most impressive."

J

[bplus]

Love the animation!

I too extended DRAW with circles, boxes, arcs filled or not and with repeat code and with variable and variable changer... but it was all static, so cool to see it made dynamic.

[Petr]

Very nice work!

[dajan]

Guys, thanks a lot for your appreciation.

@bplus: do you have a link or code somewhere by chance? Now, I'm rather interested in your approach, since I also got involved into DRAW enhancing. I have been thinking about some kind of variables too, but it seemed too hardcore and I decided to keep it rather simple.

[Dimster]

I have never used "Draw" statement, this was pretty cool Dan. Thanks for same. I would imagine it would be pretty difficult to add a "dimension" factor to Draw statement or perhaps would that simply be a matter of a slight offset to multiple Frames or multiple parallel lines?

[FellippeHeitor]

Wow! This is really impressive, man!

[TempodiBasic]

Hi dajan
I like it very much!
and for three reasons:
1 movement into a single string of command
2 multiple shapes into a single string of command
3 player interacting with user

Some time ago I made some experiment to use DRAW in 32 bit mode and moreover  to build a library of simple shapes on a 2D plane. For polygons I used a method posted on [abandoned, outdated and now likely malicious qb64 dot net website - don’t go there] in a thread of Steve SmcNeill and peharps also for the whole circle.
For scaling the size of the images I use the inner command of DRAW.
The next step, for now left on the world of ideas, was to build an editor to draw on a graphic panel and to convert the final image painted in a sequence of DRAW statements or/and in DATA. (for saving as images to load them after using _LOADIMAGE there are too professional programs like Windows MsPaint, Gimp, IconEditor etc etc)

[dajan]

@FellippeHeitor: thanks man, glad to hear that.

@Dimster: That is actualy pretty interesting idea, to add the third dimension to DRAW graphical statement M and also add 2 new directional statements to U, D, L, R for forward and backward direction.  Then the DRAW sub would get the camera position as parameter in addition. Two problems with that anyway: it would be hell of a drawing to create something reasonable = long and comlicated string. Also, the demo clip included in the code above alone completely devastates one CPU core (mainly due to extensive use of strings operations), I could not imagine how would the 3D DRAW manage.

@TempodiBasic: actually, it was my intention, to squeeze the whole movie into one, shortest string possible. This 60 sec. demo clip has 1251 characters (without spaces), it is possible to 7zip it to 661 bytes. And yes, it also came to my mind to build a graphuic GUI, where you could build the string with mouse and keyboard. Long strings are fairly CPU intensive, however, so it is more suitable to use it as single object animation tool in some kind of minigames. I will put an example here some time soon, cause I 'm having an idea yet.

[FellippeHeitor]

Your idea was both innovative and so well executed. I love that you can control the animation, moving the playing head back and forth.

Also, your code is very neatly organised and so easy to follow.

If you do actually come up with a way to build the strings with mouse and keyboard, that'll be amazing.

Kudos, man. Way to go.

[bplus]

@bplus: do you have a link or code somewhere by chance? Now, I'm rather interested in your approach, since I also got involved into DRAW enhancing. I have been thinking about some kind of variables too, but it seemed too hardcore and I decided to keep it rather simple.

OK just translated and did a little update to 1st pentagon screen demo the rest is mostly as it was in 2017:

Code: QB64: [Select]

