bmp-1.2.6.3: Read and write uncompressed BMP image files.

Safe HaskellNone
LanguageHaskell98

Codec.BMP

Contents

Description

Reading and writing uncompressed BMP files.

Supports uncompressed 24bit RGB and 32bit RGBA WindowsV3, WindowsV4 and WindowsV5 formats.

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
   ... 

Release Notes:

 * bmp 1.2.5
   Add support for writing uncompressed 32-bit files.

 * bmp 1.2.4
   Update to use binary 0.6.

 * bmp 1.2.3
   Add pure parseBMP / renderBMP API.

 * bmp 1.2.2
   Allow the physical image buffer to be larger than the image
    size stated in the header, to accept output of foolish Win7 codec.

Synopsis

Data Structures

data BMP #

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.

Instances

Show BMP # 

Methods

showsPrec :: Int -> BMP -> ShowS #

show :: BMP -> String #

showList :: [BMP] -> ShowS #

data FileHeader #

BMP file header.

Constructors

FileHeader 

Fields

data BitmapInfo #

A wrapper for the various image header types.

data BitmapInfoV3 #

Device Independent Bitmap (DIB) header for Windows V3.

Constructors

BitmapInfoV3 

Fields

data BitmapInfoV4 #

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

Constructors

BitmapInfoV4 

Fields

data BitmapInfoV5 #

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

Constructors

BitmapInfoV5 

Fields

data CIEXYZ #

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

Constructors

CIEXYZ Word32 Word32 Word32 

Instances

data Error #

Things that can go wrong when loading a BMP file.

Constructors

ErrorBadMagic

Magic number was not at the start of the file, so this probably isn't a BMP file.

Fields

ErrorFileHeaderTruncated

File is too short to contain a file header.

ErrorImageHeaderTruncated

File is too short to contain an image header.

ErrorImageDataTruncated

File is too short to contain the image data.

ErrorReservedFieldNotZero

Reserved fields should be zero.

ErrorDodgyFileHeaderFieldOffset

The offset to the image data from the file header doesn't point anywhere sensible.

ErrorUnhandledBitmapHeaderSize

We handle V3 V4 and V5 image headers, but the size of the header indicates it has some other format.

ErrorUnhandledPlanesCount

We only handle single color planes.

ErrorUnhandledColorDepth

We only handle 24 and 32 bit images.

ErrorUnhandledCompressionMode

We only handle uncompressed images.

ErrorImagePhysicalSizeMismatch

Mismatch between the image size stated in the header and that which is calculuated from the other fields.

ErrorInternalErrorPleaseReport

Something went wrong in the library.

Instances

Eq Error # 

Methods

(==) :: Error -> Error -> Bool #

(/=) :: Error -> Error -> Bool #

Show Error # 

Methods

showsPrec :: Int -> Error -> ShowS #

show :: Error -> String #

showList :: [Error] -> ShowS #

Reading

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

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

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

Get a BMP image from a file handle.

parseBMP :: ByteString -> Either Error BMP #

Parse a BMP image from a lazy ByteString

Writing

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

Wrapper for hPutBMP

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

Put a BMP image to a file handle.

renderBMP :: BMP -> ByteString #

Render a BMP image to a lazy ByteString.

Pack and Unpack

packRGBA32ToBMP #

Arguments

:: Int

Width of image (must be positive).

-> Int

Height of image (must be positive).

-> ByteString

A string of RGBA component values. Must have length (width * height * 4)

-> BMP 

Pack a string of RGBA component values into a 32-bit BMP image.

Alias for packRGBA32ToBMP32.

packRGBA32ToBMP32 #

Arguments

:: Int

Width of image (must be positive).

-> Int

Height of image (must be positive).

-> ByteString

A string of RGBA component values. Must have length (width * height * 4)

-> BMP 

Pack a string of RGBA component values into a 32-bit BMP image.

  • If the given dimensions don't match the input string then error.
  • If the width or height fields are negative then error.

packRGBA32ToBMP24 #

Arguments

:: Int

Width of image (must be positive).

-> Int

Height of image (must be positive).

-> ByteString

A string of RGBA component values. Must have length (width * height * 4)

-> BMP 

Pack a string of RGBA component values into a 24-bit BMP image, discarding the alpha channel of the source data.

  • If the given dimensions don't match the input string then error.
  • If the width or height fields are negative then error.

unpackBMPToRGBA32 :: BMP -> ByteString #

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

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

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