'This program is built from RLseries.BAS.  10-23-10
'This program is modified to read text files and plot the the data.
'It plots sampled voltage vs time. The text file is unformatted raw text. Initial default text file is "out.txt", but can be changed in the program.
'The name of the coil can be held in the text file. It is in the first line after "NAME".
'The file name convention is: 2Char for make. 2Char for resistance in ohms.
'1Char H or C for hot or cold. 1CHar M or U for mounted or unmounted.
'2Char for sequence number for when there is more than one type of the same coil.
'The start of a sampling cycle is designated with an "$". The end with an "&".  Notes can be written before $ or after & for any sample cycle.
'Each time-current pair is listed as "t" followed by time in usec, then "," then "v" followed by current data as a sample value (0 to 1023),
'followed by a ",". There may be spaces interspersed along with carriage returns. Those need to be ignored.
'There can be multiple sets of data in one file. The program will display each one at a time and will prompt before each.
'After the last one is drawn, there will be a blank graph before starting over with the first set.
'Lou Dudzik Updated 10/15/16

DECLARE SUB Intro ()
DECLARE SUB SetTscale ()
DECLARE SUB DrawScreen ()
DECLARE SUB DrawScreen ()
DECLARE SUB DrawGrid ()
DECLARE SUB PrintVar ()
DECLARE SUB Plot ()            'Plots charging function
DECLARE SUB GetCoilFile ()
DECLARE SUB GetCoilName ()
DECLARE SUB FindData ()
DECLARE FUNCTION ValidFilename (FileName$)
DECLARE FUNCTION subtract# (aaa#, bbb#)
DECLARE FUNCTION FileExists (FileName$)
DECLARE SUB ZZLou24bIT (FileName$, invertBW$)

DIM SHARED GrphSize             'holds whether the graph should be big or small
DIM SHARED Fault AS INTEGER     'This holds a fault code
DIM SHARED StyleHex             'This holds the alternating style pattern to create the dotted plot.
DIM SHARED tscale AS DOUBLE      'tScale is the range of the x axis in seconds.
DIM SHARED vMax AS DOUBLE        'vMax is the max of the y axis in volts and amps.
DIM SHARED vMin AS DOUBLE        'vMin is the min of the y axis in volts and amps.
DIM SHARED iLimit AS DOUBLE      'this is the maximum current to graph. This is used to stop plotting points on a graph after a certain value is reached.
DIM SHARED GrphColor AS INTEGER  'Holds the color to be used for each plot. The color value increments for each successive plot.
DIM SHARED CoilName AS STRING    'Holds the name of the coil to be plotted.
DIM SHARED NewCoilN AS STRING    'This is the new coil name as found in the data file to be selected.
DIM SHARED CoilFile AS STRING    'Holds the name of the file to be used to create the plot.
DIM SHARED NewCoilF AS STRING    'This holds the name of the data files that are scrolled through when selecting CoilFile.
DIM SHARED SkipSel AS INTEGER    'This holds whether to select the DatFileN or skip it.
DIM SHARED Continue   AS INTEGER   'This justs holds a dummy input. It's used to continue the program after an error message is given to user.
DIM SHARED PntOrLin AS INTEGER   'holds whether to plot points or connect them into lines. 0 for points. 1 for lines.
DIM SHARED FilNmeErr AS INTEGER 'Holds the error code for filename validity check.

SCREEN 12
CLS 0            'Clears everything
Intro
CLS 0            'Clears everything
'----------This initializes the variables.------------
GrphSize = 1     '1 = Big size. 0 = small size
PntOrLin = 1     '1 = draw as lines. 0 = draw points
iLimit = 7.5     'After a graph reaches this limit in amps, stop plotting that graph.
tscale = .005
CoilName = "Coil 1"
CoilFile = "out.txt"
IF FileExists(CoilFile) = 1 THEN
   OPEN CoilFile FOR INPUT AS #1
ELSE
   VIEW PRINT 27 TO 30
   PRINT CoilFile;
   INPUT " does not exist or was empty and now deleted. Press enter.", Continue
END IF
GrphColor = 9    'This initializes the color for the plot. Each successive plot changes color. Color choice is based what they will be after converting to 24bit, then gif, then inverted.
'----------------------------------------------------
DrawScreen       'Setup the graphics port and print the graph scales.
DrawGrid



