| |
| /* |
| * 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 { |
| public: |
| /** 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(); |
| |
| private: |
| /** Return a new, closest matching typeface given either an existing family |
| (specified by a typeface in that family) or by a familyName and a |
| requested style. |
| 1) If familyFace is null, use familyName. |
| 2) If familyName is null, use data (UTF-16 to cover). |
| 3) If all are null, return the default font that best matches style |
| */ |
| static SkTypeface* CreateTypeface(const SkTypeface* familyFace, |
| const char familyName[], |
| SkTypeface::Style style); |
| |
| /** Return a new typeface given the data buffer. If the data does not |
| represent a valid font, returns null. |
| |
| If a typeface instance is returned, the caller is responsible for |
| calling unref() on the typeface when they are finished with it. |
| |
| The returned typeface may or may not have called ref() on the stream |
| parameter. If the typeface has not called ref(), then it may have made |
| a copy of the releveant data. In either case, the caller is still |
| responsible for its refcnt ownership of the stream. |
| */ |
| static SkTypeface* CreateTypefaceFromStream(SkStream*); |
| |
| /** Return a new typeface from the specified file path. If the file does not |
| represent a valid font, this returns null. If a typeface is returned, |
| the caller is responsible for calling unref() when it is no longer used. |
| */ |
| static SkTypeface* CreateTypefaceFromFile(const char path[]); |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| friend class SkScalerContext; |
| friend class SkTypeface; |
| }; |
| |
| #endif |