001 /*
002 * Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.awt.print;
027
028 import java.awt.Graphics;
029
030 /**
031 * The <code>Printable</code> interface is implemented
032 * by the <code>print</code> methods of the current
033 * page painter, which is called by the printing
034 * system to render a page. When building a
035 * {@link Pageable}, pairs of {@link PageFormat}
036 * instances and instances that implement
037 * this interface are used to describe each page. The
038 * instance implementing <code>Printable</code> is called to
039 * print the page's graphics.
040 * <p>
041 * A <code>Printable(..)</code> may be set on a <code>PrinterJob</code>.
042 * When the client subsequently initiates printing by calling
043 * <code>PrinterJob.print(..)</code> control
044 * <p>
045 * is handed to the printing system until all pages have been printed.
046 * It does this by calling <code>Printable.print(..)</code> until
047 * all pages in the document have been printed.
048 * In using the <code>Printable</code> interface the printing
049 * commits to image the contents of a page whenever
050 * requested by the printing system.
051 * <p>
052 * The parameters to <code>Printable.print(..)</code> include a
053 * <code>PageFormat</code> which describes the printable area of
054 * the page, needed for calculating the contents that will fit the
055 * page, and the page index, which specifies the zero-based print
056 * stream index of the requested page.
057 * <p>
058 * For correct printing behaviour, the following points should be
059 * observed:
060 * <ul>
061 * <li> The printing system may request a page index more than once.
062 * On each occasion equal PageFormat parameters will be supplied.
063 *
064 * <li>The printing system will call <code>Printable.print(..)</code>
065 * with page indexes which increase monotonically, although as noted above,
066 * the <code>Printable</code> should expect multiple calls for a page index
067 * and that page indexes may be skipped, when page ranges are specified
068 * by the client, or by a user through a print dialog.
069 *
070 * <li>If multiple collated copies of a document are requested, and the
071 * printer cannot natively support this, then the document may be imaged
072 * multiple times. Printing will start each copy from the lowest print
073 * stream page index page.
074 *
075 * <li>With the exception of re-imaging an entire document for multiple
076 * collated copies, the increasing page index order means that when
077 * page N is requested if a client needs to calculate page break position,
078 * it may safely discard any state related to pages < N, and make current
079 * that for page N. "State" usually is just the calculated position in the
080 * document that corresponds to the start of the page.
081 *
082 * <li>When called by the printing system the <code>Printable</code> must
083 * inspect and honour the supplied PageFormat parameter as well as the
084 * page index. The format of the page to be drawn is specified by the
085 * supplied PageFormat. The size, orientation and imageable area of the page
086 * is therefore already determined and rendering must be within this
087 * imageable area.
088 * This is key to correct printing behaviour, and it has the
089 * implication that the client has the responsibility of tracking
090 * what content belongs on the specified page.
091 *
092 * <li>When the <code>Printable</code> is obtained from a client-supplied
093 * <code>Pageable</code> then the client may provide different PageFormats
094 * for each page index. Calculations of page breaks must account for this.
095 * </ul>
096 * <p>
097 * @see java.awt.print.Pageable
098 * @see java.awt.print.PageFormat
099 * @see java.awt.print.PrinterJob
100 */
101 public interface Printable {
102
103 /**
104 * Returned from {@link #print(Graphics, PageFormat, int)}
105 * to signify that the requested page was rendered.
106 */
107 int PAGE_EXISTS = 0;
108
109 /**
110 * Returned from <code>print</code> to signify that the
111 * <code>pageIndex</code> is too large and that the requested page
112 * does not exist.
113 */
114 int NO_SUCH_PAGE = 1;
115
116 /**
117 * Prints the page at the specified index into the specified
118 * {@link Graphics} context in the specified
119 * format. A <code>PrinterJob</code> calls the
120 * <code>Printable</code> interface to request that a page be
121 * rendered into the context specified by
122 * <code>graphics</code>. The format of the page to be drawn is
123 * specified by <code>pageFormat</code>. The zero based index
124 * of the requested page is specified by <code>pageIndex</code>.
125 * If the requested page does not exist then this method returns
126 * NO_SUCH_PAGE; otherwise PAGE_EXISTS is returned.
127 * The <code>Graphics</code> class or subclass implements the
128 * {@link PrinterGraphics} interface to provide additional
129 * information. If the <code>Printable</code> object
130 * aborts the print job then it throws a {@link PrinterException}.
131 * @param graphics the context into which the page is drawn
132 * @param pageFormat the size and orientation of the page being drawn
133 * @param pageIndex the zero based index of the page to be drawn
134 * @return PAGE_EXISTS if the page is rendered successfully
135 * or NO_SUCH_PAGE if <code>pageIndex</code> specifies a
136 * non-existent page.
137 * @exception java.awt.print.PrinterException
138 * thrown when the print job is terminated.
139 */
140 int print(Graphics graphics, PageFormat pageFormat, int pageIndex)
141 throws PrinterException;
142
143 }
|