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* Copyright 2006 The Android Open Source Project
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkFontHost_DEFINED
#define SkFontHost_DEFINED
#include "SkTypeface.h"
class SkDescriptor;
class SkScalerContext;
struct SkScalerContextRec;
class SkStream;
class SkWStream;
/** \class SkFontHost
This class is ported to each environment. It is responsible for bridging
the gap between the (sort of) abstract class SkTypeface and the
platform-specific implementation that provides access to font files.
One basic task is for each create (subclass of) SkTypeface, the FontHost is
responsible for assigning a uniqueID. The ID should be unique for the
underlying font file/data, not unique per typeface instance. Thus it is
possible/common to request a typeface for the same font more than once
(e.g. asking for the same font by name several times). The FontHost may
return seperate typeface instances in that case, or it may choose to use a
cache and return the same instance (but calling typeface->ref(), since the
caller is always responsible for calling unref() on each instance that is
returned). Either way, the fontID for those instance(s) will be the same.
In addition, the fontID should never be set to 0. That value is used as a
sentinel to indicate no-font-id.
The major aspects are:
1) Given either a name/style, return a subclass of SkTypeface that
references the closest matching font available on the host system.
2) Given the data for a font (either in a stream or a file name), return
a typeface that allows access to that data.
3) Each typeface instance carries a 32bit ID for its corresponding font.
SkFontHost turns that ID into a stream to access the font's data.
4) Given a font ID, return a subclass of SkScalerContext, which connects a
font scaler (e.g. freetype or other) to the font's data.
5) Utilites to manage the font cache (budgeting) and gamma correction
class SK_API SkFontHost {
/** LCDs either have their color elements arranged horizontally or
vertically. When rendering subpixel glyphs we need to know which way
round they are.
Note, if you change this after startup, you'll need to flush the glyph
cache because it'll have the wrong type of masks cached.
@deprecated use SkPixelGeometry instead.
enum LCDOrientation {
kHorizontal_LCDOrientation = 0, //!< this is the default
kVertical_LCDOrientation = 1
/** @deprecated set on Device creation. */
static void SetSubpixelOrientation(LCDOrientation orientation);
/** @deprecated get from Device. */
static LCDOrientation GetSubpixelOrientation();
/** LCD color elements can vary in order. For subpixel text we need to know
the order which the LCDs uses so that the color fringes are in the
correct place.
Note, if you change this after startup, you'll need to flush the glyph
cache because it'll have the wrong type of masks cached.
kNONE_LCDOrder means that the subpixel elements are not spatially
separated in any usable fashion.
@deprecated use SkPixelGeometry instead.
enum LCDOrder {
kRGB_LCDOrder = 0, //!< this is the default
kBGR_LCDOrder = 1,
kNONE_LCDOrder = 2
/** @deprecated set on Device creation. */
static void SetSubpixelOrder(LCDOrder order);
/** @deprecated get from Device. */
static LCDOrder GetSubpixelOrder();