REM command section-------------------------------------------------------------------------------
DO
COLOR 7
VIEW PRINT 27 TO 30
CLS 2
PrintVar
COLOR 15
PRINT "1 clear. 2 exit. 3 time scale. 4 vertical. 47 bitmap. 57 invertBitmap."
PRINT "5 points. 6 lines. n coil name. f select file."
INPUT " Or enter to plot. ", Comand$
CLS 2
IF Comand$ = "2" THEN
   SYSTEM
ELSEIF Comand$ = "1" THEN
   CLS 0
   DrawScreen
   DrawGrid
ELSEIF Comand$ = "47" OR Comand$ = "57" THEN
   Color$ = Comand$   'Color$ holds whether the colors should be as on the screen, or inverted. 57 is inverted. 47 is normal.
   DO
      'The default name of the bmp will be the last file data name selected. Options in case it already exists.
      BMPname$ = LEFT$(CoilFile, LEN(CoilFile) - 4) 'BMPname$ will take the filename of the COilFile minus the period and filetype.
      BMPname$ = BMPname$ + ".BMP"                  'add the filetype to the file name.
      BMPname$ = UCASE$(BMPname$)                   'convert to upper case
      PRINT "Enter a new filename, or press enter to use "; BMPname$; "  ";
      INPUT Comand$
      IF Comand$ <> "" THEN                         'If Comand$ is other than "", then...
         BMPname$ = UCASE$(Comand$)                 'Convert comand$ to upper case and make it the BMPname$.
         IF RIGHT$(BMPname$, 4) = ".BMP" THEN       'if the filetype was already entered, then keep it.
            BMPname$ = BMPname$
         ELSE
            BMPname$ = BMPname$ + ".BMP"             'Else add ".BMP" to the filename.
         END IF
      END IF
      FilNmeErr = ValidFilename(BMPname$)           'Check filename validity and print error warning.
      IF FilNmeErr > 0 THEN
         PRINT "Filename invalid. ";
         IF FilNmeErr = 1 THEN PRINT "Too long.";
         IF FilNmeErr = 2 THEN PRINT "Too short.";
         IF FilNmeErr = 3 THEN PRINT "Bad format.";
         IF FilNmeErr = 4 THEN PRINT "Bad character.";
         PRINT " Format => xxxxxxxx.xxx "
      ELSE
         IF FileExists(BMPname$) = 1 THEN                  'Check if file already exists.
            FilNmeErr = 5                                  'set error code if exists
            INPUT "File already exists. Press enter to try another name, or o to overwrite it."; Comand$
         END IF
      END IF
   LOOP WHILE FilNmeErr > 0 AND Comand$ <> "o"
   CLS 2
   PRINT "A bitmap of this screen called "; BMPname$; " is being generated. Please wait. "
   'the previously set VIEW and WINDOW commands have to be cleared for the sub to work.
   VIEW
   WINDOW
   CLOSE #1     'close the open text file
   ZZLou24bIT BMPname$, Color$
   'must now reinstate the VIEW and WINDOW
   DrawScreen
   VIEW PRINT 28 TO 30
   CLS 2
   LOCATE 29, 1
   PRINT "Image file "; BMPname$; " is saved in the folder in which this program resides."
   INPUT "Enter to continue. ", Continue
   IF FileExists(CoilFile) = 1 THEN OPEN CoilFile FOR INPUT AS #1    'Re open text file for graphing
ELSEIF Comand$ = "3" THEN
   VIEW PRINT 1 TO 30  'needed to expand the text port
   CLS 2
   SetTscale
   CLS 0
   DrawScreen
   DrawGrid
ELSEIF Comand$ = "4" THEN
   IF GrphSize = 1 THEN     'this flips the graph size from big to small or vice versa.
      GrphSize = 0
   ELSE
      GrphSize = 1
   END IF
   CLS 0
   DrawScreen
   DrawGrid
ELSEIF Comand$ = "5" THEN
   PntOrLin = 0    'print as points.
ELSEIF Comand$ = "6" THEN
   PntOrLin = 1    'print as lines.
ELSEIF Comand$ = "n" THEN
   'This overrides the coil name that was found on the CoilFile (assuming there was one).
   CLS 2
   INPUT "Enter the name of the coil. ", CoilName
ELSEIF Comand$ = "f" THEN
   SkipSel = 0
   SHELL "dir > PXT4938.TXT" 'This is the temporary text file which contains the filenames within the current directory.
   OPEN "PXT4938.TXT" FOR INPUT AS #10
   DO
      GetCoilFile   'Will set NewCoilF = "" if no data files found, or no more data files found.
      CLS 2
      IF NewCoilF <> "" THEN   'If NewCoilF is valid...
         OPEN NewCoilF FOR INPUT AS #20
         GetCoilName   'Try to get a coil name from the file NewCoilF.
         CLOSE #20
         PRINT "Enter 0 to skip.    Enter 1 to select."
         PRINT "Enter 2 to select without changing coil name."
         PRINT NewCoilF, NewCoilN;
         INPUT "  ", SkipSel
      ELSE
         INPUT "No more data files. Press enter.  ", Continue
      END IF
   LOOP WHILE SkipSel <> 1 AND SkipSel <> 2 AND NewCoilF <> ""    'Keep looping through txt files until 1 or 2 is selected, or if NewCoilF is blank.
   IF SkipSel = 1 THEN
      CoilFile = NewCoilF
      CoilName = NewCoilN
   ELSEIF SkipSel = 2 THEN
      CoilFile = NewCoilF
   END IF
   CLOSE #10
   KILL "pxt4938.txt"
   CLOSE #1                        'close the old file
   IF FileExists(CoilFile) = 1 THEN
      OPEN CoilFile FOR INPUT AS #1
   'ELSE                            'This section is redundant with not selecting a new file.
   '   CLS 2
   '   Print CoilFile;
   '   INPUT " did not exist or was empty and now deleted. Hit enter.", Continue
   END IF
ELSEIF Comand$ = "" THEN
   IF FileExists(CoilFile) = 1 THEN
      'GrphColor = GrphColor + 1   'plot color increment now happens in plot function
      IF GrphColor = 15 THEN GrphColor = 9
      COLOR GrphColor
      IF GrphSize = 1 THEN VIEW PRINT 21 TO 27
      IF GrphSize = 0 THEN VIEW PRINT 12 TO 27
      LOCATE 26
      PRINT ""     'This allows the maintaining of text and scroll up. Otherwise every view/locate command will overwrite.
      'PRINT CoilName, CoilFile   'Printing of the coil file name is now being done in the plot function.
      Plot
   ELSE
      VIEW PRINT 27 TO 30
      PRINT CoilFile;
      INPUT " does not exist or was empty and now deleted. Hit enter.  ", Continue
   END IF
END IF
LOOP
REM command section---------------------------------------------------------------------

