1 /* 2 * Copyright (c) 2007, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.font; 27 28 import java.awt.geom.GeneralPath; 29 import java.awt.geom.Point2D; 30 import java.awt.geom.Rectangle2D; 31 import java.lang.ref.WeakReference; 32 33 import sun.java2d.Disposer; 34 import sun.java2d.DisposerRecord; 35 36 /* FontScaler is "internal interface" to font rasterizer library. 37 * 38 * Access to native rasterizers without going through this interface is 39 * strongly discouraged. In particular, this is important because native 40 * data could be disposed due to runtime font processing error at any time. 41 * 42 * FontScaler represents combination of particular rasterizer implementation 43 * and particular font. It does not include rasterization attributes such as 44 * transform. These attributes are part of native scalerContext object. 45 * This approach allows to share same scaler for different requests related 46 * to the same font file. 47 * 48 * Note that scaler may throw FontScalerException on any operation. 49 * Generally this means that runtime error had happened and scaler is not 50 * usable. Subsequent calls to this scaler should not cause crash but will 51 * likely cause exceptions to be thrown again. 52 * 53 * It is recommended that callee should replace its reference to the scaler 54 * with something else. For instance it could be FontManager.getNullScaler(). 55 * Note that NullScaler is trivial and will not actually rasterize anything. 56 * 57 * Alternatively, callee can use more sophisticated error recovery strategies 58 * and for instance try to substitute failed scaler with new scaler instance 59 * using another font. 60 * 61 * Note that in case of error there is no need to call dispose(). Moreover, 62 * dispose() generally is called by Disposer thread and explicit calls to 63 * dispose might have unexpected sideeffects because scaler can be shared. 64 * 65 * Current disposing logic is the following: 66 * - scaler is registered in the Disposer by the FontManager (on creation) 67 * - scalers are disposed when associated Font2D object (e.g. TruetypeFont) 68 * is garbage collected. That's why this object implements DisposerRecord 69 * interface directly (as it is not used as indicator when it is safe 70 * to release native state) and that's why we have to use WeakReference 71 * to Font internally. 72 * - Majority of Font2D objects are linked from various mapping arrays 73 * (e.g. FontManager.localeFullNamesToFont). So, they are not collected. 74 * This logic only works for fonts created with Font.createFont() 75 * 76 * Notes: 77 * - Eventually we may consider releasing some of the scaler resources if 78 * it was not used for a while but we do not want to be too aggressive on 79 * this (and this is probably more important for Type1 fonts). 80 */ 81 public abstract class FontScaler implements DisposerRecord { 82 83 private static FontScaler nullScaler = null; 84 85 //Find preferred font scaler 86 // 87 //NB: we can allow property based preferences 88 // (theoretically logic can be font type specific) 89 90 /* This is the only place to instantiate new FontScaler. 91 * Therefore this is very convinient place to register 92 * scaler with Disposer as well as trigger deregistering a bad font 93 * when the scaler reports this. 94 */ 95 public static FontScaler getScaler(Font2D font, 96 int indexInCollection, 97 boolean supportsCJK, 98 int filesize) { 99 FontScaler scaler = null; 100 101 try { 102 scaler = new FreetypeFontScaler(font, indexInCollection, 103 supportsCJK, filesize); 104 Disposer.addObjectRecord(font, scaler); 105 } catch (Throwable e) { 106 scaler = getNullScaler(); 107 108 //if we can not instantiate scaler assume a bad font 109 //NB: technically it could be also because of internal scaler 110 // error but here we are assuming scaler is ok. 111 FontManager fm = FontManagerFactory.getInstance(); 112 fm.deRegisterBadFont(font); 113 } 114 return scaler; 115 } 116 117 /* 118 * At the moment it is harmless to create 2 null scalers so, technically, 119 * syncronized keyword is not needed. 120 * 121 * But it is safer to keep it to avoid subtle problems if we will be adding 122 * checks like whether scaler is null scaler. 