Module java.desktop
Package javax.imageio.stream

# Interface ImageOutputStream

All Superinterfaces:
  `AutoCloseable`, `Closeable`, `DataInput`, `DataOutput`, `ImageInputStream`

All Known Implementing Classes:
  `FileCacheImageOutputStream`, `FileImageOutputStream`, `ImageOutputStreamImpl`, `MemoryCacheImageOutputStream`

public interface ImageOutputStream extends ImageInputStream, DataOutput
A seekable output stream interface for use by `ImageWriter`s. Various output destinations, such as `OutputStream`s and `File`s, as well as future fast I/O destinations may be "wrapped" by a suitable implementation of this interface for use by the Image I/O API.

Unlike a standard `OutputStream`, ImageOutputStream extends its counterpart, `ImageInputStream`. Thus it is possible to read from the stream as it is being written. The same seek and flush positions apply to both reading and writing, although the semantics for dealing with a non-zero bit offset before a byte-aligned write are necessarily different from the semantics for dealing with a non-zero bit offset before a byte-aligned read. When reading bytes, any bit offset is set to 0 before the read; when writing bytes, a non-zero bit offset causes the remaining bits in the byte to be written as 0s. The byte-aligned write then starts at the next byte position.

See Also:
  - `ImageInputStream`

## Method Summary

Modifier and Type
Method
Description
`void`
`flushBefore(long pos)`
Flushes all data prior to the given position to the underlying destination, such as an `OutputStream` or `File`.
`void`
`write(byte[] b)`
Writes a sequence of bytes to the stream at the current position.
`void`
`write(byte[] b, int off, int len)`
Writes a sequence of bytes to the stream at the current position.
`void`
`write(int b)`
Writes a single byte to the stream at the current position.
`void`
`writeBit(int bit)`
Writes a single bit, given by the least significant bit of the argument, to the stream at the current bit offset within the current byte position.
`void`
`writeBits(long bits, int numBits)`
Writes a sequence of bits, given by the `numBits` least significant bits of the `bits` argument in left-to-right order, to the stream at the current bit offset within the current byte position.
`void`
`writeBoolean(boolean v)`
Writes a `boolean` value to the stream.
`void`
`writeByte(int v)`
Writes the 8 low-order bits of `v` to the stream.
`void`
`writeBytes(String s)`
Writes a string to the output stream.
`void`
`writeChar(int v)`
This method is a synonym for `writeShort`.
`void`
`writeChars(char[] c, int off, int len)`
Writes a sequence of chars to the stream at the current position.
`void`
`writeChars(String s)`
Writes a string to the output stream.
`void`
`writeDouble(double v)`
Writes a `double` value, which is comprised of four bytes, to the output stream.
`void`
`writeDoubles(double[] d, int off, int len)`
Writes a sequence of doubles to the stream at the current position.
`void`
`writeFloat(float v)`
Writes a `float` value, which is comprised of four bytes, to the output stream.
`void`
`writeFloats(float[] f, int off, int len)`
Writes a sequence of floats to the stream at the current position.
`void`
`writeInt(int v)`
Writes the 32 bits of `v` to the stream.
`void`
`writeInts(int[] i, int off, int len)`
Writes a sequence of ints to the stream at the current position.
`void`
`writeLong(long v)`
Writes the 64 bits of `v` to the stream.
`void`
`writeLongs(long[] l, int off, int len)`
Writes a sequence of longs to the stream at the current position.
`void`
`writeShort(int v)`
Writes the 16 low-order bits of `v` to the stream.
`void`
`writeShorts(short[] s, int off, int len)`
Writes a sequence of shorts to the stream at the current position.
`void`
`writeUTF(String s)`
Writes two bytes of length information to the output stream in network byte order, followed by the modified UTF-8 representation of every character in the string `s`.

### Methods declared in interface javax.imageio.stream.ImageInputStream

`close, flush, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, isCached, isCachedFile, isCachedMemory, length, mark, read, read, read, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, seek, setBitOffset, setByteOrder, skipBytes, skipBytes`

## Method Details

### write

void write(int b) throws IOException
Writes a single byte to the stream at the current position. The 24 high-order bits of `b` are ignored.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write. Implementers can use the `flushBits` method of `ImageOutputStreamImpl` to guarantee this.

