Text 902, 345 rader
Skriven 2006-10-17 23:11:08 av DAVID WILLIAMS (1:250/514)
     Kommentar till en text av Miles Maxted
Ärende: Re: Daylight Saving Time
================================
I found a version of that sundial-designing program of mine that runs 
in QBasic under DOS. If you have an antique PC, and especially if you 
have an old Epson-type dot-matrix printer, you should be able to use it 
to design a dial for use in NZ, or anywhere else. 
  
                            dow 
  
--------------------------------------------------------- 
  
' SUNDIAL.BAS.  David Williams. 2002 
' david.williams@ablelink.org 
  
DECLARE SUB Lcopy11 () 
DECLARE SUB KeyPause () 
DECLARE SUB Choice (N%, C%, L$) 
DECLARE FUNCTION YesNo$ () 
  
CLS 
DEFDBL A-Z 
PRINT "This program designs a horizontal sundial, for use at any" 
PRINT "location. Three diagrams are produced. The first is the" 
PRINT "horizontal plate, showing the hour lines. This should be" 
PRINT "mounted so the north-south line shown on the design is aligned" 
PRINT "true north-south, pointing away from the nearer pole (so the" 
PRINT "line should point southward in the northern hemisphere)." 
PRINT 
PRINT "The second diagram is a template for the sundial's gnomon." 
PRINT "This should be mounted in a north-south vertical plane, in a" 
PRINT "line with the north-south line on the horizontal plate. The" 
PRINT "left end of the base of the gnomon should be at the point" 
PRINT "where all the hour-lines intersect. The sloping edge of the" 
PRINT "gnomon will be pointing at the nearer celestial pole, i.e. at" 
PRINT "the Pole Star in the northern hemisphere." 
PRINT 
PRINT "The third diagram is produced only if you have selected that" 
PRINT "the dial show clock time. It is a graph that shows the number" 
PRINT "of minutes that must be added to the dial reading to make it" 
PRINT "agree with a clock." 
PRINT 
PRINT "When the program pauses at any point (such as right now)," 
PRINT "press any key to continue." 
CALL KeyPause 
CLS 
PRINT "You can select whether to have the diagrams appear only on the" 
PRINT "screen, or if they should also be printed by an Epson-type" 
PRINT "printer, and/or saved to disk for later printing by some other" 
PRINT "utility. If you select to save them to disk, you will be asked" 
PRINT "for a filename. Suppose you select FNAME. The three files on" 
PRINT "disk will be named FNAME.DG1, FNAME.DG2 and FNAME.DG3. The" 
PRINT "files are BSAVEd from screen memory. The first seven bytes of" 
PRINT "each file contain addresses, etc.. The rest is a string of" 
PRINT "bytes that are the bytes in memory representing the SCREEN 11" 
PRINT "image." 
CALL KeyPause 
CLS 
PRINT "Should the dial show <c>lock or local <s>olar time? "; 
DO 
  K$ = LCASE$(INKEY$) 
LOOP UNTIL K$ = "c" OR K$ = "s" 
PRINT K$ 
PRINT 
PI = 4 * ATN(1) 
PI2 = PI / 2 
DR = PI / 180 
RH = PI / 12 
PRINT "Use negative numbers for directions opposite from those shown." 
INPUT "Latitude (deg. N)"; LT 
IF K$ = "c" THEN 
  INPUT "Longitude (deg. E)"; LG 
  INPUT "Time Zone Offset (hours ahead of GMT)"; TZ 
  A0 = TZ * RH - DR * LG 
ELSE 
  A0 = 0 
END IF 
ST = SIN(DR * LT) 
C% = 0 
PRINT 
PRINT "Should the dial be printed on Epson-type printer"; 
IF YesNo$ = "Y" THEN 
  C% = 1 
  BEEP 
  PRINT "Ensure printer is ready, then press any key." 