1. _TITLE "Draw Strings trans" 'b+ 2020-01-19 translate from
2. ' Draw strings 2.bas SmallBASIC 0.12.9 (B+=MGA) 2017-05-06
3. 'Deluxe draw strings.sdlbas [B+=MGA] 2017-01-03
4. 'translated from:
5. 'v2 turtle strings.bas  SmallBASIC 0.12.2 [B+=MGA] 2016-04-04
6. '2017-05-08 fixes Box d and e for width and height
7. ' test draw strings fixed for arc
8.  
9. '=================================================================
10. '                   Commands Set
11. '==================================================================
12. 'Note all commands are a letter for function followed by number n
13.  
14. 'commands pn -1 to 15, 0-15 are QB colors,  -1 is pen up
15.  
16. 'command xn set absolute screen coordinate for turtle x
17.  
18. 'command yn set absolute screen coordinate for turtle y
19.  
20. 'command gn move turtle relative to its current x position
21. '        + n = right, -n = left (pneumonic g for go!)
22.  
23. 'command hn move turtle relative to its current y position
24. '        + n down?, -n up?  depends which way the angle is set
25. '        (pnuemonic h follows g like y follows x)
26.  
27. 'command fn draws at current ta angle a distance of n (set ta turtle angle first by tn or an)
28. '        (pnuemonic f is for forward use -n for back)
29.  
30. 'command an sets angle or heading of turtle
31. '        (pnuemonic a is for angle (degrees)
32. '        0 degrees is true North or 12 o'clock)
33.  
34. 'command tn (turns) t=right n degrees when positive
35. '        and turn left n degrees when negative
36.  
37. 'v2 2016-04-05 the great and powerful repeat uses recursive sub
38.  
39. 'command rn repeat drawstrings n amount of times
40.  
41. 'command tv for setting a turtle var probably need another
42.  
43. 'add 2 more commands for setting and incrementing the tv variable
44.  
45. 'command sn will set tv at n value
46.  
47. 'command in will increment tv with n value
48.  
49. 'Deluxe draw strings 2017-01-03
50. ' draw filled box  current tx, ty is one corner
51.  
52. 'command zn for pen siZe radius to draw thick lines
53.  
54. 'command dn sets box width
55.  
56. 'command en sets box height
57.  
58. 'command bn for Box color n = 0 - 15
59.  
60. 'command un to set a circle radius
61.  
62. 'command cn to draw a filled circle of color n = 0 - 15
63.  
64. 'command jn to set the arc deg angle start
65.  
66. 'command kn to set the arc deg angle end
67.  
68. 'command ln draw arc color n = 0 - 15
69.  
70. '================================================ QB64 translation notes
71. 'Looks like we will need to setup screen with _newimage(xmax, ymax, 12) for easy color numbers for pen p, p9 = blue
72. ' p-1 means no drawing color = just moving pen into a new position, p0 is pen with Black ink
73. CONST xmax = 800, ymax = 600 'standard 800 x 600 screen
74. SCREEN _NEWIMAGE(xmax, ymax, 12)
75. _SCREENMOVE 300, 40 'center
76. '======================================================================
77. 'turtle globals should you translate to another dialect
78. DIM SHARED scale, tx, ty, tx2, ty2, tr, taStart, taStop, tc, ta, tv, tz 'keep all these as single?
79. 'initialize turle constants
80. scale = 1 'external to string settings
81. tx = 0: ty = 0 ' x, y turtle position
82. tx2 = 0: ty2 = 0 ' 2nd x,y for fill box or for ellipse width and height
83. taStart = 0 ' turtle arc Start
84. taStop = 0 ' turtle arc Stop
85. tc = 15 ' turtle color (QB colors 0 - 15 and -1 means pen up
86. ta = 0 ' turtle angle
87. tv = 0 ' new turtle increment var for changing tv
88. tz = 1 ' tz is tracking pen size
89. tr = 0 ' radius
90.  
91. 'tests
92. 'blue pentagon, line thickness 8
93. tt "z1p-1x400y100z12p4t126" 'start at top point turn 90 + 36
94. tt "r5f300t72"
95. scale = .75
96. tt "z1p-1x400y160z6p2"
97. tt "r5f300t72"
98. scale = .5
99. tt "z1p-1x400y220z3p1"
100. tt "r5f300t72"
101. scale = 1
102. LOCATE 1, 1: PRINT "Pentagons: 12 thick dark red, 6 thick dark green, 3 thick dark blue,     press any for next test..."
103. SLEEP
104. CLS
105.  
106. '===================== Tomaaz/Johnno's turtle art
107. tt "z2" 'single thick pen
108. FOR i = 1 TO 2
109.     tt "a0p12x110y300"
110.     tt "r100f250t-198"
111.     tt "a0p10x230y440"
112.     tt "r10g2h2r18f-20p10t10f-20p-1t10"
113.     tt "a0p6x350y550"
114.     tt "s500r248i-2fvt90.5"
115.     COLOR 15
116.     LOCATE 1, 1
117.     PRINT "Scale: "; scale;
118.     PRINT " Turtle art from Johnno and Tomaaz,"
119.     PRINT " again with z (Pen size) set at"; tz
120.     PRINT "  press any to continue.."
121.     SLEEP
122.     tt "z1" 'single thickness
123.     scale = .75 'scale is used for tt drawing
124.     CLS
125. NEXT
126.  
127. '== latest mods box bn, circle cn, arc ln <<< fixed
128. PRINT "Testing arcs, boxes (filled) and circles (filled)"
129. scale = 1
130. tt "z1a0p9x300y200d50e50r4b12p-1t-90f100"
131. tt "p9r4f-100t90"
132. tt "g-40h30p9a270r8f16.6t-45"
133. tt "p-1x600y275u50c14"
134. tt "p-1z2x600y275p12u30j40k140l12"
135. tt "p-1x585y270p12u5c9"
136. tt "p-1x615y270p12u5c9"
137. SLEEP
138.  
139. SUB tt (tstring$)