SUB DrawGrid '-------------DrawGrid------------------------------------------------------
COLOR 8
IF GrphSize = 1 THEN                  'draw 1/4 amp lines on the big screen
   FOR y = 9 TO 0 STEP -.25
      LINE (0, y)-(tscale, y)                    'draws horizontal gray lines
   NEXT y
END IF
FOR y = 9 TO 0 STEP -.5              'draws 1/2 amp lines
LINE (0, y)-(tscale, y)                    'draws horizontal gray lines
NEXT y

IF tscale = .005 THEN
   FOR x = 0 TO tscale + tscale / 100 STEP tscale / 50   'draws 1/100 time lines
   LINE (x, 0)-(x, 9)                                     'draws vertical gray lines
   NEXT x
ELSE
   FOR x = 0 TO tscale + tscale / 100 STEP tscale / 100   'draws 1/100 time lines
   LINE (x, 0)-(x, 9)                                     'draws vertical gray lines
   NEXT x
END IF

COLOR 7
FOR y = 9 TO 0 STEP -1                     'draws 1 amp lines
LINE (0, y)-(tscale, y)                    'draws horizontal gray lines
NEXT y
IF tscale = .02 THEN
   FOR x = 0 TO tscale + tscale / 10 STEP tscale / 20     'draws 1/20 time lines
   LINE (x, 0)-(x, 9)                      'draws vertical gray lines
   NEXT x
ELSE
   FOR x = 0 TO tscale + tscale / 10 STEP tscale / 10     'draws 1/10 time lines
   LINE (x, 0)-(x, 9)                      'draws vertical gray lines
   NEXT x
END IF

COLOR 15
LINE (0, 0)-(tscale, 0)                    'adds horizontal zero line in white
LINE (0, 0)-(0, 9)                    'vertical zero line in white
END SUB'-------------------DrawGrid--------------------------------------------------------

SUB DrawScreen '---------------------------DrawScreen-----------------------------------
'The graphics port is set to leave room to the left and bottom for scale indicators.
'Vertically, 0-368 gives 23 spaces, but 1/2 is wasted on top and 1/2 is wasted on bottom to leave room for the scale numbers so the center of the number lines up with the graph lines.
'The graph is broken into 22 useable spaces vertically with a 1/2 unused on top, and 1/2 unused on bottom for a total of 23, and the scale gets 22 numbers.
'It has to be that way in order for the vertical scale numbers to line up.
'Vertically, one line of text takes 16 vertical pixels. 368/23 = 16   .
'If more vertical space is needed at the bottom for text, the graph loses 16 pixels per line.

IF GrphSize = 1 THEN
   VIEW (39, 0)-(639, 304)         'must be 601 by 305  (The View and Window commands are also reinstated after bitmap generator call.)
   WINDOW (0, 9.25)-(tscale, -.25)
   VIEW PRINT 1 TO 21
END IF
IF GrphSize = 0 THEN
   VIEW (39, 0)-(639, 160)         'must be 601 by 161
   WINDOW (0, 9.5)-(tscale, -.5)
   VIEW PRINT 1 TO 12
END IF
'Show the scale numbers of the y axis.
'note: using "PRINT USING" command to force the formatting. Without it, extra spaces get printed.

