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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 | } | ||