Mercurial > projects > dwt-linux
view dwt/internal/image/JPEGQuantizationTable.d @ 13:3d9bbe0a83a0
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author | Frank Benoit <benoit@tionex.de> |
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date | Sun, 06 Jan 2008 22:54:14 +0100 |
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children | fc2b263b8a3f |
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/******************************************************************************* * Copyright (c) 2000, 2006 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ module dwt.internal.image.JPEGQuantizationTable; import dwt.internal.image.LEDataInputStream; import dwt.internal.image.JPEGVariableSizeSegment; import dwt.internal.image.JPEGFileFormat; final class JPEGQuantizationTable : JPEGVariableSizeSegment { public static byte[] DefaultLuminanceQTable = [ cast(byte)255, cast(byte)219, 0, 67, 0, 16, 11, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55, 14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62, 18, 22, 37, 56, 68, 109, 103, 77, 24, 35, 55, 64, 81, 104, 113, 92, 49, 64, 78, 87, 103, 121, 120, 101, 72, 92, 95, 98, 112, 100, 103, 99 ]; public static byte[] DefaultChrominanceQTable = [ cast(byte)255, cast(byte)219, 0, 67, 1, 17, 18, 24, 47, 99, 99, 99, 99, 18, 21, 26, 66, 99, 99, 99, 99, 24, 26, 56, 99, 99, 99, 99, 99, 47, 66, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99 ]; public this(byte[] reference) { super(reference); } public this(LEDataInputStream byteStream) { super(byteStream); } public static JPEGQuantizationTable defaultChrominanceTable() { return new JPEGQuantizationTable(DefaultChrominanceQTable.dup); } public static JPEGQuantizationTable defaultLuminanceTable() { return new JPEGQuantizationTable(DefaultLuminanceQTable.dup); } public int[] getQuantizationTablesKeys() { int[] keys = new int[4]; int keysIndex = 0; int totalLength = getSegmentLength() - 2; int ofs = 4; while (totalLength > 64) { int tq = reference[ofs] & 0xF; int pq = (reference[ofs] & 0xFF) >> 4; if (pq == 0) { ofs += 65; totalLength -= 65; } else { ofs += 129; totalLength -= 129; } if (keysIndex >= keys.length) { keys.length = keys.length + 4; } keys[keysIndex] = tq; keysIndex++; } return keys[ 0 .. keysIndex ].dup; } public int[][] getQuantizationTablesValues() { int[][] values = new int[][](4); int valuesIndex = 0; int totalLength = getSegmentLength() - 2; int ofs = 4; while (totalLength > 64) { int[] qk = new int[64]; int pq = (reference[ofs] & 0xFF) >> 4; if (pq == 0) { for (int i = 0; i < qk.length; i++) { qk[i] = reference[ofs + i + 1] & 0xFF; } ofs += 65; totalLength -= 65; } else { for (int i = 0; i < qk.length; i++) { int idx = (i - 1) * 2 ; qk[i] = (reference[ofs + idx + 1] & 0xFF) * 256 + (reference[ofs + idx + 2] & 0xFF); } ofs += 129; totalLength -= 129; } if (valuesIndex >= values.length) { values.length = values.length + 4; } values[valuesIndex] = qk; valuesIndex++; } return values[ 0 .. valuesIndex ].dup; } public void scaleBy(int qualityFactor) { int qFactor = qualityFactor; if (qFactor <= 0) { qFactor = 1; } if (qFactor > 100) { qFactor = 100; } if (qFactor < 50) { qFactor = 5000 / qFactor; } else { qFactor = 200 - (qFactor * 2); } int totalLength = getSegmentLength() - 2; int ofs = 4; while (totalLength > 64) { // int tq = reference[ofs] & 0xFF; int pq = (reference[ofs] & 0xFF) >> 4; if (pq == 0) { for (int i = ofs + 1; i <= ofs + 64; i++) { int temp = ((reference[i] & 0xFF) * qFactor + 50) / 100; if (temp <= 0) temp = 1; if (temp > 255) temp = 255; reference[i] = cast(byte)temp; } ofs += 65; totalLength -= 65; } else { for (int i = ofs + 1; i <= ofs + 128; i += 2) { int temp = (((reference[i] & 0xFF) * 256 + (reference[i + 1] & 0xFF)) * qFactor + 50) / 100; if (temp <= 0) temp = 1; if (temp > 32767) temp = 32767; reference[i] = cast(byte)(temp >> 8); reference[i + 1] = cast(byte)(temp & 0xFF); } ofs += 129; totalLength -= 129; } } } public int signature() { return JPEGFileFormat.DQT; } }