LOCATE 1, 1

FOR y = 9 TO 0 STEP -1
   PRINT USING "##"; y;
   PRINT " A"
   IF GrphSize = 1 THEN PRINT ""                'prints a blank line if drawing the big size screen
NEXT y


IF GrphSize = 1 THEN LOCATE 20, 1
IF GrphSize = 0 THEN LOCATE 11, 1
IF tscale = .0001 THEN PRINT "    0msec .01ms  .02ms   .03ms  .04ms   .05ms  .06ms   .07ms  .08ms   .09ms .1ms"
IF tscale = .001 THEN PRINT "    0sec  .0001  .0002   .0003  .0004   .0005  .0006   .0007  .0008   .0009 .001"
IF tscale = .005 THEN PRINT "    0sec  .0005  .0010   .0015  .0020   .0025  .0030   .0035  .0040   .0045 .005"
IF tscale = .01 THEN PRINT "    0sec  .001    .002   .003    .004   .005    .006   .007    .008   .009   .01"
IF tscale = .02 THEN PRINT "    0sec  .002    .004   .006    .008   .010    .012   .014    .016   .018   .02"
IF tscale = .1 THEN PRINT "    0sec   .01    .02     .03    .04     .05    .06     .07    .08     .09    .1"
IF tscale = 1 THEN PRINT "    0sec   .1      .2     .3      .4     .5      .6     .7      .8     .9      1"
IF tscale = 10 THEN PRINT "    0sec    1       2      3       4      5       6      7       8      9     10"
IF tscale = 100 THEN PRINT "    0sec   10      20     30      40     50      60     70      80     90    100"
IF tscale = 1000 THEN PRINT "    0sec   100     200    300     400    500     600    700     800    900  1000"
IF tscale = 10000 THEN PRINT "    0sec   1k      2k     3k      4k     5k      6k     7k      8k     9k    10k"
END SUB'--------------------------------------DrawScreen----------------------------------------

FUNCTION FileExists (FileName$) '-----------------FileExists--------------------
'Checks to see if the file exists. Returns 1 if exists. 0 if not.  (Note, if the file existed, but was empty, this reports it did not exist and then deletes it.)
FileExists = 0
OPEN FileName$ FOR BINARY AS #99   'open or create it, to measure it
FileLen& = LOF(99)                                 'measure it
IF FileLen& > 0 THEN                               'if it's not empty, report it exists
   FileExists = 1
   CLOSE #99
ELSE
   CLOSE #99                                        'if empty, close it.
   KILL FileName$                                   'delete it.
END IF
END FUNCTION '------------------FileExists----------

SUB GetCoilFile '-------------GetCoilFile---------------------------
'This reads the temporary text file (pxt4938.txt) containing directory information, as #10.
'It sets NewCoilF to the next txt file in the directory.
'If the end is reached before a txt file is found, then NewCoilF = ""
NewCoilF = ""   'Clear NewCoilF
DO
   LINE INPUT #10, DirLine$   'Read a line
   IF MID$(DirLine$, 10, 3) = "TXT" THEN    'If the line contains the name of a text file (chars 10, 11, 12 are "TXT")...
      NewCoilF = MID$(DirLine$, 1, 8)
      NewCoilF = RTRIM$(NewCoilF)
      NewCoilF = NewCoilF + ".TXT"  'first 8 chars of line is possible new coil file.
   END IF
   IF NewCoilF = "PXT4938.TXT" THEN NewCoilF = ""  'The temporary directory file should be ignored.
LOOP WHILE EOF(10) = 0 AND NewCoilF = ""   'Loop until reach end of file, or NewCoilF is a valid file.
END SUB '--------------------GetCoilFile----------------

SUB GetCoilName '-------------GetCoilName---------------------------
'this extracts the NewCoilN (possible new coil name) from the NewCoilF (possible new coil file).
NewCoilN = ""   'Clear NewCoilN
LINE INPUT #20, FileLine$   'Read a line
   IF MID$(FileLine$, 1, 4) = "NAME" THEN    'If the first 4 chars of the first line contains the word "NAME"...
      NewCoilN = MID$(FileLine$, 5, 60)  'first 200 chars of line (after the first 4) is possible new coil name.
      NewCoilN = RTRIM$(NewCoilN)
      NewCoilN = LTRIM$(NewCoilN)
   END IF
END SUB '--------------------GetCoilName----------

