Graphics.Vty.Output.Interface

Documentation

data Mode

Modal terminal features that can be enabled and disabled.

Constructors

Mouse

BracketedPaste

Instances

Eq Mode

Methods

(==) :: Mode -> Mode -> Bool

(/=) :: Mode -> Mode -> Bool

Read Mode

Methods

readsPrec :: Int -> ReadS Mode

readList :: ReadS [Mode]

readPrec :: ReadPrec Mode

readListPrec :: ReadPrec [Mode]

Show Mode

Methods

showsPrec :: Int -> Mode -> ShowS

show :: Mode -> String

showList :: [Mode] -> ShowS

data Output

Constructors

Output

Fields

• terminalID :: String

  Text identifier for the output device. Used for debugging.

• releaseTerminal :: forall m. MonadIO m => m ()
• reserveDisplay :: forall m. MonadIO m => m ()

  Clear the display and initialize the terminal to some initial display state.

  The expectation of a program is that the display starts in some initial state. The initial state would consist of fixed values:

  • cursor at top left
  • UTF-8 character encoding
  • drawing characteristics are the default

  The abstract operation I think all these behaviors are instances of is reserving exclusive access to a display such that:

  • The previous state cannot be determined
  • When exclusive access to a display is released the display returns to the previous state.
• releaseDisplay :: forall m. MonadIO m => m ()

  Return the display to the state before reserveDisplay If no previous state then set the display state to the initial state.

• displayBounds :: forall m. MonadIO m => m DisplayRegion

  Returns the current display bounds.

• outputByteBuffer :: ByteString -> IO ()

  Output the byte string to the terminal device.

• contextColorCount :: Int

  Maximum number of colors supported by the context.

• supportsCursorVisibility :: Bool

  if the cursor can be shown / hidden

• supportsMode :: Mode -> Bool

  Indicates support for terminal modes for this output device

• setMode :: forall m. MonadIO m => Mode -> Bool -> m ()

  Enables or disables a mode (does nothing if the mode is unsupported)

• getModeStatus :: forall m. MonadIO m => Mode -> m Bool

  Returns whether a mode is enabled

• assumedStateRef :: IORef AssumedState
• mkDisplayContext :: forall m. MonadIO m => Output -> DisplayRegion -> m DisplayContext

  Acquire display access to the given region of the display. Currently all regions have the upper left corner of (0,0) and the lower right corner at (max displayWidth providedWidth, max displayHeight providedHeight)

• ringTerminalBell :: forall m. MonadIO m => m ()

  Ring the terminal bell if supported.

• supportsBell :: forall m. MonadIO m => m Bool

  Returns whether the terminal has an audio bell feature.

displayContext :: MonadIO m => Output -> DisplayRegion -> m DisplayContext

data AssumedState

Constructors

AssumedState

Fields

• prevFattr :: Maybe FixedAttr
• prevOutputOps :: Maybe DisplayOps

initialAssumedState :: AssumedState

data DisplayContext

Constructors

DisplayContext

Fields

• contextDevice :: Output
• contextRegion :: DisplayRegion

  Provide the bounds of the display context.

• writeMoveCursor :: Int -> Int -> Write
• writeShowCursor :: Write
• writeHideCursor :: Write
• writeSetAttr :: FixedAttr -> Attr -> DisplayAttrDiff -> Write
• writeDefaultAttr :: Write

  Reset the display attributes to the default display attributes

• writeRowEnd :: Write
• inlineHack :: IO ()

  See inlineHack

writeUtf8Text :: ByteString -> Write

All terminals serialize UTF8 text to the terminal device exactly as serialized in memory.

outputPicture :: MonadIO m => DisplayContext -> Picture -> m ()

Displays the given Picture.

1. The image is cropped to the display size.
2. Converted into a sequence of attribute changes and text spans.
3. The cursor is hidden.
4. Serialized to the display.
5. The cursor is then shown and positioned or kept hidden.

todo: specify possible IO exceptions. abstract from IO monad to a MonadIO instance.

writeOutputOps :: DisplayContext -> FixedAttr -> [Bool] -> DisplayOps -> Write

writeSpanOps :: DisplayContext -> Int -> FixedAttr -> SpanOps -> Write

writeSpanOp :: DisplayContext -> SpanOp -> FixedAttr -> (Write, FixedAttr)

data CursorOutputMap

The cursor position is given in X,Y character offsets. Due to multi-column characters this needs to be translated to column, row positions.

Constructors

CursorOutputMap

Fields

• charToOutputPos :: (Int, Int) -> (Int, Int)

cursorOutputMap :: DisplayOps -> Cursor -> CursorOutputMap

cursorColumnOffset :: DisplayOps -> Int -> Int -> Int

limitAttrForDisplay :: Output -> Attr -> Attr

Not all terminals support all display attributes. This filters a display attribute to what the given terminal can display.