gd-3000.3.0: A Haskell binding to a subset of the GD graphics library Contents Index

Graphics.GD

Contents Types Creating and copying images Memory management Loading images JPEG PNG GIF Saving images JPEG PNG GIF Getting image information 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) 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 :: String -> Double -> Double -> Point -> String -> Color -> Image -> IO (Point, Point, Point, Point) measureString :: String -> Double -> Double -> Point -> String -> Color -> IO (Point, Point, Point, Point) drawStringCircle :: Point -> Double -> Double -> Double -> String -> Double -> String -> String -> Color -> Image -> IO () rgb :: Int -> Int -> Int -> Color rgba :: Int -> Int -> Int -> Int -> Color

Types

data Image

type Size = (Int, Int)

type Point = (Int, Int)

type Color = CInt

Creating and copying images

newImage :: Size -> IO Image

Create a new empty image.

copyImage :: Image -> IO Image

Make a copy of an image.

copyRegion

:: 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

:: 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

:: 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

Load a JPEG image from a file.

loadJpegData

:: Int Buffer size. -> Ptr a Buffer with image data. -> IO Image Load a JPEG image from a buffer.

loadJpegByteString :: ByteString -> IO Image

Load a JPEG image from a ByteString

PNG

loadPngFile :: FilePath -> IO Image

Load a PNG image from a file.

loadPngData

:: Int Buffer size. -> Ptr a Buffer with image data. -> IO Image Load a PNG image from a buffer.

loadPngByteString :: ByteString -> IO Image

Load a PNG image from a ByteString

GIF

loadGifFile :: FilePath -> IO Image

Load a GIF image from a file.

loadGifData

:: Int Buffer size. -> Ptr a Buffer with image data. -> IO Image Load a GIF image from a buffer.

loadGifByteString :: ByteString -> IO Image

Load a GIF image from a ByteString

Saving images

JPEG

saveJpegFile

:: Int quality: 0-95, or negative for default quality. -> FilePath -> Image -> IO () Save an image as a JPEG file.

saveJpegByteString :: Int -> Image -> IO ByteString

Write a JPEG format ByteString of an image.

PNG

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

Save an image as a PNG file.

savePngByteString :: Image -> IO ByteString

Write a PNG format ByteString of an image.

GIF

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

Save an image as a GIF file.

saveGifByteString :: Image -> IO ByteString

Write a GIF format ByteString of an image.

Getting image information

imageSize

:: Image -> IO (Int, Int) (width, height) Get the size of an image.

Manipulating images

resizeImage

:: 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

:: 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 ()

Fill the entire image with the given color.

drawFilledRectangle

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

drawFilledEllipse

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

drawLine

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

drawArc

:: 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

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

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

Text

useFontConfig :: Bool -> IO Bool

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

drawString

:: String Font name -> Double Font point size -> Double Angle in counterclockwise radians -> Point Origin -> String 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

:: String Font name -> Double Font point size -> Double Angle in counterclockwise radians -> Point Origin -> String 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

:: 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 -> String Font name -> Double Font size hint -> String Text to write on the top of the circle -> String 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

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

rgba

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

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