SUB Intro '----------------------Intro--------------------------------
PRINT "This program plots current versus time for ignition coils. The input values"
PRINT "come from a text file produced by a coil test circuit sampled by an Arduino"
PRINT "microcontroller. The sampler measures voltage on a resistor to get current"
PRINT "data. The data is actually voltage, but this program will convert it to"
PRINT "current. Each data point has a voltage value and time value. The time value"
PRINT "is the number of microseconds since the voltage was applied to the coil."
PRINT "Timescale can be changed, and the current scale can be changed to produce"
PRINT "two different size graphs. The graph itself can be sampled points only,"
PRINT "or made up of lines connecting the points. The program plots one sample"
PRINT "cycle at a time, but the text file can contain multiple cycles. It will plot"
PRINT "them in the order they exist in the file. When it reaches the end of the file,"
PRINT "it will plot a blank plot, then repeat the cycles after that. If there is an"
PRINT "incomplete set of data before the end of the file, it will simply stop plotting."
PRINT "After any plot, a new name for the next plot can be given, and/or a new"
PRINT "file can be chosen to take data from."
PRINT "The X axis is time in seconds."
PRINT "The Y axis is current in amps."
PRINT "Printing: This progam can generate a bitmap file of the screen. The files"
PRINT "will be saved in the folder in which this program resides. If it will be "
PRINT "printed out, there is also an option to invert the colors, which will show up"
PRINT "better on paper. The files will be in 24bit format BMP. This should be "
PRINT "opened in MSpaint, then saved as a 256 color BMP, then saved as a gif."
INPUT "Enter to continue.  ", Continue
END SUB'----------------------Intro----------------------------------

SUB Plot '--------------------- Plot ---------------------------
'This sub reads the file and converts it to point to plot.
DIM t AS DOUBLE   'time in seconds
DIM v AS SINGLE   'sample value (0 to 1023) then converted to voltage in volts
DIM i AS SINGLE   'current in amps
DIM Char AS STRING   'holds the character being read.
DO UNTIL (EOF(1)) OR Char = "&"                           'loop until the end of file #1 is reached, or end of cycle is reached.
   Char = INPUT$(1, #1)                                   'this line reads the next character in the file.
   IF Char = "$" THEN                                     '$ means start of sample cycle.
      PSET (0, 0)                                         'plot a point at the origin.
      DO UNTIL Char = "&"                                 'loop until the end of sample cycle is reached
         Char = INPUT$(1, #1)                             'this line reads the next character in the file.
         IF Char = "t" THEN                               'if character is a t, then next number is time (in usec)
            INPUT #1, t                                   'read the number as time, and the ","
            Char = INPUT$(1, #1)                          'this line reads the next character in the file.
            IF Char = "v" THEN                            'verify that "v" is next char
               INPUT #1, v                                'read the number as raw sample data for current, and the ","
               t = t / 1000000                            'put t into seconds from usec
               IF t > (2# * tscale) THEN t = 2# * tscale  'prevents plots from wrapping around due to being too far off scale (like checkrange for t)
               v = v * 1.1 / 1023                         'the correction for v will be complicated
               i = v * 10                                 'current is just 10 times the voltage
               IF i <= iLimit OR t < .00008 THEN          'if the current is less than the limit set by iLimit, or time is less than 80usec... then plot. The time factor allows for plotting graphs that have a glitch at the beginning of max current.
                  IF PntOrLin = 0 THEN                    'if PntOrLin is 0, plot points
                     PSET (t, i)                          'plot point
                  ELSEIF PntOrLin = 1 THEN                'if PntOrLin is 1, plot lines
                     LINE STEP(0, 0)-(t, i)               'Step (0,0) means draw line from current cursor position
                  END IF
               ELSE
                  DO UNTIL (EOF(1)) OR Char = "&"         'If the current goes above iLimit, then end the set by reading all characters until "&" or EOF.
                     Char = INPUT$(1, #1)                 'read next character in file
                  LOOP
               END IF
            ELSE
               VIEW PRINT 28 TO 30
               CLS 2
               INPUT "Data error. Not v. Hit enter. ", Continue      'if it was not "v" then it is an error.
               Char = "&"                                 'setting Char to e will exit graphing loop
            END IF
         ELSEIF Char = "&" OR Char = " " OR Char = CHR$(13) OR Char = CHR$(10) THEN
            'do nothing. skip "&", spaces, Carriage return (CR), and Line feeds (LF)
         ELSE
            VIEW PRINT 28 TO 30
            CLS 2
            INPUT "Data error. Not t. Hit enter. ", Continue      'if it was not "t" then it is an error.
            Char = "&"                           'setting Char to & will exit graphing loop
         END IF
      LOOP
      PRINT CoilName, CoilFile
      GrphColor = GrphColor + 1
   END IF
LOOP
IF (EOF(1)) THEN                                'if the end of the file was reached
   CLOSE #1                                       'close the file
   OPEN CoilFile FOR INPUT AS #1   're-open the file
END IF
END SUB '---------------------------Plot----------------------------------------

