1 /* 2 * Copyright (c) 2020, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import java.awt.image.BufferedImage; 25 import java.awt.image.RenderedImage; 26 27 /** 28 * @test 29 * @author Martin Desruisseaux 30 */ 31 public final class GetTileGridOffset { 32 public static void main(final String[] args) { 33 final BufferedImage image = new BufferedImage( 34 20, 20, BufferedImage.TYPE_BYTE_GRAY); 35 validate(image); 36 37 final BufferedImage subImage = image.getSubimage(5, 5, 10, 10); 38 verifyConsistency(subImage); 39 validate(subImage); 40 } 41 42 /** 43 * Verifies that the tile grid offsets of given image are consistent with 44 * other properties (minimum pixel coordinates, minimum tile indices and 45 * tile size). This method verifies the general contract, ignoring 46 * simplifications brought by the {@link BufferedImage} specialization. 47 * The purpose of this method is to demonstrate why tile grid offsets 48 * need to be zero in the {@link BufferedImage} case. 49 */ 50 private static void verifyConsistency(final RenderedImage image) { 51 /* 52 * This test will convert the coordinates of an arbitrary pixel in 53 * the first tile to the indices of that tile. The expected result 54 * is (minTileX, minTileY). We take the pixel in lower-right corner 55 * of the first tile (the upper-left corner does not demonstrate 56 * bug 8166038). 57 */ 58 final int tileWidth = image.getTileWidth(); 59 final int tileHeight = image.getTileHeight(); 60 final int x = image.getMinX() + tileWidth - 1; 61 final int y = image.getMinY() + tileHeight - 1; 62 /* 63 * From javax.media.jai.PlanarImage.XToTileX(int) 64 * (omitting rounding toward negative infinity): 65 * 66 * tileX = (x - tileGridXOffset) / tileWidth 67 */ 68 int tileX = Math.floorDiv(x - image.getTileGridXOffset(), tileWidth); 69 int tileY = Math.floorDiv(y - image.getTileGridYOffset(), tileHeight); 70 int minTileX = image.getMinTileX(); // Expected value 71 int minTileY = image.getMinTileY(); 72 if (tileX != minTileX || tileY != minTileY) { 73 throw new RuntimeException("Tile indices of upper-left tile" 74 + " shall be (" + minTileX + ", " + minTileY + ")." 75 + " But using the provided tileGridOffsets we got" 76 + " (" + tileX + ", " + tileY + ")."); 77 } 78 } 79 80 /** 81 * Verifies that tile grid offsets are zero as required by 82 * {@link BufferedImage} specification. 83 */ 84 private static void validate(final BufferedImage image) { 85 final int tileGridXOffset = image.getTileGridXOffset(); 86 final int tileGridYOffset = image.getTileGridYOffset(); 87 if (tileGridXOffset != 0) { 88 throw new RuntimeException("BufferedImage.getTileGridXOffset()" 89 + " shall be zero. Got " + tileGridXOffset); 90 } 91 if (tileGridYOffset != 0) { 92 throw new RuntimeException("BufferedImage.getTileGridTOffset()" 93 + " shall be zero. Got " + tileGridYOffset); 94 } 95 } 96 }