Safe Haskell	Safe-Inferred
Language	Haskell98

Graphics.GD.ByteString.Lazy

Contents

Types
Creating and copying images
Memory management
Loading images
- JPEG
- PNG
- GIF
Saving images
- JPEG
- PNG
- GIF
Getting image information
Querying
Manipulating images
Drawing
Text
Colors

Synopsis

data Image
type Size = (Int, Int)
type Point = (Int, Int)
type Color = CInt
newImage :: Size -> IO Image
copyImage :: Image -> IO Image
copyRegion :: Point -> Size -> Image -> Point -> Image -> IO ()
copyRegionScaled :: Point -> Size -> Image -> Point -> Size -> Image -> IO ()
withImage :: IO Image -> (Image -> IO b) -> IO b
loadJpegFile :: FilePath -> IO Image
loadJpegData :: Int -> Ptr a -> IO Image
loadJpegByteString :: ByteString -> IO Image
loadPngFile :: FilePath -> IO Image
loadPngData :: Int -> Ptr a -> IO Image
loadPngByteString :: ByteString -> IO Image
loadGifFile :: FilePath -> IO Image
loadGifData :: Int -> Ptr a -> IO Image
loadGifByteString :: ByteString -> IO Image
saveJpegFile :: Int -> FilePath -> Image -> IO ()
saveJpegByteString :: Int -> Image -> IO ByteString
savePngFile :: FilePath -> Image -> IO ()
savePngByteString :: Image -> IO ByteString
saveGifFile :: FilePath -> Image -> IO ()
saveGifByteString :: Image -> IO ByteString
imageSize :: Image -> IO (Int, Int)
getPixel :: (Int, Int) -> Image -> IO Color
resizeImage :: Int -> Int -> Image -> IO Image
rotateImage :: Int -> Image -> IO Image
fillImage :: Color -> Image -> IO ()
drawFilledRectangle :: Point -> Point -> Color -> Image -> IO ()
drawFilledEllipse :: Point -> Size -> Color -> Image -> IO ()
drawLine :: Point -> Point -> Color -> Image -> IO ()
drawArc :: Point -> Size -> Int -> Int -> Color -> Image -> IO ()
antiAliased :: (Color -> Image -> IO a) -> Color -> Image -> IO a
setPixel :: Point -> Color -> Image -> IO ()
useFontConfig :: Bool -> IO Bool
drawString :: ByteString -> Double -> Double -> Point -> ByteString -> Color -> Image -> IO (Point, Point, Point, Point)
measureString :: ByteString -> Double -> Double -> Point -> ByteString -> Color -> IO (Point, Point, Point, Point)
drawStringCircle :: Point -> Double -> Double -> Double -> ByteString -> Double -> ByteString -> ByteString -> Color -> Image -> IO ()
rgb :: Int -> Int -> Int -> Color
rgba :: Int -> Int -> Int -> Int -> Color
toRGBA :: Color -> (Int, Int, Int, Int)

Types

data Image Source #

type Size = (Int, Int) Source #

type Point = (Int, Int) Source #

type Color = CInt Source #

Creating and copying images

newImage :: Size -> IO Image Source #

Create a new empty image.

copyImage :: Image -> IO Image Source #

Make a copy of an image.

copyRegion Source #

Arguments

:: Point	Source upper left-hand corner
-> Size	Size of copied region
-> Image	Source image
-> Point	Destination upper left-hand corner
-> Image	Destination image
-> IO ()

Copy a region of one image into another

copyRegionScaled Source #

Arguments

:: Point	Source upper left-hand corner
-> Size	Size of source region
-> Image	Source image
-> Point	Destination upper left-hand corner
-> Size	Size of destination region
-> Image	Destination image
-> IO ()

Copy a region of one image into another, rescaling the region

Memory management

withImage Source #

Arguments

:: IO Image	Image creation action.
-> (Image -> IO b)	Some operation on the image. The result should not reference the `Image`.
-> IO b

Creates an image, performs an operation on the image, and frees it. This function allows block scoped management of Image objects. If you are handling large images, the delay before the finalizer which frees the image runs may cause significant temporary extra memory use. Use this function to force the image to be freed as soons as you are done with it. Note that it is unsafe to hold on to the Image after the function is done.

