.PCX 1/2

 BBS: Inland Empire Archive
Date: 03-02-94 (00:16)             Number: 377
From: PETER MIKALAJUNAS            Refer#: NONE
  To: JEFFREY ZAPATKA               Recvd: NO  
Subj: .PCX                  1/2      Conf: (2) Quik_Bas

JZ>Can Anyone help me with a routinie or file to give an
JZ>example on how I'd JZ>begin (or do it) to view a .PCX file
JZ>in my QuickBASIC Program? JZ>                 - Jeffrey
JZ>Zapatka

' Date: Mon 10-18-93  From: FRANCOIS ROY  To: PETER MIKALAJUNAS
' Subject: Re: Using PCX images
' This code was posted via Fido Basic7 echo to me
' I have no idea if the author is or is not Francois Roy
' nor do I know if it is public domain, but I assume so.
' I might also add, that I recently saw the code to read a
PCX file ' posted in C.  It has some very good comments and
explains quite a bit ' about the PCX format.  I will try
and grab just the comments and post ' them separately.  In
the meantime, this should get you going.
DECLARE SUB SetPalette (pcxpal$)
DECLARE SUB SelectScreen ()
DECLARE SUB ReadPcxLine (PcxFile%, TotalBytes%, ScanLine%())
DECLARE SUB ReadPcxByte (PcxFile%, value%)
DECLARE SUB OpenPcxFile (PcxName$, xsize%, ysize%,
TotalBytes%, pcxpal$) DECLARE SUB ShowPcx (PcxName$)
DEFINT A-Z
TYPE PCXHeaderStruc
    Manufacxturer AS STRING * 1
    Version AS STRING * 1
    Encoding AS STRING * 1
    BitsPerPixel AS STRING * 1
    xmin AS INTEGER
    ymin AS INTEGER
    xmax AS INTEGER
    ymax AS INTEGER
    Hres AS INTEGER
    Vres AS INTEGER
    ColorMap AS STRING * 48
    Reserved1 AS STRING * 1
    NumPlanes AS STRING * 1
    BytesPerLine AS INTEGER
    PaletteType AS INTEGER
    HScrSize AS INTEGER
    VScrSize AS INTEGER
    Resreved2 AS STRING * 54
END TYPE
DIM SHARED PCXheader AS PCXHeaderStruc
DIM SHARED PcxFile
DIM SHARED ScrMode, ScrMaxX, ScrMaxY
DIM SHARED ScrMaxColor, ScrBitsPerPixel
DIM SHARED Byte AS STRING * 1
DIM SHARED MaxScrMode
SCREEN 0
Cm$ = COMMAND$
IF Cm$ = "" THEN
PRINT "Please enter the complete name of the pcx file"
END
END IF
CALL ShowPcx(Cm$)
NoVGA:
MaxScrMode = 9
' the following section was not part of the original post
SCREEN 0
Version = ASC(PCXheader.Version)
plan = ASC(PCXheader.NumPlanes)
xsize = PCXheader.xmax - PCXheader.xmin + 1
ysize = PCXheader.ymax - PCXheader.ymin + 1
' there appears to be a bug somewhere in this source code
' it sometimes incorrectly identifies the size and the planes
' also it does not always correctly display the palette
' however it does work, so it is a good starting point
' that is why I added this section to the original post.
PRINT "info retrieved"
PRINT "PCX_Version"; Version
PRINT "Planes"; plan
PRINT "Xsize"; xsize
PRINT "Ysize"; ysize

SUB OpenPcxFile (PcxName$, xsize, ysize, TotalBytes, pcxpal$)
 PcxFile = FREEFILE
OPEN PcxName$ FOR BINARY AS #PcxFile
GET #PcxFile, 1, PCXheader
pcxpal$ = LEFT$(PCXheader.ColorMap + STRING$(768, 0), 768)
IF ASC(PCXheader.Version) = 5 THEN
   SEEK #PcxFile, LOF(PcxFile) - 768&
   GET #PcxFile, , Byte
   IF ASC(Byte) = 12 THEN GET #PcxFile, , pcxpal$
END IF
xsize = PCXheader.xmax - PCXheader.xmin + 1
ysize = PCXheader.ymax - PCXheader.ymin + 1
TotalBytes = ASC(PCXheader.NumPlanes) * PCXheader.BytesPerLine
END SUB
SUB ReadPcxByte (PcxFile, value)
STATIC count, CountValue, BufferLOC, Buffer$
IF count > 0 THEN
   value = CountValue
   count = count - 1
ELSE
   IF BufferLOC > LEN(Buffer$) OR LEN(Buffer$) = 0 THEN
      BufferLEN& = LOF(PcxFile) - LOC(PcxFile)
       IF BufferLEN& > 15000 THEN
         BufferLEN& = 15000
      END IF
      IF BufferLEN& <= 0 OR EOF(PcxFile) THEN
         EXIT SUB
      END IF
      Buffer$ = SPACE$(BufferLEN&)
      GET #PcxFile, , Buffer$
      BufferLOC = 1
   END IF
   value = ASC(MID$(Buffer$, BufferLOC, 1))
   BufferLOC = BufferLOC + 1
   IF value >= 192 THEN
      count = value - 193
      IF BufferLOC >= LEN(Buffer$) THEN
         BufferLEN& = LOF(PcxFile) - LOC(PcxFile)
         IF BufferLEN& > 15000 THEN
            BufferLEN& = 15000
         END IF
         IF BufferLEN& <= 0 OR EOF(PcxFile) THEN
            EXIT SUB
         END IF
         Buffer$ = SPACE$(BufferLEN&)
          GET #PcxFile, , Buffer$
         BufferLOC = 1
      END IF
      CountValue = ASC(MID$(Buffer$, BufferLOC, 1))
      BufferLOC = BufferLOC + 1
      value = CountValue
   END IF
END IF
END SUB
SUB ReadPcxLine (PcxFile, TotalBytes, ScanLine())
zero$ = CHR$(0)
index = LBOUND(ScanLine) + 2
count = 0
DO
   ReadPcxByte PcxFile, pixels
   ScanLine(index) = pixels
   IF count = TotalBytes THEN EXIT DO
   ReadPcxByte PcxFile, pixels
   ScanLine(index) = ScanLine(index) + CVI(zero$ + CHR$(pixels))
   count = count + 2
   index = index + 1
 LOOP WHILE count < TotalBytes
END SUB
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