Specified by:
  `write` in interface `DataOutput`
Parameters:
  `b` - an `int` whose lower 8 bits are to be written.
Throws:
  `IOException` - if an I/O error occurs.

### write

void write(byte[] b) throws IOException
Writes a sequence of bytes to the stream at the current position. If `b.length` is 0, nothing is written. The byte `b[0]` is written first, then the byte `b[1]`, and so on.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `write` in interface `DataOutput`
Parameters:
  `b` - an array of `byte`s to be written.
Throws:
  `NullPointerException` - if `b` is `null`.
  `IOException` - if an I/O error occurs.

### write

void write(byte[] b, int off, int len) throws IOException
Writes a sequence of bytes to the stream at the current position. If `len` is 0, nothing is written. The byte `b[off]` is written first, then the byte `b[off + 1]`, and so on.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write. Implementers can use the `flushBits` method of `ImageOutputStreamImpl` to guarantee this.

Specified by:
  `write` in interface `DataOutput`
Parameters:
  `b` - an array of `byte`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `byte`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `b.length`.
  `NullPointerException` - if `b` is `null`.
  `IOException` - if an I/O error occurs.

### writeBoolean

void writeBoolean(boolean v) throws IOException
Writes a `boolean` value to the stream. If `v` is true, the value `(byte)1` is written; if `v` is false, the value `(byte)0` is written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeBoolean` in interface `DataOutput`
Parameters:
  `v` - the `boolean` to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeByte

void writeByte(int v) throws IOException
Writes the 8 low-order bits of `v` to the stream. The 24 high-order bits of `v` are ignored. (This means that `writeByte` does exactly the same thing as `write` for an integer argument.)

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeByte` in interface `DataOutput`
Parameters:
  `v` - an `int` containing the byte value to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeShort

void writeShort(int v) throws IOException
Writes the 16 low-order bits of `v` to the stream. The 16 high-order bits of `v` are ignored. If the stream uses network byte order, the bytes written, in order, will be:

     (byte)((v >> 8) & 0xff)
     (byte)(v & 0xff)

Otherwise, the bytes written will be:

     (byte)(v & 0xff)
     (byte)((v >> 8) & 0xff)

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeShort` in interface `DataOutput`
Parameters:
  `v` - an `int` containing the short value to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeChar

void writeChar(int v) throws IOException
This method is a synonym for `writeShort`.

Specified by:
  `writeChar` in interface `DataOutput`
Parameters:
  `v` - an `int` containing the char (unsigned short) value to be written.
Throws:
  `IOException` - if an I/O error occurs.
See Also:
  - `writeShort(int)`

### writeInt

void writeInt(int v) throws IOException
Writes the 32 bits of `v` to the stream. If the stream uses network byte order, the bytes written, in order, will be:

     (byte)((v >> 24) & 0xff)
     (byte)((v >> 16) & 0xff)
     (byte)((v >> 8) & 0xff)
     (byte)(v & 0xff)

Otherwise, the bytes written will be:

     (byte)(v & 0xff)
     (byte)((v >> 8) & 0xff)
     (byte)((v >> 16) & 0xff)
     (byte)((v >> 24) & 0xff)

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeInt` in interface `DataOutput`
Parameters:
  `v` - an `int` containing the value to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeLong

void writeLong(long v) throws IOException
Writes the 64 bits of `v` to the stream. If the stream uses network byte order, the bytes written, in order, will be:

     (byte)((v >> 56) & 0xff)
     (byte)((v >> 48) & 0xff)
     (byte)((v >> 40) & 0xff)
     (byte)((v >> 32) & 0xff)
     (byte)((v >> 24) & 0xff)
     (byte)((v >> 16) & 0xff)
     (byte)((v >> 8) & 0xff)
     (byte)(v & 0xff)

Otherwise, the bytes written will be:

     (byte)(v & 0xff)
     (byte)((v >> 8) & 0xff)
     (byte)((v >> 16) & 0xff)
     (byte)((v >> 24) & 0xff)
     (byte)((v >> 32) & 0xff)
     (byte)((v >> 40) & 0xff)
     (byte)((v >> 48) & 0xff)
     (byte)((v >> 56) & 0xff)

