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 /* Used by the OpenType engine for mark positioning. */
185 abstract Point2D.Float getGlyphPoint(long pScalerContext,
186 int glyphCode, int ptNumber)
187 throws FontScalerException;
188
189 abstract long getUnitsPerEm();
190
191 /* Returns pointer to native structure describing rasterization attributes.
192 Format of this structure is scaler-specific.
193
194 Callee is responsible for freeing scaler context (using free()).
195
196 Note:
197 Context is tightly associated with strike and it is actually
198 freed when corresponding strike is being released.
199 */
200 abstract long createScalerContext(double[] matrix,
201 int aa, int fm,
202 float boldness, float italic,
203 boolean disableHinting);
204
205 /* Marks context as invalid because native scaler is invalid.
206 Notes:
207 - pointer itself is still valid and has to be released
208 - if pointer to native scaler was cached it
209 should not be neither disposed nor used.
210 it is very likely it is already disposed by this moment. */
211 abstract void invalidateScalerContext(long ppScalerContext);
212 }