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module Data.Text.ParagraphLayout.Internal.Rich.ParagraphLayout
( ParagraphLayout (..)
, appendContents
, emptyParagraphLayout
, filterLine
, paragraphOriginX
, paragraphOriginY
, paragraphSafeWidth
, shapedRuns
, shiftContents
, topDistance
)
where
import Data.Int (Int32)
import Data.Text.ParagraphLayout.Internal.Fragment
import Data.Text.ParagraphLayout.Internal.Line
import Data.Text.ParagraphLayout.Internal.LineNumbers
import Data.Text.ParagraphLayout.Internal.LinePagination
import Data.Text.ParagraphLayout.Internal.ParagraphExtents
import Data.Text.ParagraphLayout.Internal.Rect
-- | The resulting layout of the whole paragraph.
data ParagraphLayout d = ParagraphLayout
{ paragraphRect :: Rect Int32
-- ^ The containing block (CSS3).
, paragraphLines :: [Line]
-- ^ Information about line boxes (CSS).
-- May describe additional empty space around text fragments.
, paragraphFragments :: [Fragment d]
-- ^ The resulting layout of all input text, divided into fragments as
-- required by the input structure, line breaking, text writing direction,
-- and changes of script.
}
deriving (Eq, Read, Show)
instance LineNumbers (ParagraphLayout d) where
lineNumbersWithDuplication pl = map fragmentLine $ paragraphFragments pl
instance LineHeight (ParagraphLayout d) where
lineHeight pl = height $ paragraphRect pl
-- | A `ParagraphLayout` with no fragments and no lines.
-- Useful as an identity element for `appendContents`.
emptyParagraphLayout :: ParagraphLayout a
emptyParagraphLayout = ParagraphLayout emptyRect [] []
-- | Distance from the paragraph origin to its topmost line.
topDistance :: ParagraphLayout d -> Int32
topDistance pl = case paragraphLines pl of
[] -> 0
ls -> maximum $ map (y_origin . lineRect) ls
-- | Keep the line with the given number and its fragments,
-- and remove everything else.
filterLine :: Int -> ParagraphLayout d -> ParagraphLayout d
filterLine num (ParagraphLayout _ ls frags) =
ParagraphLayout pRect' ls' frags'
where
pRect' = containRects $ map lineRect ls
ls' = filter ((== num) . lineNumber) ls
frags' = filter ((== num) . fragmentLine) frags
-- | Add @dx@ and @dy@ to the origins of each line and fragment,
-- effectively shifting the whole paragraph by the given amount.
shiftContents :: Int32 -> Int32 -> ParagraphLayout d -> ParagraphLayout d
shiftContents dx dy (ParagraphLayout _ ls frags) =
ParagraphLayout pRect' ls' frags'
where
pRect' = containRects $ map lineRect ls
ls' = map (shiftLine dx dy) ls
frags' = map (shiftFragment dx dy) frags
-- | Combine fragments from two `ParagraphLayout`s.
appendContents :: ParagraphLayout d -> ParagraphLayout d -> ParagraphLayout d
appendContents (ParagraphLayout _ ls1 frags1) (ParagraphLayout _ ls2 frags2) =
ParagraphLayout pRect ls frags
where
pRect = containRects $ map lineRect ls
ls = ls1 ++ ls2
frags = frags1 ++ frags2
-- | Return all shaped runs in the paragraph.
shapedRuns :: ParagraphLayout d -> [ShapedRun]
shapedRuns pl = map shapedRun $ paragraphFragments pl
-- | Width of the widest line, including spacing.
--
-- This is the smallest `Data.Text.ParagraphLayout.Rich.paragraphMaxWidth`
-- that will not introduce new line breaks.
--
-- When `Data.Text.ParagraphLayout.Rich.paragraphMaxWidth` is set to `maxBound`,
-- `paragraphSafeWidth` can be used to determine the @max-content@ width of the
-- paragraph for CSS.
paragraphSafeWidth :: ParagraphLayout d -> Int32
paragraphSafeWidth pl = maximum $ map (lineWidth pl) $ lineNumbers pl
lineWidth :: ParagraphLayout d -> Int -> Int32
lineWidth pl line = sum $ map fragmentWidth $ lineFragments pl line
fragmentWidth :: Fragment d -> Int32
fragmentWidth f = width $ fragmentSpacedRect f
lineFragments :: ParagraphLayout d -> Int -> [Fragment d]
lineFragments pl line = filter byLine $ paragraphFragments pl
where
byLine frag = line == fragmentLine frag