J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.awt.print; |
| 27 | |
| 28 | import java.awt.Graphics; |
| 29 | |
| 30 | /** |
| 31 | * The <code>Printable</code> interface is implemented |
| 32 | * by the <code>print</code> methods of the current |
| 33 | * page painter, which is called by the printing |
| 34 | * system to render a page. When building a |
| 35 | * {@link Pageable}, pairs of {@link PageFormat} |
| 36 | * instances and instances that implement |
| 37 | * this interface are used to describe each page. The |
| 38 | * instance implementing <code>Printable</code> is called to |
| 39 | * print the page's graphics. |
| 40 | * <p> |
| 41 | * A <code>Printable(..)</code> may be set on a <code>PrinterJob</code>. |
| 42 | * When the client subsequently initiates printing by calling |
| 43 | * <code>PrinterJob.print(..)</code> control |
| 44 | * <p> |
| 45 | * is handed to the printing system until all pages have been printed. |
| 46 | * It does this by calling <code>Printable.print(..)</code> until |
| 47 | * all pages in the document have been printed. |
| 48 | * In using the <code>Printable</code> interface the printing |
| 49 | * commits to image the contents of a page whenever |
| 50 | * requested by the printing system. |
| 51 | * <p> |
| 52 | * The parameters to <code>Printable.print(..)</code> include a |
| 53 | * <code>PageFormat</code> which describes the printable area of |
| 54 | * the page, needed for calculating the contents that will fit the |
| 55 | * page, and the page index, which specifies the zero-based print |
| 56 | * stream index of the requested page. |
| 57 | * <p> |
| 58 | * For correct printing behaviour, the following points should be |
| 59 | * observed: |
| 60 | * <ul> |
| 61 | * <li> The printing system may request a page index more than once. |
| 62 | * On each occasion equal PageFormat parameters will be supplied. |
| 63 | * |
| 64 | * <li>The printing system will call <code>Printable.print(..)</code> |
| 65 | * with page indexes which increase monotonically, although as noted above, |
| 66 | * the <code>Printable</code> should expect multiple calls for a page index |
| 67 | * and that page indexes may be skipped, when page ranges are specified |
| 68 | * by the client, or by a user through a print dialog. |
| 69 | * |
| 70 | * <li>If multiple collated copies of a document are requested, and the |
| 71 | * printer cannot natively support this, then the document may be imaged |
| 72 | * multiple times. Printing will start each copy from the lowest print |
| 73 | * stream page index page. |
| 74 | * |
| 75 | * <li>With the exception of re-imaging an entire document for multiple |
| 76 | * collated copies, the increasing page index order means that when |
| 77 | * page N is requested if a client needs to calculate page break position, |
| 78 | * it may safely discard any state related to pages < N, and make current |
| 79 | * that for page N. "State" usually is just the calculated position in the |
| 80 | * document that corresponds to the start of the page. |
| 81 | * |
| 82 | * <li>When called by the printing system the <code>Printable</code> must |
| 83 | * inspect and honour the supplied PageFormat parameter as well as the |
| 84 | * page index. The format of the page to be drawn is specified by the |
| 85 | * supplied PageFormat. The size, orientation and imageable area of the page |
| 86 | * is therefore already determined and rendering must be within this |
| 87 | * imageable area. |
| 88 | * This is key to correct printing behaviour, and it has the |
| 89 | * implication that the client has the responsibility of tracking |
| 90 | * what content belongs on the specified page. |
| 91 | * |
| 92 | * <li>When the <code>Printable</code> is obtained from a client-supplied |
| 93 | * <code>Pageable</code> then the client may provide different PageFormats |
| 94 | * for each page index. Calculations of page breaks must account for this. |
| 95 | * </ul> |
| 96 | * <p> |
| 97 | * @see java.awt.print.Pageable |
| 98 | * @see java.awt.print.PageFormat |
| 99 | * @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 | } |