1 files changed, 83 insertions, 1 deletions

diff --git a/src/MinXft.hsc b/src/MinXft.hsc
index 327e95e..b2299af 100644
--- a/src/MinXft.hsc
+++ b/src/MinXft.hsc
@@ -2,7 +2,7 @@
 ------------------------------------------------------------------------------
 -- |
 -- Module: MinXft
--- Copyright: (c) 2012 Jose Antonio Ortega Ruiz
+-- Copyright: (c) 2012, 2014 Jose Antonio Ortega Ruiz
 --            (c) Clemens Fruhwirth <clemens@endorphin.org> 2007
 -- License: BSD3-style (see LICENSE)
 --
@@ -26,13 +26,18 @@ module MinXft ( AXftColor
               , freeAXftColor
               , withAXftDraw
               , drawXftString
+              , drawXftString'
               , drawXftRect
               , openAXftFont
               , closeAXftFont
               , xftTxtExtents
+              , xftTxtExtents'
               , xft_ascent
+              , xft_ascent'
               , xft_descent
+              , xft_descent'
               , xft_height
+              , xft_height'
               )
 
 where
@@ -45,6 +50,7 @@ import Foreign
 import Foreign.C.Types
 import Foreign.C.String
 import Codec.Binary.UTF8.String as UTF8
+import Data.Char (ord)
 
 #include <X11/Xft/Xft.h>
 
@@ -73,12 +79,21 @@ newtype AXftFont = AXftFont (Ptr AXftFont)
 xft_ascent :: AXftFont -> IO Int
 xft_ascent (AXftFont p) = peekCUShort p #{offset XftFont, ascent}
 
+xft_ascent' :: [AXftFont] -> IO Int
+xft_ascent' = (fmap maximum) . (mapM xft_ascent)
+
 xft_descent :: AXftFont -> IO Int
 xft_descent (AXftFont p) = peekCUShort p #{offset XftFont, descent}
 
+xft_descent' :: [AXftFont] -> IO Int
+xft_descent' = (fmap maximum) . (mapM xft_descent)
+
 xft_height :: AXftFont -> IO Int
 xft_height (AXftFont p) = peekCUShort p #{offset XftFont, height}
 
+xft_height' :: [AXftFont] -> IO Int
+xft_height' = (fmap maximum) . (mapM xft_height)
+
 foreign import ccall "XftTextExtentsUtf8"
   cXftTextExtentsUtf8 :: Display -> AXftFont -> CString -> CInt -> Ptr XGlyphInfo -> IO ()
 
@@ -90,6 +105,12 @@ xftTxtExtents d f string =
       cXftTextExtentsUtf8 d f str_ptr (fi len) cglyph
       peek cglyph
 
+xftTxtExtents' :: Display -> [AXftFont] -> String -> IO XGlyphInfo
+xftTxtExtents' d fs string = do
+    chunks <- getChunks d fs string
+    let (_, _, gi, _, _) = last chunks
+    return gi
+
 foreign import ccall "XftFontOpenName"
   c_xftFontOpen :: Display -> CInt -> CString -> IO AXftFont
 
@@ -101,6 +122,14 @@ openAXftFont dpy screen name =
 foreign import ccall "XftFontClose"
   closeAXftFont :: Display -> AXftFont -> IO ()
 
+foreign import ccall "XftCharExists"
+  cXftCharExists :: Display -> AXftFont -> (#type FcChar32) -> IO (#type FcBool)
+
+xftCharExists :: Display -> AXftFont -> Char -> IO Bool
+xftCharExists d f c = bool `fmap` cXftCharExists d f (fi $ ord c)
+  where
+    bool 0 = False
+    bool _ = True
 -- Drawing
 
 fi :: (Integral a, Num b) => a -> b
@@ -111,6 +140,9 @@ newtype AXftDraw = AXftDraw (Ptr AXftDraw)
 foreign import ccall "XftDrawCreate"
   c_xftDrawCreate :: Display -> Drawable -> Visual -> Colormap -> IO AXftDraw
 
+foreign import ccall "XftDrawDisplay"
+  c_xftDrawDisplay :: AXftDraw -> IO Display
+
 foreign import ccall "XftDrawDestroy"
   c_xftDrawDestroy :: AXftDraw -> IO ()
 
@@ -130,6 +162,56 @@ drawXftString d c f x y string =
     withArrayLen (map fi (UTF8.encode string))
       (\len ptr -> cXftDrawStringUtf8 d c f (fi x) (fi y) ptr (fi len))
 
+drawXftString' :: AXftDraw ->
+                  AXftColor ->
+                  [AXftFont] ->
+                  Integer ->
+                  Integer ->
+                  String -> IO ()
+drawXftString' d c fs x y string = do
+    display <- c_xftDrawDisplay d
+    chunks <- getChunks display fs string
+    mapM_ (\(f, s, _, xo, yo) -> drawXftString d c f (x+xo) (y+yo) s) chunks
+
+-- Split string and determine fonts/offsets for individual parts
+getChunks :: Display -> [AXftFont] -> [Char] ->
+             IO [(AXftFont, String, XGlyphInfo, Integer, Integer)]
+getChunks disp fts str = do
+    chunks <- getFonts disp fts str
+    getOffsets (XGlyphInfo 0 0 0 0 0 0) chunks
+  where
+    -- Split string and determine fonts for individual parts
+    getFonts _ [] _ = return []
+    getFonts _ _ [] = return []
+    getFonts _ [ft] s = return [(ft, s)]
+    getFonts d fonts@(ft:_) s = do
+        -- Determine which glyph can be rendered by current font
+        glyphs <- mapM (xftCharExists d ft) s
+        -- Split string into parts that can/cannot be rendered
+        let splits = split (runs glyphs) s
+        -- Determine which font to render each chunk with
+        concat `fmap` mapM (getFont d fonts) splits
+
+    -- Determine fonts for substrings
+    getFont _ [] _ = return []
+    getFont _ [ft] (_, s) = return [(ft, s)] -- Last font, use it
+    getFont _ (ft:_) (True, s) = return [(ft, s)] -- Current font can render this substring
+    getFont d (_:fs) (False, s) = getFonts d fs s -- Fallback to next font
+
+    -- Helpers
+    runs [] = []
+    runs (x:xs) = let (h, t) = span (==x) xs in (x, length h + 1) : runs t
+    split [] _ = []
+    split ((x, c):xs) s = let (h, t) = splitAt c s in (x, h) : split xs t
+
+    -- Determine coordinates for chunks using extents
+    getOffsets _ [] = return []
+    getOffsets (XGlyphInfo _ _ x y xo yo) ((f, s):chunks) = do
+        (XGlyphInfo w' h' _ _ xo' yo') <- xftTxtExtents disp f s
+        let gi = XGlyphInfo (xo+w') (yo+h') x y (xo+xo') (yo+yo')
+        rest <- getOffsets gi chunks
+        return $ (f, s, gi, fromIntegral xo, fromIntegral yo) : rest
+
 foreign import ccall "XftDrawRect"
   cXftDrawRect :: AXftDraw -> AXftColor -> CInt -> CInt -> CUInt -> CUInt -> IO ()