io.jar is a component in iText Java library to provide input/output functionalities. iText Java library allows you to generate and manage PDF documents.

The Source Code files are provided together with the JAR file in the binary packge like iText7-Core-7.1.4.zip. You can download it at iText 7 Core Download site.

You can compile it to generate your JAR file, using io.pom as the build configuration file.

The source code of io-7.1.4.jar is provided below:

⏎ com/itextpdf/io/font/FontMetrics.java

/*

    This file is part of the iText (R) project.
    Copyright (c) 1998-2018 iText Group NV
    Authors: Bruno Lowagie, Paulo Soares, et al.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License version 3
    as published by the Free Software Foundation with the addition of the
    following permission added to Section 15 as permitted in Section 7(a):
    FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
    ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
    OF THIRD PARTY RIGHTS

    This program 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 Affero General Public License for more details.
    You should have received a copy of the GNU Affero General Public License
    along with this program; if not, see http://www.gnu.org/licenses or write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA, 02110-1301 USA, or download the license from the following URL:
    http://itextpdf.com/terms-of-use/

    The interactive user interfaces in modified source and object code versions
    of this program must display Appropriate Legal Notices, as required under
    Section 5 of the GNU Affero General Public License.

    In accordance with Section 7(b) of the GNU Affero General Public License,
    a covered work must retain the producer line in every PDF that is created
    or manipulated using iText.

    You can be released from the requirements of the license by purchasing
    a commercial license. Buying such a license is mandatory as soon as you
    develop commercial activities involving the iText software without
    disclosing the source code of your own applications.
    These activities include: offering paid services to customers as an ASP,
    serving PDFs on the fly in a web application, shipping iText with a closed
    source product.

    For more information, please contact iText Software Corp. at this
    address: sales@itextpdf.com
 */
package com.itextpdf.io.font;

import java.io.Serializable;

public class FontMetrics implements Serializable {

    private static final long serialVersionUID = -7113134666493365588L;

    protected float normalizationCoef = 1f;

    // head.unitsPerEm
    private int unitsPerEm = 1000;
    // maxp.numGlyphs
    private int numOfGlyphs;
    // hmtx
    private int[] glyphWidths;
    // os_2.sTypoAscender * normalization
    private int typoAscender = 800;
    // os_2.sTypoDescender * normalization
    private int typoDescender = -200;
    // os_2.sCapHeight * normalization
    private int capHeight = 700;
    // os_2.sxHeight * normalization
    private int xHeight = 0;
    // post.italicAngle
    private float italicAngle = 0;
    // llx: head.xMin * normalization; lly: head.yMin * normalization
    // urx: head.xMax * normalization; ury: head.yMax * normalization
    private int[] bbox = new int[]{-50, -200, 1000, 900};
    // hhea.Ascender * normalization
    private int ascender;
    // hhea.Descender * normalization
    private int descender;
    // hhea.LineGap * normaliztion (leading)
    private int lineGap;
    // os_2.winAscender * normalization
    private int winAscender;
    // os_2.winDescender * normalization
    private int winDescender;
    // hhea.advanceWidthMax * normalization
    private int advanceWidthMax;
    // (post.underlinePosition - post.underlineThickness / 2) * normalization
    private int underlinePosition = -100;
    // post.underlineThickness * normalization
    private int underlineThickness = 50;
    // os_2.yStrikeoutPosition * normalization
    private int strikeoutPosition;
    // os_2.yStrikeoutSize * normalization
    private int strikeoutSize;
    // os_2.ySubscriptYSize * normalization
    private int subscriptSize;
    // -os_2.ySubscriptYOffset * normalization
    private int subscriptOffset;
    // os_2.ySuperscriptYSize * normalization
    private int superscriptSize;
    // os_2.ySuperscriptYOffset * normalization
    private int superscriptOffset;
    // in type1/cff it is stdVW
    private int stemV = 80;
    // in type1/cff it is stdHW
    private int stemH = 0;
    // post.isFixedPitch (monospaced)
    private boolean isFixedPitch;


    public int getUnitsPerEm() {
        return unitsPerEm;
    }

    public int getNumberOfGlyphs() {
        return numOfGlyphs;
    }

    public int[] getGlyphWidths() {
        return glyphWidths;
    }

    public int getTypoAscender() {
        return typoAscender;
    }

    public int getTypoDescender() {
        return typoDescender;
    }

    public int getCapHeight() {
        return capHeight;
    }

    public int getXHeight() {
        return xHeight;
    }

    public float getItalicAngle() {
        return italicAngle;
    }

    public int[] getBbox() {
        return bbox;
    }

    public void setBbox(int llx, int lly, int urx, int ury){
        bbox[0] = llx;
        bbox[1] = lly;
        bbox[2] = urx;
        bbox[3] = ury;
    }

