Cleanup in IndexedImageWriter and add some safety

Author: MaximDude

types/IndexedImageWriter.bmx

@@ -1,55 +1,25 @@
 Import "Utility.bmx"
 Import "IndexedPixmap.bmx"
 
-'//// INDEXED IMAGE WRITER //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+'//// RGB COLOR /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 Struct RGBColor
 	Field m_R:Byte
 	Field m_G:Byte
 	Field m_B:Byte
 EndStruct
 
-'////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+'//// INDEXED IMAGE WRITER //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 Type IndexedImageWriter
-	Field m_PalR:Byte[256]
-	Field m_PalG:Byte[256]
-	Field m_PalB:Byte[256]
-
 	Field m_Palette:RGBColor[256]
 
-	'Field m_CRCTable:Int[256]
-
 '////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 	Method New()
 		LoadDefaultPalette()
-Rem
-		'Initialize CRC table
-		For Local i:Int = 0 To 255
-			Local value:Int = i
-			For Local j:Int = 0 To 7
-				If (value & $1) Then
-					value = (value Shr 1) ~ $EDB88320 '~ for XOR
-				Else
-					value = (value Shr 1)
-				EndIf
-			Next
-			m_CRCTable[i] = value
-		Next
-EndRem
 	EndMethod
 
-'////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-Rem
-	Method GenerateCRC32FromBank:Int(bank:TBank)
-		Local crcResult:Int = $FFFFFFFF
-		For Local i:Int = 0 Until BankSize(bank)
-			crcResult = (crcResult Shr 8) ~ m_CRCTable[PeekByte(bank, i) ~ (crcResult & $FF)]
-		Next
-		Return ~crcResult '~ for bitwise complement
-	EndMethod
-EndRem
 '////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 	Method LoadDefaultPalette()
@@ -59,13 +29,9 @@ EndRem
 
 		Local paletteStream:TStream = ReadFile("Incbin::Assets/Palette")
 		For Local index:Int = 0 To 255
-			m_PalR[index] = ReadByte(paletteStream)
-			m_PalG[index] = ReadByte(paletteStream)
-			m_PalB[index] = ReadByte(paletteStream)
-
-			m_Palette[index].m_R = m_PalR[index]
-			m_Palette[index].m_G = m_PalG[index]
-			m_Palette[index].m_B = m_PalB[index]
+			m_Palette[index].m_R = ReadByte(paletteStream)
+			m_Palette[index].m_G = ReadByte(paletteStream)
+			m_Palette[index].m_B = ReadByte(paletteStream)
 		Next
 		CloseStream(paletteStream)
 	EndMethod
@@ -85,9 +51,9 @@ EndRem
 				Local bestIndex:Int = 0
 				Local bestDistance:Int = 17000000 'Out of bounds color value (max is 16777215)
 				For Local index:Int = 0 To 255
-					Local redDiff:Int = Abs(((pixelData & $00FF0000) Shr 16) - m_PalR[index])
-					Local greenDiff:Int = Abs(((pixelData & $FF00) Shr 8) - m_PalG[index])
-					Local blueDiff:Int = Abs((pixelData & $FF) - m_PalB[index])
+					Local redDiff:Int = Abs(((pixelData & $00FF0000) Shr 16) - m_Palette[index].m_R)
+					Local greenDiff:Int = Abs(((pixelData & $FF00) Shr 8) - m_Palette[index].m_G)
+					Local blueDiff:Int = Abs((pixelData & $FF) - m_Palette[index].m_B)
 					Local distance:Int = (redDiff ^ 2) + (greenDiff ^ 2) + (blueDiff ^ 2)
 
 					If distance <= bestDistance Then
@@ -113,6 +79,9 @@ EndRem
 
 			'Begin writing BMP file manually
 			Local outputStream:TStream = LittleEndianStream(WriteFile(filename)) 'Bitmap file data is stored in little-endian format (least-significant byte first)
+			If Not outputStream Then
+				Return False
+			EndIf
 
 			'Bitmap File Header
 			WriteShort(outputStream, 19778)				'File ID (2 bytes) - 19778 (decimal) or 42 4D (hex) or BM (ascii) for bitmap
@@ -133,12 +102,12 @@ EndRem
 			WriteInt(outputStream, 256)					'Number of colors in the color palette (4 bytes)
 			WriteInt(outputStream, 0)					'Number of important colors (4 bytes) - 0 when every color is important
 
