~alcinnz/CatTrap

ref: f68556183c80c7ae18c8c583ebcaaf7b2c151f28 CatTrap/Graphics/Layout/Inline/CSS.hs -rw-r--r-- 2.0 KiB
f6855618 — Adrian Cochrane Enforce harfbuzz scaling to be of Double type. 1 year, 8 months ago
                                                                                
f5fbeaa6 Adrian Cochrane
6099cfd9 Adrian Cochrane
f5fbeaa6 Adrian Cochrane
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{-# LANGUAGE OverloadedStrings #-}
module Graphics.Layout.Inline.CSS where

import Data.CSS.Syntax.Tokens (Token(..))
import Stylist (PropertyParser(..))
import qualified Data.Text.Lazy as Lz
import qualified Data.Text as Txt
import Data.Text.Internal (Text(..))
import Data.Text.ParagraphLayout (Span(..), SpanOptions(..), LineHeight(..),
                                Paragraph(..), ParagraphOptions(..))

import Graphics.Layout.CSS.Internal (Font'(..), hbScale)

data CSSInline = CSSInline Lz.Text SpanOptions

instance PropertyParser CSSInline where
    temp = CSSInline "" SpanOptions {
        spanLanguage = "Zxx"
    }
    inherit (CSSInline _ opts) = CSSInline "" opts

    longhand _ (CSSInline _ opts) "content" toks
        | all isString toks =
            Just $ CSSInline (Lz.concat [Lz.fromStrict x | String x <- toks]) opts
      where
        isString (String _) = True
        isString _ = False
    longhand _ (CSSInline txt opts) "-argo-lang" [String x] =
        Just $ CSSInline txt opts { spanLanguage = Txt.unpack x }
    longhand _ _ _ _ = Nothing

data ParagraphBuilder = ParagraphBuilder Lz.Text [Span]

buildParagraph :: CSSInline -> ParagraphBuilder
buildParagraph (CSSInline txt opts) = ParagraphBuilder txt [Span 0 opts]
concatParagraph :: ParagraphBuilder -> ParagraphBuilder -> ParagraphBuilder
concatParagraph (ParagraphBuilder aTxt aOpts) (ParagraphBuilder bTxt bOps) =
    ParagraphBuilder (aTxt `Lz.append` bTxt)
                    (aOpts ++ [Span (toEnum (fromEnum $ Lz.length aTxt) + off) opts
                                | Span off opts <- bOps])
finalizeParagraph :: ParagraphBuilder -> Font' -> Paragraph
finalizeParagraph (ParagraphBuilder txt ops) font' = Paragraph txt' 0 ops pOps
    where
        Text txt' _ _ = Lz.toStrict txt
        pOps = ParagraphOptions {
            paragraphFont = hbFont font',
            paragraphLineHeight = Absolute $ round (lineheight font' * hbScale font'),
            paragraphMaxWidth = 0 -- This is what we're computing!
        }