--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/com/glavsoft/drawing/ColorDecoder.java	Tue Jul 03 13:20:49 2012 +0900
@@ -0,0 +1,132 @@
+// Copyright (C) 2010, 2011 GlavSoft LLC.
+// All rights reserved.
+//
+//-------------------------------------------------------------------------
+// This file is part of the TightVNC software.  Please visit our Web site:
+//
+//                       http://www.tightvnc.com/
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, write to the Free Software Foundation, Inc.,
+// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+//-------------------------------------------------------------------------
+//
+
+package com.glavsoft.drawing;
+
+import com.glavsoft.exceptions.TransportException;
+import com.glavsoft.rfb.encoding.PixelFormat;
+import com.glavsoft.transport.Reader;
+
+public class ColorDecoder {
+	protected byte redShift;
+	protected byte greenShift;
+	protected byte blueShift;
+	public short redMax;
+	public short greenMax;
+	public short blueMax;
+	private final int bytesPerPixel;
+	private final int bytesPerPixelSignificant;
+	private final byte[] buff;
+
+	private int startShift;
+	private int startShiftCompact;
+	private int addShiftItem;
+	private final boolean isTightSpecific;
+
+	public ColorDecoder(PixelFormat pf) {
+		redShift = pf.redShift;
+		greenShift = pf.greenShift;
+		blueShift = pf.blueShift;
+		redMax = pf.redMax;
+		greenMax = pf.greenMax;
+		blueMax = pf.blueMax;
+		bytesPerPixel = pf.bitsPerPixel / 8;
+		bytesPerPixelSignificant = 24 == pf.depth && 32 == pf.bitsPerPixel ? 3 : bytesPerPixel;
+		buff = new byte[bytesPerPixel];
+		if (0 == pf.bigEndianFlag) {
+			startShift = 0;
+			startShiftCompact = 0;
+			addShiftItem = 8;
+		} else {
+			startShift = pf.bitsPerPixel - 8;
+			startShiftCompact = Math.max(0, pf.depth - 8);
+			addShiftItem = -8;
+		}
+		isTightSpecific = 4==bytesPerPixel && 3==bytesPerPixelSignificant &&
+				255 == redMax && 255 == greenMax && 255 == blueMax;
+	}
+
+	protected int readColor(Reader reader) throws TransportException {
+		return getColor(reader.readBytes(buff, 0, bytesPerPixel), 0);
+	}
+
+	protected int readCompactColor(Reader reader) throws TransportException {
+		return getCompactColor(reader.readBytes(buff, 0, bytesPerPixelSignificant), 0);
+	}
+
+	protected int readTightColor(Reader reader) throws TransportException {
+		return getTightColor(reader.readBytes(buff, 0, bytesPerPixelSignificant), 0);
+	}
+
+	protected int convertColor(int rawColor) {
+		return  255 * (rawColor >> redShift & redMax) / redMax << 16 |
+				255 * (rawColor >> greenShift & greenMax) / greenMax << 8 |
+				255 * (rawColor >> blueShift & blueMax) / blueMax;
+	}
+
+	public void fillRawComponents(byte[] comp, byte[] bytes, int offset) {
+		int rawColor = getRawTightColor(bytes, offset);
+		comp[0] = (byte) (rawColor >> redShift & redMax);
+		comp[1] = (byte) (rawColor >> greenShift & greenMax);
+		comp[2] = (byte) (rawColor >> blueShift & blueMax);
+	}
+
+	protected int getTightColor(byte[] bytes, int offset) {
+		return convertColor(getRawTightColor(bytes, offset));
+	}
+
+	private int getRawTightColor(byte[] bytes, int offset) {
+		if (isTightSpecific)
+			return (bytes[offset++] & 0xff)<<16 |
+					(bytes[offset++] & 0xff)<<8 |
+					bytes[offset++] & 0xff;
+		else
+			return getRawColor(bytes, offset);
+	}
+
+	protected int getColor(byte[] bytes, int offset) {
+		return convertColor(getRawColor(bytes, offset));
+	}
+
+	private int getRawColor(byte[] bytes, int offset) {
+		int shift = startShift;
+		int item = addShiftItem;
+		int rawColor = (bytes[offset++] & 0xff)<<shift;
+		for (int i=1; i<bytesPerPixel; ++i) {
+			rawColor |= (bytes[offset++] & 0xff)<<(shift+=item);
+		}
+		return rawColor;
+	}
+
+	protected int getCompactColor(byte[] bytes, int offset) {
+		int shift = startShiftCompact;
+		int item = addShiftItem;
+		int rawColor = (bytes[offset++] & 0xff)<<shift;
+		for (int i=1; i<bytesPerPixelSignificant; ++i) {
+			rawColor |= (bytes[offset++] & 0xff)<<(shift+=item);
+		}
+		return convertColor(rawColor);
+	}
+
+}
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