-			'Color Table (4 bytes (ARGB) times the amount of colors in the palette)
-			For Local index:Int = 0 To 255
-				WriteByte(outputStream, m_PalB[index])	'Blue (1 byte)
-				WriteByte(outputStream, m_PalG[index])	'Green (1 byte)
-				WriteByte(outputStream, m_PalR[index])	'Red (1 byte)
-				WriteByte(outputStream, 0)				'Reserved (1 byte) - Alpha channel, irrelevant for indexed bitmaps
+			'Color Table (4 bytes (RGBA) times the amount of colors in the palette)
+			For Local paletteIndex:RGBColor = EachIn m_Palette
+				WriteByte(outputStream, paletteIndex.m_R)	'Blue (1 byte)
+				WriteByte(outputStream, paletteIndex.m_G)	'Green (1 byte)
+				WriteByte(outputStream, paletteIndex.m_B)	'Red (1 byte)
+				WriteByte(outputStream, 0)					'Reserved (1 byte) - Alpha channel, irrelevant for indexed bitmaps
 			Next
 
 			'Pixel Array
@@ -162,87 +131,6 @@ EndRem
 		EndIf
 	EndMethod
 
-'////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-Rem
-	Method WriteIndexedPNGFromPixmap:Int(sourcePixmap:TPixmap, filename:String)
-		If filename = Null Then
-			Return False
-		Else
-			Local pngWidth:Int = sourcePixmap.Width
-			Local pngWidthM4:Int = ((pngWidth + 3) / 4) * 4 'pngWidth adjusted to be divisible by 4. Written file is spaghetti if not adjusted!
-			Local pngHeight:Int = sourcePixmap.Height
-			Local pngSizeTotal:Int = pngWidthM4 * pngHeight 'dimensions (with adjusted width)
-			Local pngSizeTotalM4:Int = ((pngSizeTotal + 3) / 4) * 4 'bmpSizeTotal adjusted to be divisible by 4. Written file is spaghetti if not adjusted!
-
-			'Begin writing PNG file manually
-			Local outputStream:TStream = BigEndianStream(WriteFile(filename)) 'PNG file data is stored in network byte order (big-endian)
-
-			'PNG file header
-			WriteByte(outputStream, 137)				'Has the high bit set to detect transmission systems that do not support 8-bit data and to reduce the chance that a text file is mistakenly interpreted as a PNG, or vice versa. 89 (hex) (1 byte)
-			WriteByte(outputStream, 80)					'File ID (in ASCII, the letters PNG). 50 4E 47 (hex) (3 bytes)
-			WriteByte(outputStream, 78)
-			WriteByte(outputStream, 71)
-			WriteShort(outputStream, 3338)				'A DOS-style line ending (CRLF) to detect DOS-Unix line ending conversion of the data. 0D 0A (hex) (2 bytes)
-			WriteByte(outputStream, 26)					'A byte that stops display of the file under DOS when the command type has been used—the end-of-file character. 1A (hex) (1 byte)
-			WriteByte(outputStream, 10)					'A Unix-style line ending (LF) to detect Unix-DOS line ending conversion. 0A (hex) (1 byte)
-
-			'IHDR chunk (file properties)
-			WriteInt(outputStream, 13)					'Chunk Length (4 bytes) - 13 bytes for IHDR
-			WriteInt(outputStream, 1229472850)			'Chunk Type (4 bytes) -  1229472850 (decimal) or 49 48 44 52 (hex) or IHDR (ascii)
-
-			WriteInt(outputStream, pngWidth)			'Image Width (4 bytes)
-			WriteInt(outputStream, pngHeight)			'Image Height (4 bytes)
-			WriteByte(outputStream, 8)					'Bit Depth (1 byte)
-			WriteByte(outputStream, 3)					'Color Type (1 byte) - 3 for indexed color
-			WriteByte(outputStream, 0)					'Compression Method (1 byte)
-			WriteByte(outputStream, 0)					'Filter Method (1 byte)
-			WriteByte(outputStream, 0)					'Interlace Method (1 byte) - 0 for no interlace
-
-			'Figure out how to generate correct CRC
-			WriteInt(outputStream, 0)					'CRC-32 checksum (4 bytes)
-
-			'PLTE chunk (color table)
-			WriteInt(outputStream, 768)					'Chunk Length (4 bytes) - 4 bytes (ARGB) times the amount of colors in the palette = 1024 bytes
-			WriteInt(outputStream, 1347179589)			'Chunk Type (4 bytes) - 1347179589 (decimal) or 50 4C 54 45 (hex) or PLTE (ascii)
-
-			For Local index:Int = 0 To 255
-				WriteByte(outputStream, m_PalB[index])	'Blue (1 byte)
-				WriteByte(outputStream, m_PalG[index])	'Green (1 byte)
-				WriteByte(outputStream, m_PalR[index])	'Red (1 byte)
-			Next
-
-			'Figure out how to generate correct CRC
-			WriteInt(outputStream, 0)					'CRC-32 checksum (4 bytes)
-
-			'IDAT chunk (pixel array)
-			WriteInt(outputStream, pngSizeTotal)		'Chunk Length (4 bytes) - width times height of the image + padding
-			WriteInt(outputStream, 1229209940)			'Chunk Type (4 bytes) - 1229209940 (decimal) or 49 44 41 54 (hex) or IDAT (ascii)
-
-			For Local pixelY:Int = pngHeight - 1 To 0 Step -1
-				For Local pixelX:Int = 0 Until pngWidth
-					If pixelX < pngWidth Then
-						WriteByte(outputStream, ConvertColorToClosestIndex(ReadPixel(sourcePixmap, pixelX, pixelY)))
-					'Else
-					'	WriteByte(outputStream, 0) 		'Line padding
-					EndIf
-				Next
-			Next
-
-			'Figure out how to generate correct CRC
-			WriteInt(outputStream, 0)					'CRC-32 checksum (4 bytes)
-
-			'IEND chunk (EOF)
-			WriteInt(outputStream, 0)					'Chunk Length (4 bytes) - 0 for IEND
-			WriteInt(outputStream, 1229278788)			'Chunk Type (4 bytes) - 1229278788 (decimal) or 49 45 4E 44 (hex) or IEND (ascii)
-
-			'Figure out how to generate correct CRC
-			WriteInt(outputStream, 0)					'CRC-32 checksum (4 bytes)
-
-			CloseStream(outputStream)
-			Return True
-		EndIf
-	EndMethod
-EndRem
 '////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 	Method WriteIndexedPNGFromPixmap:Int(sourcePixmap:TPixmap, filename:String, compression:Int = 5)
@@ -251,29 +139,33 @@ EndRem
 		Else
 			'Begin writing PNG file manually
 			Local outputStream:TStream = WriteStream(filename)
+			If Not outputStream Then
+				Return False
+			EndIf
 
