package ar.com.hjg.pngj;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.List;
import ar.com.hjg.pngj.chunks.ChunkCopyBehaviour;
import ar.com.hjg.pngj.chunks.ChunkHelper;
import ar.com.hjg.pngj.chunks.ChunkPredicate;
import ar.com.hjg.pngj.chunks.ChunksList;
import ar.com.hjg.pngj.chunks.ChunksListForWrite;
import ar.com.hjg.pngj.chunks.PngChunk;
import ar.com.hjg.pngj.chunks.PngChunkIEND;
import ar.com.hjg.pngj.chunks.PngChunkIHDR;
import ar.com.hjg.pngj.chunks.PngChunkPLTE;
import ar.com.hjg.pngj.chunks.PngMetadata;
import ar.com.hjg.pngj.pixels.PixelsWriter;
import ar.com.hjg.pngj.pixels.PixelsWriterDefault;
/**
* Writes a PNG image, line by line.
*/
public class PngWriter {
public final ImageInfo imgInfo;
/**
* last writen row number, starting from 0
*/
protected int rowNum = -1;
private final ChunksListForWrite chunksList;
private final PngMetadata metadata;
/**
* Current chunk grounp, (0-6) already read or reading
* <p>
* see {@link ChunksList}
*/
protected int currentChunkGroup = -1;
private int passes = 1; //Some writes might require two passes
private int currentpass = 0; // numbered from 1
private boolean shouldCloseStream = true;
private int idatMaxSize = 0; // 0=use default (PngIDatChunkOutputStream 64k)
private PngIDatChunkOutputStream datStream;
protected PixelsWriter pixelsWriter;
private final OutputStream os;
private ChunkPredicate copyFromPredicate = null;
private ChunksList copyFromList = null;
protected StringBuilder debuginfo = new StringBuilder();
/**
* Opens a file for writing.
* <p>
* Sets shouldCloseStream=true. For more info see {@link #PngWriter(OutputStream, ImageInfo)}
*
* @param file
* @param imgInfo
* @param allowoverwrite If false and file exists, an {@link PngjOutputException} is thrown
*/
public PngWriter(File file, ImageInfo imgInfo, boolean allowoverwrite) {
this(PngHelperInternal.ostreamFromFile(file, allowoverwrite), imgInfo);
setShouldCloseStream(true);
}
/**
* @see #PngWriter(File, ImageInfo, boolean) (overwrite=true)
*/
public PngWriter(File file, ImageInfo imgInfo) {
this(file, imgInfo, true);
}
/**
* Constructs a new PngWriter from a output stream. After construction nothing is writen yet. You
* still can set some parameters (compression, filters) and queue chunks before start writing the
* pixels.
* <p>
*
* @param outputStream Open stream for binary writing
* @param imgInfo Basic image parameters
*/
public PngWriter(OutputStream outputStream, ImageInfo imgInfo) {
this.os = outputStream;
this.imgInfo = imgInfo;
// prealloc
chunksList = new ChunksListForWrite(imgInfo);
metadata = new PngMetadata(chunksList);
pixelsWriter = createPixelsWriter(imgInfo);
setCompLevel(9);
}
private void initIdat() { // this triggers the writing of first chunks
datStream = new PngIDatChunkOutputStream(this.os, idatMaxSize);
pixelsWriter.setOs(datStream);
writeSignatureAndIHDR();
writeFirstChunks();
}
private void writeEndChunk() {
PngChunkIEND c = new PngChunkIEND(imgInfo);
c.createRawChunk().writeChunk(os);
chunksList.getChunks().add(c);
}
private void writeFirstChunks() {
if (currentChunkGroup >= ChunksList.CHUNK_GROUP_4_IDAT)
return;
int nw = 0;
currentChunkGroup = ChunksList.CHUNK_GROUP_1_AFTERIDHR;
queueChunksFromOther();
nw = chunksList.writeChunks(os, currentChunkGroup);
currentChunkGroup = ChunksList.CHUNK_GROUP_2_PLTE;
nw = chunksList.writeChunks(os, currentChunkGroup);
if (nw > 0 && imgInfo.greyscale)
throw new PngjOutputException("cannot write palette for this format");
if (nw == 0 && imgInfo.indexed)
throw new PngjOutputException("missing palette");
currentChunkGroup = ChunksList.CHUNK_GROUP_3_AFTERPLTE;
nw = chunksList.writeChunks(os, currentChunkGroup);
currentChunkGroup = ChunksList.CHUNK_GROUP_4_IDAT;
}
private void writeLastChunks() { // not including end
queueChunksFromOther();
currentChunkGroup = ChunksList.CHUNK_GROUP_5_AFTERIDAT;
chunksList.writeChunks(os, currentChunkGroup);
// should not be unwriten chunks
List<PngChunk> pending = chunksList.getQueuedChunks();
if (!pending.isEmpty())
throw new PngjOutputException(pending.size() + " chunks were not written! Eg: "
+ pending.get(0).toString());
currentChunkGroup = ChunksList.CHUNK_GROUP_6_END;
