src/Graphics/Vty/Picture.hs · vty

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vty/src/Graphics/Vty/Picture.hs

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2module Graphics.Vty.Picture ( module Graphics.Vty.Picture

3 , Image

4 , image_width

5 , image_height

6 , (<|>)

7 , (<->)

8 , horiz_cat

9 , vert_cat

10 , background_fill

11 , char

12 , string

13 , iso_10646_string

14 , utf8_string

15 , utf8_bytestring

16 , char_fill

17 , empty_image

18 , translate

19 -- | The possible display attributes used in constructing an `Image`.

20 , module Graphics.Vty.Attributes

21 )

22 where

24import Graphics.Vty.Attributes

25import Graphics.Vty.Image hiding ( attr )

27import Data.Word

29-- |The type of images to be displayed using 'update'.

30-- Can be constructed directly or using `pic_for_image`. Which provides an initial instance with

31-- reasonable defaults for pic_cursor and pic_background.

32data Picture = Picture

33 { pic_cursor :: Cursor

34 , pic_image :: Image

35 , pic_background :: Background

36 }

38-- | Create a picture for display for the given image. The picture will not have a displayed cursor

39-- and the background display attribute will be `current_attr`.

40pic_for_image :: Image -> Picture

41pic_for_image i = Picture

42 { pic_cursor = NoCursor

43 , pic_image = i

44 , pic_background = Background ' ' current_attr

45 }

47-- | A picture can be configured either to not show the cursor or show the cursor at the specified

48-- character position.

49--

50-- There is not a 1 to 1 map from character positions to a row and column on the screen due to

51-- characters that take more than 1 column.

52--

53-- todo: The Cursor can be given a (character,row) offset outside of the visible bounds of the

54-- output region. In this case the cursor will not be shown.

55data Cursor =

56 NoCursor

57 | Cursor Word Word

59-- | Unspecified regions are filled with the picture's background pattern. The background pattern

60-- can specify a character and a display attribute. If the display attribute used previously should

61-- be used for a background fill then use `current_attr` for the background attribute. This is the

62-- default background display attribute.

63--

64-- (tofix) The current attribute is always set to the default attributes at the start of updating the

65-- screen to a picture.

66--

67-- (tofix) The background character *must* occupy a single column and no more.

68data Background = Background

69 { background_char :: Char

70 , background_attr :: Attr

71 }