1 /* 2 * Copyright (c) 2007, 2011, 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 import java.lang.reflect.Constructor; 33 34 import sun.java2d.Disposer; 35 import sun.java2d.DisposerRecord; 36 37 /* FontScaler is "internal interface" to font rasterizer library. 38 * 39 * Access to native rasterizers without going through this interface is 40 * strongly discouraged. In particular, this is important because native 41 * data could be disposed due to runtime font processing error at any time. 42 * 43 * FontScaler represents combination of particular rasterizer implementation 44 * and particular font. It does not include rasterization attributes such as 45 * transform. These attributes are part of native scalerContext object. 46 * This approach allows to share same scaler for different requests related 47 * to the same font file. 48 * 49 * Note that scaler may throw FontScalerException on any operation. 50 * Generally this means that runtime error had happened and scaler is not 51 * usable. Subsequent calls to this scaler should not cause crash but will 52 * likely cause exceptions to be thrown again. 53 * 54 * It is recommended that callee should replace its reference to the scaler 55 * with something else. For instance it could be FontManager.getNullScaler(). 56 * Note that NullScaler is trivial and will not actually rasterize anything. 57 * 58 * Alternatively, callee can use more sophisticated error recovery strategies 59 * and for instance try to substitute failed scaler with new scaler instance 60 * using another font. 61 * 62 * Note that in case of error there is no need to call dispose(). Moreover, 63 * dispose() generally is called by Disposer thread and explicit calls to 64 * dispose might have unexpected sideeffects because scaler can be shared. 65 * 66 * Current disposing logic is the following: 67 * - scaler is registered in the Disposer by the FontManager (on creation) 68 * - scalers are disposed when associated Font2D object (e.g. TruetypeFont) 69 * is garbage collected. That's why this object implements DisposerRecord 70 * interface directly (as it is not used as indicator when it is safe 71 * to release native state) and that's why we have to use WeakReference 72 * to Font internally. 73 * - Majority of Font2D objects are linked from various mapping arrays 74 * (e.g. FontManager.localeFullNamesToFont). So, they are not collected. 75 * This logic only works for fonts created with Font.createFont() 76 * 77 * Notes: 78 * - Eventually we may consider releasing some of the scaler resources if 79 * it was not used for a while but we do not want to be too aggressive on 80 * this (and this is probably more important for Type1 fonts). 81 */ 82 public abstract class FontScaler implements DisposerRecord { 83 84 private static FontScaler nullScaler = null; 85 private static Constructor<FontScaler> scalerConstructor = null; 86 87 //Find preferred font scaler 88 // 89 //NB: we can allow property based preferences 90 // (theoretically logic can be font type specific) 91 static { 92 Class scalerClass = null; 93 Class arglst[] = new Class[] {Font2D.class, int.class, 94 boolean.class, int.class}; 95 96 try { 97 if (FontUtilities.isOpenJDK) { 98 scalerClass = Class.forName("sun.font.FreetypeFontScaler"); 99 } else { 100 scalerClass = Class.forName("sun.font.T2KFontScaler"); 101 } 102 } catch (ClassNotFoundException e) { 103 scalerClass = NullFontScaler.class; 104 } 105 106 //NB: rewrite using factory? constructor is ugly way 107 try { 108 scalerConstructor = scalerClass.getConstructor(arglst); 109 } catch (NoSuchMethodException e) { 110 //should not happen 111 } 112 } 113 114 /* This is the only place to instantiate new FontScaler. 115 * Therefore this is very convinient place to register 116 * scaler with Disposer as well as trigger deregistring bad font 117 * in case when scaler reports this. 118 */ 119 public static FontScaler getScaler(Font2D font, 120 int indexInCollection, 121 boolean supportsCJK, 122 int filesize) { 123 FontScaler scaler = null; 124 125 try { 126 Object args[] = new Object[] {font, indexInCollection, 127 supportsCJK, filesize}; 128 scaler = scalerConstructor.newInstance(args); 129 Disposer.addObjectRecord(font, scaler); 130 } catch (Throwable e) { 131 scaler = nullScaler; 132 133 //if we can not instantiate scaler assume bad font 134 //NB: technically it could be also because of internal scaler 135 // error but here we are assuming scaler is ok. 136 FontManager fm = FontManagerFactory.getInstance(); 137 fm.deRegisterBadFont(font); 138 } 139 return scaler; 140 } 141 142 /* 143 * At the moment it is harmless to create 2 null scalers so, technically, 144 * syncronized keyword is not needed. 