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	/*
	* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.font;

	import java.awt.geom.GeneralPath;
	import java.awt.geom.Point2D;
	import java.awt.geom.Rectangle2D;
	import java.lang.ref.WeakReference;
	import java.lang.reflect.Constructor;

	import sun.java2d.Disposer;
	import sun.java2d.DisposerRecord;

	/* FontScaler is "internal interface" to font rasterizer library.
	*
	* Access to native rasterizers without going through this interface is
	* strongly discouraged. In particular, this is important because native
	* data could be disposed due to runtime font processing error at any time.
	*
	* FontScaler represents combination of particular rasterizer implementation
	* and particular font. It does not include rasterization attributes such as
	* transform. These attributes are part of native scalerContext object.
	* This approach allows to share same scaler for different requests related
	* to the same font file.
	*
	* Note that scaler may throw FontScalerException on any operation.
	* Generally this means that runtime error had happened and scaler is not
	* usable. Subsequent calls to this scaler should not cause crash but will
	* likely cause exceptions to be thrown again.
	*
	* It is recommended that callee should replace its reference to the scaler
	* with something else. For instance it could be FontManager.getNullScaler().
	* Note that NullScaler is trivial and will not actually rasterize anything.
	*
	* Alternatively, callee can use more sophisticated error recovery strategies
	* and for instance try to substitute failed scaler with new scaler instance
	* using another font.
	*
	* Note that in case of error there is no need to call dispose(). Moreover,
	* dispose() generally is called by Disposer thread and explicit calls to
	* dispose might have unexpected sideeffects because scaler can be shared.
	*
	* Current disposing logic is the following:
	* - scaler is registered in the Disposer by the FontManager (on creation)
	* - scalers are disposed when associated Font2D object (e.g. TruetypeFont)
	* is garbage collected. That's why this object implements DisposerRecord
	* interface directly (as it is not used as indicator when it is safe
	* to release native state) and that's why we have to use WeakReference
	* to Font internally.
	* - Majority of Font2D objects are linked from various mapping arrays
	* (e.g. FontManager.localeFullNamesToFont). So, they are not collected.
	* This logic only works for fonts created with Font.createFont()
	*
	* Notes:
	* - Eventually we may consider releasing some of the scaler resources if
	* it was not used for a while but we do not want to be too aggressive on
	* this (and this is probably more important for Type1 fonts).
	*/
	public abstract class FontScaler implements DisposerRecord {

	private static FontScaler nullScaler = null;
	private static Constructor<FontScaler> scalerConstructor = null;

	//Find preferred font scaler
	//
	//NB: we can allow property based preferences
	// (theoretically logic can be font type specific)
	static {
	Class scalerClass = null;
	Class arglst[] = new Class[] {Font2D.class, int.class,
	boolean.class, int.class};

	try {
	if (FontUtilities.isOpenJDK) {
	scalerClass = Class.forName("sun.font.FreetypeFontScaler");
	} else {
	scalerClass = Class.forName("sun.font.T2KFontScaler");
	}
	} catch (ClassNotFoundException e) {
	scalerClass = NullFontScaler.class;
	}

	//NB: rewrite using factory? constructor is ugly way
	try {
	scalerConstructor = scalerClass.getConstructor(arglst);
	} catch (NoSuchMethodException e) {
	//should not happen
	}
	}

	/* This is the only place to instantiate new FontScaler.
	* Therefore this is very convinient place to register
	* scaler with Disposer as well as trigger deregistring bad font
	* in case when scaler reports this.
	*/
	public static FontScaler getScaler(Font2D font,
	int indexInCollection,
	boolean supportsCJK,
	int filesize) {
	FontScaler scaler = null;

	try {
	Object args[] = new Object[] {font, indexInCollection,
	supportsCJK, filesize};
	scaler = scalerConstructor.newInstance(args);
	Disposer.addObjectRecord(font, scaler);
	} catch (Throwable e) {
	scaler = nullScaler;

	//if we can not instantiate scaler assume bad font
	//NB: technically it could be also because of internal scaler
	// error but here we are assuming scaler is ok.
	FontManager fm = FontManagerFactory.getInstance();
	fm.deRegisterBadFont(font);
	}
	return scaler;
	}