  PRINT 
  CALL KeyPause 
END IF 
PRINT "Should screens be saved to disk, for later printing"; 
IF YesNo$ = "Y" THEN 
  DO 
    INPUT "Filename (8 chars max, no suffix)"; F$ 
    IF LEN(F$) > 0 AND LEN(F$) < 9 AND INSTR(F$, ".") = 0 THEN 
      EXIT DO 
    ELSE 
      BEEP 
      PRINT 
      PRINT "Illegal entry!" 
      PRINT 
    END IF 
  LOOP 
  C% = C% OR 2 
END IF 
' draw horizontal sundial plate 
SCREEN 11 
CLS 
IF K$ = "c" THEN 
  NH% = 12 + TZ - LG / 15 
ELSE 
  NH% = 12 
END IF 
FOR X% = NH% - 7 TO NH% + 7 
  A = RH * (X% - 12) - A0 
  Q% = SGN(A * LT) 
  D = ABS(A) - PI2 
  IF ABS(D) < .0000000001# THEN 
     AZ = PI2 * Q% 
  ELSE 
     AZ = ATN(ST * TAN(A)) 
     IF D > 0 THEN AZ = AZ + PI * Q% 
  END IF 
  ' AZ is direction of hour-line in radians clockwise from pole 
  SZ = SIN(AZ) / 2 
  CA = AZ + ATN(SZ / SQR(1 - SZ * SZ)) 
  ' CA is direction from centre of dial to end of hour line 
  CS = SIN(CA) 
  CC = COS(CA) 
  LOCATE 15.2 - 13.5 * CC, 40.5 + 27.5 * CS 
  PRINT MID$(STR$(X% + 12 * (X% > 12)), 2); 
  LINE (320, 340)-(320 + 200 * CS, 240 - 200 * CC) 
NEXT 
CIRCLE (320, 240), 200 
CIRCLE (320, 240), 239 
LINE (320, 340)-(320, 479) 
LOCATE 26, 39 
PRINT "N - S"; 
LOCATE 27, 38 
PRINT "L I N E"; 
CALL Choice(1, C%, F$) 
'draw gnomon template 
'gnomon size makes shadow of tip just reach 
'circumference of dial at noon on summer solstice. 
CLS 
AT = 23.5 * DR' axial tilt 
R = 150 / COS(AT)' radius of circumscribed circle (locus of tip) 
A = 2 * ABS(LT) * DR - AT' tip angle above horizontal wrt centre 
PX% = R * COS(A) 
PY% = 300 - R * (SIN(AT) + SIN(A)) 
SELECT CASE PX% 
  CASE IS > 150 
    ZX% = 150 
  CASE IS < -75 
    ZX% = -75 
  CASE ELSE 
    ZX% = PX% 
END SELECT 
XS% = 357 - ZX% \ 2 
OX% = XS% - 150 
PX% = PX% + XS% 
ZX% = ZX% + XS% 
PRINT TAB(27); "GNOMON TEMPLATE"; 
LINE (OX%, 300)-(PX%, PY%) 
LINE (OX%, 300)-(ZX%, 300) 
LINE (ZX%, 300)-(PX%, PY%) 
L$ = "South" 
R$ = "North" 
IF LT < 0 THEN SWAP L$, R$ 
LOCATE 20, 21 
PRINT L$; " <-      Base      -> "; R$ 
PRINT 
PRINT TAB(15); "Gnomon should be in North-South vertical plane, with " 
PRINT TAB(15); L$; " end of base at intersection of hour lines."; 
CALL Choice(2, C%, F$) 
IF K$ = "c" THEN ' do equation of time if clock time selected 
  ' draw equation of time graph 
  CLS 
  PRINT TAB(30); "EQUATION OF TIME" 
  PRINT 
  PRINT 
  PRINT TAB(15); "Graph shows difference in minutes between clock" 
  PRINT TAB(15); "and sundial time. Positive difference means" 
  PRINT TAB(15); "clock is ahead of sundial, and vice versa." 
  DC = 8 * ATN(1) / 365 
  LOCATE 16, 67 
  PRINT "-="; 
  FOR T = -20 TO 15 STEP 5 
    LINE (137, 247 - 6.4 * T)-(530, 247 - 6.4 * T) 
    LOCATE 16 - T / 2.5, 14 
    PRINT RIGHT$(" " + STR$(T), 3); 
    IF T = 0 THEN PRINT " ="; 
  NEXT 
  LOCATE 9, 20 
  PRINT "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec"; 
  T = 0 
  D = 0 
  FOR M = 0 TO 384 
    IF M = T THEN 
      LINE (147 + M, 128)-(147 + M, 375) 
      READ L 
      T = T + L 
    ELSE 
      Q = D + 2 * SIN((D - 2) * DC) 
      Z = 9.8 * SIN(2 * (Q + 11) * DC) + 7.7 * SIN((Q - 2) * DC) 
      PSET (147 + M, 247 - 6.4 * Z) 
      D = D + 1 
    END IF 
    IF L = 33 AND M = T - 18 THEN M = M + 1 
  NEXT 
  DATA 33,29,33,31,33,31,33,33,31,33,31,33,0 
  CALL Choice(3, C%, F$) 
END IF 
SCREEN 0 
END 
  
