{-# LINE 2 "./Graphics/Rendering/Pango/Cairo.chs" #-}
-- -*-haskell-*-
-- GIMP Toolkit (GTK) Cair Pango integration
--
-- Author : Duncan Coutts, Axel Simon
--
-- Created: 17 August 2005
--
-- Copyright (C) 2005 Duncan Coutts
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public
-- License as published by the Free Software Foundation; either
-- version 2.1 of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- Lesser General Public License for more details.
--
-- |
-- Maintainer : gtk2hs-users@lists.sourceforge.net
-- Stability : provisional
-- Portability : portable (depends on GHC)
--
--
-- Pango specific functions to for redering with Cairo.
--
-- Cairo is a graphics library that supports vector graphics and image
-- compositing that can be used with Pango. The functions in this module provide
-- ways of rendering text in Cairo using Pango.
--
module Graphics.Rendering.Pango.Cairo (
  -- * Global Cairo settings.
  cairoFontMapGetDefault,
  cairoFontMapSetResolution,
  cairoFontMapGetResolution,
  cairoCreateContext,
  cairoContextSetResolution,
  cairoContextGetResolution,
  cairoContextSetFontOptions,
  cairoContextGetFontOptions,
  -- * Functions for the 'Render' monad.
  setSourceColor,
  updateContext,
  createLayout,
  updateLayout,
  showGlyphString,
  showLayoutLine,
  showLayout,
  glyphStringPath,
  layoutLinePath,
  layoutPath
  ) where

import Control.Exception (bracket)

import System.Glib.FFI
import System.Glib.GObject (constructNewGObject, makeNewGObject,
  objectRef, objectUnref)
import Graphics.Rendering.Pango.Types
{-# LINE 62 "./Graphics/Rendering/Pango/Cairo.chs" #-}
import Graphics.Rendering.Pango.BasicTypes
{-# LINE 63 "./Graphics/Rendering/Pango/Cairo.chs" #-}
import Graphics.Rendering.Pango.Structs ( pangoItemGetFont, Color(..) )
import Graphics.Rendering.Pango.Layout ( layoutSetText )
import Data.IORef

import Graphics.Rendering.Cairo.Types as Cairo
import qualified Graphics.Rendering.Cairo.Internal as Cairo.Internal
import qualified Graphics.Rendering.Cairo as Cairo
import Graphics.Rendering.Cairo.Internal (Render(Render))
import Control.Monad.Reader


{-# LINE 74 "./Graphics/Rendering/Pango/Cairo.chs" #-}

--------------------
-- Methods

-- | Sets the specified 'Color' as the source color of the 'Render' context.
--
setSourceColor :: Color -> Render ()
setSourceColor (Color red green blue) =
  Cairo.setSourceRGB
    (realToFrac red / 65535.0)
    (realToFrac green / 65535.0)
    (realToFrac blue / 65535.0)

-- cairo_font_map_new cannot be bound due to incorrect memory management
-- in functions like font_map_list_families that create new structures
-- that store the font map without referencing them

-- | Retrieve the default 'Graphics.Rendering.Pango.FontMap' that contains a
-- list of available fonts.
--
-- * One purpose of creating an explicit
-- 'Graphics.Rendering.Pango.Font.FontMap' is to set
-- a different scaling factor between font sizes (in points, pt) and
-- Cairo units (in pixels). The default is 96dpi (dots per inch) which
-- corresponds to an average screen as output medium. A 10pt font will
-- therefore scale to
-- @10pt * (1\/72 pt\/inch) * (96 pixel\/inch) = 13.3 pixel@.
--
cairoFontMapGetDefault :: IO FontMap
cairoFontMapGetDefault =
  makeNewGObject mkFontMap $ pango_cairo_font_map_get_default
{-# LINE 105 "./Graphics/Rendering/Pango/Cairo.chs" #-}

-- | Set the scaling factor between font size and Cairo units.
--
-- * Value is in dots per inch (dpi). See 'cairoFontMapGetDefault'.
--
cairoFontMapSetResolution :: FontMap -> Double -> IO ()
cairoFontMapSetResolution (FontMap fm) dpi =
  withForeignPtr fm $ \fmPtr ->
  pango_cairo_font_map_set_resolution
{-# LINE 114 "./Graphics/Rendering/Pango/Cairo.chs" #-}
    (castPtr fmPtr) (realToFrac dpi)