SUB PrintVar '---------------------------PrintVar---------------
'Just prints whether it will be line or point plot, then coil's name, and data file's name.
IF PntOrLin = 0 THEN PRINT "Point plot. ";
IF PntOrLin = 1 THEN PRINT "Line plot.  ";
'PRINT CoilFile, CoilName                   'Not enough room to print CoilFile and everything else.
PRINT CoilName
END SUB '--------------------------------PrintVar----------------

SUB SetTscale '----------------------------SetTscale-------------------------------
PRINT " Eleven different time scales can be chosen from."
PRINT "0 to .0001 sec."
PRINT "0 to .001 sec."
PRINT "0 to .005 sec."
PRINT "0 to .01 sec."
PRINT "0 to .02 sec."
PRINT "0 to .1 sec."
PRINT "0 to 1 sec."
PRINT "0 to 10 sec."
PRINT "0 to 100 sec."
PRINT "0 to 1000 sec."
PRINT "0 to 10,000 sec."
DO
   INPUT "Enter the number of seconds for the x axis (default is .005).  ", tscale
LOOP WHILE tscale < 0
IF tscale = 0 THEN
   tscale = .005  'default case
ELSEIF tscale < .00011 THEN tscale = .0001
ELSEIF tscale < .0011 THEN tscale = .001
ELSEIF tscale < .0051 THEN tscale = .005
ELSEIF tscale < .011 THEN tscale = .01
ELSEIF tscale < .021 THEN tscale = .02
ELSEIF tscale < .11 THEN tscale = .1
ELSEIF tscale < 1.1 THEN tscale = 1
ELSEIF tscale < 11 THEN tscale = 10
ELSEIF tscale < 110 THEN tscale = 100
ELSEIF tscale < 1100 THEN tscale = 1000
ELSE tscale = 10000
END IF
END SUB'----------------------------SetTscale-------------------------------

FUNCTION subtract# (aaa#, bbb#) '---------------Subtraction function--------------
' The purpose of this function is to avoid loss-of-significance errors.
' subtract# = aaa# - bbb#
' But, if both aaa and bbb are positive or both negative, then loss-of-sig is possible.
' In that case, check the ratio of aaa to bbb, and bbb to aaa. (Use different ratio for Double and Single precision math.)
' If too close, then loss of sig is going to happen.
' In that case, subtract# = 0.
subtract# = aaa# - bbb#
IF (aaa# > 0# AND bbb# > 0#) OR (aaa# < 0# AND bbb# < 0#) THEN
   IF ((aaa# / bbb#) < 1.0000000000001# AND (aaa# / bbb#) > 1#) OR ((bbb# / aaa#) < 1.0000000000001# AND (bbb# / aaa#) > 1#) THEN
   subtract# = 0
   END IF
END IF
END FUNCTION'----------------------------------Subtraction function--------------

FUNCTION ValidFilename (FileName$) '------- Function ValidFilename ---------------
'This sub checks to make sure a file name is valid.
'It returns an error code based on what's wrong.
'It assumes the 8.3 (8 chars plus 3 char filetype)  convention for file names.
'0 = valid file name
'1 = too long
'2 = too short
'3 = period not in 4th place from right
'4 = invalid character used
ValidFilename = 0
IF LEN(FileName$) > 12 THEN
   ValidFilename = 1     '1=Filename too long.
ELSEIF LEN(FileName$) < 5 THEN
   ValidFilename = 2     '2=Filename too short.
ELSEIF MID$(RIGHT$(FileName$, 4), 1, 1) <> "." THEN
   ValidFilename = 3     '3=No period to separate filetype.
ELSE                     'If there is no length error or period error, check each character
   FOR Char = 1 TO LEN(FileName$) - 4               'this loop checks the characters in the name
      CharAsc = ASC(MID$(FileName$, Char, 1))       'this gets the acsii value for each character
      IF CharAsc < 48 OR CharAsc > 122 THEN         'if outside the ascii range for alpha-numeric
         ValidFilename = 4                          '4=invalid character
      ELSEIF CharAsc > 57 AND CharAsc < 65 THEN     'if greater than numerals, and less than upper case
         ValidFilename = 4                          '4=invalid character          
      ELSEIF CharAsc > 90 AND CharAsc < 95 THEN     'if greater than upper case, and less than underscore
         ValidFilename = 4                          '4=invalid character
      ELSEIF CharAsc > 95 AND CharAsc < 97 THEN     'if greater than underscore, and less than lower case
         ValidFilename = 4                          '4=invalid character
      END IF
   NEXT Char
   FOR Char = LEN(FileName$) - 2 TO LEN(FileName$)  'This loop checks the filetype characters
      CharAsc = ASC(MID$(FileName$, Char, 1))       'this gets the acsii value for each character
      IF CharAsc < 48 OR CharAsc > 122 THEN         'if outside the ascii range for alpha-numeric
         ValidFilename = 4                          '4=invalid character
      ELSEIF CharAsc > 57 AND CharAsc < 65 THEN     'if greater than numerals, and less than upper case
         ValidFilename = 4                          '4=invalid character          
      ELSEIF CharAsc > 90 AND CharAsc < 95 THEN     'if greater than upper case, and less than underscore
         ValidFilename = 4                          '4=invalid character
      ELSEIF CharAsc > 95 AND CharAsc < 97 THEN     'if greater than underscore, and less than lower case
         ValidFilename = 4                          '4=invalid character
      END IF
   NEXT Char
END IF
END FUNCTION'----------------------ValidFilename-------------------------

