What Is fop.jar? I got it from the fop-2.7-bin.zip.

fop.jar in fop-2.7-bin.zip is the JAR file for FOP 2.7, which is a print formatter driven by XSL formatting objects (XSL-FO). You can obtain fop.jar from the build folder of the fop-2.7-bin.zip file.

Below is the information about the fop.jar (2.2) file:

JAR File Size and Download Location:

JAR name: fop.jar, fop-2.7.jar
Target JDK version: 1.7
File name: fop.jar
File size: 4442817 bytes
Release date: 20-Jan-2022
Download: Apache FOP Website

Java source code files for fop.jar:

⏎ org/apache/fop/fonts/FontDescriptor.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* $Id: FontDescriptor.java 1175754 2011-09-26 09:48:20Z phancock $ */

package org.apache.fop.fonts;


/**
 * This interface enhances the font metrics interface with access methods to
 * value needed to register fonts in various target formats like PDF or
 * PostScript.
 */
public interface FontDescriptor extends FontMetrics {

    /**
     * Returns the ascender value of the font. (Ascent in pdf spec)
     * @return the ascender
     */
    int getAscender();


    /**
     * Returns the capital height of the font.
     * @return the capital height
     */
    int getCapHeight();


    /**
     * Returns the descender value of the font. (Descent in pdf spec)
     * @return the descender value
     */
    int getDescender();


    /**
     * Returns the flags for the font. (See pdf spec)
     * @return the flags
     */
    int getFlags();

    /**
     * Indicates whether the font is a symbolic font.
     * @return true if the font is a symbolic font (i.e. Symbol or ZapfDingbats)
     */
    boolean isSymbolicFont();
    /**
     * Returns the font's bounding box.
     * @return the bounding box
     */
    int[] getFontBBox();


    /**
     * Returns the italic angle for the font.
     * @return the italic angle
     */
    int getItalicAngle();


    /**
     * Returns the vertical stem width for the font.
     * @return the vertical stem width
     */
    int getStemV();


    /**
     * Indicates if this font may be embedded.
     * @return True, if embedding is possible/permitted
     */
    boolean isEmbeddable();

    /**
     * Indicates whether this font is subset embedded.
     * @return true if this font is subset embedded
     */
    boolean isSubsetEmbedded();

}

⏎ org/apache/fop/fonts/FontDescriptor.java

Or download all of them as a single archive file:

File name: fop-2.7-src.zip
File size: 3401312 bytes
Release date: 2022-01-20
Download 

⇒ "fop" Command in fop-2.7-bin.zip

⇐ What Is fop-2.7-bin.zip

⇑ Download and Installing of FOP 2.x

⇑⇑ FAQ for FOP (Formatting Object Processor)