1 /*
   2  * Copyright (c) 1999, 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 
  27 /*
  28  * (C) Copyright IBM Corp. 1999,  All rights reserved.
  29  */
  30 
  31 package sun.font;
  32 
  33 import java.awt.Font;
  34 import java.awt.GraphicsEnvironment;
  35 import java.awt.font.TextAttribute;
  36 import java.text.AttributedCharacterIterator;
  37 import java.util.ArrayList;
  38 import java.util.Map;
  39 
  40 /**
  41  * This class maps an individual character to a Font family which can
  42  * display it.  The character-to-Font mapping does not depend on the
  43  * character's context, so a particular character will be mapped to the
  44  * same font family each time.
  45  * <p>
  46  * Typically, clients will call getIndexFor(char) for each character
  47  * in a style run.  When getIndexFor() returns a different value from
  48  * ones seen previously, the characters up to that point will be assigned
  49  * a font obtained from getFont().
  50  */
  51 public final class FontResolver {
  52 
  53     // An array of all fonts available to the runtime.  The fonts
  54     // will be searched in order.
  55     private Font[] allFonts;
  56     private Font[] supplementaryFonts;
  57     private int[]  supplementaryIndices;
  58 
  59     // Default size of Fonts (if created from an empty Map, for instance).
  60     private static final int DEFAULT_SIZE = 12; // from Font
  61 
  62     private Font defaultFont = new Font(Font.DIALOG, Font.PLAIN, DEFAULT_SIZE);
  63 
  64     // The results of previous lookups are cached in a two-level
  65     // table.  The value for a character c is found in:
  66     //     blocks[c>>SHIFT][c&MASK]
  67     // although the second array is only allocated when needed.
  68     // A 0 value means the character's font has not been looked up.
  69     // A positive value means the character's font is in the allFonts
  70     // array at index (value-1).
  71     private static final int SHIFT = 9;
  72     private static final int BLOCKSIZE = 1<<(16-SHIFT);
  73     private static final int MASK = BLOCKSIZE-1;
  74     private int[][] blocks = new int[1<<SHIFT][];
  75 
  76     private FontResolver() {
  77     }
  78 
  79     private Font[] getAllFonts() {
  80         if (allFonts == null) {
  81             allFonts =
  82             GraphicsEnvironment.getLocalGraphicsEnvironment().getAllFonts();
  83             for (int i=0; i < allFonts.length; i++) {
  84                 allFonts[i] = allFonts[i].deriveFont((float)DEFAULT_SIZE);
  85             }
  86         }
  87         return allFonts;
  88     }
  89 
  90     /**
  91      * Search fonts in order, and return "1" to indicate its in the default
  92      * font, (or not found at all),  or the index of the first font
  93      * which can display the given character, plus 2, if it is not
  94      * in the default font.
  95      */
  96     private int getIndexFor(char c) {
  97 
  98         if (defaultFont.canDisplay(c)) {
  99             return 1;
 100         }
 101         for (int i=0; i < getAllFonts().length; i++) {
 102             if (allFonts[i].canDisplay(c)) {
 103                 return i+2;
 104             }
 105         }
 106         return 1;
 107     }
 108 
 109     private Font [] getAllSCFonts() {
 110 
 111         if (supplementaryFonts == null) {
 112             ArrayList<Font> fonts = new ArrayList<Font>();
 113             ArrayList<Integer> indices = new ArrayList<Integer>();
 114 
 115             for (int i=0; i<getAllFonts().length; i++) {
 116                 Font font = allFonts[i];
 117                 Font2D font2D = FontUtilities.getFont2D(font);
 118                 if (font2D.hasSupplementaryChars()) {
 119                     fonts.add(font);
 120                     indices.add(Integer.valueOf(i));
 121                 }
 122             }
 123 
 124             int len = fonts.size();
 125             supplementaryIndices = new int[len];
 126             for (int i=0; i<len; i++) {
 127                 supplementaryIndices[i] = indices.get(i);
 128             }
 129             supplementaryFonts = fonts.toArray(new Font[len]);
 130         }
 131         return supplementaryFonts;
 132     }
 133 
 134     /* This method is called only for character codes >= 0x10000 - which
 135      * are assumed to be legal supplementary characters.
