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-- GIMP Toolkit (GTK) - text layout functions: Font
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-- Created: 16 October 2005
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-- Version $Revision: 1.1 $ from $Date: 2005/10/25 19:51:37 $
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-- Copyright (C) 1999-2005 Axel Simon
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-- This library is free software; you can redistribute it and/or
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-- modify it under the terms of the GNU Lesser General Public
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-- License as published by the Free Software Foundation; either
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-- version 2.1 of the License, or (at your option) any later version.
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-- This library is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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-- Lesser General Public License for more details.
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-- Maintainer : gtk2hs-users@lists.sourceforge.net
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-- Stability : provisional
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-- Portability : portable (depends on GHC)
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-- Fonts. The selection of an appropriate font to render text becomes a
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-- substantial task in the presence of Unicode where a single font does not
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-- over the whole range of possible characters. Pango provides several
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-- concepts to find appropriate fonts and to query information about them:
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-- * 'FontDescription': Font descriptions provide a way to query and state
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-- fonts. This data structure has several fields describing different
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-- characteristics of a font. Each of these fields can be set of left
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-- * 'FontMap' : A font map represents the set of fonts available for a
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-- particular rendering system. In particular this map defines the
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-- relation between font size and pixel size in terms of the output medium.
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-- * 'FontFamily' : A font family represents a set of fonts that have
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-- related faces, that is, their faces share a common design, but differ
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-- in slant, weight, width and other aspects.
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-- * 'FontFace': A face is a specific font where all characteristics are
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-- fixed except for the size.
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-- * 'FontMetrics': Information about the font that will be used to render
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-- a specific 'Graphics.UI.Gtk.Pango.Context.Context' or
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-- 'Graphics.UI.Gtk.Pango.Rendering.PangoItem'.
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module Graphics.UI.Gtk.Pango.Font (
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-- Functions to manage font descriptions.
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module Graphics.UI.Gtk.Pango.Description,
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pangoFontMapListFamilies,
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#if PANGO_CHECK_VERSION(1,4,0)
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pangoFontFamilyIsMonospace,
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pangoFontFamilyListFaces,
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#if PANGO_CHECK_VERSION(1,4,0)
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pangoFontFaceListSizes,
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pangoFontFaceDescribe,
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import System.Glib.FFI
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import System.Glib.UTFString
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{#import Graphics.UI.Gtk.Types#}
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import System.Glib.GObject (makeNewGObject)
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{#import Graphics.UI.Gtk.Pango.Types#}
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import Graphics.UI.Gtk.Pango.Description
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{# context lib="pango" prefix="pango" #}
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-- | Ask for the different font families that a particular back-end supports.
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-- * The given 'FontMap' can be acquired by calling
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-- 'Graphics.UI.Gtk.Cairo.cairoFontMapNew' or
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pangoFontMapListFamilies :: FontMap -> IO [FontFamily]
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pangoFontMapListFamilies fm = alloca $ \arrPtrPtr -> alloca $ \sizePtr -> do
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{#call unsafe font_map_list_families#} fm arrPtrPtr sizePtr
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arrPtr <- peek arrPtrPtr
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ffsPtr <- peekArray (fromIntegral size)
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(castPtr arrPtr::Ptr (Ptr FontFamily)) -- c2hs is wrong here
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ffs <- mapM (makeNewGObject mkFontFamily . return . castPtr) ffsPtr
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{#call unsafe g_free#} (castPtr arrPtr)
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instance Show FontFamily where
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show ff = unsafePerformIO $ do
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strPtr <- {#call unsafe font_family_get_name#} ff
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#if PANGO_CHECK_VERSION(1,4,0)
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-- | Ask if the given family contains monospace fonts.
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-- * A monospace font is a font designed for text display where the
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-- characters form a regular grid. For Western languages this would
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-- mean that the advance width of all characters are the same, but
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-- this categorization also includes Asian fonts which include
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-- double-width characters: characters that occupy two grid cells.
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-- * The best way to find out the grid-cell size is to query the members
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-- of the according 'FontMetrics' structure.
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pangoFontFamilyIsMonospace :: FontFamily -> Bool
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pangoFontFamilyIsMonospace ff = unsafePerformIO $
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liftM toBool $ {#call unsafe font_family_is_monospace#} ff
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-- | Ask for the faces contained in a particular family.
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-- * Asks for all font faces in the given family. The faces in a family
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-- share a common design, but differ in slant, weight, width and other
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-- aspects. For example, the font family "Sans" contains several fonts
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-- such as Helvetica and Arial.
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pangoFontFamilyListFaces :: FontFamily -> IO [FontFace]
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pangoFontFamilyListFaces ff = alloca $ \arrPtrPtr -> alloca $ \sizePtr -> do
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{#call unsafe font_family_list_faces#} ff arrPtrPtr sizePtr
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arrPtr <- peek arrPtrPtr
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ffsPtr <- peekArray (fromIntegral size)
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(castPtr arrPtr::Ptr (Ptr FontFace)) -- c2hs is wrong here
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ffs <- mapM (makeNewGObject mkFontFace . return . castPtr) ffsPtr
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{#call unsafe g_free#} (castPtr arrPtr)
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instance Show FontFace where
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show ff = unsafePerformIO $ do
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strPtr <- {#call unsafe font_face_get_face_name#} ff
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#if PANGO_CHECK_VERSION(1,4,0)
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-- | Ask for available sizes of this font face.
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-- * List the available sizes for a font. This is only applicable to bitmap
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-- fonts since all other fonts can be scaled arbitrarily. For scalable
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-- fonts, this function returns @Nothing@. The sizes returned are in
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-- ascending order, their unit is points (1\/72 inch).
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pangoFontFaceListSizes :: FontFace -> IO (Maybe [PangoUnit])
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pangoFontFaceListSizes ff = alloca $ \arrPtrPtr -> alloca $ \sizePtr -> do
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{#call unsafe font_face_list_sizes#} ff arrPtrPtr sizePtr
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arrPtr <- peek arrPtrPtr
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if arrPtr==nullPtr then return Nothing else do
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sizes <- peekArray (fromIntegral size) arrPtr
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{#call unsafe g_free#} (castPtr arrPtr)
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return (Just (map intToPu sizes))
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-- | Ask for a description of this face.
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-- * Returns the family, style, variant, weight and stretch of a 'FontFace'.
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-- The size field of the resulting font description will be unset.
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pangoFontFaceDescribe :: FontFace -> IO FontDescription
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pangoFontFaceDescribe ff = do
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fdPtr <- {#call unsafe font_face_describe#} ff
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makeNewFontDescription fdPtr
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gtk/Graphics/UI/Gtk/Pango/Font.chs.pp
