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| 1 | +/* | |
| 2 | + * Copyright (c) 2007, Oracle and/or its affiliates. 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package sun.java2d.pipe; | |
| 27 | + | |
| 28 | +/** | |
| 29 | + * The API for an object that generates alpha coverage tiles for a given | |
| 30 | + * path. | |
| 31 | + * The {@link RenderingEngine} will be consulted as a factory to return | |
| 32 | + * one of these objects for a given Shape and a given set of rendering | |
| 33 | + * attributes. | |
| 34 | + * This object will iterate through the bounds of the rendering primitive | |
| 35 | + * and return tiles of a constant size as specified by the getTileWidth() | |
| 36 | + * and getTileHeight() parameters. | |
| 37 | + * The iteration order of the tiles will be as specified by the pseudo-code: | |
| 38 | + * <pre> | |
| 39 | + * int bbox[] = {left, top, right, bottom}; | |
| 40 | + * AATileGenerator aatg = renderengine.getAATileGenerator(..., bbox); | |
| 41 | + * int tw = aatg.getTileWidth(); | |
| 42 | + * int th = aatg.getTileHeight(); | |
| 43 | + * byte tile[] = new byte[tw * th]; | |
| 44 | + * for (y = top; y < bottom; y += th) { | |
| 45 | + * for (x = left; x < right; x += tw) { | |
| 46 | + * int a = aatg.getTypicalAlpha(); | |
| 47 | + * int w = Math.min(tw, right-x); | |
| 48 | + * int h = Math.min(th, bottom-y); | |
| 49 | + * if (a == 0x00) { | |
| 50 | + * // can skip this tile... | |
| 51 | + * aatg.nextTile(); | |
| 52 | + * } else if (a == 0xff) { | |
| 53 | + * // can treat this tile like a fillRect | |
| 54 | + * aatg.nextTile(); | |
| 55 | + * doFill(x, y, w, h); | |
| 56 | + * } else { | |
| 57 | + * aatg.getAlpha(tile, 0, tw); | |
| 58 | + * handleAlpha(tile, x, y, w, h); | |
| 59 | + * } | |
| 60 | + * } | |
| 61 | + * } | |
| 62 | + * aatg.dispose(); | |
| 63 | + * </pre> | |
| 64 | + * The bounding box for the iteration will be returned by the | |
| 65 | + * {@code RenderingEngine} via an argument to the getAATileGenerator() method. | |
| 66 | + */ | |
| 67 | +public interface AATileGenerator { | |
| 68 | + /** | |
| 69 | + * Gets the width of the tiles that the generator batches output into. | |
| 70 | + * @return the width of the standard alpha tile | |
| 71 | + */ | |
| 72 | + public int getTileWidth(); | |
| 73 | + | |
| 74 | + /** | |
| 75 | + * Gets the height of the tiles that the generator batches output into. | |
| 76 | + * @return the height of the standard alpha tile | |
| 77 | + */ | |
| 78 | + public int getTileHeight(); | |
| 79 | + | |
| 80 | + /** | |
| 81 | + * Gets the typical alpha value that will characterize the current | |
| 82 | + * tile. | |
| 83 | + * The answer may be 0x00 to indicate that the current tile has | |
| 84 | + * no coverage in any of its pixels, or it may be 0xff to indicate | |
| 85 | + * that the current tile is completely covered by the path, or any | |
| 86 | + * other value to indicate non-trivial coverage cases. | |
| 87 | + * @return 0x00 for no coverage, 0xff for total coverage, or any other | |
| 88 | + * value for partial coverage of the tile | |
| 89 | + */ | |
| 90 | + public int getTypicalAlpha(); | |
| 91 | + | |
| 92 | + /** | |
| 93 | + * Skips the current tile and moves on to the next tile. | |
| 94 | + * Either this method, or the getAlpha() method should be called | |
| 95 | + * once per tile, but not both. | |
| 96 | + */ | |
| 97 | + public void nextTile(); | |
| 98 | + | |
| 99 | + /** | |
| 100 | + * Gets the alpha coverage values for the current tile. | |
| 101 | + * Either this method, or the nextTile() method should be called | |
| 102 | + * once per tile, but not both. | |
| 103 | + */ | |
| 104 | + public void getAlpha(byte tile[], int offset, int rowstride); | |
| 105 | + | |
| 106 | + /** | |
| 107 | + * Disposes this tile generator. | |
| 108 | + * No further calls will be made on this instance. | |
| 109 | + */ | |
| 110 | + public void dispose(); | |
| 111 | +} | |