private PngChunk processHeadChunks(PngImage result, Iterator<PngChunk> itChunks)
throws IOException {
PngChunk chunk = null;
while (itChunks.hasNext()) {
chunk = itChunks.next();
if (PngChunk.IMAGE_DATA.equals(chunk.getTypeString())) {
break;
}
if (chunk.isRequired()) {
ByteArrayOutputStream bytes = new ByteArrayOutputStream(chunk.getLength());
DataOutputStream data = new DataOutputStream(bytes);
data.write(chunk.getData());
data.close();
PngChunk newChunk = new PngChunk(chunk.getType(), bytes.toByteArray());
if (PngChunk.IMAGE_HEADER.equals(chunk.getTypeString())) {
newChunk.setInterlace((byte) 0);
}
result.addChunk(newChunk);
}
}
return chunk;
}
private byte[] getInflatedImageData(PngChunk chunk, Iterator<PngChunk> itChunks)
throws IOException {
ByteArrayOutputStream imageBytes =
new ByteArrayOutputStream(chunk == null ? 0 : chunk.getLength());
DataOutputStream imageData = new DataOutputStream(imageBytes);
while (chunk != null) {
if (PngChunk.IMAGE_DATA.equals(chunk.getTypeString())) {
imageData.write(chunk.getData());
} else {
break;
}
chunk = itChunks.hasNext() ? itChunks.next() : null;
}
imageData.close();
return this.pngCompressionHandler.inflate(imageBytes);
}
private PngChunk processTailChunks(
PngImage result, Iterator<PngChunk> itBaseChunks, PngChunk lastBaseChunk) throws IOException {
while (lastBaseChunk != null) {
if (lastBaseChunk.isCritical()) {
ByteArrayOutputStream bytes = new ByteArrayOutputStream(lastBaseChunk.getLength());
DataOutputStream data = new DataOutputStream(bytes);
data.write(lastBaseChunk.getData());
data.close();
PngChunk newChunk = new PngChunk(lastBaseChunk.getType(), bytes.toByteArray());
result.addChunk(newChunk);
}
lastBaseChunk = itBaseChunks.hasNext() ? itBaseChunks.next() : null;
}
return lastBaseChunk;
}
