PngWriter (PNGJ 2.1.1-SNAPSHOT API)

java.lang.Object
- ar.com.hjg.pngj.PngWriter

Direct Known Subclasses:

PngWriterHc
```
public class PngWriter
extends Object
```
Writes a PNG image, line by line.

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`currentChunkGroup` Current chunk grounp, (0-6) already written or currently writing (this is advanced when just starting to write the new group, not when finalizing the previous)
`protected StringBuilder`	`debuginfo`
`ImageInfo`	`imgInfo`
`protected PixelsWriter`	`pixelsWriter`
`protected int`	`rowNum` last writen row number, starting from 0

Constructor Summary

Constructors
Constructor and Description
`PngWriter(File file, ImageInfo imgInfo)`
`PngWriter(File file, ImageInfo imgInfo, boolean allowoverwrite)` Opens a file for writing.
`PngWriter(OutputStream outputStream, ImageInfo imgInfo)` Constructs a new PngWriter from a output stream.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Closes and releases resources
`double`	`computeCompressionRatio()` Computes compressed size/raw size, approximate.
`void`	`copyChunksFrom(ChunksList chunks)` Copy all chunks from origin.
`void`	`copyChunksFrom(ChunksList chunks, ChunkPredicate predicate)` Copy chunks from origin depending on some `ChunkPredicate`
`void`	`copyChunksFrom(ChunksList chunks, int copyMask)` Sets an origin (typically from a `PngReader`) of Chunks to be copied.
`protected PixelsWriter`	`createPixelsWriter(ImageInfo imginfo)` Factory method for pixels writer.
`void`	`end()` Finalizes all the steps and closes the stream.
`ChunksListForWrite`	`getChunksList()` returns the chunks list (queued and writen chunks)
`String`	`getDebuginfo()`
`PngMetadata`	`getMetadata()` Retruns a high level wrapper over for metadata handling
`PixelsWriter`	`getPixelsWriter()`
`void`	`queueChunk(PngChunk chunk)` Queues an ancillary chunk for writing.
`void`	`setCompLevel(int complevel)` This is kept for backwards compatibility, now the PixelsWriter object should be used for setting compression/filtering options
`void`	`setFilterPreserve(boolean filterPreserve)`
`void`	`setFilterType(FilterType filterType)` Sets internal prediction filter type, or strategy to choose it.
`void`	`setIdatMaxSize(int idatMaxSize)` Sets maximum size of IDAT fragments.
`void`	`setShouldCloseStream(boolean shouldCloseStream)` If true, output stream will be closed after ending write
`void`	`writeRow(IImageLine imgline)` Writes next row, does not check row number.
`void`	`writeRow(IImageLine imgline, int rownumber)`
`void`	`writeRowInt(int[] buf)` Utility method, uses internaly a ImageLineInt
`void`	`writeRows(IImageLineSet<? extends IImageLine> imglines)` Writes the full set of row.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - imgInfo
```
public final ImageInfo imgInfo
```
  - rowNum
```
protected int rowNum
```
    last writen row number, starting from 0
  - currentChunkGroup
```
protected int currentChunkGroup
```
    Current chunk grounp, (0-6) already written or currently writing (this is advanced when just starting to write the new group, not when finalizing the previous)
    see ChunksList
  - pixelsWriter
```
protected PixelsWriter pixelsWriter
```
  - debuginfo
```
protected StringBuilder debuginfo
```
- Constructor Detail
  - PngWriter
```
public PngWriter(File file,
         ImageInfo imgInfo,
         boolean allowoverwrite)
```
    Opens a file for writing.
    Sets shouldCloseStream=true. For more info see PngWriter(OutputStream, ImageInfo)
    
    Parameters:
    file -
    imgInfo -
    allowoverwrite - If false and file exists, an PngjOutputException is thrown
  - PngWriter
```
public PngWriter(File file,
         ImageInfo imgInfo)
```
    See Also:
    (overwrite=true)
  - PngWriter
```
public PngWriter(OutputStream outputStream,
         ImageInfo imgInfo)
```
    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.
    
    Parameters:
    outputStream - Open stream for binary writing
    imgInfo - Basic image parameters
- Method Detail
  - queueChunk
```
public void queueChunk(PngChunk chunk)
```
    Queues an ancillary chunk for writing.
    If a "equivalent" chunk is already queued (see {@link ChunkHelper#equivalent(PngChunk, PngChunk)), this overwrites it.
    The chunk will be written as late as possible, unless the priority is set.
    