140.     'local cmd, ds, i, c, d, tst, across, down, lngth, dx, dy, j, aa, stepper
141.     tstring$ = UCASE$(tstring$)
142.     cmd$ = "": d$ = ""
143.     FOR i = 1 TO LEN(tstring$)
144.         c$ = MID$(tstring$, i, 1)
145.         IF c$ = "V" THEN ds$ = STR$(tv)
146.         IF INSTR("0123456789.-", c$) THEN ds$ = ds$ + c$
147.         IF INSTR("ABCDEFGHIJKLPRSTUXYZ", c$) OR i = LEN(tstring$) THEN
148.             'execute last cmd if one
149.             IF cmd$ <> "" THEN
150.                 n = VAL(ds$)
151.                 SELECT CASE cmd$
152.                     CASE "G": tx = tx + n 'move relative to tx, ty
153.                     CASE "H": ty = ty + n
154.                     CASE "X": tx = n 'move to absolute screen x, y
155.                     CASE "Y": ty = n
156.                     CASE "D": tx2 = n '2nd corner box relative to tx
157.                     CASE "E": ty2 = n '2nd corner box relative to ty
158.                     CASE "J": taStart = n 'arc start angle
159.                     CASE "K": taStop = n 'arc stop angle
160.                     CASE "P": tc = n 'pen to qb color, -1 no pen
161.                     CASE "Z": tz = n 'pen size
162.                     CASE "A": ta = n 'set angle
163.                     CASE "T": ta = ta + n 'change angle - = left, + = right
164.                     CASE "U": tr = n 'set radius for circle (R used for repeat)
165.                     CASE "I": tv = tv + n 'increment variable
166.                     CASE "S": tv = n 'set or reset variable
167.                     CASE "R" ' repeat calls out for another call to tt
168.                         tst$ = MID$(tstring$, i) ' this assumes the rest of the string
169.                         repete tst$, n ' is the repeat part.
170.                         EXIT FOR
171.                     CASE "F" 'Forward d distance according to angle ta
172.                         across = scale * n * COS(_D2R(ta - 90))
173.                         down = scale * n * SIN(_D2R(ta - 90))
174.                         IF tc > -1 THEN
175.                             IF tz <= 1 THEN
176.                                 LINE (tx, ty)-STEP(across, down), tc
177.                             ELSE
178.                                 lngth = ((across) ^ 2 + (down) ^ 2) ^ .5
179.                                 IF lngth THEN
180.                                     dx = across / lngth: dy = down / lngth
181.                                     FOR j = 0 TO lngth
182.                                         fcirc tx + dx * j, ty + dy * j, tz, tc
183.                                     NEXT
184.                                 END IF
185.                             END IF
186.                         END IF
187.                         tx = tx + across: ty = ty + down 'update turtle position
188.                     CASE "B"
189.                         LINE (tx - tx2 / 2, ty - ty2 / 2)-(tx + tx2 / 2, ty + ty2 / 2), n, BF
190.                     CASE "C"
191.                         fcirc tx, ty, tr, n
192.                     CASE "L" 'arc ld u sets radius, j and k set start and end angle
193.                         IF tc > -1 THEN
194.                             stepper = 1 / (3 * _PI * tr)
195.                             FOR aa = taStart TO taStop STEP stepper
196.                                 dx = tr * COS(_D2R(aa))
197.                                 dy = tr * SIN(_D2R(aa))
198.                                 IF tz < 1 THEN
199.                                     PSET (tx + dx, ty + dy), n
200.                                 ELSE
201.                                     fcirc tx + dx, ty + dy, tz, n
202.                                 END IF
203.                             NEXT
204.                         END IF
205.                 END SELECT
206.                 ds$ = "": cmd$ = "" 'reset for next build of ds and cmd
207.             END IF
208.             cmd$ = c$
209.         END IF
210.     NEXT
211. END SUB
212.  
213. SUB repete (tts$, times)
214.     'local i
215.     FOR i = 1 TO times
216.         tt tts$
217.     NEXT
218. END SUB
219.  
220. 'from Steve Gold standard
221. SUB fcirc (CX AS INTEGER, CY AS INTEGER, R AS INTEGER, C AS _UNSIGNED LONG)
222.     DIM Radius AS INTEGER, RadiusError AS INTEGER
223.     DIM X AS INTEGER, Y AS INTEGER
224.     Radius = ABS(R): RadiusError = -Radius: X = Radius: Y = 0
225.     IF Radius = 0 THEN PSET (CX, CY), C: EXIT SUB
226.     LINE (CX - X, CY)-(CX + X, CY), C, BF
227.     WHILE X > Y
228.         RadiusError = RadiusError + Y * 2 + 1
229.         IF RadiusError >= 0 THEN
230.             IF X <> Y + 1 THEN
231.                 LINE (CX - Y, CY - X)-(CX + Y, CY - X), C, BF
232.                 LINE (CX - Y, CY + X)-(CX + Y, CY + X), C, BF
233.             END IF
234.             X = X - 1
235.             RadiusError = RadiusError - X * 2
236.         END IF
237.         Y = Y + 1
238.         LINE (CX - X, CY - Y)-(CX + X, CY - Y), C, BF
239.         LINE (CX - X, CY + Y)-(CX + X, CY + Y), C, BF
240.     WEND
241. END SUB
242.  
243.  

