Gets all kerning pairs of a Font.

Description

Demo Code

/*/*from  w w w .  j a  v a2s.  c  o  m*/
 *  Copyright (C) 2010-2015 JPEXS, All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3.0 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.
 */
import java.awt.Font;
import java.awt.FontFormatException;
import java.awt.GraphicsEnvironment;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.font.TextAttribute;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.text.AttributedCharacterIterator;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import javax.swing.JPanel;

public class Main{
    /**
     * Gets all kerning pairs of a Font. It is very slow.
     *
     * @param font
     * @param size
     * @return
     */
    public static List<KerningPair> getFontKerningPairs(Font font, int size) {
        File fontFile = getFontFile(font);
        if (fontFile != null
                && fontFile.getName().toLowerCase().endsWith(".ttf")) {
            KerningLoader k = new KerningLoader();
            try {
                return k.loadFromTTF(fontFile, size);
            } catch (IOException | FontFormatException ex) {
                // ignore
            }
        }
        List<KerningPair> ret = new ArrayList<>();

        List<Character> availableChars = new ArrayList<>();
        for (char c1 = 0; c1 < Character.MAX_VALUE; c1++) {
            if (font.canDisplay((int) c1)) {
                availableChars.add(c1);
            }
        }
        for (char c1 : availableChars) {
            ret.addAll(getFontKerningPairsOneChar(availableChars, font, c1));

        }
        return ret;
    }
    public static File getFontFile(Font f) {
        try {
            Class pfClass = Class.forName("sun.font.PhysicalFont");
            Field platName = pfClass.getDeclaredField("platName");
            platName.setAccessible(true);
            String fontPath = (String) platName.get(getFont2d(f));
            platName.setAccessible(false);
            return new File(fontPath);
        } catch (Throwable e) {
            return null;
        }
    }
    private static List<KerningPair> getFontKerningPairsOneChar(
            List<Character> availableChars, Font font, char firstChar) {
        List<KerningPair> ret = new ArrayList<>();

        char[] chars = new char[availableChars.size() * 2];

        for (int i = 0; i < availableChars.size(); i++) {
            chars[i * 2] = firstChar;
            chars[i * 2 + 1] = availableChars.get(i);
        }

        Map<AttributedCharacterIterator.Attribute, Object> withKerningAttrs = new HashMap<>();

        withKerningAttrs.put(TextAttribute.FONT, font);
        withKerningAttrs.put(TextAttribute.KERNING,
                TextAttribute.KERNING_ON);
        Font withKerningFont = Font.getFont(withKerningAttrs);
        GlyphVector withKerningVector = withKerningFont.layoutGlyphVector(
                getFontRenderContext(withKerningFont), chars, 0,
                chars.length, Font.LAYOUT_LEFT_TO_RIGHT);
        int withKerningX[] = new int[availableChars.size()];
        for (int i = 0; i < availableChars.size(); i++) {
            withKerningX[i] = withKerningVector.getGlyphLogicalBounds(
                    i * 2 + 1).getBounds().x;
        }

        Map<AttributedCharacterIterator.Attribute, Object> noKerningAttrs = new HashMap<>();
        noKerningAttrs.put(TextAttribute.FONT, font);
        noKerningAttrs.put(TextAttribute.KERNING, 0);
        Font noKerningFont = Font.getFont(noKerningAttrs);
        GlyphVector noKerningVector = noKerningFont.layoutGlyphVector(
                getFontRenderContext(noKerningFont), chars, 0,
                chars.length, Font.LAYOUT_LEFT_TO_RIGHT);
        for (int i = 0; i < availableChars.size(); i++) {
            int noKerningX = noKerningVector.getGlyphLogicalBounds(
                    i * 2 + 1).getBounds().x;
            int kerning = withKerningX[i] - noKerningX;
            if (kerning > 0) {
                ret.add(new KerningPair(firstChar, availableChars.get(i),
                        kerning));
            }
        }
        return ret;
    }
    private static Object getFont2d(Font f) throws ClassNotFoundException,
            NoSuchMethodException, IllegalAccessException,
            IllegalArgumentException, InvocationTargetException {
        Object fm = getFontManager();
        return Class
                .forName("sun.font.FontManager")
                .getDeclaredMethod("findFont2D", String.class, int.class,
                        int.class)
                .invoke(fm, f.getFontName(), f.getStyle(), 2/*LOGICAL_FALLBACK*/);
    }
    private static FontRenderContext getFontRenderContext(Font font) {
        return (new JPanel()).getFontMetrics(font).getFontRenderContext();
    }
    private static Object getFontManager() throws ClassNotFoundException,
            NoSuchMethodException, IllegalAccessException,
            IllegalArgumentException, InvocationTargetException {
        Class<?> clFmFactory = Class.forName("sun.font.FontManagerFactory");
        return clFmFactory.getDeclaredMethod("getInstance").invoke(null);
    }
}
Gets all kerning pairs of a Font. - Java 2D Graphics

Description

Demo Code

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