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The main purpose of this libraryis to modernize and maintain the slick2D library.
The newest version!
/*
* Copyright (c) 2008-2010, Matthias Mann
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Matthias Mann nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.github.mathiewz.slick.opengl;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.zip.CRC32;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
/**
* A PNGDecoder. The slick PNG decoder is based on this class :)
*
* @author Matthias Mann
*/
public class PNGDecoder {
public static Format ALPHA = new Format(1, true);
public static Format LUMINANCE = new Format(1, false);
public static Format LUMINANCE_ALPHA = new Format(2, true);
public static Format RGB = new Format(3, false);
public static Format RGBA = new Format(4, true);
public static Format BGRA = new Format(4, true);
public static Format ABGR = new Format(4, true);
public static class Format {
final int numComponents;
final boolean hasAlpha;
private Format(int numComponents, boolean hasAlpha) {
this.numComponents = numComponents;
this.hasAlpha = hasAlpha;
}
public int getNumComponents() {
return numComponents;
}
public boolean isHasAlpha() {
return hasAlpha;
}
}
private static final byte[] SIGNATURE = { (byte) 137, 80, 78, 71, 13, 10, 26, 10 };
private static final int IHDR = 0x49484452;
private static final int PLTE = 0x504C5445;
private static final int tRNS = 0x74524E53;
private static final int IDAT = 0x49444154;
private static final byte COLOR_GREYSCALE = 0;
private static final byte COLOR_TRUECOLOR = 2;
private static final byte COLOR_INDEXED = 3;
private static final byte COLOR_GREYALPHA = 4;
private static final byte COLOR_TRUEALPHA = 6;
private final InputStream input;
private final CRC32 crc;
private final byte[] buffer;
private int chunkLength;
private int chunkType;
private int chunkRemaining;
private int width;
private int height;
private int bitdepth;
private int colorType;
private int bytesPerPixel;
private byte[] palette;
private byte[] paletteA;
private byte[] transPixel;
public PNGDecoder(InputStream input) throws IOException {
this.input = input;
crc = new CRC32();
buffer = new byte[4096];
readFully(buffer, 0, SIGNATURE.length);
if (!checkSignature(buffer)) {
throw new IOException("Not a valid PNG file");
}
openChunk(IHDR);
readIHDR();
closeChunk();
searchIDAT: for (;;) {
openChunk();
switch (chunkType) {
case IDAT:
break searchIDAT;
case PLTE:
readPLTE();
break;
case tRNS:
readtRNS();
break;
}
closeChunk();
}
if (colorType == COLOR_INDEXED && palette == null) {
throw new IOException("Missing PLTE chunk");
}
}
public int getHeight() {
return height;
}
public int getWidth() {
return width;
}
public boolean hasAlpha() {
return colorType == COLOR_TRUEALPHA || paletteA != null || transPixel != null;
}
public boolean isRGB() {
return colorType == COLOR_TRUEALPHA || colorType == COLOR_TRUECOLOR || colorType == COLOR_INDEXED;
}
/**
* Computes the implemented format conversion for the desired format.
*
* @param fmt
* the desired format
* @return format which best matches the desired format
* @throws UnsupportedOperationException
* if this PNG file can't be decoded
*/
public Format decideTextureFormat(Format fmt) {
switch (colorType) {
case COLOR_TRUECOLOR:
if (fmt == ABGR || fmt == RGBA || fmt == BGRA || fmt == RGB) {
return fmt;
}
return RGB;
case COLOR_TRUEALPHA:
if (fmt == ABGR || fmt == RGBA || fmt == BGRA || fmt == RGB) {
return fmt;
}
return RGBA;
case COLOR_GREYSCALE:
if (fmt == LUMINANCE || fmt == ALPHA) {
return fmt;
}
return LUMINANCE;
case COLOR_GREYALPHA:
return LUMINANCE_ALPHA;
case COLOR_INDEXED:
if (fmt == ABGR || fmt == RGBA || fmt == BGRA) {
return fmt;
}
return RGBA;
default:
throw new UnsupportedOperationException("Not yet implemented");
}
}
public void decode(ByteBuffer buffer, int stride, Format fmt) throws IOException {
final int offset = buffer.position();
final int lineSize = (width * bitdepth + 7) / 8 * bytesPerPixel;
byte[] curLine = new byte[lineSize + 1];
byte[] prevLine = new byte[lineSize + 1];
byte[] palLine = bitdepth < 8 ? new byte[width + 1] : null;
final Inflater inflater = new Inflater();
try {
for (int y = 0; y < height; y++) {
readChunkUnzip(inflater, curLine, 0, curLine.length);
unfilter(curLine, prevLine);
buffer.position(offset + y * stride);
switch (colorType) {
case COLOR_TRUECOLOR:
if (fmt == ABGR) {
copyRGBtoABGR(buffer, curLine);
} else if (fmt == RGBA) {
copyRGBtoRGBA(buffer, curLine);
} else if (fmt == BGRA) {
copyRGBtoBGRA(buffer, curLine);
} else if (fmt == RGB) {
copy(buffer, curLine);
} else {
throw new UnsupportedOperationException("Unsupported format for this image");
}
break;
case COLOR_TRUEALPHA:
if (fmt == ABGR) {
copyRGBAtoABGR(buffer, curLine);
} else if (fmt == RGBA) {
copy(buffer, curLine);
} else if (fmt == BGRA) {
copyRGBAtoBGRA(buffer, curLine);
break;
} else if (fmt == RGB) {
copyRGBAtoRGB(buffer, curLine);
break;
} else {
throw new UnsupportedOperationException("Unsupported format for this image");
}
break;
case COLOR_GREYSCALE:
if (fmt == LUMINANCE || fmt == ALPHA) {
copy(buffer, curLine);
} else {
throw new UnsupportedOperationException("Unsupported format for this image");
}
break;
case COLOR_GREYALPHA:
if (fmt == LUMINANCE_ALPHA) {
copy(buffer, curLine);
} else {
throw new UnsupportedOperationException("Unsupported format for this image");
}
break;
case COLOR_INDEXED:
switch (bitdepth) {
case 8:
palLine = curLine;
break;
case 4:
expand4(curLine, palLine);
break;
case 2:
expand2(curLine, palLine);
break;
case 1:
expand1(curLine, palLine);
break;
default:
throw new UnsupportedOperationException("Unsupported bitdepth for this image");
}
if (fmt == ABGR) {
copyPALtoABGR(buffer, palLine);
} else if (fmt == RGBA) {
copyPALtoRGBA(buffer, palLine);
} else if (fmt == BGRA) {
copyPALtoBGRA(buffer, palLine);
} else {
throw new UnsupportedOperationException("Unsupported format for this image");
}
break;
default:
throw new UnsupportedOperationException("Not yet implemented");
}
byte[] tmp = curLine;
curLine = prevLine;
prevLine = tmp;
}
} finally {
inflater.end();
}
}
private void copy(ByteBuffer buffer, byte[] curLine) {
buffer.put(curLine, 1, curLine.length - 1);
}
private void copyRGBtoABGR(ByteBuffer buffer, byte[] curLine) {
if (transPixel != null) {
byte tr = transPixel[1];
byte tg = transPixel[3];
byte tb = transPixel[5];
for (int i = 1, n = curLine.length; i < n; i += 3) {
byte r = curLine[i];
byte g = curLine[i + 1];
byte b = curLine[i + 2];
byte a = (byte) 0xFF;
if (r == tr && g == tg && b == tb) {
a = 0;
}
buffer.put(a).put(b).put(g).put(r);
}
} else {
for (int i = 1, n = curLine.length; i < n; i += 3) {
buffer.put((byte) 0xFF).put(curLine[i + 2]).put(curLine[i + 1]).put(curLine[i]);
}
}
}
private void copyRGBtoRGBA(ByteBuffer buffer, byte[] curLine) {
if (transPixel != null) {
byte tr = transPixel[1];
byte tg = transPixel[3];
byte tb = transPixel[5];
for (int i = 1, n = curLine.length; i < n; i += 3) {
byte r = curLine[i];
byte g = curLine[i + 1];
