/* * Copyright (c) 2007, 2014, 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 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 { @SuppressWarnings("unchecked") Class tmp = (Class) (!FontUtilities.useT2K ? Class.forName("sun.font.FreetypeFontScaler") : Class.forName("sun.font.T2KFontScaler")); scalerClass = tmp; } 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 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() {} /* 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); }