gd-3000.7.3: A Haskell binding to a subset of the GD graphics library

Safe HaskellSafe-Infered

Graphics.GD.ByteString

Contents

Synopsis

Types

type Size = (Int, Int)Source

type Point = (Int, Int)Source

Creating and copying images

newImage :: Size -> IO ImageSource

Create a new empty image.

copyImage :: Image -> IO ImageSource

Make a copy of an image.

copyRegionSource

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

copyRegionScaledSource

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

withImageSource

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 ImageSource

Load a JPEG image from a file.

loadJpegDataSource

Arguments

:: Int

Buffer size.

-> Ptr a

Buffer with image data.

-> IO Image 

Load a JPEG image from a buffer.

loadJpegByteString :: ByteString -> IO ImageSource

Load a JPEG image from a ByteString

PNG

loadPngFile :: FilePath -> IO ImageSource

Load a PNG image from a file.

loadPngDataSource

Arguments

:: Int

Buffer size.

-> Ptr a

Buffer with image data.

-> IO Image 

Load a PNG image from a buffer.

loadPngByteString :: ByteString -> IO ImageSource

Load a PNG image from a ByteString

GIF

loadGifFile :: FilePath -> IO ImageSource

Load a GIF image from a file.

loadGifDataSource

Arguments

:: Int

Buffer size.

-> Ptr a

Buffer with image data.

-> IO Image 

Load a GIF image from a buffer.

loadGifByteString :: ByteString -> IO ImageSource

Load a GIF image from a ByteString

Saving images

JPEG

saveJpegFileSource

Arguments

:: Int

quality: 0-95, or negative for default quality.

-> FilePath 
-> Image 
-> IO () 

Save an image as a JPEG file.

saveJpegByteString :: Int -> Image -> IO ByteStringSource

Write a JPEG format ByteString of an image.

PNG

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

Save an image as a PNG file.

savePngByteString :: Image -> IO ByteStringSource

Write a PNG format ByteString of an image.

GIF

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

Save an image as a GIF file.

saveGifByteString :: Image -> IO ByteStringSource

Write a GIF format ByteString of an image.

Getting image information

imageSizeSource

Arguments

:: Image 
-> IO (Int, Int)

(width, height)

Get the size of an image.

Querying

getPixel :: (Int, Int) -> Image -> IO ColorSource

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

Manipulating images

resizeImageSource

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.

rotateImageSource

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.

drawFilledRectangleSource

Arguments

:: Point

Upper left corner

-> Point

Lower right corner

-> Color 
-> Image 
-> IO () 

drawFilledEllipseSource

Arguments

:: Point

Center

-> Size

Width and height

-> Color 
-> Image 
-> IO () 

drawLineSource

Arguments

:: Point

Start

-> Point

End

-> Color 
-> Image 
-> IO () 

drawArcSource

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 aSource

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

Text

useFontConfig :: Bool -> IO BoolSource

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

drawStringSource

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

measureStringSource

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.

drawStringCircleSource

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

rgbSource

Arguments

:: Int

Red (0-255)

-> Int

Green (0-255)

-> Int

Blue (0-255)

-> Color 

rgbaSource

Arguments

:: Int

Red (0-255)

-> Int

Green (0-255)

-> Int

Blue (0-255)

-> Int

Alpha (0-127), 0 is opaque, 127 is transparent

-> Color