-- | Ask for the scaling factor between font size and Cairo units.
--
-- * Value is in dots per inch (dpi). See 'cairoFontMapGetDefault'.
--
cairoFontMapGetResolution :: FontMap -> IO Double
cairoFontMapGetResolution (FontMap fm) = liftM realToFrac $
  withForeignPtr fm $ \fmPtr ->
  pango_cairo_font_map_get_resolution (castPtr fmPtr)

-- | Create a 'PangoContext'.
--
-- * If no 'FontMap' is specified, it uses the default 'FontMap' that
-- has a scaling factor of 96 dpi. See 'cairoFontMapGetDefault'.
--
cairoCreateContext :: Maybe FontMap -> IO PangoContext
cairoCreateContext (Just (FontMap fm)) = constructNewGObject mkPangoContext $
  withForeignPtr fm $ \fmPtr -> -- PangoCairoFontMap /= PangoFontMap
  pango_cairo_font_map_create_context (castPtr fmPtr)
cairoCreateContext Nothing = do
  fmPtr <- pango_cairo_font_map_get_default
{-# LINE 136 "./Graphics/Rendering/Pango/Cairo.chs" #-}
  constructNewGObject mkPangoContext $
    pango_cairo_font_map_create_context (castPtr fmPtr)

-- | Set the scaling factor of the 'PangoContext'.
--
-- * Supplying zero or a negative value will result in the resolution value
-- of the underlying 'FontMap' to be used. See also 'cairoFontMapGetDefault'.
--
cairoContextSetResolution :: PangoContext -> Double -> IO ()
cairoContextSetResolution pc dpi =
  (\(PangoContext arg1) arg2 -> withForeignPtr arg1 $ \argPtr1 ->pango_cairo_context_set_resolution argPtr1 arg2) pc (realToFrac dpi)

-- | Ask for the scaling factor of the 'PangoContext'.
--
-- * A negative value will be returned if no resolution has been set.
-- See 'cairoContextSetResolution'.
--
cairoContextGetResolution :: PangoContext -> IO Double
cairoContextGetResolution pc = liftM realToFrac $
  (\(PangoContext arg1) -> withForeignPtr arg1 $ \argPtr1 ->pango_cairo_context_get_resolution argPtr1) pc

-- | Set Cairo font options.
--
-- * Apply the given font options to the context. Values set through this
-- functions override those that are set by 'updateContext'.
--
cairoContextSetFontOptions :: PangoContext -> FontOptions -> IO ()
cairoContextSetFontOptions pc fo =
  (\(PangoContext arg1) (FontOptions arg2) -> withForeignPtr arg1 $ \argPtr1 ->withForeignPtr arg2 $ \argPtr2 ->pango_cairo_context_set_font_options argPtr1 argPtr2) pc fo

-- | Reset Cairo font options.
--
cairoContextResetFontOptions :: PangoContext -> IO ()
cairoContextResetFontOptions pc =
  (\(PangoContext arg1) (FontOptions arg2) -> withForeignPtr arg1 $ \argPtr1 ->withForeignPtr arg2 $ \argPtr2 ->pango_cairo_context_set_font_options argPtr1 argPtr2) pc
    (Cairo.Internal.FontOptions nullForeignPtr)

-- | Retrieve Cairo font options.
--
cairoContextGetFontOptions :: PangoContext -> IO FontOptions
cairoContextGetFontOptions pc = do
  foPtr <- (\(PangoContext arg1) -> withForeignPtr arg1 $ \argPtr1 ->pango_cairo_context_get_font_options argPtr1) pc
  Cairo.Internal.mkFontOptions foPtr

-- | Update a 'PangoContext' with respect to changes in a 'Render'
-- environment.
--
-- * The 'PangoContext' must have been created with
-- 'cairoCreateContext'. Any 'PangoLayout's that have been
-- previously created with this context have to be update using
-- 'Graphics.Rendering.Pango.Layout.layoutContextChanged'.
--
updateContext :: PangoContext -> Render ()
updateContext pc = Render $ do
  cr <- ask
  liftIO $ (\(Cairo arg1) (PangoContext arg2) -> withForeignPtr arg2 $ \argPtr2 ->pango_cairo_update_context arg1 argPtr2) cr pc

