/**********		SplitBMfont(fn$) **************************

Description:	Uses a text file to determine how to split a bitmap font sheet
				The text file should have the same name as the font and be in the same folder

Parameters:		fn$ - The full RAW PATH file name of the text file that holds the data for the split 
				NOT including any file extension
				
Returns:		Returns nothing but CREATES a subimages.txt file to use for the bitmap font sheet

Notes:			The text file should be in the following format
				100
				A:M
				N:Z
				0:9
				
				And saved with the same filename as the bitmap font
				
				The above example demonstrates how the file should be formatted
				100 = The Height of each row of text
				Each subsequent row is the range characters on each line which must be in correct ASCII order
*/
function SplitBMfont(fn$)
	fn$ = "raw:" + fn$
	OpenToRead(1, fn$+".txt")
		height = val(ReadLine(1))
		imgFont = LoadImage(fn$+".png")
		mbFont = CreateMemblockFromImage(imgFont)
		y = 0
		OpenToWrite(2, fn$ + " subimages.txt")
			avg = 0
			avgCount = 0
			repeat
				ln$ = ReadLine(1)
				startASC = asc(left(ln$, 1))
				endASC = asc(right(ln$, 1))

				ascii = startASC			
				startX = 0
					while ascii <= endASC
						inc avgCount
						repeat
							test = ColumnIsAllAlpha(mbFont, startX, y, y+height-1)
							if test = TRUE
								inc startX
							endif
						until test = FALSE
						endX = startX+1
						
						repeat
							test = ColumnHasNonAlpha(mbFont, endX, y, y+height-1)
							if test = TRUE
								inc endX
							endif
						until test = FALSE
						WriteLine(2, str(ascii) + ":" + str(startX) + ":" + str(y)+":"+str(endX-startX)+":"+str(height))
						inc ascii
						inc avg, endX-startX
						startX = endX+1
					endwhile 
					
					inc y, height
			until FileEOF(1)
			//Create Space that is half the width of the average of all characters
			//And place it at the begining of the file
			WriteLine(2, "32:0:0:"+str(avg/avgCount)+":"+str(height))
		CloseFile(2)
	CloseFile(1)
endfunction
		



function GetMemblockImageOffset(mb, x, y)
	w = GetMemblockInt(mb, 0)
	h = GetMemblockInt(mb, 4)
	yy = 12 + (4*w*y)
	xx = 4*x
	ret = xx+yy
endfunction ret



function ColumnIsAllAlpha(mb, x, startY, endY)
	for y = startY to endY
		pix = GetMemblockImageOffset(mb, x, y)
		if GetMemblockByte(mb, pix+3) > 0
			exitfunction FALSE
		endif
	next y
endfunction TRUE



function ColumnHasNonAlpha(mb, x, startY, endY)
	for y = startY to endY
		pix = GetMemblockImageOffset(mb, x, y)
		if GetMemblockByte(mb, pix+3) > 0
			exitfunction TRUE
		endif
	next y
endfunction FALSE