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SWT is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.
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/*******************************************************************************
* Copyright (c) 2000, 2011 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 JPEGFrameHeader extends JPEGVariableSizeSegment {
int maxVFactor;
int maxHFactor;
public int[] componentIdentifiers;
public int[][] componentParameters;
public JPEGFrameHeader(byte[] reference) {
super(reference);
}
public JPEGFrameHeader(LEDataInputStream byteStream) {
super(byteStream);
initializeComponentParameters();
}
public int getSamplePrecision() {
return reference[4] & 0xFF;
}
public int getNumberOfLines() {
return (reference[5] & 0xFF) << 8 | (reference[6] & 0xFF);
}
public int getSamplesPerLine() {
return (reference[7] & 0xFF) << 8 | (reference[8] & 0xFF);
}
public int getNumberOfImageComponents() {
return reference[9] & 0xFF;
}
public void setSamplePrecision(int precision) {
reference[4] = (byte)(precision & 0xFF);
}
public void setNumberOfLines(int anInteger) {
reference[5] = (byte)((anInteger & 0xFF00) >> 8);
reference[6] = (byte)(anInteger & 0xFF);
}
public void setSamplesPerLine(int samples) {
reference[7] = (byte)((samples & 0xFF00) >> 8);
reference[8] = (byte)(samples & 0xFF);
}
public void setNumberOfImageComponents(int anInteger) {
reference[9] = (byte)(anInteger & 0xFF);
}
public int getMaxHFactor() {
return maxHFactor;
}
public int getMaxVFactor() {
return maxVFactor;
}
public void setMaxHFactor(int anInteger) {
maxHFactor = anInteger;
}
public void setMaxVFactor(int anInteger) {
maxVFactor = anInteger;
}
/* Used when decoding. */
void initializeComponentParameters() {
int nf = getNumberOfImageComponents();
componentIdentifiers = new int[nf];
int[][] compSpecParams = new int[0][];
int hmax = 1;
int vmax = 1;
for (int i = 0; i < nf; i++) {
int ofs = i * 3 + 10;
int ci = reference[ofs] & 0xFF;
componentIdentifiers[i] = ci;
int hi = (reference[ofs + 1] & 0xFF) >> 4;
int vi = reference[ofs + 1] & 0xF;
int tqi = reference[ofs + 2] & 0xFF;
if (hi > hmax) {
hmax = hi;
}
if (vi > vmax) {
vmax = vi;
}
int[] compParam = new int[5];
compParam[0] = tqi;
compParam[1] = hi;
compParam[2] = vi;
if (compSpecParams.length <= ci) {
int[][] newParams = new int[ci + 1][];
System.arraycopy(compSpecParams, 0, newParams, 0, compSpecParams.length);
compSpecParams = newParams;
}
compSpecParams[ci] = compParam;
}
int x = getSamplesPerLine();
int y = getNumberOfLines();
int[] multiples = new int[] { 8, 16, 24, 32 };
for (int i = 0; i < nf; i++) {
int[] compParam = compSpecParams[componentIdentifiers[i]];
int hi = compParam[1];
int vi = compParam[2];
int compWidth = (x * hi + hmax - 1) / hmax;
int compHeight = (y * vi + vmax - 1) / vmax;
int dsWidth = roundUpToMultiple(compWidth, multiples[hi - 1]);
int dsHeight = roundUpToMultiple(compHeight, multiples[vi - 1]);
compParam[3] = dsWidth;
compParam[4] = dsHeight;
}
setMaxHFactor(hmax);
setMaxVFactor(vmax);
componentParameters = compSpecParams;
}
/* Used when encoding. */
public void initializeContents() {
int nf = getNumberOfImageComponents();
if (nf == 0 || nf != componentParameters.length) {
SWT.error(SWT.ERROR_INVALID_IMAGE);
}
int hmax = 0;
int vmax = 0;
int[][] compSpecParams = componentParameters;
for (int i = 0; i < nf; i++) {
int ofs = i * 3 + 10;
int[] compParam = compSpecParams[componentIdentifiers[i]];
int hi = compParam[1];
int vi = compParam[2];
if (hi * vi > 4) {
SWT.error(SWT.ERROR_INVALID_IMAGE);
}
reference[ofs] = (byte)(i + 1);
reference[ofs + 1] = (byte)(hi * 16 + vi);
reference[ofs + 2] = (byte)(compParam[0]);
if (hi > hmax) hmax = hi;
if (vi > vmax) vmax = vi;
}
int x = getSamplesPerLine();
int y = getNumberOfLines();
int[] multiples = new int[] {8, 16, 24, 32};
for (int i = 0; i < nf; i++) {
int[] compParam = compSpecParams[componentIdentifiers[i]];
int hi = compParam[1];
int vi = compParam[2];
int compWidth = (x * hi + hmax - 1) / hmax;
int compHeight = (y * vi + vmax - 1) / vmax;
int dsWidth = roundUpToMultiple(compWidth, multiples[hi - 1]);
int dsHeight = roundUpToMultiple(compHeight, multiples[vi - 1]);
compParam[3] = dsWidth;
compParam[4] = dsHeight;
}
setMaxHFactor(hmax);
setMaxVFactor(vmax);
}
int roundUpToMultiple(int anInteger, int mInteger) {
int a = anInteger + mInteger - 1;
return a - (a % mInteger);
}
/*
* Verify the information contained in the receiver is correct.
* Answer true if the header contains a valid marker. Otherwise,
* answer false. Valid Start Of Frame markers are:
* SOF_0 - Baseline DCT, Huffman coding
* SOF_1 - Extended sequential DCT, Huffman coding
* SOF_2 - Progressive DCT, Huffman coding
* SOF_3 - Lossless (sequential), Huffman coding
* SOF_5 - Differential sequential, Huffman coding
* SOF_6 - Differential progressive, Huffman coding
* SOF_7 - Differential lossless, Huffman coding
* SOF_9 - Extended sequential DCT, arithmetic coding
* SOF_10 - Progressive DCT, arithmetic coding
* SOF_11 - Lossless (sequential), arithmetic coding
* SOF_13 - Differential sequential, arithmetic coding
* SOF_14 - Differential progressive, arithmetic coding
* SOF_15 - Differential lossless, arithmetic coding
*/
public boolean verify() {
int marker = getSegmentMarker();
return (marker >= JPEGFileFormat.SOF0 && marker <= JPEGFileFormat.SOF3) ||
(marker >= JPEGFileFormat.SOF5 && marker <= JPEGFileFormat.SOF7) ||
(marker >= JPEGFileFormat.SOF9 && marker <= JPEGFileFormat.SOF11) ||
(marker >= JPEGFileFormat.SOF13 && marker <= JPEGFileFormat.SOF15);
}
public boolean isProgressive() {
int marker = getSegmentMarker();
return marker == JPEGFileFormat.SOF2
|| marker == JPEGFileFormat.SOF6
|| marker == JPEGFileFormat.SOF10
|| marker == JPEGFileFormat.SOF14;
}
public boolean isArithmeticCoding() {
return getSegmentMarker() >= JPEGFileFormat.SOF9;
}
}