Codec.BMP

Description

Reading and writing uncompressed BMP files.

Reading works for both uncompressed 24bit RGB WindowsV3 and 32bit RGBA WindowsV4 formats.

Writing is limited to the uncompressed 24bit RGB WindowsV3 format.

We don't support the plain OS/2 BitmapCoreHeader and BitmapCoreHeader2 image headers, but I haven't yet seen one of these in the wild.

To write a file do something like:

 do let rgba   = Data.ByteString.pack [some list of Word8s]
    let bmp    = packRGBA32ToBMP width height rgba
    writeBMP fileName bmp

To read a file do something like:

 do Right bmp  <- readBMP fileName
    let rgba   =  unpackBMPToRGBA32 bmp
    let (width, height) = bmpDimensions bmp
    ...

Synopsis

Documentation

data BMP Source

A BMP image. For an uncompressed image, the image data contains triples of BGR component values. Each line may also have zero pad values on the end, to bring them up to a multiple of 4 bytes in length.

Constructors

BMP
Fields bmpFileHeader :: FileHeader bmpBitmapInfo :: BitmapInfo bmpRawImageData :: ByteString

Instances

Show BMP

data FileHeader Source

BMP file header.

Constructors

FileHeader
Fields fileHeaderType :: Word16 (+0) Magic numbers 0x42 0x4d fileHeaderFileSize :: Word32 (+2) Size of the file, in bytes. fileHeaderReserved1 :: Word16 (+6) Reserved, must be zero. fileHeaderReserved2 :: Word16 (+8) Reserved, must be zero. fileHeaderOffset :: Word32 (+10) Offset in bytes to the start of the pixel data.

Instances

Show FileHeader
Binary FileHeader

data BitmapInfo Source

A wrapper for the various image header types.

Constructors

InfoV3 BitmapInfoV3
InfoV4 BitmapInfoV4
InfoV5 BitmapInfoV5

Instances

Show BitmapInfo
Binary BitmapInfo

data BitmapInfoV3 Source

Device Independent Bitmap (DIB) header for Windows V3.

Constructors

BitmapInfoV3

Fields

dib3Size :: Word32: (+0) Size of the image header, in bytes.
dib3Width :: Word32: (+4) Width of the image, in pixels.
dib3Height :: Word32: (+8) Height of the image, in pixels.
dib3Planes :: Word16: (+12) Number of color planes.
dib3BitCount :: Word16: (+14) Number of bits per pixel.
dib3Compression :: Compression: (+16) Image compression mode.
dib3ImageSize :: Word32: (+20) Size of raw image data.
dib3PelsPerMeterX :: Word32: (+24) Prefered resolution in pixels per meter, along the X axis.
dib3PelsPerMeterY :: Word32: (+28) Prefered resolution in pixels per meter, along the Y axis.
dib3ColorsUsed :: Word32: (+32) Number of color entries that are used.
dib3ColorsImportant :: Word32: (+36) Number of significant colors.

Instances

Show BitmapInfoV3
Binary BitmapInfoV3

data BitmapInfoV4 Source

Device Independent Bitmap (DIB) header for Windows V4 (95 and newer)

Constructors

BitmapInfoV4

Fields

dib4InfoV3 :: BitmapInfoV3: Size of the image header, in bytes.
dib4RedMask :: Word32: Color masks specify components of each pixel. Only used with the bitfields compression mode.
dib4GreenMask :: Word32
dib4BlueMask :: Word32
dib4AlphaMask :: Word32
dib4ColorSpaceType :: Word32: The color space used by the image.
dib4Endpoints :: (CIEXYZ, CIEXYZ, CIEXYZ): Specifies the XYZ coords of the three colors that correspond to the RGB endpoints for the logical color space associated with the bitmap. Only used when ColorSpaceType specifies a calibrated image.
dib4GammaRed :: Word32: Toned response curves for each component. Only used when the ColorSpaceType specifies a calibrated image.
dib4GammaGreen :: Word32
dib4GammaBlue :: Word32

Instances

Show BitmapInfoV4
Binary BitmapInfoV4

data BitmapInfoV5 Source

Device Independent Bitmap (DIB) header for Windows V5 (98/2000 and newer)

Constructors

BitmapInfoV5
Fields dib5InfoV4 :: BitmapInfoV4 dib5Intent :: Word32 Rendering intent for the bitmap. dib5ProfileData :: Word32 Offset (in bytes) from the beginning of the header to the start of the profile data. dib5ProfileSize :: Word32 Size (in bytes) of embedded profile data. dib5Reserved :: Word32 Reserved, should be zero.

Instances

Show BitmapInfoV5
Binary BitmapInfoV5

data Compression Source

Constructors

CompressionRGB
CompressionRLE8
CompressionRLE4
CompressionBitFields
CompressionJPEG
CompressionPNG
CompressionUnknown Word32

Instances

Eq Compression
Show Compression
Binary Compression

data CIEXYZ Source

Contains the XYZ coordinates of a specific color in a specified color space.

Constructors

CIEXYZ Word32 Word32 Word32

Instances

Show CIEXYZ
Binary CIEXYZ

data Error Source

Things that can go wrong when loading a BMP file.

Instances

Eq Error
Show Error

readBMP :: FilePath -> IO (Either Error BMP)Source

Wrapper for hGetBMP

writeBMP :: FilePath -> BMP -> IO ()Source

Wrapper for hPutBMP

hGetBMP :: Handle -> IO (Either Error BMP)Source

Get a BMP image from a file handle. The file is checked for problems and unsupported features when read. If there is anything wrong this gives an Error instead.

hPutBMP :: Handle -> BMP -> IO ()Source

Put a BMP image to a file handle.

packRGBA32ToBMP Source

Arguments

:: Int	Width of image.
-> Int	Height of image.
-> ByteString	A string of RGBA component values. Must have length (`width * height * 4`)
-> BMP

Pack a string of RGBA component values into a BMP image. If the given dimensions don't match the input string then error. This currently ignores the alpha component of the input string and produces a 24bit RGB image.

unpackBMPToRGBA32 :: BMP -> ByteString Source

Unpack a BMP image to a string of RGBA component values.

bmpDimensions :: BMP -> (Int, Int)Source

Get the width and height of an image. It's better to use this function than to access the headers directly.

ErrorReadOfFileHeaderFailed
ErrorReadOfImageHeaderFailed
ErrorReadOfImageDataFailed
ErrorBadMagic Word16
ErrorReservedFieldNotZero
ErrorDodgyFileHeaderFieldOffset Int
ErrorDodgyFileHeaderFieldFileSize Int
ErrorFileIsTruncated
ErrorUnhandledBitmapHeaderSize Int
ErrorUnhandledPlanesCount Int
ErrorUnhandledColorDepth Int
ErrorUnhandledCompressionMode
ErrorZeroImageSize
ErrorLacksWholeNumberOfLines