'===========================================================================
' Subject: PB PCX DECODER                    Date: 10-21-95 (18:54)       
' Author:  Dave Navarro, Jr.                 Code: PB                     
' Origin:  FidoNet POWER_BAS Echo          Packet: GRAPHICS.ABC
'===========================================================================
'Decode PCX files
'by Dave Navarro, Jr.

DEFINT A-Z

TYPE PcxHeader
        Mfg    AS BYTE
        Ver    AS BYTE
        Enc    AS BYTE
        Bpp    AS BYTE
        XMin   AS INTEGER
        YMin   AS INTEGER
        XMax   AS INTEGER
        YMax   AS INTEGER
        Hres   AS INTEGER
        Vres   AS INTEGER
        Pal    AS STRING * 48
        Resrv  AS BYTE
        ColPl  AS BYTE
        Bpl    AS INTEGER
        PalTyp AS INTEGER
        Filler AS STRING * 58
END TYPE

DIM Header AS PcxHeader
DIM ByteBuffer AS BYTE

OPEN "B",1,"TMP.PCX"
         GET# 1,,Header
         IF Header.Mfg <> 10 AND Header.Ver <> 5 THEN
                 PRINT "Not a 256 color PCX file!"
                 END
         END IF

         Tmp& = LOF(1) - 768
         SEEK# 1, Tmp&
         GET$ 1,768,Palete$

         FOR I = 1 TO 768
                 Tmp? = ASC(MID$(Palete$,I,1))
                 SHIFT RIGHT Tmp?,2
                 MID$(Palete$,I,1)=CHR$(Tmp?)
         NEXT I

         SEEK# 1, 128

         Wid = Header.Xmax - Header.Xmin + 1
         Dep = Header.Ymax - Header.Ymin + 1
         Byt = Header.Bpl

         PRINT Wid;"x";Dep;"x";2^Header.Bpp

         I$=INPUT$(1)

         Mode13 1

         REG 1, &H1012
         REG 2, 0
         REG 3, 256
         REG 4, STRPTR(Palete$)
         REG 9, STRSEG(Palete$)
         CALL INTERRUPT &H10

   FOR Y = 0 TO Dep - 1
                 FOR X = 0 TO Byt - 1
                         GET# 1,,ByteBuffer
                         ByteBuffer = ByteBuffer AND &HFF
                         IF (ByteBuffer AND &HC0) = &HC0 THEN
                                 Times = ByteBuffer AND &H3F
                                 GET# 1,,ByteBuffer
                                 FOR I = 1 TO Times
                                         PlotPixel ByteBuffer
                                 NEXT I
                                ELSE
                                         PlotPixel ByteBuffer
                         END IF
                 NEXT X
         NEXT Y

CLOSE 1

BEEP
I$=INPUT$(1)
Mode13 0
END


SUB PlotPixel(Z AS BYTE)
        SHARED Wid
        STATIC X, Y
        DEF SEG = &HA000
                POKE Y*320+X, Z
        DEF SEG
        INCR X
        IF X > Wid THEN
                X = 0
                INCR Y
        END IF
END SUB

SUB Mode13(Bool)
        IF Bool THEN
                REG 1, &H0013
         ELSE
                REG 1, &H0003
        END IF
        CALL INTERRUPT &H10
END SUB