}
/**
* Write id signature and also "IHDR" chunk
*/
private void writeSignatureAndIHDR() {
currentChunkGroup = ChunksList.CHUNK_GROUP_0_IDHR;
PngHelperInternal.writeBytes(os, PngHelperInternal.getPngIdSignature()); // signature
PngChunkIHDR ihdr = new PngChunkIHDR(imgInfo);
// http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html
ihdr.setCols(imgInfo.cols);
ihdr.setRows(imgInfo.rows);
ihdr.setBitspc(imgInfo.bitDepth);
int colormodel = 0;
if (imgInfo.alpha)
colormodel += 0x04;
if (imgInfo.indexed)
colormodel += 0x01;
if (!imgInfo.greyscale)
colormodel += 0x02;
ihdr.setColormodel(colormodel);
ihdr.setCompmeth(0); // compression method 0=deflate
ihdr.setFilmeth(0); // filter method (0)
ihdr.setInterlaced(0); // we never interlace
ihdr.createRawChunk().writeChunk(os);
chunksList.getChunks().add(ihdr);
}
private void queueChunksFromOther() {
if (copyFromList == null || copyFromPredicate == null)
return;
boolean idatDone = currentChunkGroup >= ChunksList.CHUNK_GROUP_4_IDAT;
for (PngChunk chunk : copyFromList.getChunks()) {
if (chunk.getRaw().data == null)
continue; // we cannot copy skipped chunks?
int group = chunk.getChunkGroup();
if (group <= ChunksList.CHUNK_GROUP_4_IDAT && idatDone)
continue;
if (group >= ChunksList.CHUNK_GROUP_4_IDAT && !idatDone)
continue;
if (chunk.crit && !chunk.id.equals(PngChunkPLTE.ID))
continue; // critical chunks (except perhaps PLTE) are never
// copied
boolean copy = copyFromPredicate.match(chunk);
if (copy) {
// but if the chunk is already queued or writen, it's ommited!
if (chunksList.getEquivalent(chunk).isEmpty()
&& chunksList.getQueuedEquivalent(chunk).isEmpty()) {
chunksList.queue(chunk);
}
}
}
}
/**
* Queues an ancillary chunk for writing.
* <p>
* If a "equivalent" chunk is already queued (see {@link ChunkHelper#equivalent(PngChunk, PngChunk)), this overwrites it.
* <p>
* The chunk will be written as late as possible, unless the priority is set.
*
* @param chunk
*/
public void queueChunk(PngChunk chunk) {
for (PngChunk other : chunksList.getQueuedEquivalent(chunk)) {
getChunksList().removeChunk(other);
}
chunksList.queue(chunk);
}
/**
* Sets an origin (typically from a {@link PngReader}) of Chunks to be copied. This should be
* called only once, before starting writing the rows. It doesn't matter the current state of the
* PngReader reading, this is a live object and what matters is that when the writer writes the
* pixels (IDAT) the reader has already read them, and that when the writer ends, the reader is
* already ended (all this is very natural).
* <p>
* Apart from the copyMask, there is some addional heuristics:
* <p>
* - The chunks will be queued, but will be written as late as possible (unless you explicitly set
* priority=true)
* <p>
* - The chunk will not be queued if an "equivalent" chunk was already queued explicitly. And it
* will be overwriten another is queued explicitly.
*
* @param chunks
* @param copyMask Some bitmask from {@link ChunkCopyBehaviour}
*
* @see #copyChunksFrom(ChunksList, ChunkPredicate)
*/
public void copyChunksFrom(ChunksList chunks, int copyMask) {
copyChunksFrom(chunks, ChunkCopyBehaviour.createPredicate(copyMask, imgInfo));
}
/**
* Copy all chunks from origin. See {@link #copyChunksFrom(ChunksList, int)} for more info
*/
public void copyChunksFrom(ChunksList chunks) {
copyChunksFrom(chunks, ChunkCopyBehaviour.COPY_ALL);
}
/**
* Copy chunks from origin depending on some {@link ChunkPredicate}
*
* @param chunks
* @param predicate The chunks (ancillary or PLTE) will be copied if and only if predicate matches
*
* @see #copyChunksFrom(ChunksList, int) for more info
*/
public void copyChunksFrom(ChunksList chunks, ChunkPredicate predicate) {
if (copyFromList != null && chunks != null)
PngHelperInternal.LOGGER.warning("copyChunksFrom should only be called once");
if (predicate == null)
throw new PngjOutputException("copyChunksFrom requires a predicate");
this.copyFromList = chunks;
this.copyFromPredicate = predicate;
}
/**
* Computes compressed size/raw size, approximate.
* <p>
* Actually: compressed size = total size of IDAT data , raw size = uncompressed pixel bytes =
* rows * (bytesPerRow + 1).