 			Try
 				Local pngPtr:Byte Ptr = png_create_write_struct("1.6.37", Null, Null, Null)
 				Local pngInfoPtr:Byte Ptr = png_create_info_struct(pngPtr)
 
 				png_set_write_fn(pngPtr, outputStream, Utility.PNGWriteStream, Utility.PNGFlushStream)
-
 				png_set_compression_level(pngPtr, Utility.Clamp(compression, 0, 9))
-				png_set_IHDR(pngPtr, pngInfoPtr, sourcePixmap.Width, sourcePixmap.Height, 8, PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT)
 
-				Local palettePtr:Byte Ptr = m_Palette
-				png_set_PLTE(pngPtr, pngInfoPtr, palettePtr, 256);
+				png_set_IHDR(pngPtr, pngInfoPtr, sourcePixmap.Width, sourcePixmap.Height, 8, PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT) 'IHDR chunk - file properties
+				png_set_PLTE(pngPtr, pngInfoPtr, Byte Ptr(m_Palette), m_Palette.Length) 'PLTE chunk - color table
 
+				'Using the RGBA8888 source pixmap produces spaghetti output because of byte alignment, so conversion to RGB332 is needed
+				'What happens is that 4 bytes are written when 1 is expected, so we're actually writing 4 pixels where the first pixel is correct and the following 3 are empty causing the output to stretch and spaghettify
 				Local convertingPixmap:IndexedPixmap = New IndexedPixmap(sourcePixmap.Width, sourcePixmap.Height)
 				For Local pixelY:Int = 0 Until sourcePixmap.Height
 					For Local pixelX:Int = 0 Until sourcePixmap.Width
+						'Convert the 32bit RGBA color value from the source pixmap to a 8bit index value and write it to the converting bitmap
 						convertingPixmap.WritePixel(pixelX, pixelY, ConvertColorToClosestIndex(ReadPixel(sourcePixmap, pixelX, pixelY)))
 					Next
 				Next
 
 				Local rows:Byte Ptr[sourcePixmap.Height]
 				For Local i = 0 Until sourcePixmap.Height
-					rows[i] = convertingPixmap.PixelPtr(0, i)
+					rows[i] = convertingPixmap.PixelPtr(0, i) 'Get row pointers from the converting bitmap (1 byte aligned so won't be spaghettified)
 				Next
 				png_set_rows(pngPtr, pngInfoPtr, rows)