byte b = curLine[i + 2];
byte a = (byte) 0xFF;
if (r == tr && g == tg && b == tb) {
a = 0;
}
buffer.put(r).put(g).put(b).put(a);
}
} else {
for (int i = 1, n = curLine.length; i < n; i += 3) {
buffer.put(curLine[i]).put(curLine[i + 1]).put(curLine[i + 2]).put((byte) 0xFF);
}
}
}
private void copyRGBtoBGRA(ByteBuffer buffer, byte[] curLine) {
if (transPixel != null) {
byte tr = transPixel[1];
byte tg = transPixel[3];
byte tb = transPixel[5];
for (int i = 1, n = curLine.length; i < n; i += 3) {
byte r = curLine[i];
byte g = curLine[i + 1];
byte b = curLine[i + 2];
byte a = (byte) 0xFF;
if (r == tr && g == tg && b == tb) {
a = 0;
}
buffer.put(b).put(g).put(r).put(a);
}
} else {
for (int i = 1, n = curLine.length; i < n; i += 3) {
buffer.put(curLine[i + 2]).put(curLine[i + 1]).put(curLine[i]).put((byte) 0xFF);
}
}
}
private void copyRGBAtoABGR(ByteBuffer buffer, byte[] curLine) {
for (int i = 1, n = curLine.length; i < n; i += 4) {
buffer.put(curLine[i + 3]).put(curLine[i + 2]).put(curLine[i + 1]).put(curLine[i]);
}
}
private void copyRGBAtoBGRA(ByteBuffer buffer, byte[] curLine) {
for (int i = 1, n = curLine.length; i < n; i += 4) {
buffer.put(curLine[i + 2]).put(curLine[i + 1]).put(curLine[i + 0]).put(curLine[i + 3]);
}
}
private void copyRGBAtoRGB(ByteBuffer buffer, byte[] curLine) {
for (int i = 1, n = curLine.length; i < n; i += 4) {
buffer.put(curLine[i]).put(curLine[i + 1]).put(curLine[i + 2]);
}
}
private void copyPALtoABGR(ByteBuffer buffer, byte[] curLine) {
if (paletteA != null) {
for (int i = 1, n = curLine.length; i < n; i += 1) {
int idx = curLine[i] & 255;
byte r = palette[idx * 3 + 0];
byte g = palette[idx * 3 + 1];
byte b = palette[idx * 3 + 2];
byte a = paletteA[idx];
buffer.put(a).put(b).put(g).put(r);
}
} else {
for (int i = 1, n = curLine.length; i < n; i += 1) {
int idx = curLine[i] & 255;
byte r = palette[idx * 3 + 0];
byte g = palette[idx * 3 + 1];
byte b = palette[idx * 3 + 2];
byte a = (byte) 0xFF;
buffer.put(a).put(b).put(g).put(r);
}
}
}
private void copyPALtoRGBA(ByteBuffer buffer, byte[] curLine) {
if (paletteA != null) {
for (int i = 1, n = curLine.length; i < n; i += 1) {
int idx = curLine[i] & 255;
byte r = palette[idx * 3 + 0];
byte g = palette[idx * 3 + 1];
byte b = palette[idx * 3 + 2];
byte a = paletteA[idx];
buffer.put(r).put(g).put(b).put(a);
}
} else {
for (int i = 1, n = curLine.length; i < n; i += 1) {
int idx = curLine[i] & 255;
byte r = palette[idx * 3 + 0];
byte g = palette[idx * 3 + 1];
byte b = palette[idx * 3 + 2];
byte a = (byte) 0xFF;
buffer.put(r).put(g).put(b).put(a);
}
}
}
private void copyPALtoBGRA(ByteBuffer buffer, byte[] curLine) {
if (paletteA != null) {
for (int i = 1, n = curLine.length; i < n; i += 1) {
int idx = curLine[i] & 255;
byte r = palette[idx * 3 + 0];
byte g = palette[idx * 3 + 1];
byte b = palette[idx * 3 + 2];
byte a = paletteA[idx];
buffer.put(b).put(g).put(r).put(a);
}
} else {
for (int i = 1, n = curLine.length; i < n; i += 1) {
int idx = curLine[i] & 255;
byte r = palette[idx * 3 + 0];
byte g = palette[idx * 3 + 1];
byte b = palette[idx * 3 + 2];
byte a = (byte) 0xFF;
buffer.put(b).put(g).put(r).put(a);
}
}
}
private void expand4(byte[] src, byte[] dst) {
for (int i = 1, n = dst.length; i < n; i += 2) {
int val = src[1 + (i >> 1)] & 255;
switch (n - i) {
default:
dst[i + 1] = (byte) (val & 15);
case 1:
dst[i] = (byte) (val >> 4);
}
}
}
private void expand2(byte[] src, byte[] dst) {
for (int i = 1, n = dst.length; i < n; i += 4) {
int val = src[1 + (i >> 2)] & 255;
switch (n - i) {
