BMP file writer actually fully functional but incredibly slow

Sped up indexing by ignoring magenta (255,0,255)
Generated file still has messed up thumbnail and doesn't open correctly in Photoshop, appears to be working fine in Paint, probably something bad in header or DIB

Author: MaximDude

cccp-bender-main.bmx

@@ -25,6 +25,9 @@ Type TBitmapIndex
 	Global palR:Byte[256]
 	Global palG:Byte[256]
 	Global palB:Byte[256]
+	
+	'Data Streams
+	Global dataStream:TStream
 
 	'Load color table file
 	Function FLoadPalette(paletteFile:String)
@@ -42,11 +45,11 @@ Type TBitmapIndex
 
 	'Indexed Bitmap File Writer
 	Function FPixmapToIndexedBitmap(image:TPixmap,filename:String)
-		'Variables 
+		'Variables
+		Local paletteIndex:Int
 		Local bmpWidth:Int, bmpWidthM4:Int
 		Local bmpHeight:Int
 		Local bmpSizeTotal:Int, bmpSizeTotalM4:Int
-		Local paletteIndex:Int = 0
 
 		'Dimensions calc
 		bmpWidth = PixmapWidth(image)
@@ -58,24 +61,19 @@ Type TBitmapIndex
 		bmpSizeTotalM4 = ((bmpSizeTotal + 3) / 4) * 4
 
 		'Begin writing BMP file manually
-		Local dataStream:TStream = WriteFile(filename)
+		dataStream = WriteFile(filename)
 
 '------ Bitmap File Header
-		'Header file data is stored in little-endian format (least-significant byte first)
+		'Data is stored in little-endian format (least-significant byte first)
 		dataStream = LittleEndianStream(dataStream)
 
 		WriteShort(dataStream,19778)			'File ID (2 bytes (short)) - 19778 (deci) or 42 4D (hex) or BM (ascii) for bitmap
 		WriteInt(dataStream,bmpSizeTotalM4)		'File Size (4 bytes (signed int))
 		WriteShort(dataStream,0)				'Reserved (2 bytes)
 		WriteShort(dataStream,0)				'Reserved (2 bytes)
 		WriteInt(dataStream,54)					'Pixel Array Offset (4 bytes) - pixel array starts at 54th byte
-		'Print("wrote header")
-
-		'CloseStream(headerStream)
 
 '------ DIB Header (File Info)
-		'dataStream = BigEndianStream(dataStream)
-
 		WriteInt(dataStream,40)					'DIB Header Size (4 bytes) - 40 bytes
 		WriteInt(dataStream,bmpWidth)			'Bitmap Width (4 bytes)
 		WriteInt(dataStream,bmpHeight)			'Bitmap Height (4 bytes)
@@ -87,59 +85,60 @@ Type TBitmapIndex
 		WriteInt(dataStream,2835)				'Vertical resolution of the image (4 bytes) - Pixels Per Metre (2835 PPM equals 72.009 DPI/PPI)
 		WriteInt(dataStream,256)				'Number of colors in the color palette (4 bytes)
 		WriteInt(dataStream,0)					'Number of important colors (4 bytes) - 0 when every color is important
-		'Print("wrote dib")
 
 '------ Color Table
 		For paletteIndex = 0 To 255
-			WriteByte(dataStream,PalB[paletteIndex])	'Blue (4 bytes) - offset 54
-			WriteByte(dataStream,PalG[paletteIndex])	'Green (4 bytes) - offset 58
-			WriteByte(dataStream,PalR[paletteIndex])	'Red (4 bytes) - offset 62
+			WriteByte(dataStream,palB[paletteIndex])	'Blue (4 bytes) - offset 54
+			WriteByte(dataStream,palG[paletteIndex])	'Green (4 bytes) - offset 58
+			WriteByte(dataStream,palR[paletteIndex])	'Red (4 bytes) - offset 62
 			WriteByte(dataStream,0)						'Alpha (4 bytes) - offset 66
-			If paletteIndex = 255 Then 
-				'Print("wrote color table") 
-			EndIf
 		Next
 
 '------ Pixel Array
 		Local px:Int, py:Int
-		Local R:Int, G:Int, B:Int, ARGB:Long
-		Local bestDistance:Int, bestIndex:Int, distance:Int
-		Local RDIFF:Int, GDIFF:Int, BDIFF:Int
-
+		Local pixelData:Long
+		Local bestIndex:Int = 0
+		Local magenta:Int = 16711935	
 		For py = bmpHeight -1 To 0 Step -1
 			For px = 0 To bmpWidthM4 -1
-				If px < bmpWidth 'if a valid pixel on canvas
-					bestDistance = 17000000
-					bestIndex = 0
-					distance = 0
-					
-					For paletteIndex = 0 To 255 ' Check all color indexes for best match by pythagora
-						ARGB = ReadPixel(image,px,py)
-						R = (ARGB & $00FF0000) Shr 16
-						G = (ARGB & $FF00) Shr 8
-						B = (ARGB & $FF)
-						RDIFF = Abs(R - palR[paletteIndex])
-						GDIFF = Abs(G - palG[paletteIndex])
-						BDIFF = Abs(B - palB[paletteIndex])
-						distance = (RDIFF^2 + GDIFF^2 + BDIFF^2)
-						If distance <= bestDistance Then
-							bestIndex = paletteIndex
-							bestDistance = distance
-						EndIf
-						'Print("working" + paletteIndex)
-					Next
+				'if a valid pixel on canvas
+				If px < bmpWidth
+					'Read pixel data
+					pixelData = ReadPixel(image,px,py)
+					'skip diffing magenta
+					If pixelData = 16711935 Then
+						WriteByte(dataStream,1)
+					Else
+						'Check all color indexes for best match by pythagora
+						Local R:Int, G:Int, B:Int
+						Local RDIFF:Int, GDIFF:Int, BDIFF:Int
+						Local bestDistance:Int = 17000000
+						Local distance:Int = 0
+						For paletteIndex = 0 To 255
+							R = (pixelData & $00FF0000) Shr 16
+							G = (pixelData & $FF00) Shr 8
+							B = (pixelData & $FF)
+							RDIFF = Abs(R - palR[paletteIndex])
+							GDIFF = Abs(G - palG[paletteIndex])
+							BDIFF = Abs(B - palB[paletteIndex])
+							distance = (RDIFF^2 + GDIFF^2 + BDIFF^2)
+							If distance <= bestDistance Then
+								bestIndex = paletteIndex
+								bestDistance = distance
+							EndIf
+						Next
+					EndIf
 					WriteByte(dataStream,bestIndex)
 				Else
-					WriteByte(dataStream,0) ' line padding
+					WriteByte(dataStream,0) 'line padding
 				EndIf
 			Next
 		Next
-		For paletteIndex = 1 To bmpSizeTotalM4 - bmpSizeTotal ' eof padding
+		For paletteIndex = 1 To bmpSizeTotalM4 - bmpSizeTotal 'eof padding
 			WriteByte(dataStream,0)
 		Next
 
 		CloseStream(dataStream)
-		'Print ("stream closed")
 	EndFunction
 
 EndType
@@ -384,7 +383,6 @@ Type TAppOutput
 		SetRotation(0)
 		'Output copy for saving
 		TAppFileIO.tempOutputImage = GrabPixmap(0,96,768,384)
-		'ConvertPixmap(TAppFileIO.tempOutputImage,PF_BGR888)
 		Flip(1)
 		If TAppFileIO.prepForSave
 			TAppFileIO.FPrepForSave()