Haven't looked at this code since 2017 but all commands are a single letter followed by a number including repeat r10 for repeat 10 times. For variable, the v letter can be used as substitute for a number to another command eg rv repeat v times, i increments v as g increments x or h increments y or t (turn) increments a for angle (degrees).

tt (main sub) is short for turtle as this is turtle drawing influenced by Johnno with a Logo at SmallBASIC forum attempt and with JB coding for one way of doing drawings  (mostly pen size = z command) Here: pen off p-1 or pen color 0 to 15, say p9 for light blue.

[johnno56]

Ah... Turtle Art...  I miss the old days when you had to sit there and watch the "turtle" draw the images... 4mhz CPU's... ya gotta love 'em....

J

[dajan]

@bplus: I see you actualy even did not use the original DRAW there, instead you invented completely new language and treated all graphics by yourself. That is quite an advantage over using DRAW, where some limitations I cannot bypass - e.g.  I can't turn the direction in decimals (TA10.25 doesn't work), which makes turning large object choppy.

@FellippeHeitor> Yes, the "come up with a way" part seems to be critical here :o) The more I'm trying to animate some compoud objects (like with more movable parts relative to each other), the more it reminds of a solving a puzzle in a simplistic language, trying to trick it's limitations, while each solution found is unique and cannot be generalized. So I'm rather skeptical at the moment, waiting for enlightment.

[STxAxTIC]

Hm, reverse engineering turtle graphics to use mouse input for shapes... this question has my attention... hmmmm. Gotta learn what DRAW does first, but this does sound interesting.