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/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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/*
 * (C) Copyright IBM Corp. 1999,  All rights reserved.
 */

package sun.font;

import java.awt.Font;
import java.awt.GraphicsEnvironment;
import java.awt.font.TextAttribute;
import java.util.ArrayList;
import java.util.Map;
import sun.text.CodePointIterator;


This class maps an individual character to a Font family which can
display it.  The character-to-Font mapping does not depend on the
character's context, so a particular character will be mapped to the
same font family each time.


Typically, clients will call getIndexFor(char) for each character
in a style run.  When getIndexFor() returns a different value from
ones seen previously, the characters up to that point will be assigned
a font obtained from getFont().

/**
 * This class maps an individual character to a Font family which can
 * display it.  The character-to-Font mapping does not depend on the
 * character's context, so a particular character will be mapped to the
 * same font family each time.
 * <p>
 * Typically, clients will call getIndexFor(char) for each character
 * in a style run.  When getIndexFor() returns a different value from
 * ones seen previously, the characters up to that point will be assigned
 * a font obtained from getFont().
 */
public final class FontResolver {

    // An array of all fonts available to the runtime.  The fonts
    // will be searched in order.
    private Font[] allFonts;
    private Font[] supplementaryFonts;
    private int[]  supplementaryIndices;

    // Default size of Fonts (if created from an empty Map, for instance).
    private static final int DEFAULT_SIZE = 12; // from Font

    private Font defaultFont = new Font(Font.DIALOG, Font.PLAIN, DEFAULT_SIZE);

    // The results of previous lookups are cached in a two-level
    // table.  The value for a character c is found in:
    //     blocks[c>>SHIFT][c&MASK]
    // although the second array is only allocated when needed.
    // A 0 value means the character's font has not been looked up.
    // A positive value means the character's font is in the allFonts
    // array at index (value-1).
    private static final int SHIFT = 9;
    private static final int BLOCKSIZE = 1<<(16-SHIFT);
    private static final int MASK = BLOCKSIZE-1;
    private int[][] blocks = new int[1<<SHIFT][];

    private FontResolver() {
    }

    private Font[] getAllFonts() {
        if (allFonts == null) {
            allFonts =
            GraphicsEnvironment.getLocalGraphicsEnvironment().getAllFonts();
            for (int i=0; i < allFonts.length; i++) {
                allFonts[i] = allFonts[i].deriveFont((float)DEFAULT_SIZE);
            }
        }
        return allFonts;
    }

    
Search fonts in order, and return "1" to indicate its in the default
font, (or not found at all),  or the index of the first font
which can display the given character, plus 2, if it is not
in the default font.

/**
     * Search fonts in order, and return "1" to indicate its in the default
     * font, (or not found at all),  or the index of the first font
     * which can display the given character, plus 2, if it is not
     * in the default font.
     */
    private int getIndexFor(char c) {

        if (defaultFont.canDisplay(c)) {
            return 1;
        }
        for (int i=0; i < getAllFonts().length; i++) {
            if (allFonts[i].canDisplay(c)) {
                return i+2;
            }
        }
        return 1;
    }

    private Font [] getAllSCFonts() {

        if (supplementaryFonts == null) {
            ArrayList<Font> fonts = new ArrayList<Font>();
            ArrayList<Integer> indices = new ArrayList<Integer>();

            for (int i=0; i<getAllFonts().length; i++) {
                Font font = allFonts[i];
                Font2D font2D = FontManager.getFont2D(font);
                if (font2D.hasSupplementaryChars()) {
                    fonts.add(font);
                    indices.add(new Integer(i));
                }
            }

            int len = fonts.size();
            supplementaryIndices = new int[len];
            for (int i=0; i<len; i++) {
                supplementaryIndices[i] = indices.get(i);
            }
            supplementaryFonts = fonts.toArray(new Font[len]);
        }
        return supplementaryFonts;
    }

