| /******************************************************************************* |
| * Copyright (c) 2000, 2005 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 |
| *******************************************************************************/ |
| package org.eclipse.swt.internal.image; |
| |
| |
| import org.eclipse.swt.*; |
| |
| final class JPEGScanHeader extends JPEGVariableSizeSegment { |
| public int[][] componentParameters; |
| |
| public JPEGScanHeader(byte[] reference) { |
| super(reference); |
| } |
| |
| public JPEGScanHeader(LEDataInputStream byteStream) { |
| super(byteStream); |
| initializeComponentParameters(); |
| } |
| |
| public int getApproxBitPositionHigh() { |
| return reference[(2 * getNumberOfImageComponents()) + 7] >> 4; |
| } |
| |
| public int getApproxBitPositionLow() { |
| return reference[(2 * getNumberOfImageComponents()) + 7] & 0xF; |
| } |
| |
| public int getEndOfSpectralSelection() { |
| return reference[(2 * getNumberOfImageComponents()) + 6]; |
| } |
| |
| public int getNumberOfImageComponents() { |
| return reference[4]; |
| } |
| |
| public int getStartOfSpectralSelection() { |
| return reference[(2 * getNumberOfImageComponents()) + 5]; |
| } |
| |
| /* Used when decoding. */ |
| void initializeComponentParameters() { |
| int compCount = getNumberOfImageComponents(); |
| componentParameters = new int[0][]; |
| for (int i = 0; i < compCount; i++) { |
| int ofs = 5 + i * 2; |
| int cid = reference[ofs] & 0xFF; |
| int dc = (reference[ofs + 1] & 0xFF) >> 4; |
| int ac = reference[ofs + 1] & 0xF; |
| if (componentParameters.length <= cid) { |
| int[][] newParams = new int[cid + 1][]; |
| System.arraycopy(componentParameters, 0, newParams, 0, componentParameters.length); |
| componentParameters = newParams; |
| } |
| componentParameters[cid] = new int[] { dc, ac }; |
| } |
| } |
| |
| /* Used when encoding. */ |
| public void initializeContents() { |
| int compCount = getNumberOfImageComponents(); |
| int[][] compSpecParams = componentParameters; |
| if (compCount == 0 || compCount != compSpecParams.length) { |
| SWT.error(SWT.ERROR_INVALID_IMAGE); |
| } |
| for (int i = 0; i < compCount; i++) { |
| int ofs = i * 2 + 5; |
| int[] compParams = compSpecParams[i]; |
| reference[ofs] = (byte)(i + 1); |
| reference[ofs + 1] = (byte)(compParams[0] * 16 + compParams[1]); |
| } |
| } |
| |
| public void setEndOfSpectralSelection(int anInteger) { |
| reference[(2 * getNumberOfImageComponents()) + 6] = (byte)anInteger; |
| } |
| |
| public void setNumberOfImageComponents(int anInteger) { |
| reference[4] = (byte)(anInteger & 0xFF); |
| } |
| |
| public void setStartOfSpectralSelection(int anInteger) { |
| reference[(2 * getNumberOfImageComponents()) + 5] = (byte)anInteger; |
| } |
| |
| public int signature() { |
| return JPEGFileFormat.SOS; |
| } |
| |
| public boolean verifyProgressiveScan() { |
| int start = getStartOfSpectralSelection(); |
| int end = getEndOfSpectralSelection(); |
| int low = getApproxBitPositionLow(); |
| int high = getApproxBitPositionHigh(); |
| int count = getNumberOfImageComponents(); |
| if ((start == 0 && end == 00) || (start <= end && end <= 63)) { |
| if (low <= 13 && high <= 13 && (high == 0 || high == low + 1)) { |
| return start == 0 || (start > 0 && count == 1); |
| } |
| } |
| return false; |
| } |
| |
| public boolean isACProgressiveScan() { |
| return getStartOfSpectralSelection() != 0 && getEndOfSpectralSelection() != 0; |
| } |
| |
| public boolean isDCProgressiveScan() { |
| return getStartOfSpectralSelection() == 0 && getEndOfSpectralSelection() == 0; |
| } |
| |
| public boolean isFirstScan() { |
| return getApproxBitPositionHigh() == 0; |
| } |
| |
| } |