--- /dev/null
+/* $RCSfile$
+ * $Author: nicove $
+ * $Date: 2007-03-30 12:26:16 -0500 (Fri, 30 Mar 2007) $
+ * $Revision: 7275 $
+ *
+ * Some portions of this file have been modified by Robert Hanson hansonr.at.stolaf.edu 2012-2017
+ * for use in SwingJS via transpilation into JavaScript using Java2Script.
+ *
+ * Copyright (C) 2002-2005 The Jmol Development Team
+ *
+ * Contact: jmol-developers@lists.sf.net
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+package javajs.img;
+
+import java.io.BufferedInputStream;
+import java.io.IOException;
+
+import javajs.util.Rdr;
+
+/**
+ * src: http://www.javaworld.com/article/2077542/learn-java/java-tip-43--how-to-
+ * read-8--and-24-bit-microsoft-windows-bitmaps-in-java-applications.html
+ *
+ * see also: http://en.wikipedia.org/wiki/BMP_file_format
+ *
+ * Modified by Bob Hanson hansonr@stolaf.edu
+ *
+ * @author Bob Hanson (hansonr@stolaf.edu)
+ *
+ */
+public class BMPDecoder {
+
+ public BMPDecoder() {
+ // for reflection
+ }
+
+ private BufferedInputStream bis;
+
+ /**
+ * original comment:
+ *
+ * loadbitmap() method converted from Windows C code. Reads only uncompressed
+ * 24- and 8-bit images. Tested with images saved using Microsoft Paint in
+ * Windows 95. If the image is not a 24- or 8-bit image, the program refuses
+ * to even try. I guess one could include 4-bit images by masking the byte by
+ * first 1100 and then 0011. I am not really interested in such images. If a
+ * compressed image is attempted, the routine will probably fail by generating
+ * an IOException. Look for variable ncompression to be different from 0 to
+ * indicate compression is present.
+ *
+ * @param bytes
+ * @return [image byte array, width, height]
+ */
+ public Object[] decodeWindowsBMP(byte[] bytes) {
+ try {
+ bis = Rdr.getBIS(bytes);
+ temp = new byte[4];
+ // read BITMAPFILEHEADER
+ if (readByte() != 'B' || readByte() != 'M')
+ return null;
+ readInt(); // file size; ignored
+ readShort(); // reserved
+ readShort(); // reserved
+ readInt(); // ptr to pixel array; ignored
+ int imageWidth, imageHeight, bitsPerPixel, nColors = 0, imageSize = 0;
+ // read BITMAP header
+ int headerSize = readInt();
+ switch (headerSize) {
+ case 12:
+ // BITMAPCOREHEADER
+ imageWidth = readShort();
+ imageHeight = readShort();
+ readShort(); // planes
+ bitsPerPixel = readShort();
+ break;
+ case 40:
+ // BITMAPINFOHEADER
+ imageWidth = readInt();
+ imageHeight = readInt();
+ readShort(); // planes
+ bitsPerPixel = readShort();
+ int ncompression = readInt();
+ if (ncompression != 0) {
+ System.out.println("BMP Compression is :" + ncompression
+ + " -- aborting");
+ return null;
+ }
+ imageSize = readInt();
+ readInt(); // hres
+ readInt(); // vres
+ nColors = readInt();
+ readInt(); // colors used
+ break;
+ default:
+ System.out.println("BMP Header unrecognized, length=" + headerSize
+ + " -- aborting");
+ return null;
+ }
+ boolean isYReversed = (imageHeight < 0);
+ if (isYReversed)
+ imageHeight = -imageHeight;
+ int nPixels = imageHeight * imageWidth;
+ int bytesPerPixel = bitsPerPixel / 8;
+ nColors = (nColors > 0 ? nColors : 1 << bitsPerPixel);
+ int npad = (bytesPerPixel == 4 ? 0
+ : imageSize == 0 ? 4 - (imageWidth % 4) : (imageSize / imageHeight)
+ - imageWidth * bytesPerPixel) % 4;
+ int[] palette;
+ int[] buf = new int[nPixels];
+ int dpt = (isYReversed ? imageWidth : -imageWidth);
+ int pt0 = (isYReversed ? 0 : nPixels + dpt);
+ int pt1 = (isYReversed ? nPixels : dpt);
+ switch (bitsPerPixel) {
+ case 32:
+ case 24:
+ for (int pt = pt0; pt != pt1; pt += dpt, pad(npad))
+ for (int i = 0; i < imageWidth; i++)
+ buf[pt + i] = readColor(bytesPerPixel);
+ break;
+ case 8:
+ palette = new int[nColors];
+ for (int i = 0; i < nColors; i++)
+ palette[i] = readColor(4);
+ for (int pt = pt0; pt != pt1; pt += dpt, pad(npad))
+ for (int i = 0; i < imageWidth; i++)
+ buf[pt + i] = palette[readByte()];
+ break;
+ case 4:
+ npad = (4 - (((imageWidth + 1) / 2) % 4)) % 4;
+ palette = new int[nColors];
+ for (int i = 0; i < nColors; i++)
+ palette[i] = readColor(4);
+ int b4 = 0;
+ for (int pt = pt0; pt != pt1; pt += dpt, pad(npad))
+ for (int i = 0, shift = 4; i < imageWidth; i++, shift = 4 - shift)
+ buf[pt + i] = palette[((shift == 4 ? (b4 = readByte()) : b4) >> shift) & 0xF];
+ break;
+ case 1:
+ int color1 = readColor(3);
+ int color2 = readColor(3);
+ npad = (4 - (((imageWidth + 7) / 8) % 4)) % 4;
+ int b = 0;
+ for (int pt = pt0; pt != pt1; pt += dpt, pad(npad))
+ for (int i = 0, bpt = -1; i < imageWidth; i++, bpt--) {
+ if (bpt < 0) {
+ b = readByte();
+ bpt = 7;
+ }
+ buf[pt + i] = ((b & (1 << bpt)) == 0 ? color1 : color2);
+ }
+ break;
+ case 64:
+ case 2:
+ default:
+ System.out
+ .println("Not a 32-, 24-, 8-, 4-, or 1-bit Windows Bitmap, aborting...");
+ return null;
+ }
+ return new Object[] { buf, Integer.valueOf(imageWidth),
+ Integer.valueOf(imageHeight) };
+ } catch (Exception e) {
+ System.out.println("Caught exception in loadbitmap!");
+ }
+ return null;
+ }
+
+ private boolean pad(int npad) throws IOException {
+ for (int i = 0; i < npad; i++)
+ readByte();
+ return true;
+ }
+
+ private byte[] temp;
+
+ private int readColor(int n) throws IOException {
+ bis.read(temp, 0, n);
+ return 0xff << 24 | ((temp[2] & 0xff) << 16)
+ | ((temp[1] & 0xff) << 8) | temp[0] & 0xff;
+ }
+
+ private int readInt() throws IOException {
+ bis.read(temp, 0, 4);
+ return ((temp[3] & 0xff) << 24) | ((temp[2] & 0xff) << 16)
+ | ((temp[1] & 0xff) << 8) | temp[0] & 0xff;
+ }
+
+ private int readShort() throws IOException {
+ bis.read(temp, 0, 2);
+ return ((temp[1] & 0xff) << 8) | temp[0] & 0xff;
+ }
+
+ private int readByte() throws IOException {
+ bis.read(temp, 0, 1);
+ return temp[0] & 0xff;
+ }
+
+}