*
* This must be called after pngw.end()
*/
public double computeCompressionRatio() {
if (currentChunkGroup < ChunksList.CHUNK_GROUP_6_END)
throw new PngjOutputException("must be called after end()");
double compressed = (double) datStream.getCountFlushed();
double raw = (imgInfo.bytesPerRow + 1) * imgInfo.rows;
return compressed / raw;
}
/**
* Finalizes all the steps and closes the stream. This must be called after writing the lines.
*/
public void end() {
if (rowNum != imgInfo.rows - 1)
throw new PngjOutputException("all rows have not been written");
try {
datStream.flush();
writeLastChunks();
writeEndChunk();
} catch (IOException e) {
throw new PngjOutputException(e);
} finally {
close();
}
}
/**
* Closes and releases resources
* <p>
* This is normally called internally from {@link #end()}, you should only call this for aborting
* the writing and release resources (close the stream).
* <p>
* Idempotent and secure - never throws exceptions
*/
public void close() {
try {
if (datStream != null)
datStream.close();
} catch (Exception e2) {
}
if (pixelsWriter != null)
pixelsWriter.close();
if (shouldCloseStream && os != null)
try {
os.close();
} catch (Exception e) {
PngHelperInternal.LOGGER.warning("Error closing writer " + e.toString());
}
}
/**
* returns the chunks list (queued and writen chunks)
*/
public ChunksListForWrite getChunksList() {
return chunksList;
}
/**
* Retruns a high level wrapper over for metadata handling
*/
public PngMetadata getMetadata() {
return metadata;
}
/**
* Sets internal prediction filter type, or strategy to choose it.
* <p>
* This must be called just after constructor, before starting writing.
* <p>
*/
public void setFilterType(FilterType filterType) {
pixelsWriter.setFilterType(filterType);
}
/**
* This is kept for backwards compatibility, now the PixelsWriter object should be used for
* setting compression/filtering options
*
* @see PixelsWriter#setCompressionFactor(double)
* @param compLevel between 0 (no compression, max speed) and 9 (max compression)
*/
public void setCompLevel(int complevel) {
pixelsWriter.setDeflaterCompLevel(complevel);
}
/**
*
*/
public void setFilterPreserve(boolean filterPreserve) {
if (filterPreserve)
pixelsWriter.setFilterType(FilterType.FILTER_PRESERVE);
else if (pixelsWriter.getFilterType() == null)
pixelsWriter.setFilterType(FilterType.FILTER_DEFAULT);
}
/**
* Sets maximum size of IDAT fragments. Incrementing this from the default has very little effect
* on compression and increments memory usage. You should rarely change this.
* <p>
*
* @param idatMaxSize default=0 : use defaultSize (32K)
*/
public void setIdatMaxSize(int idatMaxSize) {
this.idatMaxSize = idatMaxSize;
}
/**
* If true, output stream will be closed after ending write
* <p>
* default=true
*/
public void setShouldCloseStream(boolean shouldCloseStream) {
this.shouldCloseStream = shouldCloseStream;
}
/**
* Writes next row, does not check row number.
*
* @param imgline
*/
public void writeRow(IImageLine imgline) {
writeRow(imgline, rowNum + 1);
}
/**
* Writes the full set of row. The ImageLineSet should contain (allow to acces) imgInfo.rows
*/
public void writeRows(IImageLineSet<? extends IImageLine> imglines) {
for (int i = 0; i < imgInfo.rows; i++)
writeRow(imglines.getImageLine(i));
}
public void writeRow(IImageLine imgline, int rownumber) {
rowNum++;
if (rowNum == imgInfo.rows)
rowNum = 0;
if (rownumber == imgInfo.rows)
rownumber = 0;
if (rownumber >= 0 && rowNum != rownumber)
throw new PngjOutputException("rows must be written in order: expected:" + rowNum
+ " passed:" + rownumber);
if (rowNum == 0)
currentpass++;
if (rownumber == 0 && currentpass == passes) {
initIdat();
writeFirstChunks();
}
byte[] rowb = pixelsWriter.getRowb();
imgline.writeToPngRaw(rowb);
pixelsWriter.processRow(rowb);
}
/**
* Utility method, uses internaly a ImageLineInt
*/
public void writeRowInt(int[] buf) {
writeRow(new ImageLineInt(imgInfo, buf));
}
/**
* Factory method for pixels writer. This will be called once at the moment at start writing a set
* of IDAT chunks (typically once in a normal PNG)
*
* This should be overriden if custom filtering strategies are desired. Remember to release this
* with close()
*
* @param imginfo Might be different than that of this object (eg: APNG with subimages)
* @param os Output stream
* @return new PixelsWriter. Don't forget to call close() when discarding it
*/
protected PixelsWriter createPixelsWriter(ImageInfo imginfo) {
PixelsWriterDefault pw = new PixelsWriterDefault(imginfo);
return pw;
}
public final PixelsWriter getPixelsWriter() {
return pixelsWriter;
}
public String getDebuginfo() {
return debuginfo.toString();
}
}