1 /*
2 * Copyright 1997-2006 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 /*
27 * (C) Copyright Taligent, Inc. 1996 - 1997, All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - 1998, All Rights Reserved
29 *
30 * The original version of this source code and documentation is
31 * copyrighted and owned by Taligent, Inc., a wholly-owned subsidiary
32 * of IBM. These materials are provided under terms of a License
33 * Agreement between Taligent and Sun. This technology is protected
34 * by multiple US and International patents.
35 *
36 * This notice and attribution to Taligent may not be removed.
37 * Taligent is a registered trademark of Taligent, Inc.
38 *
39 */
40
41 package java.awt.font;
42
43 import java.awt.geom.Rectangle2D;
44
45 /**
46 * The <code>GlyphMetrics</code> class represents infomation for a
47 * single glyph. A glyph is the visual representation of one or more
48 * characters. Many different glyphs can be used to represent a single
49 * character or combination of characters. <code>GlyphMetrics</code>
50 * instances are produced by {@link java.awt.Font Font} and are applicable
51 * to a specific glyph in a particular <code>Font</code>.
52 * <p>
53 * Glyphs are either STANDARD, LIGATURE, COMBINING, or COMPONENT.
54 * <ul>
55 * <li>STANDARD glyphs are commonly used to represent single characters.
56 * <li>LIGATURE glyphs are used to represent sequences of characters.
57 * <li>COMPONENT glyphs in a {@link GlyphVector} do not correspond to a
58 * particular character in a text model. Instead, COMPONENT glyphs are
59 * added for typographical reasons, such as Arabic justification.
60 * <li>COMBINING glyphs embellish STANDARD or LIGATURE glyphs, such
61 * as accent marks. Carets do not appear before COMBINING glyphs.
62 * </ul>
63 * <p>
64 * Other metrics available through <code>GlyphMetrics</code> are the
65 * components of the advance, the visual bounds, and the left and right
66 * side bearings.
67 * <p>
68 * Glyphs for a rotated font, or obtained from a <code>GlyphVector</code>
69 * which has applied a rotation to the glyph, can have advances that
70 * contain both X and Y components. Usually the advance only has one
71 * component.
72 * <p>
73 * The advance of a glyph is the distance from the glyph's origin to the
74 * origin of the next glyph along the baseline, which is either vertical
75 * or horizontal. Note that, in a <code>GlyphVector</code>,
76 * the distance from a glyph to its following glyph might not be the
77 * glyph's advance, because of kerning or other positioning adjustments.
78 * <p>
79 * The bounds is the smallest rectangle that completely contains the
80 * outline of the glyph. The bounds rectangle is relative to the
81 * glyph's origin. The left-side bearing is the distance from the glyph
82 * origin to the left of its bounds rectangle. If the left-side bearing is
83 * negative, part of the glyph is drawn to the left of its origin. The
84 * right-side bearing is the distance from the right side of the bounds
85 * rectangle to the next glyph origin (the origin plus the advance). If
86 * negative, part of the glyph is drawn to the right of the next glyph's
87 * origin. Note that the bounds does not necessarily enclose all the pixels
88 * affected when rendering the glyph, because of rasterization and pixel
89 * adjustment effects.
90 * <p>
91 * Although instances of <code>GlyphMetrics</code> can be directly
92 * constructed, they are almost always obtained from a
93 * <code>GlyphVector</code>. Once constructed, <code>GlyphMetrics</code>
94 * objects are immutable.
95 * <p>
96 * <strong>Example</strong>:<p>
97 * Querying a <code>Font</code> for glyph information
98 * <blockquote><pre>
99 * Font font = ...;
100 * int glyphIndex = ...;
101 * GlyphMetrics metrics = GlyphVector.getGlyphMetrics(glyphIndex);
102 * int isStandard = metrics.isStandard();
103 * float glyphAdvance = metrics.getAdvance();
104 * </pre></blockquote>
105 * @see java.awt.Font
106 * @see GlyphVector
107 */
108
109 public final class GlyphMetrics {
110 /**
111 * Indicates whether the metrics are for a horizontal or vertical baseline.
112 */
113 private boolean horizontal;
114
115 /**
116 * The x-component of the advance.
117 */
118 private float advanceX;
119
120 /**
121 * The y-component of the advance.
122 */
123 private float advanceY;
124
125 /**
126 * The bounds of the associated glyph.
127 */
128 private Rectangle2D.Float bounds;
129
130 /**
131 * Additional information about the glyph encoded as a byte.
132 */
133 private byte glyphType;
134
135 /**
136 * Indicates a glyph that represents a single standard
137 * character.
138 */
139 public static final byte STANDARD = 0;
140
141 /**
142 * Indicates a glyph that represents multiple characters
143 * as a ligature, for example 'fi' or 'ffi'. It is followed by
144 * filler glyphs for the remaining characters. Filler and combining
145 * glyphs can be intermixed to control positioning of accent marks
146 * on the logically preceeding ligature.
147 */
148 public static final byte LIGATURE = 1;
149
150 /**
151 * Indicates a glyph that represents a combining character,
152 * such as an umlaut. There is no caret position between this glyph
153 * and the preceeding glyph.
154 */
155 public static final byte COMBINING = 2;
156
157 /**
158 * Indicates a glyph with no corresponding character in the
159 * backing store. The glyph is associated with the character
160 * represented by the logicaly preceeding non-component glyph. This
161 * is used for kashida justification or other visual modifications to
162 * existing glyphs. There is no caret position between this glyph
163 * and the preceeding glyph.