123 */ 124 public static synchronized FontScaler getNullScaler() { 125 if (nullScaler == null) { 126 nullScaler = new NullFontScaler(); 127 } 128 return nullScaler; 129 } 130 131 protected WeakReference<Font2D> font = null; 132 protected long nativeScaler = 0; //used by decendants 133 //that have native state 134 protected boolean disposed = false; 135 136 abstract StrikeMetrics getFontMetrics(long pScalerContext) 137 throws FontScalerException; 138 139 abstract float getGlyphAdvance(long pScalerContext, int glyphCode) 140 throws FontScalerException; 141 142 abstract void getGlyphMetrics(long pScalerContext, int glyphCode, 143 Point2D.Float metrics) 144 throws FontScalerException; 145 146 /* 147 * Returns pointer to native GlyphInfo object. 148 * Callee is responsible for freeing this memory. 149 * 150 * Note: 151 * currently this method has to return not 0L but pointer to valid 152 * GlyphInfo object. Because Strike and drawing releated logic does 153 * expect that. 154 * In the future we may want to rework this to allow 0L here. 155 */ 156 abstract long getGlyphImage(long pScalerContext, int glyphCode) 157 throws FontScalerException; 158 159 abstract Rectangle2D.Float getGlyphOutlineBounds(long pContext, 160 int glyphCode) 161 throws FontScalerException; 162 163 abstract GeneralPath getGlyphOutline(long pScalerContext, int glyphCode, 164 float x, float y) 165 throws FontScalerException; 166 167 abstract GeneralPath getGlyphVectorOutline(long pScalerContext, int[] glyphs, 168 int numGlyphs, float x, float y) 169 throws FontScalerException; 170 171 /* Used by Java2D disposer to ensure native resources are released. 172 Note: this method does not release any of created 173 scaler context objects! */ 174 public void dispose() {} 175 176 /* At the moment these 3 methods are needed for Type1 fonts only. 177 * For Truetype fonts we extract required info outside of scaler 178 * on java layer. 179 */ 180 abstract int getNumGlyphs() throws FontScalerException; 181 abstract int getMissingGlyphCode() throws FontScalerException; 182 abstract int getGlyphCode(char charCode) throws FontScalerException; 183 184 /* This method returns table cache used by native layout engine. 185 * This cache is essentially just small collection of 186 * pointers to various truetype tables. See definition of TTLayoutTableCache 187 * in the fontscalerdefs.h for more details. 188 * 189 * Note that tables themselves have same format as defined in the truetype 190 * specification, i.e. font scaler do not need to perform any preprocessing. 191 * 192 * Probably it is better to have API to request pointers to each table 193 * separately instead of requesting pointer to some native structure. 194 * (then there is not need to share its definition by different 195 * implementations of scaler). 196 * However, this means multiple JNI calls and potential impact on performance. 197 * 198 * Note: return value 0 is legal. 199 * This means tables are not available (e.g. type1 font). 200 */ 201 abstract long getLayoutTableCache() throws FontScalerException; 202 203 /* Used by the OpenType engine for mark positioning. */ 204 abstract Point2D.Float getGlyphPoint(long pScalerContext, 205 int glyphCode, int ptNumber) 206 throws FontScalerException; 207 208 abstract long getUnitsPerEm(); 209 210 /* Returns pointer to native structure describing rasterization attributes. 211 Format of this structure is scaler-specific. 212 213 Callee is responsible for freeing scaler context (using free()). 214 215 Note: 216 Context is tightly associated with strike and it is actually 217 freed when corresponding strike is being released. 218 */ 219 abstract long createScalerContext(double[] matrix, 220 int aa, int fm, 221 float boldness, float italic, 222 boolean disableHinting); 223 224 /* Marks context as invalid because native scaler is invalid. 225 Notes: 226 - pointer itself is still valid and has to be released 227 - if pointer to native scaler was cached it 228 should not be neither disposed nor used. 229 it is very likely it is already disposed by this moment. */ 230 abstract void invalidateScalerContext(long ppScalerContext); 231 }