~alcinnz/fontconfig-pure

ref: 5b204783d56e15ab49d018c64c27a8de67e4c460 fontconfig-pure/Graphics/Text/Font/Choose/FontSet.hs -rw-r--r-- 2.1 KiB
5b204783 — Adrian Cochrane Start implementing CSS bindings with font-family, build underlying infrastructure. 2 years ago 
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
-- NOTE: Untested!
module Graphics.Text.Font.Choose.FontSet where

import Graphics.Text.Font.Choose.Pattern
import Graphics.Text.Font.Choose.Result (throwFalse, throwNull)

import Foreign.Ptr (Ptr, castPtr, nullPtr)
import Foreign.Storable (pokeElemOff, sizeOf)
import Foreign.Marshal.Alloc (allocaBytes)
import Foreign.Marshal.Array (peekArray)
import Control.Monad (forM)
import Control.Exception (bracket)

type FontSet = [Pattern]

------
--- Low-level
------
data FontSet'
type FontSet_ = Ptr FontSet'

withNewFontSet :: (FontSet_ -> IO a) -> IO a
withNewFontSet = bracket fcFontSetCreate fcFontSetDestroy
foreign import ccall "FcFontSetCreate" fcFontSetCreate :: IO FontSet_
foreign import ccall "FcFontSetDestroy" fcFontSetDestroy :: FontSet_ -> IO ()

withFontSet :: FontSet -> (FontSet_ -> IO a) -> IO a
withFontSet fonts cb = withNewFontSet $ \fonts' -> do
    forM fonts $ \font -> do
        font' <- patternAsPointer font
        throwFalse <$> fcFontSetAdd fonts' font'
    cb fonts'
foreign import ccall "FcFontSetAdd" fcFontSetAdd :: FontSet_ -> Pattern_ -> IO Bool

withFontSets :: [FontSet] -> (Ptr FontSet_ -> Int -> IO a) -> IO a
withFontSets fontss cb = let n = length fontss in
    allocaBytes (sizeOf (undefined :: FontSet_) * n) $ \fontss' ->
        withFontSets' fontss 0 fontss' $ cb fontss' n
withFontSets' :: [FontSet] -> Int -> Ptr FontSet_ -> IO a -> IO a
withFontSets' [] _ _ cb = cb
withFontSets' (fonts:fontss) i fontss' cb = withFontSet fonts $ \fonts' -> do
    pokeElemOff fontss' i fonts'
    withFontSets' fontss (succ i) fontss' cb

thawFontSet :: FontSet_ -> IO FontSet
thawFontSet fonts' = do
    n <- get_fontSet_nfont fonts'
    array <- get_fontSet_fonts fonts'
    if n == 0 || array == nullPtr
    then return []
    else do
        list <- peekArray n array
        forM list (thawPattern . throwNull)
foreign import ccall "get_fontSet_nfont" get_fontSet_nfont :: FontSet_ -> IO Int
foreign import ccall "get_fontSet_fonts" get_fontSet_fonts :: FontSet_ -> IO (Ptr Pattern_)

thawFontSet_ :: IO FontSet_ -> IO FontSet
thawFontSet_ cb = bracket (throwNull <$> cb) fcFontSetDestroy thawFontSet