default:
dst[i + 3] = (byte) (val & 3);
case 3:
dst[i + 2] = (byte) (val >> 2 & 3);
case 2:
dst[i + 1] = (byte) (val >> 4 & 3);
case 1:
dst[i] = (byte) (val >> 6);
}
}
}
private void expand1(byte[] src, byte[] dst) {
for (int i = 1, n = dst.length; i < n; i += 8) {
int val = src[1 + (i >> 3)] & 255;
switch (n - i) {
default:
dst[i + 7] = (byte) (val & 1);
case 7:
dst[i + 6] = (byte) (val >> 1 & 1);
case 6:
dst[i + 5] = (byte) (val >> 2 & 1);
case 5:
dst[i + 4] = (byte) (val >> 3 & 1);
case 4:
dst[i + 3] = (byte) (val >> 4 & 1);
case 3:
dst[i + 2] = (byte) (val >> 5 & 1);
case 2:
dst[i + 1] = (byte) (val >> 6 & 1);
case 1:
dst[i] = (byte) (val >> 7);
}
}
}
private void unfilter(byte[] curLine, byte[] prevLine) throws IOException {
switch (curLine[0]) {
case 0: // none
break;
case 1:
unfilterSub(curLine);
break;
case 2:
unfilterUp(curLine, prevLine);
break;
case 3:
unfilterAverage(curLine, prevLine);
break;
case 4:
unfilterPaeth(curLine, prevLine);
break;
default:
throw new IOException("invalide filter type in scanline: " + curLine[0]);
}
}
private void unfilterSub(byte[] curLine) {
final int bpp = bytesPerPixel;
for (int i = bpp + 1, n = curLine.length; i < n; ++i) {
curLine[i] += curLine[i - bpp];
}
}
private void unfilterUp(byte[] curLine, byte[] prevLine) {
for (int i = 1, n = curLine.length; i < n; ++i) {
curLine[i] += prevLine[i];
}
}
private void unfilterAverage(byte[] curLine, byte[] prevLine) {
final int bpp = bytesPerPixel;
int i;
for (i = 1; i <= bpp; ++i) {
curLine[i] += (byte) ((prevLine[i] & 0xFF) >>> 1);
}
for (int n = curLine.length; i < n; ++i) {
curLine[i] += (byte) ((prevLine[i] & 0xFF) + (curLine[i - bpp] & 0xFF) >>> 1);
}
}
private void unfilterPaeth(byte[] curLine, byte[] prevLine) {
final int bpp = bytesPerPixel;
int i;
for (i = 1; i <= bpp; ++i) {
curLine[i] += prevLine[i];
}
for (int n = curLine.length; i < n; ++i) {
int a = curLine[i - bpp] & 255;
int b = prevLine[i] & 255;
int c = prevLine[i - bpp] & 255;
int p = a + b - c;
int pa = p - a;
if (pa < 0) {
pa = -pa;
}
int pb = p - b;
if (pb < 0) {
pb = -pb;
}
int pc = p - c;
if (pc < 0) {
pc = -pc;
}
if (pa <= pb && pa <= pc) {
c = a;
} else if (pb <= pc) {
c = b;
}
curLine[i] += (byte) c;
}
}
private void readIHDR() throws IOException {
checkChunkLength(13);
readChunk(buffer, 0, 13);
width = readInt(buffer, 0);
height = readInt(buffer, 4);
bitdepth = buffer[8] & 255;
colorType = buffer[9] & 255;
switch (colorType) {
case COLOR_GREYSCALE:
if (bitdepth != 8) {
throw new IOException("Unsupported bit depth: " + bitdepth);
}
bytesPerPixel = 1;
break;
case COLOR_GREYALPHA:
if (bitdepth != 8) {
throw new IOException("Unsupported bit depth: " + bitdepth);
}
bytesPerPixel = 2;
break;
case COLOR_TRUECOLOR:
if (bitdepth != 8) {
throw new IOException("Unsupported bit depth: " + bitdepth);
}
bytesPerPixel = 3;
break;
case COLOR_TRUEALPHA:
if (bitdepth != 8) {
throw new IOException("Unsupported bit depth: " + bitdepth);
}
bytesPerPixel = 4;
break;
case COLOR_INDEXED:
switch (bitdepth) {
case 8:
case 4:
case 2:
case 1:
bytesPerPixel = 1;
break;
default:
throw new IOException("Unsupported bit depth: " + bitdepth);
}
break;
default:
throw new IOException("unsupported color format: " + colorType);
}
if (buffer[10] != 0) {
throw new IOException("unsupported compression method");
}
if (buffer[11] != 0) {
throw new IOException("unsupported filtering method");
}
if (buffer[12] != 0) {
throw new IOException("unsupported interlace method");
}
}
private void readPLTE() throws IOException {