    Parameters:
    chunk -
  - copyChunksFrom
```
public void copyChunksFrom(ChunksList chunks,
                  int copyMask)
```
    Sets an origin (typically from a 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).
    Apart from the copyMask, there is some addional heuristics:
    - The chunks will be queued, but will be written as late as possible (unless you explicitly set priority=true)
    - The chunk will not be queued if an "equivalent" chunk was already queued explicitly. And it will be overwriten another is queued explicitly.
    
    Parameters:
    chunks -
    copyMask - Some bitmask from ChunkCopyBehaviour
    See Also:
    copyChunksFrom(ChunksList, ChunkPredicate)
  - copyChunksFrom
```
public void copyChunksFrom(ChunksList chunks)
```
    Copy all chunks from origin. See copyChunksFrom(ChunksList, int) for more info
  - copyChunksFrom
```
public void copyChunksFrom(ChunksList chunks,
                  ChunkPredicate predicate)
```
    Copy chunks from origin depending on some ChunkPredicate
    
    Parameters:
    chunks -
    predicate - The chunks (ancillary or PLTE) will be copied if and only if predicate matches
    See Also:
    for more info
  - computeCompressionRatio
```
public double computeCompressionRatio()
```
    Computes compressed size/raw size, approximate.
    Actually: compressed size = total size of IDAT data , raw size = uncompressed pixel bytes = rows * (bytesPerRow + 1). This must be called after pngw.end()
  - end
```
public void end()
```
    Finalizes all the steps and closes the stream. This must be called after writing the lines. Idempotent
  - close
```
public void close()
```
    Closes and releases resources
    This is normally called internally from end(), you should only call this for aborting the writing and release resources (close the stream).
    Idempotent and secure - never throws exceptions
  - getChunksList
```
public ChunksListForWrite getChunksList()
```
    returns the chunks list (queued and writen chunks)
  - getMetadata
```
public PngMetadata getMetadata()
```
    Retruns a high level wrapper over for metadata handling
  - setFilterType
```
public void setFilterType(FilterType filterType)
```
    Sets internal prediction filter type, or strategy to choose it.
    This must be called just after constructor, before starting writing.
  - setCompLevel
```
public void setCompLevel(int complevel)
```
    This is kept for backwards compatibility, now the PixelsWriter object should be used for setting compression/filtering options
    
    Parameters:
    compLevel - between 0 (no compression, max speed) and 9 (max compression)
    See Also:
    PixelsWriter#setCompressionFactor(double)
  - setFilterPreserve
```
public void setFilterPreserve(boolean filterPreserve)
```
  - setIdatMaxSize
```
public void setIdatMaxSize(int idatMaxSize)
```
    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.
    
    Parameters:
    idatMaxSize - default=0 : use defaultSize (32K)
  - setShouldCloseStream
```
public void setShouldCloseStream(boolean shouldCloseStream)
```
    If true, output stream will be closed after ending write
    default=true
  - writeRow
```
public void writeRow(IImageLine imgline)
```
    Writes next row, does not check row number.
    
    Parameters:
    imgline -
  - writeRows
```
public void writeRows(IImageLineSet<? extends IImageLine> imglines)
```
    Writes the full set of row. The ImageLineSet should contain (allow to acces) imgInfo.rows
  - writeRow
```
public void writeRow(IImageLine imgline,
            int rownumber)
```
  - writeRowInt
```
public void writeRowInt(int[] buf)
```
    Utility method, uses internaly a ImageLineInt
  - createPixelsWriter
```
protected PixelsWriter createPixelsWriter(ImageInfo imginfo)
```
    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()
    
    Parameters:
    imginfo - Might be different than that of this object (eg: APNG with subimages)
    os - Output stream
    
    Returns:
    new PixelsWriter. Don't forget to call close() when discarding it
  - getPixelsWriter
```
public final PixelsWriter getPixelsWriter()
```
  - getDebuginfo
```
public String getDebuginfo()
```

Class PngWriter

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

imgInfo

rowNum

currentChunkGroup

pixelsWriter

debuginfo

Constructor Detail

PngWriter

PngWriter

PngWriter

Method Detail

queueChunk

copyChunksFrom

copyChunksFrom

copyChunksFrom

computeCompressionRatio

end

close

getChunksList

getMetadata

setFilterType

setCompLevel

setFilterPreserve

setIdatMaxSize

setShouldCloseStream

writeRow

writeRows

writeRow

writeRowInt

createPixelsWriter

getPixelsWriter

getDebuginfo