	/*
	* At the moment it is harmless to create 2 null scalers so, technically,
	* syncronized keyword is not needed.
	*
	* But it is safer to keep it to avoid subtle problems if we will be adding
	* checks like whether scaler is null scaler.
	*/
	public static synchronized FontScaler getNullScaler() {
	if (nullScaler == null) {
	nullScaler = new NullFontScaler();
	}
	return nullScaler;
	}

	protected WeakReference<Font2D> font = null;
	protected long nativeScaler = 0; //used by decendants
	//that have native state
	protected boolean disposed = false;

	abstract StrikeMetrics getFontMetrics(long pScalerContext)
	throws FontScalerException;

	abstract float getGlyphAdvance(long pScalerContext, int glyphCode)
	throws FontScalerException;

	abstract void getGlyphMetrics(long pScalerContext, int glyphCode,
	Point2D.Float metrics)
	throws FontScalerException;

	/*
	* Returns pointer to native GlyphInfo object.
	* Callee is responsible for freeing this memory.
	*
	* Note:
	* currently this method has to return not 0L but pointer to valid
	* GlyphInfo object. Because Strike and drawing releated logic does
	* expect that.
	* In the future we may want to rework this to allow 0L here.
	*/
	abstract long getGlyphImage(long pScalerContext, int glyphCode)
	throws FontScalerException;

	abstract Rectangle2D.Float getGlyphOutlineBounds(long pContext,
	int glyphCode)
	throws FontScalerException;

	abstract GeneralPath getGlyphOutline(long pScalerContext, int glyphCode,
	float x, float y)
	throws FontScalerException;

	abstract GeneralPath getGlyphVectorOutline(long pScalerContext, int[] glyphs,
	int numGlyphs, float x, float y)
	throws FontScalerException;

	/* Used by Java2D disposer to ensure native resources are released.
	Note: this method does not release any of created
	scaler context objects! */
	public void dispose() {}

	/**
	* Used when the native resources held by the scaler need
	* to be released before the 2D disposer runs.
	*/
	public void disposeScaler() {}

	/* At the moment these 3 methods are needed for Type1 fonts only.
	* For Truetype fonts we extract required info outside of scaler
	* on java layer.
	*/
	abstract int getNumGlyphs() throws FontScalerException;
	abstract int getMissingGlyphCode() throws FontScalerException;
	abstract int getGlyphCode(char charCode) throws FontScalerException;

	/* This method returns table cache used by native layout engine.
	* This cache is essentially just small collection of
	* pointers to various truetype tables. See definition of TTLayoutTableCache
	* in the fontscalerdefs.h for more details.
	*
	* Note that tables themselves have same format as defined in the truetype
	* specification, i.e. font scaler do not need to perform any preprocessing.
	*
	* Probably it is better to have API to request pointers to each table
	* separately instead of requesting pointer to some native structure.
	* (then there is not need to share its definition by different
	* implementations of scaler).
	* However, this means multiple JNI calls and potential impact on performance.
	*
	* Note: return value 0 is legal.
	* This means tables are not available (e.g. type1 font).
	*/
	abstract long getLayoutTableCache() throws FontScalerException;

	/* Used by the OpenType engine for mark positioning. */
	abstract Point2D.Float getGlyphPoint(long pScalerContext,
	int glyphCode, int ptNumber)
	throws FontScalerException;

	abstract long getUnitsPerEm();

	/* Returns pointer to native structure describing rasterization attributes.
	Format of this structure is scaler-specific.

	Callee is responsible for freeing scaler context (using free()).

	Note:
	Context is tightly associated with strike and it is actually
	freed when corresponding strike is being released.
	*/
	abstract long createScalerContext(double[] matrix,
	int aa, int fm,
	float boldness, float italic,
	boolean disableHinting);

	/* Marks context as invalid because native scaler is invalid.
	Notes:
	- pointer itself is still valid and has to be released
	- if pointer to native scaler was cached it
	should not be neither disposed nor used.
	it is very likely it is already disposed by this moment. */
	abstract void invalidateScalerContext(long ppScalerContext);
	}

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