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package jogamp.opengl.util.pngj.chunks;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import jogamp.opengl.util.pngj.ImageInfo;
import jogamp.opengl.util.pngj.PngHelperInternal;
import jogamp.opengl.util.pngj.PngjException;
/**
* zTXt chunk.
* <p>
* see http://www.w3.org/TR/PNG/#11zTXt
*/
public class PngChunkZTXT extends PngChunkTextVar {
public final static String ID = ChunkHelper.zTXt;
// http://www.w3.org/TR/PNG/#11zTXt
public PngChunkZTXT(ImageInfo info) {
super(ID, info);
}
@Override
public ChunkRaw createRawChunk() {
if (key.isEmpty())
throw new PngjException("Text chunk key must be non empty");
try {
ByteArrayOutputStream ba = new ByteArrayOutputStream();
ba.write(key.getBytes(PngHelperInternal.charsetLatin1));
ba.write(0); // separator
ba.write(0); // compression method: 0
byte[] textbytes = ChunkHelper.compressBytes(val.getBytes(PngHelperInternal.charsetLatin1), true);
ba.write(textbytes);
byte[] b = ba.toByteArray();
ChunkRaw chunk = createEmptyChunk(b.length, false);
chunk.data = b;
return chunk;
} catch (IOException e) {
throw new PngjException(e);
}
}
@Override
public void parseFromRaw(ChunkRaw c) {
int nullsep = -1;
for (int i = 0; i < c.data.length; i++) { // look for first zero
if (c.data[i] != 0)
continue;
nullsep = i;
break;
}
if (nullsep < 0 || nullsep > c.data.length - 2)
throw new PngjException("bad zTXt chunk: no separator found");
key = new String(c.data, 0, nullsep, PngHelperInternal.charsetLatin1);
int compmet = (int) c.data[nullsep + 1];
if (compmet != 0)
throw new PngjException("bad zTXt chunk: unknown compression method");
byte[] uncomp = ChunkHelper.compressBytes(c.data, nullsep + 2, c.data.length - nullsep - 2, false); // uncompress
val = new String(uncomp, PngHelperInternal.charsetLatin1);
}
@Override
public void cloneDataFromRead(PngChunk other) {
PngChunkZTXT otherx = (PngChunkZTXT) other;
key = otherx.key;
val = otherx.val;
}
}
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