J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2007 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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 sun.java2d.DisposerRecord; |
| 33 | |
| 34 | /* FontScaler is "internal interface" to font rasterizer library. |
| 35 | * |
| 36 | * Access to native rasterizers without going through this interface is |
| 37 | * strongly discouraged. In particular, this is important because native |
| 38 | * data could be disposed due to runtime font processing error at any time. |
| 39 | * |
| 40 | * FontScaler represents combination of particular rasterizer implementation |
| 41 | * and particular font. It does not include rasterization attributes such as |
| 42 | * transform. These attributes are part of native scalerContext object. |
| 43 | * This approach allows to share same scaler for different requests related |
| 44 | * to the same font file. |
| 45 | * |
| 46 | * Note that scaler may throw FontScalerException on any operation. |
| 47 | * Generally this means that runtime error had happened and scaler is not |
| 48 | * usable. Subsequent calls to this scaler should not cause crash but will |
| 49 | * likely cause exceptions to be thrown again. |
| 50 | * |
| 51 | * It is recommended that callee should replace its reference to the scaler |
| 52 | * with something else. For instance it could be FontManager.getNullScaler(). |
| 53 | * Note that NullScaler is trivial and will not actually rasterize anything. |
| 54 | * |
| 55 | * Alternatively, callee can use more sophisticated error recovery strategies |
| 56 | * and for instance try to substitute failed scaler with new scaler instance |
| 57 | * using another font. |
| 58 | * |
| 59 | * Note that in case of error there is no need to call dispose(). Moreover, |
| 60 | * dispose() generally is called by Disposer thread and explicit calls to |
| 61 | * dispose might have unexpected sideeffects because scaler can be shared. |
| 62 | * |
| 63 | * Current disposing logic is the following: |
| 64 | * - scaler is registered in the Disposer by the FontManager (on creation) |
| 65 | * - scalers are disposed when associated Font2D object (e.g. TruetypeFont) |
| 66 | * is garbage collected. That's why this object implements DisposerRecord |
| 67 | * interface directly (as it is not used as indicator when it is safe |
| 68 | * to release native state) and that's why we have to use WeakReference |
| 69 | * to Font internally. |
| 70 | * - Majority of Font2D objects are linked from various mapping arrays |
| 71 | * (e.g. FontManager.localeFullNamesToFont). So, they are not collected. |
| 72 | * This logic only works for fonts created with Font.createFont() |
| 73 | * |
| 74 | * Notes: |
| 75 | * - Eventually we may consider releasing some of the scaler resources if |
| 76 | * it was not used for a while but we do not want to be too aggressive on |
| 77 | * this (and this is probably more important for Type1 fonts). |
| 78 | */ |
| 79 | public abstract class FontScaler implements DisposerRecord { |
| 80 | protected WeakReference<Font2D> font = null; |
| 81 | protected long nativeScaler = 0; //used by decendants |
| 82 | //that have native state |
| 83 | protected boolean disposed = false; |
| 84 | |
| 85 | abstract StrikeMetrics getFontMetrics(long pScalerContext) |
| 86 | throws FontScalerException; |
| 87 | |
| 88 | abstract float getGlyphAdvance(long pScalerContext, int glyphCode) |
| 89 | throws FontScalerException; |
| 90 | |
| 91 | abstract void getGlyphMetrics(long pScalerContext, int glyphCode, |
| 92 | Point2D.Float metrics) |
| 93 | throws FontScalerException; |
| 94 | |
| 95 | /* |
| 96 | * Returns pointer to native GlyphInfo object. |
| 97 | * Callee is responsible for freeing this memory. |
| 98 | * |
| 99 | * Note: |
| 100 | * currently this method has to return not 0L but pointer to valid |
| 101 | * GlyphInfo object. Because Strike and drawing releated logic does |
| 102 | * expect that. |
| 103 | * In the future we may want to rework this to allow 0L here. |
| 104 | */ |
| 105 | abstract long getGlyphImage(long pScalerContext, int glyphCode) |
| 106 | throws FontScalerException; |
| 107 | |
| 108 | abstract Rectangle2D.Float getGlyphOutlineBounds(long pContext, |
| 109 | int glyphCode) |
| 110 | throws FontScalerException; |
| 111 | |
| 112 | abstract GeneralPath getGlyphOutline(long pScalerContext, int glyphCode, |
| 113 | float x, float y) |
| 114 | throws FontScalerException; |
| 115 | |
| 116 | abstract GeneralPath getGlyphVectorOutline(long pScalerContext, int[] glyphs, |
| 117 | int numGlyphs, float x, float y) |
| 118 | throws FontScalerException; |
| 119 | |
| 120 | /* Used by Java2D disposer to ensure native resources are released. |
| 121 | Note: this method does not release any of created |
| 122 | scaler context objects! */ |
| 123 | public void dispose() {} |
| 124 | |
| 125 | /* At the moment these 3 methods are needed for Type1 fonts only. |
| 126 | * For Truetype fonts we extract required info outside of scaler |
| 127 | * on java layer. |
| 128 | */ |
| 129 | abstract int getNumGlyphs() throws FontScalerException; |
| 130 | abstract int getMissingGlyphCode() throws FontScalerException; |
| 131 | abstract int getGlyphCode(char charCode) throws FontScalerException; |
| 132 | |
| 133 | /* This method returns table cache used by native layout engine. |
| 134 | * This cache is essentially just small collection of |
| 135 | * pointers to various truetype tables. See definition of TTLayoutTableCache |
| 136 | * in the fontscalerdefs.h for more details. |
| 137 | * |
| 138 | * Note that tables themselves have same format as defined in the truetype |
| 139 | * specification, i.e. font scaler do not need to perform any preprocessing. |
| 140 | * |
| 141 | * Probably it is better to have API to request pointers to each table |
| 142 | * separately instead of requesting pointer to some native structure. |
| 143 | * (then there is not need to share its definition by different |
| 144 | * implementations of scaler). |
| 145 | * However, this means multiple JNI calls and potential impact on performance. |
| 146 | * |
| 147 | * Note: return value 0 is legal. |
| 148 | * This means tables are not available (e.g. type1 font). |
| 149 | */ |
| 150 | abstract long getLayoutTableCache() throws FontScalerException; |
| 151 | |
| 152 | /* Used by the OpenType engine for mark positioning. */ |
| 153 | abstract Point2D.Float getGlyphPoint(long pScalerContext, |
| 154 | int glyphCode, int ptNumber) |
| 155 | throws FontScalerException; |
| 156 | |
| 157 | abstract long getUnitsPerEm(); |
| 158 | |
| 159 | /* Returns pointer to native structure describing rasterization attributes. |
| 160 | Format of this structure is scaler-specific. |
| 161 | |
| 162 | Callee is responsible for freeing scaler context (using free()). |
| 163 | |
| 164 | Note: |
| 165 | Context is tightly associated with strike and it is actually |
| 166 | freed when corresponding strike is being released. |
| 167 | */ |
| 168 | abstract long createScalerContext(double[] matrix, |
| 169 | boolean fontType, |
| 170 | int aa, int fm, |
| 171 | float boldness, float italic); |
| 172 | |
| 173 | /* Marks context as invalid because native scaler is invalid. |
| 174 | Notes: |
| 175 | - pointer itself is still valid and has to be released |
| 176 | - if pointer to native scaler was cached it |
| 177 | should not be neither disposed nor used. |
| 178 | it is very likely it is already disposed by this moment. */ |
| 179 | abstract void invalidateScalerContext(long ppScalerContext); |
| 180 | } |