f91c47d91d
R=mtklein@google.com, tomhudson@google.com, djsollen@google.com Author: bungeman@google.com Review URL: https://codereview.chromium.org/105223006
96 lines
3.5 KiB
C++
96 lines
3.5 KiB
C++
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/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkFontHost_DEFINED
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#define SkFontHost_DEFINED
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#include "SkTypeface.h"
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class SkDescriptor;
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class SkScalerContext;
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struct SkScalerContextRec;
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class SkStream;
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class SkWStream;
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/** \class SkFontHost
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This class is ported to each environment. It is responsible for bridging
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the gap between the (sort of) abstract class SkTypeface and the
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platform-specific implementation that provides access to font files.
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One basic task is for each create (subclass of) SkTypeface, the FontHost is
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responsible for assigning a uniqueID. The ID should be unique for the
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underlying font file/data, not unique per typeface instance. Thus it is
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possible/common to request a typeface for the same font more than once
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(e.g. asking for the same font by name several times). The FontHost may
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return seperate typeface instances in that case, or it may choose to use a
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cache and return the same instance (but calling typeface->ref(), since the
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caller is always responsible for calling unref() on each instance that is
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returned). Either way, the fontID for those instance(s) will be the same.
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In addition, the fontID should never be set to 0. That value is used as a
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sentinel to indicate no-font-id.
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The major aspects are:
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1) Given either a name/style, return a subclass of SkTypeface that
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references the closest matching font available on the host system.
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2) Given the data for a font (either in a stream or a file name), return
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a typeface that allows access to that data.
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3) Each typeface instance carries a 32bit ID for its corresponding font.
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SkFontHost turns that ID into a stream to access the font's data.
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4) Given a font ID, return a subclass of SkScalerContext, which connects a
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font scaler (e.g. freetype or other) to the font's data.
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5) Utilites to manage the font cache (budgeting) and gamma correction
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*/
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class SK_API SkFontHost {
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public:
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/** LCDs either have their color elements arranged horizontally or
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vertically. When rendering subpixel glyphs we need to know which way
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round they are.
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Note, if you change this after startup, you'll need to flush the glyph
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cache because it'll have the wrong type of masks cached.
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@deprecated use SkPixelGeometry instead.
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*/
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enum LCDOrientation {
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kHorizontal_LCDOrientation = 0, //!< this is the default
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kVertical_LCDOrientation = 1
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};
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/** @deprecated set on Device creation. */
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static void SetSubpixelOrientation(LCDOrientation orientation);
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/** @deprecated get from Device. */
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static LCDOrientation GetSubpixelOrientation();
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/** LCD color elements can vary in order. For subpixel text we need to know
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the order which the LCDs uses so that the color fringes are in the
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correct place.
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Note, if you change this after startup, you'll need to flush the glyph
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cache because it'll have the wrong type of masks cached.
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kNONE_LCDOrder means that the subpixel elements are not spatially
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separated in any usable fashion.
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@deprecated use SkPixelGeometry instead.
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*/
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enum LCDOrder {
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kRGB_LCDOrder = 0, //!< this is the default
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kBGR_LCDOrder = 1,
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kNONE_LCDOrder = 2
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};
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/** @deprecated set on Device creation. */
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static void SetSubpixelOrder(LCDOrder order);
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/** @deprecated get from Device. */
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static LCDOrder GetSubpixelOrder();
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};
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#endif
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