164 */
165 public static final byte COMPONENT = 3;
166
167 /**
168 * Indicates a glyph with no visual representation. It can
169 * be added to the other code values to indicate an invisible glyph.
170 */
171 public static final byte WHITESPACE = 4;
172
173 /**
174 * Constructs a <code>GlyphMetrics</code> object.
175 * @param advance the advance width of the glyph
176 * @param bounds the black box bounds of the glyph
177 * @param glyphType the type of the glyph
178 */
179 public GlyphMetrics(float advance, Rectangle2D bounds, byte glyphType) {
180 this.horizontal = true;
181 this.advanceX = advance;
182 this.advanceY = 0;
183 this.bounds = new Rectangle2D.Float();
184 this.bounds.setRect(bounds);
185 this.glyphType = glyphType;
186 }
187
188 /**
189 * Constructs a <code>GlyphMetrics</code> object.
190 * @param horizontal if true, metrics are for a horizontal baseline,
191 * otherwise they are for a vertical baseline
192 * @param advanceX the X-component of the glyph's advance
193 * @param advanceY the Y-component of the glyph's advance
194 * @param bounds the visual bounds of the glyph
195 * @param glyphType the type of the glyph
196 * @since 1.4
197 */
198 public GlyphMetrics(boolean horizontal, float advanceX, float advanceY,
199 Rectangle2D bounds, byte glyphType) {
200
201 this.horizontal = horizontal;
202 this.advanceX = advanceX;
203 this.advanceY = advanceY;
204 this.bounds = new Rectangle2D.Float();
205 this.bounds.setRect(bounds);
206 this.glyphType = glyphType;
207 }
208
209 /**
210 * Returns the advance of the glyph along the baseline (either
211 * horizontal or vertical).
212 * @return the advance of the glyph
213 */
214 public float getAdvance() {
215 return horizontal ? advanceX : advanceY;
216 }
217
218 /**
219 * Returns the x-component of the advance of the glyph.
220 * @return the x-component of the advance of the glyph
221 * @since 1.4
222 */
223 public float getAdvanceX() {
224 return advanceX;
225 }
226
227 /**
228 * Returns the y-component of the advance of the glyph.
229 * @return the y-component of the advance of the glyph
230 * @since 1.4
231 */
232 public float getAdvanceY() {
233 return advanceY;
234 }
235
236 /**
237 * Returns the bounds of the glyph. This is the bounding box of the glyph outline.
238 * Because of rasterization and pixel alignment effects, it does not necessarily
239 * enclose the pixels that are affected when rendering the glyph.
240 * @return a {@link Rectangle2D} that is the bounds of the glyph.
241 */
242 public Rectangle2D getBounds2D() {
243 return new Rectangle2D.Float(bounds.x, bounds.y, bounds.width, bounds.height);
244 }
245
246 /**
247 * Returns the left (top) side bearing of the glyph.
248 * <p>
249 * This is the distance from 0, 0 to the left (top) of the glyph
250 * bounds. If the bounds of the glyph is to the left of (above) the
251 * origin, the LSB is negative.
252 * @return the left side bearing of the glyph.
253 */
254 public float getLSB() {
255 return horizontal ? bounds.x : bounds.y;
256 }
257
258 /**
259 * Returns the right (bottom) side bearing of the glyph.
260 * <p>
261 * This is the distance from the right (bottom) of the glyph bounds to
262 * the advance. If the bounds of the glyph is to the right of (below)
263 * the advance, the RSB is negative.
264 * @return the right side bearing of the glyph.
265 */
266 public float getRSB() {
267 return horizontal ?
268 advanceX - bounds.x - bounds.width :
269 advanceY - bounds.y - bounds.height;
270 }
271
272 /**
273 * Returns the raw glyph type code.
274 * @return the raw glyph type code.
275 */
276 public int getType() {
277 return glyphType;
278 }
279
280 /**
281 * Returns <code>true</code> if this is a standard glyph.
282 * @return <code>true</code> if this is a standard glyph;
283 * <code>false</code> otherwise.
284 */
285 public boolean isStandard() {
286 return (glyphType & 0x3) == STANDARD;
287 }
288
289 /**
290 * Returns <code>true</code> if this is a ligature glyph.
291 * @return <code>true</code> if this is a ligature glyph;
292 * <code>false</code> otherwise.
293 */
294 public boolean isLigature() {
295 return (glyphType & 0x3) == LIGATURE;
296 }
297
298 /**
299 * Returns <code>true</code> if this is a combining glyph.
300 * @return <code>true</code> if this is a combining glyph;
301 * <code>false</code> otherwise.
302 */
303 public boolean isCombining() {
304 return (glyphType & 0x3) == COMBINING;
305 }
306
307 /**
308 * Returns <code>true</code> if this is a component glyph.
309 * @return <code>true</code> if this is a component glyph;
310 * <code>false</code> otherwise.
311 */
312 public boolean isComponent() {
313 return (glyphType & 0x3) == COMPONENT;
314 }
315
316 /**
317 * Returns <code>true</code> if this is a whitespace glyph.
318 * @return <code>true</code> if this is a whitespace glyph;
319 * <code>false</code> otherwise.
320 */
321 public boolean isWhitespace() {
322 return (glyphType & 0x4) == WHITESPACE;
323 }
324 }
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