SUB Choice (N%, C%, F$) 
  IF C% AND 2 THEN 
    F1$ = F$ + ".DG" + RIGHT$(STR$(N%), 1) 
    DEF SEG = &HA000 
    BSAVE F1$, 0, 80& * 480 
    DEF SEG 
  END IF 
  IF C% AND 1 THEN 
    CALL Lcopy11 
  ELSE 
    CALL KeyPause 
  END IF 
END SUB 
  
SUB KeyPause 
   DO WHILE INKEY$ <> "" 
   LOOP 
   DO WHILE INKEY$ = "" 
   LOOP 
END SUB 
  
SUB Lcopy11 
  
' Copies monochrome SCREEN 11 image to printer, with printed image 
' aligned with long axis across the page. Note: To fit on 8-inch 
' wide paper, 32-pixel margins on both sides are not printed. 
  
  DEFINT A-Y 
  DEFLNG Z 
  
  DIM V(0 TO 7), A(0 TO 7, 4 TO 75)' col's 0-3 and 76-79 not printed 
  
  V(7) = 1  ' reVerse-order bits 
  FOR X = 7 TO 1 STEP -1 
    V(X - 1) = V(X) + V(X) 
  NEXT 
  
  F = FREEFILE 
  OPEN "PRN" FOR BINARY AS F 
  
  DEF SEG = &HA000 
  OUT &H3CE, 4 
  OUT &H3CF, 0 
  
  N$ = STRING$(8, 0)                    ' 8 nulls for empty square 
  
  E$ = CHR$(27)                         ' ESC character 
  
  L$ = E$ + "C" + CHR$(0) + CHR$(11)    ' page length = 11 inches 
  PUT F, , L$ 
  
  L$ = E$ + "A" + CHR$(8)               ' set printer to 8/72 lpi 
  PUT F, , L$ 
  
  Z = 4 
  
  FOR S = 0 TO 59  ' 60 stripes, each 8 rows deep 
  
    N = -1             ' null-stripe flag 
  
    FOR R = 0 TO 7             ' read 8 rows into array 
      FOR C = 4 TO 75 
        A(R, C) = PEEK(Z) 
        IF N THEN IF A(R, C) THEN N = 0 
        Z = Z + 1 
      NEXT 
      Z = Z + 8 
    NEXT 
  
    IF NOT N THEN    ' not null stripe 
  
      L$ = E$ + "*" + CHR$(5) + MKI$(576)  ' set plotter mode 
      PUT F, , L$ 
  
      FOR C = 4 TO 75 
        Q = 0 
        FOR R = 0 TO 7 
          IF A(R, C) THEN Q = 1: EXIT FOR 
        NEXT 
        IF Q THEN       ' not null square 
          FOR Y = 0 TO 7    ' analyse 8 bits per byte 
            B = 0 
            FOR R = 0 TO 7  ' 8 bytes to be analysed 
              IF A(R, C) AND V(Y) THEN B = B OR V(R) 
            NEXT R 
            L$ = CHR$(B)  ' send byte to printer 
            PUT F, , L$ 
          NEXT Y 
        ELSE    ' null square 
          PUT F, , N$ 
        END IF 
      NEXT C 
  
    END IF 
  
    L$ = CHR$(13) + CHR$(10)            ' terminate line (stripe) 
    PUT F, , L$ 
  
  NEXT S 
  
  L$ = CHR$(12)                         ' form feed 
  PUT F, , L$ 
  
  L$ = E$ + "@"                         ' reset printer 
  PUT F, , L$ 
  
  CLOSE F 
  
  DEF SEG 
  
END SUB 
  
DEFDBL A-Z 
FUNCTION YesNo$ 
    PRINT "? (y/N) "; 
    T$ = " YyNn" + CHR$(13) 
    DO 
    LOOP UNTIL INKEY$ = "" 
    DO 
      K$ = INKEY$ 
    LOOP UNTIL INSTR(T$, K$) > 1 
    IF K$ = CHR$(13) THEN 
      K$ = "N" 
    ELSE 
      K$ = UCASE$(K$) 
    END IF 
    PRINT K$ 
    PRINT 
    YesNo$ = K$ 
END FUNCTION 
  
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--- Platinum Xpress/Win/WINServer v3.0pr5
 * Origin: The Bayman BBS,Toronto, (416)698-6573 - 1:250/514 (1:250/514)