Graphics.Blank

Starting blank-canvas

blankCanvas :: Int -> (Context -> IO ()) -> IO ()

blankCanvas is the main entry point into blank-canvas. A typical invocation would be

module Main where

import Graphics.Blank

main = blankCanvas 3000 $ \ context -> do
        send context $ do
                moveTo(50,50)
                lineTo(200,100)
                lineWidth 10
                strokeStyle "red"
                stroke()

Graphics Context

data Context

Context is our abstact handle into a specific 2d-context inside a browser.

send :: Context -> Canvas a -> IO a

Sends a set of Canvas commands to the canvas. Attempts to common up as many commands as possible.

events :: Context -> IO EventQueue

Drawing pictures using the Canvas DSL

data Canvas

Instances

Monad Canvas

Functor Canvas

Applicative Canvas

arc :: (Float, Float, Float, Float, Float, Bool) -> Canvas ()

beginPath :: () -> Canvas ()

bezierCurveTo :: (Float, Float, Float, Float, Float, Float) -> Canvas ()

clearRect :: (Float, Float, Float, Float) -> Canvas ()

closePath :: () -> Canvas ()

fill :: () -> Canvas ()

fillRect :: (Float, Float, Float, Float) -> Canvas ()

fillStyle :: String -> Canvas ()

fillText :: (String, Float, Float) -> Canvas ()

font :: String -> Canvas ()

globalAlpha :: Float -> Canvas ()

lineCap :: String -> Canvas ()

lineJoin :: String -> Canvas ()

lineTo :: (Float, Float) -> Canvas ()

lineWidth :: Float -> Canvas ()

miterLimit :: Float -> Canvas ()

moveTo :: (Float, Float) -> Canvas ()

restore :: () -> Canvas ()

rotate :: Float -> Canvas ()

scale :: (Float, Float) -> Canvas ()

save :: () -> Canvas ()

stroke :: () -> Canvas ()

strokeRect :: (Float, Float, Float, Float) -> Canvas ()

strokeText :: (String, Float, Float) -> Canvas ()

strokeStyle :: String -> Canvas ()

textAlign :: String -> Canvas ()

textBaseline :: String -> Canvas ()

transform :: (Float, Float, Float, Float, Float, Float) -> Canvas ()

translate :: (Float, Float) -> Canvas ()

readEvent :: EventName -> Canvas Event

read a specific event; wait for it if the event is not in queue. **Thows away all other events while waiting.**

readEvents :: [EventName] -> Canvas NamedEvent

read a specific set of events; wait for it if the event/events is not in queue. **Throws away all other non-named events while waiting.**

tryReadEvent :: EventName -> Canvas (Maybe Event)

read a specific event. **Throws away all events not named**

tryReadEvents :: [EventName] -> Canvas (Maybe NamedEvent)

read a specific set of events. **Throws away all non-named events while waiting.**

size :: Canvas (Float, Float)

size of the canvas

Events

data Event

Basic Event from Browser, the code is event-type specific.

Constructors

Event

Fields

jsCode :: Int

jsMouse :: Maybe (Int, Int)

Instances

Show Event

data EventName

EventName mirrors event names from jquery, where 'map toLower (show name)' gives the jquery event name.

Constructors

KeyPress

KeyDown

KeyUp

MouseDown

MouseEnter

MouseMove

MouseOut

MouseOver

MouseUp

Instances

Bounded EventName

Enum EventName

Eq EventName

Ord EventName

Show EventName

data NamedEvent

When an event is sent to the application, it always has a name.

Constructors

NamedEvent EventName Event

Instances

Show NamedEvent

FromJSON NamedEvent

type EventQueue = TChan NamedEvent

EventQueue is a STM channel (TChan) of Events. Intentionally, EventQueue is not abstract.

readEventQueue :: EventQueue -> IO NamedEvent

tryReadEventQueue :: EventQueue -> IO (Maybe NamedEvent)