    /* This method is called only for character codes >= 0x10000 - which
     * are assumed to be legal supplementary characters.
     * It looks first at the default font (to avoid calling getAllFonts if at
     * all possible) and if that doesn't map the code point, it scans
     * just the fonts that may contain supplementary characters.
     * The index that is returned is into the "allFonts" array so that
     * callers see the same value for both supplementary and base chars.
     */
    private int getIndexFor(int cp) {

        if (defaultFont.canDisplay(cp)) {
            return 1;
        }

        for (int i = 0; i < getAllSCFonts().length; i++) {
            if (supplementaryFonts[i].canDisplay(cp)) {
                return supplementaryIndices[i]+2;
            }
        }
        return 1;
    }

    
Return an index for the given character.  The index identifies a
font family to getFont(), and has no other inherent meaning.

Params:
  • c – the character to map
See Also:
Returns:a value for consumption by getFont()
/**
     * Return an index for the given character.  The index identifies a
     * font family to getFont(), and has no other inherent meaning.
     * @param c the character to map
     * @return a value for consumption by getFont()
     * @see #getFont
     */
    public int getFontIndex(char c) {

        int blockIndex = c>>SHIFT;
        int[] block = blocks[blockIndex];
        if (block == null) {
            block = new int[BLOCKSIZE];
            blocks[blockIndex] = block;
        }

        int index = c & MASK;
        if (block[index] == 0) {
            block[index] = getIndexFor(c);
        }
        return block[index];
    }

    public int getFontIndex(int cp) {
        if (cp < 0x10000) {
            return getFontIndex((char)cp);
        }
        return getIndexFor(cp);
    }

    
Determines the font index for the code point at the current position in the
iterator, then advances the iterator to the first code point that has
a different index or until the iterator is DONE, and returns the font index.

Params:
  • iter – a code point iterator, this will be advanced past any code
            points that have the same font index
Returns:the font index for the initial code point found, or 1 if the iterator
was empty.
/**
     * Determines the font index for the code point at the current position in the
     * iterator, then advances the iterator to the first code point that has
     * a different index or until the iterator is DONE, and returns the font index.
     * @param iter a code point iterator, this will be advanced past any code
     *             points that have the same font index
     * @return the font index for the initial code point found, or 1 if the iterator
     * was empty.
     */
    public int nextFontRunIndex(CodePointIterator iter) {
        int cp = iter.next();
        int fontIndex = 1;
        if (cp != CodePointIterator.DONE) {
            fontIndex = getFontIndex(cp);

            while ((cp = iter.next()) != CodePointIterator.DONE) {
                if (getFontIndex(cp) != fontIndex) {
                    iter.prev();
                    break;
                }
            }
        }
        return fontIndex;
    }

    
Return a Font from a given font index with properties
from attributes.  The font index, which should have been produced
by getFontIndex(), determines a font family.  The size and style
of the Font reflect the properties in attributes.  Any Font or
font family specifications in attributes are ignored, on the
assumption that clients have already handled them.

Params:
  • index – an index from getFontIndex() which determines the
       font family
  • attributes – a Map from which the size and style of the Font
       are determined.  The default size is 12 and the default style
       is Font.PLAIN
See Also:
/**
     * Return a Font from a given font index with properties
     * from attributes.  The font index, which should have been produced
     * by getFontIndex(), determines a font family.  The size and style
     * of the Font reflect the properties in attributes.  Any Font or
     * font family specifications in attributes are ignored, on the
     * assumption that clients have already handled them.
     * @param index an index from getFontIndex() which determines the
     *        font family
     * @param attributes a Map from which the size and style of the Font
     *        are determined.  The default size is 12 and the default style
     *        is Font.PLAIN
     * @see #getFontIndex
     */
    public Font getFont(int index, Map attributes) {
        Font font = defaultFont;

        if (index >= 2) {
            font = allFonts[index-2];
        }

        return font.deriveFont(attributes);
    }

    private static FontResolver INSTANCE;

    
Return a shared instance of FontResolver.

/**
     * Return a shared instance of FontResolver.
     */
    public static FontResolver getInstance() {
        if (INSTANCE == null) {
            INSTANCE = new FontResolver();
        }
        return INSTANCE;
    }
}