1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/core/SkFontHost.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,131 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2006 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#ifndef SkFontHost_DEFINED
1.14 +#define SkFontHost_DEFINED
1.15 +
1.16 +#include "SkTypeface.h"
1.17 +
1.18 +class SkDescriptor;
1.19 +class SkScalerContext;
1.20 +struct SkScalerContextRec;
1.21 +class SkStream;
1.22 +class SkWStream;
1.23 +
1.24 +/** \class SkFontHost
1.25 +
1.26 + This class is ported to each environment. It is responsible for bridging
1.27 + the gap between the (sort of) abstract class SkTypeface and the
1.28 + platform-specific implementation that provides access to font files.
1.29 +
1.30 + One basic task is for each create (subclass of) SkTypeface, the FontHost is
1.31 + responsible for assigning a uniqueID. The ID should be unique for the
1.32 + underlying font file/data, not unique per typeface instance. Thus it is
1.33 + possible/common to request a typeface for the same font more than once
1.34 + (e.g. asking for the same font by name several times). The FontHost may
1.35 + return seperate typeface instances in that case, or it may choose to use a
1.36 + cache and return the same instance (but calling typeface->ref(), since the
1.37 + caller is always responsible for calling unref() on each instance that is
1.38 + returned). Either way, the fontID for those instance(s) will be the same.
1.39 + In addition, the fontID should never be set to 0. That value is used as a
1.40 + sentinel to indicate no-font-id.
1.41 +
1.42 + The major aspects are:
1.43 + 1) Given either a name/style, return a subclass of SkTypeface that
1.44 + references the closest matching font available on the host system.
1.45 + 2) Given the data for a font (either in a stream or a file name), return
1.46 + a typeface that allows access to that data.
1.47 + 3) Each typeface instance carries a 32bit ID for its corresponding font.
1.48 + SkFontHost turns that ID into a stream to access the font's data.
1.49 + 4) Given a font ID, return a subclass of SkScalerContext, which connects a
1.50 + font scaler (e.g. freetype or other) to the font's data.
1.51 + 5) Utilites to manage the font cache (budgeting) and gamma correction
1.52 +*/
1.53 +class SK_API SkFontHost {
1.54 +public:
1.55 + /** LCDs either have their color elements arranged horizontally or
1.56 + vertically. When rendering subpixel glyphs we need to know which way
1.57 + round they are.
1.58 +
1.59 + Note, if you change this after startup, you'll need to flush the glyph
1.60 + cache because it'll have the wrong type of masks cached.
1.61 +
1.62 + @deprecated use SkPixelGeometry instead.
1.63 + */
1.64 + enum LCDOrientation {
1.65 + kHorizontal_LCDOrientation = 0, //!< this is the default
1.66 + kVertical_LCDOrientation = 1
1.67 + };
1.68 +
1.69 + /** @deprecated set on Device creation. */
1.70 + static void SetSubpixelOrientation(LCDOrientation orientation);
1.71 + /** @deprecated get from Device. */
1.72 + static LCDOrientation GetSubpixelOrientation();
1.73 +
1.74 + /** LCD color elements can vary in order. For subpixel text we need to know
1.75 + the order which the LCDs uses so that the color fringes are in the
1.76 + correct place.
1.77 +
1.78 + Note, if you change this after startup, you'll need to flush the glyph
1.79 + cache because it'll have the wrong type of masks cached.
1.80 +
1.81 + kNONE_LCDOrder means that the subpixel elements are not spatially
1.82 + separated in any usable fashion.
1.83 +
1.84 + @deprecated use SkPixelGeometry instead.
1.85 + */
1.86 + enum LCDOrder {
1.87 + kRGB_LCDOrder = 0, //!< this is the default
1.88 + kBGR_LCDOrder = 1,
1.89 + kNONE_LCDOrder = 2
1.90 + };
1.91 +
1.92 + /** @deprecated set on Device creation. */
1.93 + static void SetSubpixelOrder(LCDOrder order);
1.94 + /** @deprecated get from Device. */
1.95 + static LCDOrder GetSubpixelOrder();
1.96 +
1.97 +private:
1.98 + /** Return a new, closest matching typeface given either an existing family
1.99 + (specified by a typeface in that family) or by a familyName and a
1.100 + requested style.
1.101 + 1) If familyFace is null, use familyName.
1.102 + 2) If familyName is null, use data (UTF-16 to cover).
1.103 + 3) If all are null, return the default font that best matches style
1.104 + */
1.105 + static SkTypeface* CreateTypeface(const SkTypeface* familyFace,
1.106 + const char familyName[],
1.107 + SkTypeface::Style style);
1.108 +
1.109 + /** Return a new typeface given the data buffer. If the data does not
1.110 + represent a valid font, returns null.
1.111 +
1.112 + If a typeface instance is returned, the caller is responsible for
1.113 + calling unref() on the typeface when they are finished with it.
1.114 +
1.115 + The returned typeface may or may not have called ref() on the stream
1.116 + parameter. If the typeface has not called ref(), then it may have made
1.117 + a copy of the releveant data. In either case, the caller is still
1.118 + responsible for its refcnt ownership of the stream.
1.119 + */
1.120 + static SkTypeface* CreateTypefaceFromStream(SkStream*);
1.121 +
1.122 + /** Return a new typeface from the specified file path. If the file does not
1.123 + represent a valid font, this returns null. If a typeface is returned,
1.124 + the caller is responsible for calling unref() when it is no longer used.
1.125 + */
1.126 + static SkTypeface* CreateTypefaceFromFile(const char path[]);
1.127 +
1.128 + ///////////////////////////////////////////////////////////////////////////
1.129 +
1.130 + friend class SkScalerContext;
1.131 + friend class SkTypeface;
1.132 +};
1.133 +
1.134 +#endif