SUB ZZLou24bIT (FileName$, invertBW$) '------------------ Sub zzLou24Bit bmp generator -------------------
'This SUB is designed to hold the colors true to the original
' qbasic colors, or close to them. But will not convert nicely
' to .gif in MSpaint, so first covert to 8-bit (256 colors) BMP in
' MS paint, then convert to gif in MSpaint.
'Make sure the filename is 8char or less and ".BMP"
'This section sets the header data
FileTYPE$ = "BM"                    'in hex it's &H42 &H4D, but will use ascii representation instead
FileSIZE& = &HE1036                 'file size is 921654 bytes. In hex it's E1036.
Reserved1% = &H0                    'always 0
Reserved2% = &H0                    'always 0
OffsetBITS& = &H36                  'offset tells where the pixel data begins. With a 24 bit bitmap, it starts at &H36
InfoHEADER& = &H28                  'always &H28
PictureWIDTH& = &H280               '640 wide
PictureHeight& = &H1E0              '480 height
NumPLANES% = &H1
BPP% = &H18                           '24 bits. In hex, 24 is &H18
Compression& = 0
ImageSIZE& = &HE1000                  'image size is 921600 bytes. in hex it's E1000
WidthPELS& = 0                        ' always 0.    Bob had 3780
DepthPELS& = 0                        ' always 0.    Bob had 3780
NumCOLORS& = 0                        ' 0 when in 24 bits.  16 if in 4 bits.
SigCOLORS& = 0                        ' 0 means all colors significant.

