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{-# LANGUAGE OverloadedStrings, ViewPatterns #-}
-- | Infrastructure for parsing & desugaring text related CSS properties.
module Graphics.Layout.Inline.CSS(CSSInline(..), applyFontInline, applyBidi) where
import Data.CSS.Syntax.Tokens (Token(..))
import Stylist (PropertyParser(..))
import qualified Data.Text as Txt
import Data.Text (Text, cons, snoc)
import Data.Text.ParagraphLayout.Rich
import Data.Text.Glyphize (Direction(..))
import Graphics.Layout.CSS.Font (Font'(..), hbUnit)
import Data.Char (isSpace)
import Debug.Trace (trace) -- To report unexpected cases.
-- | Document text with Balkón styling options, CSS stylable.
data CSSInline = CSSInline Txt.Text TextOptions UnicodeBidi
-- | To what degree is the text direction isolated?
data UnicodeBidi = BdNormal | BdEmbed | BdOverride | BdIsolate
| BdIsolateOverride | BdPlainText deriving (Eq, Ord, Enum, Read, Show)
instance PropertyParser CSSInline where
temp = CSSInline "" (defaultTextOptions DirLTR) BdNormal
inherit (CSSInline _ opts _) = CSSInline "" opts BdNormal
priority _ = ["direction"] -- To inform logical spacing in caller!
longhand _ (CSSInline _ opts bidi) "content" [Ident "initial"] =
Just $ CSSInline "" opts bidi
longhand _ (CSSInline _ opts bidi) "content" toks
| all isString toks =
Just $ CSSInline (Txt.concat [x | String x <- toks]) opts bidi
where
isString (String _) = True
isString _ = False
longhand _ (CSSInline t o b) "-argo-lang" [Ident kw]
| kw `elem` ["initial", "auto"] = Just $ CSSInline t o {textLanguage=""} b
longhand _ (CSSInline txt opts bidi) "-argo-lang" [String x] =
Just $ CSSInline txt opts { textLanguage = Txt.unpack x } bidi
longhand _ (CSSInline txt opts bidi) "direction" [Ident "ltr"] =
Just $ CSSInline txt opts { textDirection = DirLTR } bidi
longhand _ (CSSInline txt opts bidi) "direction" [Ident "rtl"] =
Just $ CSSInline txt opts { textDirection = DirRTL } bidi
longhand _ (CSSInline txt opts bidi) "direction" [Ident "initial"] =
Just $ CSSInline txt opts { textDirection = DirLTR } bidi
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "initial"] =
Just $ CSSInline txt opts BdNormal
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "normal"] =
Just $ CSSInline txt opts BdNormal
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "embed"] =
Just $ CSSInline txt opts BdEmbed
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "isolate"] =
Just $ CSSInline txt opts BdIsolate
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "bidi-override"] =
Just $ CSSInline txt opts BdOverride
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "isolate-override"] =
Just $ CSSInline txt opts BdIsolateOverride
longhand _ (CSSInline txt opts _) "unicode-bidi" [Ident "plaintext"] =
Just $ CSSInline txt opts BdPlainText
longhand _ _ _ _ = Nothing
applyFontInline :: TextOptions -> Font' -> TextOptions
applyFontInline opts font = opts {
textFont = hbFont font,
textLineHeight = Absolute $ toEnum $ fromEnum $ lineheight font * hbUnit
}
-- | Apply Bidi chars around the inline text. FIXME: Handle the tree!
applyBidi :: CSSInline -> Text
applyBidi (CSSInline txt _ BdNormal) = txt
applyBidi (CSSInline txt (textDirection -> DirLTR) BdEmbed) =
chLREmbed `cons` txt `snoc` chPopDir
applyBidi (CSSInline txt (textDirection -> DirRTL) BdEmbed) =
chRLEmbed `cons` txt `snoc` chPopDir
applyBidi (CSSInline txt (textDirection -> DirLTR) BdIsolate) =
chLRIsolate `cons` txt `snoc` chPopDirIsolate
applyBidi (CSSInline txt (textDirection -> DirRTL) BdIsolate) =
chRLIsolate `cons` txt `snoc` chPopDirIsolate
applyBidi (CSSInline txt (textDirection -> DirLTR) BdOverride) =
chLROverride `cons` txt `snoc` chPopDir
applyBidi (CSSInline txt (textDirection -> DirRTL) BdOverride) =
chRLOverride `cons` txt `snoc` chPopDir
applyBidi (CSSInline txt (textDirection -> DirLTR) BdIsolateOverride) =
ch1stStrongIsolate `cons` chLROverride `cons` txt
`snoc` chPopDir `snoc` chPopDirIsolate
applyBidi (CSSInline txt (textDirection -> DirRTL) BdIsolateOverride) =
ch1stStrongIsolate `cons` chRLOverride `cons` txt
`snoc` chPopDir `snoc` chPopDirIsolate
applyBidi (CSSInline txt _ BdPlainText) =
ch1stStrongIsolate `cons` txt `snoc` chPopDirIsolate
applyBidi (CSSInline txt (textDirection -> dir) _) =
trace ("Unexpected direction! " ++ show dir) txt
chLREmbed = '\x202A'
chRLEmbed = '\x202B'
chLROverride = '\x202D'
chRLOverride = '\x202E'
chPopDir = '\x202C'
chLRIsolate = '\x2066'
chRLIsolate = '\x2067'
ch1stStrongIsolate = '\x2068'
chPopDirIsolate = '\x2069'