 136      * It looks first at the default font (to avoid calling getAllFonts if at
 137      * all possible) and if that doesn't map the code point, it scans
 138      * just the fonts that may contain supplementary characters.
 139      * The index that is returned is into the "allFonts" array so that
 140      * callers see the same value for both supplementary and base chars.
 141      */
 142     private int getIndexFor(int cp) {
 143 
 144         if (defaultFont.canDisplay(cp)) {
 145             return 1;
 146         }
 147 
 148         for (int i = 0; i < getAllSCFonts().length; i++) {
 149             if (supplementaryFonts[i].canDisplay(cp)) {
 150                 return supplementaryIndices[i]+2;
 151             }
 152         }
 153         return 1;
 154     }
 155 
 156     /**
 157      * Return an index for the given character.  The index identifies a
 158      * font family to getFont(), and has no other inherent meaning.
 159      * @param c the character to map
 160      * @return a value for consumption by getFont()
 161      * @see #getFont
 162      */
 163     public int getFontIndex(char c) {
 164 
 165         int blockIndex = c>>SHIFT;
 166         int[] block = blocks[blockIndex];
 167         if (block == null) {
 168             block = new int[BLOCKSIZE];
 169             blocks[blockIndex] = block;
 170         }
 171 
 172         int index = c & MASK;
 173         if (block[index] == 0) {
 174             block[index] = getIndexFor(c);
 175         }
 176         return block[index];
 177     }
 178 
 179     public int getFontIndex(int cp) {
 180         if (cp < 0x10000) {
 181             return getFontIndex((char)cp);
 182         }
 183         return getIndexFor(cp);
 184     }
 185 
 186     /**
 187      * Determines the font index for the code point at the current position in the
 188      * iterator, then advances the iterator to the first code point that has
 189      * a different index or until the iterator is DONE, and returns the font index.
 190      * @param iter a code point iterator, this will be advanced past any code
 191      *             points that have the same font index
 192      * @return the font index for the initial code point found, or 1 if the iterator
 193      * was empty.
 194      */
 195     public int nextFontRunIndex(CodePointIterator iter) {
 196         int cp = iter.next();
 197         int fontIndex = 1;
 198         if (cp != CodePointIterator.DONE) {
 199             fontIndex = getFontIndex(cp);
 200 
 201             while ((cp = iter.next()) != CodePointIterator.DONE) {
 202                 if (getFontIndex(cp) != fontIndex) {
 203                     iter.prev();
 204                     break;
 205                 }
 206             }
 207         }
 208         return fontIndex;
 209     }
 210 
 211     /**
 212      * Return a Font from a given font index with properties
 213      * from attributes.  The font index, which should have been produced
 214      * by getFontIndex(), determines a font family.  The size and style
 215      * of the Font reflect the properties in attributes.  Any Font or
 216      * font family specifications in attributes are ignored, on the
 217      * assumption that clients have already handled them.
 218      * @param index an index from getFontIndex() which determines the
 219      *        font family
 220      * @param attributes a Map from which the size and style of the Font
 221      *        are determined.  The default size is 12 and the default style
 222      *        is Font.PLAIN
 223      * @see #getFontIndex
 224      */
 225     public Font getFont(int index,
 226                         Map<? extends AttributedCharacterIterator.Attribute, ?> attributes) {
 227         Font font = defaultFont;
 228 
 229         if (index >= 2) {
 230             font = allFonts[index-2];
 231         }
 232 
 233         return font.deriveFont(attributes);
 234     }
 235 
 236     private static FontResolver INSTANCE;
 237 
 238     /**
 239      * Return a shared instance of FontResolver.
 240      */
 241     public static FontResolver getInstance() {
 242         if (INSTANCE == null) {
 243             INSTANCE = new FontResolver();
 244         }
 245         return INSTANCE;
 246     }
 247 }