Saving a 4-bit BMP in SCREEN 12 (thread314-747791 )

DEFINT A-Z
DECLARE SUB SAVE4BIT (FileName$, MinX, MinY, MaxX, MaxY)

TYPE BMPHeader
	ValidID AS STRING * 2
	SizeOfFile AS LONG
	Reserved AS LONG
	OffsetOfBitMap AS LONG
END TYPE

TYPE WindowsBMPInfoHeader
	SizeOfHeader AS LONG
	Widthz AS LONG
	Heightz AS LONG
	Planes AS INTEGER
	BitsPerPixel AS INTEGER
	CompressMethod AS LONG
	ImageSizeInBytes AS LONG
	HorizontalResol AS LONG
	VerticalResol AS LONG
	ColorsUsed AS LONG
	ImportantColors AS LONG
END TYPE

SCREEN 12

FOR Y = 0 TO 49
	LINE (0, Y)-(50, Y), (Y MOD 15)
NEXT Y

x2 = 7
y2 = 7
LOCATE 7, 1: PRINT "Width: "; (x2 + 1), "Height: "; (y2 + 1)
LOCATE 9, 1: PRINT "Use arrow keys to change image size."
LOCATE 10, 1: PRINT "Press the Spacebar to capture as bmp"

SAVE4BIT "4bit.bmp", 0, 0, x2, y2

DO
	A$ = INKEY$
	IF (A$ <> "") THEN
		SELECT CASE (A$)
			CASE CHR$(0) + CHR$(72): y2 = y2 + 1 'Up Arrow
			CASE CHR$(0) + CHR$(80): y2 = y2 - 1 'Down Arrow
			CASE CHR$(0) + CHR$(75): x2 = x2 - 1 'Left Arrow
			CASE CHR$(0) + CHR$(77): x2 = x2 + 1 'Right Arrow
			CASE CHR$(32): SAVE4BIT "4bit.bmp", 0, 0, x2, y2
		END SELECT
		IF (y2 < 0) THEN y2 = 0
		IF (x2 < 0) THEN x2 = 0
		LOCATE 7, 1: PRINT "Width: "; (x2 + 1), "Height: "; (y2 + 1)
	END IF
LOOP WHILE A$ <> CHR$(27)
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SUB SAVE4BIT (FileName$, MinX, MinY, MaxX, MaxY)
	DIM BMPHeader AS BMPHeader
	DIM WindowsBMPInfoHeader AS WindowsBMPInfoHeader

	OPEN FileName$ FOR BINARY AS #255
	IF LOF(255) <> 0 THEN
		CLOSE #255
		KILL FileName$
		OPEN FileName$ FOR BINARY AS #255
	END IF
	
	ImageWidth = (MaxX - MinX) + 1: ImageHeight = (MaxY - MinY) + 1
	WindowsBMPInfoHeader.SizeOfHeader = 40
	WindowsBMPInfoHeader.Widthz = ImageWidth
	WindowsBMPInfoHeader.Heightz = ImageHeight
	WindowsBMPInfoHeader.Planes = 1
	WindowsBMPInfoHeader.BitsPerPixel = 4
	WindowsBMPInfoHeader.CompressMethod = 0
	WindowsBMPInfoHeader.ColorsUsed = 16
	WindowsBMPInfoHeader.ImportantColors = 16
	PUT #255, 15, WindowsBMPInfoHeader
	Empty$ = SPACE$(1)
  
	FOR Colors = 0 TO 15
		OUT &H3C6, &HFF
		OUT &H3C7, Colors
		Red$ = CHR$(INP(&H3C9) * 4): Green$ = CHR$(INP(&H3C9) * 4)
		Blue$ = CHR$(INP(&H3C9) * 4): AllColorz$ = Blue$ + Green$ + Red$ + Empty$
		PUT #255, , AllColorz$
	NEXT Colors

	Padding$ = SPACE$(0)
	IF (4 - ((BMPInfoHeader.Widthz MOD 8) / 2)) <> 4 THEN
		Padding$ = SPACE$((4 - ((BMPInfoHeader.Widthz MOD 8) / 2)))
	END IF

	FOR Loops = MaxY TO MinY STEP -1
		FOR Lips = MinX TO MaxX STEP 2
			Byte = POINT(Lips, Loops) * 16
		  
			IF (Lips + 1 <= MaxX) THEN
				Byte = (Byte OR POINT(Lips + 1, Loops))
			END IF
																																									
			Bytez$ = Bytez$ + CHR$(Byte)
			Byte = 0
		NEXT Lips
		PUT #255, , Bytez$
		PUT #255, , Padding$
		Bytez$ = ""
		
	NEXT Loops
	BMPHeader.ValidID = "BM"
	BMPHeader.SizeOfFile = LOF(255)
	BMPHeader.OffsetOfBitMap = 118
	PUT #255, 1, BMPHeader
	CLOSE #255
END SUB