-- | Create a 'PangoLayout' within a 'Render' context.
--
-- * This is a convenience function that creates a new 'PangoContext'
-- within this 'Render' context and creates a new 'PangoLayout'.
-- If the transformation or target surface of the 'Render' context
-- change, 'updateLayout' has to be called on this layout.
--
createLayout :: String -> Render PangoLayout
createLayout text = Render $ do
  cr <- ask
  liftIO $ do
    layRaw <- constructNewGObject mkPangoLayoutRaw $
       (\(Cairo arg1) -> pango_cairo_create_layout arg1) cr
    textRef <- newIORef undefined
    let pl = (PangoLayout textRef layRaw)
    layoutSetText pl text
    return pl

-- | Propagate changed to the 'Render' context to a 'PangoLayout'.
--
-- * This is a convenience function that calls 'updateContext' on the
-- (private) 'PangoContext' of the given layout to propagate changes
-- from the 'Render' context to the 'PangoContext' and then calls
-- 'Graphics.Rendering.Pango.Layout.layoutContextChanged' on the layout.
-- This function is necessary for
-- 'createLayout' since a private 'PangoContext' is created that is
-- not visible to the user.
--
updateLayout :: PangoLayout -> Render ()
updateLayout (PangoLayout _ lay) = Render $ do
  cr <- ask
  liftIO $ (\(Cairo arg1) (PangoLayoutRaw arg2) -> withForeignPtr arg2 $ \argPtr2 ->pango_cairo_update_layout arg1 argPtr2) cr lay

-- | Draw a glyph string.
--
-- * The origin of the glyphs (the left edge of the baseline) will be drawn
-- at the current point of the cairo context.
--
showGlyphString :: GlyphItem -> Render ()
showGlyphString (GlyphItem pi gs) = Render $ do
  cr <- ask
  font <- liftIO $ pangoItemGetFont pi
  liftIO $ (\(Cairo arg1) (Font arg2) (GlyphStringRaw arg3) -> withForeignPtr arg2 $ \argPtr2 ->withForeignPtr arg3 $ \argPtr3 ->pango_cairo_show_glyph_string arg1 argPtr2 argPtr3) cr font gs

-- | Draw a 'LayoutLine'.
--
-- * The origin of the glyphs (the left edge of the baseline) will be drawn
-- at the current point of the cairo context.
--
showLayoutLine :: LayoutLine -> Render ()
showLayoutLine (LayoutLine _ ll) = Render $ do
  cr <- ask
  liftIO $ (\(Cairo arg1) (LayoutLineRaw arg2) -> withForeignPtr arg2 $ \argPtr2 ->pango_cairo_show_layout_line arg1 argPtr2) cr ll

-- | Draw a 'PangoLayout'.
--
-- * The top-left corner of the 'PangoLayout' will be drawn at the current
-- point of the cairo context.
--
showLayout :: PangoLayout -> Render ()
showLayout (PangoLayout _ lay) = Render $ do
  cr <- ask
  liftIO $ (\(Cairo arg1) (PangoLayoutRaw arg2) -> withForeignPtr arg2 $ \argPtr2 ->pango_cairo_show_layout arg1 argPtr2) cr lay


-- | Add the extent of a glyph string to the current path.
--
-- * The origin of the glyphs (the left edge of the line) will be at the
-- current point of the cairo context.
--
glyphStringPath :: GlyphItem -> Render ()
glyphStringPath (GlyphItem pi gs) = Render $ do
  cr <- ask
  font <- liftIO $ pangoItemGetFont pi
  liftIO $ (\(Cairo arg1) (Font arg2) (GlyphStringRaw arg3) -> withForeignPtr arg2 $ \argPtr2 ->withForeignPtr arg3 $ \argPtr3 ->pango_cairo_glyph_string_path arg1 argPtr2 argPtr3) cr font gs