int paletteEntries = chunkLength / 3;
if (paletteEntries < 1 || paletteEntries > 256 || chunkLength % 3 != 0) {
throw new IOException("PLTE chunk has wrong length");
}
palette = new byte[paletteEntries * 3];
readChunk(palette, 0, palette.length);
}
private void readtRNS() throws IOException {
switch (colorType) {
case COLOR_GREYSCALE:
checkChunkLength(2);
transPixel = new byte[2];
readChunk(transPixel, 0, 2);
break;
case COLOR_TRUECOLOR:
checkChunkLength(6);
transPixel = new byte[6];
readChunk(transPixel, 0, 6);
break;
case COLOR_INDEXED:
if (palette == null) {
throw new IOException("tRNS chunk without PLTE chunk");
}
paletteA = new byte[palette.length / 3];
Arrays.fill(paletteA, (byte) 0xFF);
readChunk(paletteA, 0, paletteA.length);
break;
default:
// just ignore it
}
}
private void closeChunk() throws IOException {
if (chunkRemaining > 0) {
// just skip the rest and the CRC
skip(chunkRemaining + 4);
} else {
readFully(buffer, 0, 4);
int expectedCrc = readInt(buffer, 0);
int computedCrc = (int) crc.getValue();
if (computedCrc != expectedCrc) {
throw new IOException("Invalid CRC");
}
}
chunkRemaining = 0;
chunkLength = 0;
chunkType = 0;
}
private void openChunk() throws IOException {
readFully(buffer, 0, 8);
chunkLength = readInt(buffer, 0);
chunkType = readInt(buffer, 4);
chunkRemaining = chunkLength;
crc.reset();
crc.update(buffer, 4, 4); // only chunkType
}
private void openChunk(int expected) throws IOException {
openChunk();
if (chunkType != expected) {
throw new IOException("Expected chunk: " + Integer.toHexString(expected));
}
}
private void checkChunkLength(int expected) throws IOException {
if (chunkLength != expected) {
throw new IOException("Chunk has wrong size");
}
}
private int readChunk(byte[] buffer, int offset, int length) throws IOException {
if (length > chunkRemaining) {
length = chunkRemaining;
}
readFully(buffer, offset, length);
crc.update(buffer, offset, length);
chunkRemaining -= length;
return length;
}
private void refillInflater(Inflater inflater) throws IOException {
while (chunkRemaining == 0) {
closeChunk();
openChunk(IDAT);
}
int read = readChunk(buffer, 0, buffer.length);
inflater.setInput(buffer, 0, read);
}
private void readChunkUnzip(Inflater inflater, byte[] buffer, int offset, int length) throws IOException {
try {
do {
int read = inflater.inflate(buffer, offset, length);
if (read <= 0) {
if (inflater.finished()) {
throw new EOFException();
}
if (inflater.needsInput()) {
refillInflater(inflater);
} else {
throw new IOException("Can't inflate " + length + " bytes");
}
} else {
offset += read;
length -= read;
}
} while (length > 0);
} catch (DataFormatException ex) {
throw (IOException) new IOException("inflate error").initCause(ex);
}
}
private void readFully(byte[] buffer, int offset, int length) throws IOException {
do {
int read = input.read(buffer, offset, length);
if (read < 0) {
throw new EOFException();
}
offset += read;
length -= read;
} while (length > 0);
}
private int readInt(byte[] buffer, int offset) {
return buffer[offset] << 24 | (buffer[offset + 1] & 255) << 16 | (buffer[offset + 2] & 255) << 8 | buffer[offset + 3] & 255;
}
private void skip(long amount) throws IOException {
while (amount > 0) {
long skipped = input.skip(amount);
if (skipped < 0) {
throw new EOFException();
}
amount -= skipped;
}
}
private static boolean checkSignature(byte[] buffer) {
for (int i = 0; i < SIGNATURE.length; i++) {
if (buffer[i] != SIGNATURE[i]) {
return false;
}
}
return true;
}
}
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