OPEN FileName$ FOR BINARY AS #1

'this section prints header data in binary
PUT #1, , FileTYPE$
PUT #1, , FileSIZE&
PUT #1, , Reserved1% 'should be zero
PUT #1, , Reserved2% 'should be zero
PUT #1, , OffsetBITS&
PUT #1, , InfoHEADER&
PUT #1, , PictureWIDTH&
PUT #1, , PictureHeight&
PUT #1, , NumPLANES%
PUT #1, , BPP%
PUT #1, , Compression&
PUT #1, , ImageSIZE&
PUT #1, , WidthPELS&
PUT #1, , DepthPELS&
PUT #1, , NumCOLORS&
PUT #1, , SigCOLORS&
IF invertBW$ = "57" THEN 'invert some colors
   FOR y = 479 TO 0 STEP -1         'bitmaps code from bottom to top
      FOR x = 0 TO 639 STEP 1       'bitmaps code from left to right
         Colr% = POINT(x, y)        'POINT returns the color at the given pixel coordinates
         IF Colr% = 0 THEN 'black                                   to white
            red$ = CHR$(&HFF): grn$ = CHR$(&HFF): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 1 THEN 'dark blue                           to blue
            red$ = CHR$(&H0): grn$ = CHR$(&H0): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 2 THEN 'dark green                         to green
            red$ = CHR$(&H0): grn$ = CHR$(&HFF): blu$ = CHR$(&H0)
         ELSEIF Colr% = 3 THEN 'dark cyan                          to cyan
            red$ = CHR$(&H0): grn$ = CHR$(&HFF): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 4 THEN 'dark red                           to red
            red$ = CHR$(&HFF): grn$ = CHR$(&H0): blu$ = CHR$(&H0)
         ELSEIF Colr% = 5 THEN 'dark magenta                       to magenta
            red$ = CHR$(&HFF): grn$ = CHR$(&H0): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 6 THEN 'dark yellow                          to yellow
            red$ = CHR$(&HFF): grn$ = CHR$(&HFF): blu$ = CHR$(&H0)
         ELSEIF Colr% = 7 THEN 'light grey                           to dark grey
            red$ = CHR$(&H80): grn$ = CHR$(&H80): blu$ = CHR$(&H80)
         ELSEIF Colr% = 8 THEN 'dark grey                            to light grey
            red$ = CHR$(&HC0): grn$ = CHR$(&HC0): blu$ = CHR$(&HC0)
         ELSEIF Colr% = 9 THEN 'blue                                 to dark blue
            red$ = CHR$(&H0): grn$ = CHR$(&H0): blu$ = CHR$(&H80)
         ELSEIF Colr% = 10 THEN 'green                             to dark green
            red$ = CHR$(&H0): grn$ = CHR$(&H80): blu$ = CHR$(&H0)
         ELSEIF Colr% = 11 THEN 'cyan                              to dark cyan
            red$ = CHR$(&H0): grn$ = CHR$(&H80): blu$ = CHR$(&H80)
         ELSEIF Colr% = 12 THEN 'red                                to dark red
            red$ = CHR$(&H80): grn$ = CHR$(&H0): blu$ = CHR$(&H0)
         ELSEIF Colr% = 13 THEN 'magenta                           to dark magenta
            red$ = CHR$(&H80): grn$ = CHR$(&H0): blu$ = CHR$(&H80)
         ELSEIF Colr% = 14 THEN 'yellow                             to dark yellow
            red$ = CHR$(&H80): grn$ = CHR$(&H80): blu$ = CHR$(&H0)
         ELSE  'Colr% = 15 then 'white                             to black
            red$ = CHR$(&H0): grn$ = CHR$(&H0): blu$ = CHR$(&H0)
         END IF
         PUT #1, , blu$
         PUT #1, , grn$
         PUT #1, , red$
         'no byte padding needed. (640 x 3 bytes = 1920 bytes. Bytes must be stacked in groups of four. Luckily 1920 divides by 4 evenly.)
      NEXT x
   NEXT y
ELSE   'use original colors
   FOR y = 479 TO 0 STEP -1         'bitmaps code from bottom to top
      FOR x = 0 TO 639 STEP 1       'bitmaps code from left to right
         Colr% = POINT(x, y)        'POINT returns the color at the given pixel coordinates
         IF Colr% = 0 THEN 'black
            red$ = CHR$(&H0): grn$ = CHR$(&H0): blu$ = CHR$(&H0)
         ELSEIF Colr% = 1 THEN 'dark blue
            red$ = CHR$(&H0): grn$ = CHR$(&H0): blu$ = CHR$(&H80)
         ELSEIF Colr% = 2 THEN 'dark green
            red$ = CHR$(&H0): grn$ = CHR$(&H80): blu$ = CHR$(&H0)
         ELSEIF Colr% = 3 THEN 'dark cyan
            red$ = CHR$(&H0): grn$ = CHR$(&H80): blu$ = CHR$(&H80)
         ELSEIF Colr% = 4 THEN 'dark red
            red$ = CHR$(&H80): grn$ = CHR$(&H0): blu$ = CHR$(&H0)
         ELSEIF Colr% = 5 THEN 'dark magenta
            red$ = CHR$(&H80): grn$ = CHR$(&H0): blu$ = CHR$(&H80)
         ELSEIF Colr% = 6 THEN 'dark yellow
            red$ = CHR$(&H80): grn$ = CHR$(&H80): blu$ = CHR$(&H0)
         ELSEIF Colr% = 7 THEN 'light grey
            red$ = CHR$(&HC0): grn$ = CHR$(&HC0): blu$ = CHR$(&HC0)
         ELSEIF Colr% = 8 THEN 'dark grey
            red$ = CHR$(&H80): grn$ = CHR$(&H80): blu$ = CHR$(&H80)
         ELSEIF Colr% = 9 THEN 'blue
            red$ = CHR$(&H0): grn$ = CHR$(&H0): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 10 THEN 'green
            red$ = CHR$(&H0): grn$ = CHR$(&HFF): blu$ = CHR$(&H0)
         ELSEIF Colr% = 11 THEN 'cyan
            red$ = CHR$(&H0): grn$ = CHR$(&HFF): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 12 THEN 'red
            red$ = CHR$(&HFF): grn$ = CHR$(&H0): blu$ = CHR$(&H0)
         ELSEIF Colr% = 13 THEN 'magenta
            red$ = CHR$(&HFF): grn$ = CHR$(&H0): blu$ = CHR$(&HFF)
         ELSEIF Colr% = 14 THEN 'yellow
            red$ = CHR$(&HFF): grn$ = CHR$(&HFF): blu$ = CHR$(&H0)
         ELSE  'Colr% = 15 then 'white
            red$ = CHR$(&HFF): grn$ = CHR$(&HFF): blu$ = CHR$(&HFF)
         END IF
         PUT #1, , blu$
         PUT #1, , grn$
         PUT #1, , red$
         'no byte padding needed. (640 x 3 bytes = 1920 bytes. Bytes must be stacked in groups of four. Luckily 1920 divides by 4 evenly.)
      NEXT x
   NEXT y
END IF
CLOSE #1
END SUB  '------------------ End Sub zzLou24Bit bmp generator ------------------