-- | Add the extent of a layout line to the current path.
--
-- * The origin of the glyphs (the left edge of the line) will be at the
-- current point of the cairo context.
--
layoutLinePath :: LayoutLine -> Render ()
layoutLinePath (LayoutLine _ ll) = Render $ do
  cr <- ask
  liftIO $ (\(Cairo arg1) (LayoutLineRaw arg2) -> withForeignPtr arg2 $ \argPtr2 ->pango_cairo_layout_line_path arg1 argPtr2) cr ll

-- | Add the layout to the current path.
--
-- * Adds the top-left corner of the text to the current path. Afterwards,
-- the path position is at the bottom-right corner of the 'PangoLayout'.
--
layoutPath :: PangoLayout -> Render ()
layoutPath (PangoLayout _ lay) = Render $ do
  cr <- ask
  liftIO $ (\(Cairo arg1) (PangoLayoutRaw arg2) -> withForeignPtr arg2 $ \argPtr2 ->pango_cairo_layout_path arg1 argPtr2) cr lay

foreign import ccall unsafe "pango_cairo_font_map_get_default"
  pango_cairo_font_map_get_default :: (IO (Ptr FontMap))

foreign import ccall unsafe "pango_cairo_font_map_set_resolution"
  pango_cairo_font_map_set_resolution :: ((Ptr ()) -> (CDouble -> (IO ())))

foreign import ccall unsafe "pango_cairo_font_map_get_resolution"
  pango_cairo_font_map_get_resolution :: ((Ptr ()) -> (IO CDouble))

foreign import ccall unsafe "pango_cairo_font_map_create_context"
  pango_cairo_font_map_create_context :: ((Ptr ()) -> (IO (Ptr PangoContext)))

foreign import ccall unsafe "pango_cairo_context_set_resolution"
  pango_cairo_context_set_resolution :: ((Ptr PangoContext) -> (CDouble -> (IO ())))

foreign import ccall unsafe "pango_cairo_context_get_resolution"
  pango_cairo_context_get_resolution :: ((Ptr PangoContext) -> (IO CDouble))

foreign import ccall unsafe "pango_cairo_context_set_font_options"
  pango_cairo_context_set_font_options :: ((Ptr PangoContext) -> ((Ptr FontOptions) -> (IO ())))

foreign import ccall unsafe "pango_cairo_context_get_font_options"
  pango_cairo_context_get_font_options :: ((Ptr PangoContext) -> (IO (Ptr FontOptions)))

foreign import ccall unsafe "pango_cairo_update_context"
  pango_cairo_update_context :: ((Ptr Cairo) -> ((Ptr PangoContext) -> (IO ())))

foreign import ccall unsafe "pango_cairo_create_layout"
  pango_cairo_create_layout :: ((Ptr Cairo) -> (IO (Ptr PangoLayoutRaw)))

foreign import ccall unsafe "pango_cairo_update_layout"
  pango_cairo_update_layout :: ((Ptr Cairo) -> ((Ptr PangoLayoutRaw) -> (IO ())))

foreign import ccall unsafe "pango_cairo_show_glyph_string"
  pango_cairo_show_glyph_string :: ((Ptr Cairo) -> ((Ptr Font) -> ((Ptr GlyphStringRaw) -> (IO ()))))

foreign import ccall unsafe "pango_cairo_show_layout_line"
  pango_cairo_show_layout_line :: ((Ptr Cairo) -> ((Ptr LayoutLineRaw) -> (IO ())))

foreign import ccall unsafe "pango_cairo_show_layout"
  pango_cairo_show_layout :: ((Ptr Cairo) -> ((Ptr PangoLayoutRaw) -> (IO ())))

foreign import ccall unsafe "pango_cairo_glyph_string_path"
  pango_cairo_glyph_string_path :: ((Ptr Cairo) -> ((Ptr Font) -> ((Ptr GlyphStringRaw) -> (IO ()))))

foreign import ccall unsafe "pango_cairo_layout_line_path"
  pango_cairo_layout_line_path :: ((Ptr Cairo) -> ((Ptr LayoutLineRaw) -> (IO ())))

foreign import ccall unsafe "pango_cairo_layout_path"
  pango_cairo_layout_path :: ((Ptr Cairo) -> ((Ptr PangoLayoutRaw) -> (IO ())))