    public int getAscender() {
        return ascender;
    }

    public int getDescender() {
        return descender;
    }

    public int getLineGap() {
        return lineGap;
    }

    public int getWinAscender() {
        return winAscender;
    }

    public int getWinDescender() {
        return winDescender;
    }

    public int getAdvanceWidthMax() {
        return advanceWidthMax;
    }

    public int getUnderlinePosition() {
        return underlinePosition - underlineThickness / 2;
    }

    public int getUnderlineThickness() {
        return underlineThickness;
    }

    public int getStrikeoutPosition() {
        return strikeoutPosition;
    }

    public int getStrikeoutSize() {
        return strikeoutSize;
    }

    public int getSubscriptSize() {
        return subscriptSize;
    }

    public int getSubscriptOffset() {
        return subscriptOffset;
    }

    public int getSuperscriptSize() {
        return superscriptSize;
    }

    public int getSuperscriptOffset() {
        return superscriptOffset;
    }

    public int getStemV() {
        return stemV;
    }

    public int getStemH() {
        return stemH;
    }

    public boolean isFixedPitch() {
        return isFixedPitch;
    }

    protected void setUnitsPerEm(int unitsPerEm) {
        this.unitsPerEm = unitsPerEm;
        normalizationCoef = (float) FontProgram.UNITS_NORMALIZATION / unitsPerEm;
    }

    protected void updateBbox(float llx, float lly, float urx, float ury) {
        bbox[0] = (int) (llx * normalizationCoef);
        bbox[1] = (int) (lly * normalizationCoef);
        bbox[2] = (int) (urx * normalizationCoef);
        bbox[3] = (int) (ury * normalizationCoef);
    }

    protected void setNumberOfGlyphs(int numOfGlyphs) {
        this.numOfGlyphs = numOfGlyphs;
    }

    protected void setGlyphWidths(int[] glyphWidths) {
        this.glyphWidths = glyphWidths;
    }

    protected void setTypoAscender(int typoAscender) {
        this.typoAscender = (int) (typoAscender * normalizationCoef);
    }

    protected void setTypoDescender(int typoDesctender) {
        this.typoDescender = (int) (typoDesctender * normalizationCoef);
    }

    protected void setCapHeight(int capHeight) {
        this.capHeight = (int) (capHeight * normalizationCoef);
    }

    protected void setXHeight(int xHeight) {
        this.xHeight = (int) (xHeight * normalizationCoef);
    }

    protected void setItalicAngle(float italicAngle) {
        this.italicAngle = italicAngle;
    }

    protected void setAscender(int ascender) {
        this.ascender = (int) (ascender * normalizationCoef);
    }

    protected void setDescender(int descender) {
        this.descender = (int) (descender * normalizationCoef);
    }

    protected void setLineGap(int lineGap) {
        this.lineGap = (int) (lineGap * normalizationCoef);
    }

    protected void setWinAscender(int winAscender) {
        this.winAscender = (int) (winAscender * normalizationCoef);
    }

    protected void setWinDescender(int winDescender) {
        this.winDescender = (int) (winDescender * normalizationCoef);
    }

    protected void setAdvanceWidthMax(int advanceWidthMax) {
        this.advanceWidthMax = (int) (advanceWidthMax * normalizationCoef);
    }

    protected void setUnderlinePosition(int underlinePosition) {
        this.underlinePosition = (int) (underlinePosition * normalizationCoef);
    }

    protected void setUnderlineThickness(int underineThickness) {
        this.underlineThickness = underineThickness;
    }

    protected void setStrikeoutPosition(int strikeoutPosition) {
        this.strikeoutPosition = (int) (strikeoutPosition * normalizationCoef);
    }

    protected void setStrikeoutSize(int strikeoutSize) {
        this.strikeoutSize = (int) (strikeoutSize * normalizationCoef);
    }

    protected void setSubscriptSize(int subscriptSize) {
        this.subscriptSize = (int) (subscriptSize * normalizationCoef);
    }

    protected void setSubscriptOffset(int subscriptOffset) {
        this.subscriptOffset = (int) (subscriptOffset * normalizationCoef);
    }

    protected void setSuperscriptSize(int superscriptSize) {
        this.superscriptSize = superscriptSize;
    }

    protected void setSuperscriptOffset(int superscriptOffset) {
        this.superscriptOffset = (int) (superscriptOffset * normalizationCoef);
    }

    //todo change to protected!
    public void setStemV(int stemV) {
        this.stemV = stemV;
    }

    protected void setStemH(int stemH) {
        this.stemH = stemH;
    }

    protected void setIsFixedPitch(boolean isFixedPitch) {
        this.isFixedPitch = isFixedPitch;
    }
}

⏎ com/itextpdf/io/font/FontMetrics.java

Or download all of them as a single archive file:

File name: io-7.1.4-sources.jar
File size: 608762 bytes
Release date: 2018-10-09
Download 

⇒ iText layout.jar Source Code

⇐ iText kernel.jar Source Code

⇑ Download and Install iText Java Library

⇑⇑ iText for PDF Generation