Graphics.Rendering.Diagrams.Engine

The core rendering engine for Graphics.Rendering.Diagrams, an embedded domain-specific language (EDSL) for creating simple diagrams.

Preprocessing

These functions take a user-generated Diagram object and preprocess it in preparation for final rendering. The preprocessing includes calculating diagram sizes and positioning diagrams by the addition of appropriate translate annotations.

sizeAndPos :: Diagram -> (Point, Diagram)

Given a Diagram, compute its total size, and produce a new version of the Diagram with all sub-Diagrams positioned properly.

Rendering

The rendering code takes a Diagram and turns it into actual graphics output, using the Cairo library to perform the low-level drawing operations.

User interface

compose

Arguments

:: SizeSpec

output width or height

-> Diagram

Diagram to render

-> (Point, Render ())

Output width and height, and Cairo action to render it

Given a target width or height and a user-constructed Diagram, render it using the Cairo rendering library. Note that compose takes care of all the rendering details, including preprocessing of the Diagram, and scaling/translating the final output so that it fits within the given width or height. compose also produces the size of the final diagram; the width or height will be equal to that specified in the input, and the other dimension will be determined by the aspect ratio of the diagram.

The background of the output diagram will be opaque white.

In order to produce a physical output, the output of compose must be given as input to an output adapter such as writePng. Normally, however, a user of the diagrams library should not need to call compose directly.

writePNG :: String -> Point -> Render () -> IO ()

Given a rendered diagram, output it to a file in PNG format with the given width and height.

writePS :: String -> Point -> Render () -> IO ()

Given a rendered diagram, output it to a file in PostScript format with the given width and height.

writePDF :: String -> Point -> Render () -> IO ()

Given a rendered diagram, output it to a file in PDF format with the given width and height.

writeSVG :: String -> Point -> Render () -> IO ()

Given a rendered diagram, output it to a file in SVG format with the given width and height.

renderWithBackend

Arguments

:: (String -> Point -> Render () -> IO ())

backend

-> String

file name

-> SizeSpec

output size specification

-> Diagram

the diagram to render

-> IO ()

Given a file name, an output size specification, and a Diagram, use a "backend" to render the Diagram to an actual physical output.

renderOverlayPNG :: FilePath -> FilePath -> Diagram -> IO ()

chooseBackend :: OutputType -> String -> Point -> Render () -> IO ()

writePagesPS :: String -> [(Point, Render ())] -> IO ()

Given a list of rendered diagrams with their height and width, output them as separate pages to a file in PostScript format

writePagesPDF :: String -> [(Point, Render ())] -> IO ()

Given a list of rendered diagrams with their height and width, output them as separate pages to a file in DFt format

renderPagesWithBackend :: (String -> [(Point, Render ())] -> IO ()) -> String -> SizeSpec -> [Diagram] -> IO ()

Given a file name, an output size specification, and a list of Diagrams, use a "backend" to render the Diagrams as separate pages to an actual physical output.

choosePagesBackend :: OutputType -> String -> [(Point, Render ())] -> IO ()

Internals

atomic :: DiaRenderM () -> DiaRenderM ()

Perform a rendering operation atomically, by saving the state and restoring it afterwards.

render :: Diagram -> DiaRenderM ()

Render a diagram.