Loading images

JPEG

loadJpegFile :: FilePath -> IO Image Source #

Load a JPEG image from a file.

loadJpegData Source #

Arguments

:: Int	Buffer size.
-> Ptr a	Buffer with image data.
-> IO Image

Load a JPEG image from a buffer.

loadJpegByteString :: ByteString -> IO Image Source #

Load a JPEG image from a ByteString

PNG

loadPngFile :: FilePath -> IO Image Source #

Load a PNG image from a file.

loadPngData Source #

Arguments

:: Int	Buffer size.
-> Ptr a	Buffer with image data.
-> IO Image

Load a PNG image from a buffer.

loadPngByteString :: ByteString -> IO Image Source #

Load a PNG image from a ByteString

GIF

loadGifFile :: FilePath -> IO Image Source #

Load a GIF image from a file.

loadGifData Source #

Arguments

:: Int	Buffer size.
-> Ptr a	Buffer with image data.
-> IO Image

Load a GIF image from a buffer.

loadGifByteString :: ByteString -> IO Image Source #

Load a GIF image from a ByteString

Saving images

JPEG

saveJpegFile Source #

Arguments

:: Int	quality: 0-95, or negative for default quality.
-> FilePath
-> Image
-> IO ()

Save an image as a JPEG file.

saveJpegByteString :: Int -> Image -> IO ByteString Source #

Write a JPEG format ByteString of an image.

PNG

savePngFile :: FilePath -> Image -> IO () Source #

Save an image as a PNG file.

savePngByteString :: Image -> IO ByteString Source #

Write a PNG format ByteString of an image.

GIF

saveGifFile :: FilePath -> Image -> IO () Source #

Save an image as a GIF file.

saveGifByteString :: Image -> IO ByteString Source #

Write a GIF format ByteString of an image.

Getting image information

imageSize Source #

Arguments

:: Image
-> IO (Int, Int)	(width, height)

Get the size of an image.

Querying

getPixel :: (Int, Int) -> Image -> IO Color Source #

Retrieves the color index or the color values of a particular pixel.

Manipulating images

resizeImage Source #

Arguments

:: Int	width in pixels of output image
-> Int	height in pixels of output image
-> Image
-> IO Image

Resize an image to a give size.

rotateImage Source #

Arguments

:: Int	1 for 90 degrees counter-clockwise, 2 for 180 degrees, etc.
-> Image
-> IO Image

Rotate an image by a multiple of 90 degrees counter-clockwise.

Drawing

fillImage :: Color -> Image -> IO () Source #

Fill the entire image with the given color.

drawFilledRectangle Source #

Arguments

:: Point	Upper left corner
-> Point	Lower right corner
-> Color
-> Image
-> IO ()

drawFilledEllipse Source #

Arguments

:: Point	Center
-> Size	Width and height
-> Color
-> Image
-> IO ()

drawLine Source #

Arguments

:: Point	Start
-> Point	End
-> Color
-> Image
-> IO ()

drawArc Source #

Arguments

:: Point	Center
-> Size	Width and height
-> Int	Starting position (degrees)
-> Int	Ending position (degrees)
-> Color
-> Image
-> IO ()

antiAliased :: (Color -> Image -> IO a) -> Color -> Image -> IO a Source #

Use anti-aliasing when performing the given drawing function. This can cause a segault with some gd versions.

setPixel :: Point -> Color -> Image -> IO () Source #

Text

useFontConfig :: Bool -> IO Bool Source #

Globally switch from using font file names to fontconfig paths | for fonts in drawString (and measureString).

drawString Source #

Arguments

:: ByteString	Font name
-> Double	Font point size
-> Double	Angle in counterclockwise radians
-> Point	Origin
-> ByteString	Text, including HTML entities
-> Color
-> Image
-> IO (Point, Point, Point, Point)	Bounding box of the drawn text

Draw a string using the FreeType 2.x library

measureString Source #

Arguments

:: ByteString	Font name
-> Double	Font point size
-> Double	Angle in counterclockwise radians
-> Point	Origin
-> ByteString	Text, including HTML entities
-> Color
-> IO (Point, Point, Point, Point)	Bounding box of the drawn text

Measure a string using the FreeType 2.x library. This computes the bounding box but does not actually draw the string to any image.

drawStringCircle Source #

Arguments

:: Point	Center of text path circle
-> Double	Outer radius of text
-> Double	Fraction of radius occupied by text
-> Double	Portion of circle arc filled by text
-> ByteString	Font name
-> Double	Font size hint
-> ByteString	Text to write on the top of the circle
-> ByteString	Text to write on the bottom of the circle
-> Color	Text color
-> Image
-> IO ()

Draw strings around the top and bottom of a torus

Colors

rgb Source #

Arguments

:: Int	Red (0-255)
-> Int	Green (0-255)
-> Int	Blue (0-255)
-> Color

rgba Source #

Arguments

:: Int	Red (0-255)
-> Int	Green (0-255)
-> Int	Blue (0-255)
-> Int	Alpha (0-127), 0 is opaque, 127 is transparent
-> Color

toRGBA :: Color -> (Int, Int, Int, Int) Source #