145 * 146 * But it is safer to keep it to avoid subtle problems if we will be adding 147 * checks like whether scaler is null scaler. 148 */ 149 public static synchronized FontScaler getNullScaler() { 150 if (nullScaler == null) { 151 nullScaler = new NullFontScaler(); 152 } 153 return nullScaler; 154 } 155 156 protected WeakReference<Font2D> font = null; 157 protected long nativeScaler = 0; //used by decendants 158 //that have native state 159 protected boolean disposed = false; 160 161 abstract StrikeMetrics getFontMetrics(long pScalerContext) 162 throws FontScalerException; 163 164 abstract float getGlyphAdvance(long pScalerContext, int glyphCode) 165 throws FontScalerException; 166 167 abstract void getGlyphMetrics(long pScalerContext, int glyphCode, 168 Point2D.Float metrics) 169 throws FontScalerException; 170 171 /* 172 * Returns pointer to native GlyphInfo object. 173 * Callee is responsible for freeing this memory. 174 * 175 * Note: 176 * currently this method has to return not 0L but pointer to valid 177 * GlyphInfo object. Because Strike and drawing releated logic does 178 * expect that. 179 * In the future we may want to rework this to allow 0L here. 180 */ 181 abstract long getGlyphImage(long pScalerContext, int glyphCode) 182 throws FontScalerException; 183 184 abstract Rectangle2D.Float getGlyphOutlineBounds(long pContext, 185 int glyphCode) 186 throws FontScalerException; 187 188 abstract GeneralPath getGlyphOutline(long pScalerContext, int glyphCode, 189 float x, float y) 190 throws FontScalerException; 191 192 abstract GeneralPath getGlyphVectorOutline(long pScalerContext, int[] glyphs, 193 int numGlyphs, float x, float y) 194 throws FontScalerException; 195 196 /* Used by Java2D disposer to ensure native resources are released. 197 Note: this method does not release any of created 198 scaler context objects! */ 199 public void dispose() {} 200 201 /* At the moment these 3 methods are needed for Type1 fonts only. 202 * For Truetype fonts we extract required info outside of scaler 203 * on java layer. 204 */ 205 abstract int getNumGlyphs() throws FontScalerException; 206 abstract int getMissingGlyphCode() throws FontScalerException; 207 abstract int getGlyphCode(char charCode) throws FontScalerException; 208 209 /* This method returns table cache used by native layout engine. 210 * This cache is essentially just small collection of 211 * pointers to various truetype tables. See definition of TTLayoutTableCache 212 * in the fontscalerdefs.h for more details. 213 * 214 * Note that tables themselves have same format as defined in the truetype 215 * specification, i.e. font scaler do not need to perform any preprocessing. 216 * 217 * Probably it is better to have API to request pointers to each table 218 * separately instead of requesting pointer to some native structure. 219 * (then there is not need to share its definition by different 220 * implementations of scaler). 221 * However, this means multiple JNI calls and potential impact on performance. 222 * 223 * Note: return value 0 is legal. 224 * This means tables are not available (e.g. type1 font). 225 */ 226 abstract long getLayoutTableCache() throws FontScalerException; 227 228 /* Used by the OpenType engine for mark positioning. */ 229 abstract Point2D.Float getGlyphPoint(long pScalerContext, 230 int glyphCode, int ptNumber) 231 throws FontScalerException; 232 233 abstract long getUnitsPerEm(); 234 235 /* Returns pointer to native structure describing rasterization attributes. 236 Format of this structure is scaler-specific. 237 238 Callee is responsible for freeing scaler context (using free()). 239 240 Note: 241 Context is tightly associated with strike and it is actually 242 freed when corresponding strike is being released. 243 */ 244 abstract long createScalerContext(double[] matrix, 245 int aa, int fm, 246 float boldness, float italic, 247 boolean disableHinting); 248 249 /* Marks context as invalid because native scaler is invalid. 250 Notes: 251 - pointer itself is still valid and has to be released 252 - if pointer to native scaler was cached it 253 should not be neither disposed nor used. 254 it is very likely it is already disposed by this moment. */ 255 abstract void invalidateScalerContext(long ppScalerContext); 256 }