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vty/src/Graphics/Vty.hs
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1-- Copyright 2009 Corey O'Connor
2{-# LANGUAGE ForeignFunctionInterface, BangPatterns, UnboxedTuples #-}
3{-# CFILES gwinsz.c #-}
5-- Good sources of documentation for terminal programming are:
6-- vt100 control sequences: http://vt100.net/docs/vt100-ug/chapter3.html#S3.3.3
7-- Xterm control sequences: http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
9module Graphics.Vty ( Vty(..)
10 , mkVty
11 , mkVtyEscDelay
12 , module Graphics.Vty.Terminal
13 , module Graphics.Vty.Picture
14 , module Graphics.Vty.DisplayRegion
15 , Key(..)
16 , Modifier(..)
17 , Button(..)
18 , Event(..)
19 )
20 where
23import Graphics.Vty.Terminal
24import Graphics.Vty.Picture
25import Graphics.Vty.DisplayRegion
26import Graphics.Vty.LLInput
28import Data.IORef
30import Data.Maybe ( maybe )
32import qualified System.Console.Terminfo as Terminfo
33import System.IO
35-- | The main object. At most one should be created.
36-- An alternative is to use unsafePerformIO to automatically create a singleton Vty instance when
37-- required.
38--
39-- This does not assure any thread safety. In theory, as long as an update action is not executed
40-- when another update action is already then it's safe to call this on multiple threads.
41--
42-- todo: Once the Terminal interface encompasses input this interface will be deprecated.
43-- Currently, just using the Terminal interface there is no support for input events.
44data Vty = Vty
45 { -- | Outputs the given Picture. Equivalent to output_picture applied to a display context
46 -- implicitly managed by Vty.
47 update :: Picture -> IO ()
48 -- | Get one Event object, blocking if necessary.
49 , next_event :: IO Event
50 -- | Handle to the terminal interface. See `Terminal`
51 --
52 -- The use of Vty typically follows this process:
53 --
54 -- 0. initialize vty
55 --
56 -- 1. use the update equation of Vty to display a picture
57 --
58 -- 2. repeat
59 --
60 -- 3. shutdown vty.
61 --
62 -- todo: provide a similar abstraction to Graphics.Vty.Terminal for input. Use haskeline's
63 -- input backend for implementation.
64 --
65 -- todo: remove explicit `shutdown` requirement.
66 , terminal :: TerminalHandle
67 -- | Refresh the display. Normally the library takes care of refreshing. Nonetheless, some
68 -- other program might output to the terminal and mess the display. In that case the user
69 -- might want to force a refresh.
70 , refresh :: IO ()
71 -- | Clean up after vty.
72 , shutdown :: IO ()
73 }
75-- | Set up the state object for using vty. At most one state object should be
76-- created at a time.
77mkVty :: IO Vty
78mkVty = mkVtyEscDelay 0
80mkVtyEscDelay :: Int -> IO Vty
81mkVtyEscDelay escDelay = do
82 term_info <- Terminfo.setupTermFromEnv
83 t <- terminal_handle
84 reserve_display t
85 (kvar, endi) <- initTermInput escDelay term_info
86 intMkVty kvar ( endi >> release_display t >> release_terminal t ) t
88intMkVty :: IO Event -> IO () -> TerminalHandle -> IO Vty
89intMkVty kvar fend t = do
90 last_pic_ref <- newIORef undefined
91 last_update_ref <- newIORef Nothing
93 let inner_update in_pic = do
94 b <- display_bounds t
95 mlast_update <- readIORef last_update_ref
96 update_data <- case mlast_update of
97 Nothing -> do
98 d <- display_context t b
99 output_picture d in_pic
100 return (b, d)
101 Just (last_bounds, last_context) -> do
102 if b /= last_bounds
103 then do
104 d <- display_context t b
105 output_picture d in_pic
106 return (b, d)
107 else do
108 output_picture last_context in_pic
109 return (b, last_context)
110 writeIORef last_update_ref $ Just update_data
111 writeIORef last_pic_ref $ Just in_pic
113 let inner_refresh
114 = writeIORef last_update_ref Nothing
115 >> readIORef last_pic_ref
116 >>= maybe ( return () ) ( \pic -> inner_update pic )
118 let gkey = do k <- kvar
119 case k of
120 (EvResize _ _) -> inner_refresh
121 >> display_bounds t
122 >>= return . ( \(DisplayRegion w h)
123 -> EvResize (fromEnum w) (fromEnum h)
124 )
125 _ -> return k
127 return $ Vty { update = inner_update
128 , next_event = gkey
129 , terminal = t
130 , refresh = inner_refresh
131 , shutdown = fend
132 }