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeLong` in interface `DataOutput`
Parameters:
  `v` - a `long` containing the value to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeFloat

void writeFloat(float v) throws IOException
Writes a `float` value, which is comprised of four bytes, to the output stream. It does this as if it first converts this `float` value to an `int` in exactly the manner of the `Float.floatToIntBits` method and then writes the int value in exactly the manner of the `writeInt` method.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeFloat` in interface `DataOutput`
Parameters:
  `v` - a `float` containing the value to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeDouble

void writeDouble(double v) throws IOException
Writes a `double` value, which is comprised of four bytes, to the output stream. It does this as if it first converts this `double` value to a `long` in exactly the manner of the `Double.doubleToLongBits` method and then writes the long value in exactly the manner of the `writeLong` method.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeDouble` in interface `DataOutput`
Parameters:
  `v` - a `double` containing the value to be written.
Throws:
  `IOException` - if an I/O error occurs.

### writeBytes

void writeBytes(String s) throws IOException
Writes a string to the output stream. For every character in the string `s`, taken in order, one byte is written to the output stream. If `s` is `null`, a `NullPointerException` is thrown.

If `s.length` is zero, then no bytes are written. Otherwise, the character `s[0]` is written first, then `s[1]`, and so on; the last character written is `s[s.length-1]`. For each character, one byte is written, the low-order byte, in exactly the manner of the `writeByte` method. The high-order eight bits of each character in the string are ignored.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeBytes` in interface `DataOutput`
Parameters:
  `s` - a `String` containing the value to be written.
Throws:
  `NullPointerException` - if `s` is `null`.
  `IOException` - if an I/O error occurs.

### writeChars

void writeChars(String s) throws IOException
Writes a string to the output stream. For every character in the string `s`, taken in order, two bytes are written to the output stream, ordered according to the current byte order setting. If network byte order is being used, the high-order byte is written first; the order is reversed otherwise. If `s` is `null`, a `NullPointerException` is thrown.

If `s.length` is zero, then no bytes are written. Otherwise, the character `s[0]` is written first, then `s[1]`, and so on; the last character written is `s[s.length-1]`.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Specified by:
  `writeChars` in interface `DataOutput`
Parameters:
  `s` - a `String` containing the value to be written.
Throws:
  `NullPointerException` - if `s` is `null`.
  `IOException` - if an I/O error occurs.

### writeUTF

void writeUTF(String s) throws IOException
Writes two bytes of length information to the output stream in network byte order, followed by the modified UTF-8 representation of every character in the string `s`. If `s` is `null`, a `NullPointerException` is thrown. Each character in the string `s` is converted to a group of one, two, or three bytes, depending on the value of the character.

If a character `c` is in the range `\u0001` through `\u007f`, it is represented by one byte:

     (byte)c

If a character `c` is `\u0000` or is in the range `\u0080` through `\u07ff`, then it is represented by two bytes, to be written in the order shown:

     (byte)(0xc0 | (0x1f & (c >> 6)))
     (byte)(0x80 | (0x3f & c))

If a character `c` is in the range `\u0800` through `uffff`, then it is represented by three bytes, to be written in the order shown:

     (byte)(0xe0 | (0x0f & (c >> 12)))
     (byte)(0x80 | (0x3f & (c >> 6)))
     (byte)(0x80 | (0x3f & c))

First, the total number of bytes needed to represent all the characters of `s` is calculated. If this number is larger than `65535`, then a `UTFDataFormatException` is thrown. Otherwise, this length is written to the output stream in exactly the manner of the `writeShort` method; after this, the one-, two-, or three-byte representation of each character in the string `s` is written.

The current byte order setting is ignored.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Note: This method should not be used in the implementation of image formats that use standard UTF-8, because the modified UTF-8 used here is incompatible with standard UTF-8.

Specified by:
  `writeUTF` in interface `DataOutput`
Parameters:
  `s` - a `String` containing the value to be written.
Throws:
  `NullPointerException` - if `s` is `null`.
  `UTFDataFormatException` - if the modified UTF-8 representation of `s` requires more than 65536 bytes.
  `IOException` - if an I/O error occurs.

### writeShorts

void writeShorts(short[] s, int off, int len) throws IOException
Writes a sequence of shorts to the stream at the current position. If `len` is 0, nothing is written. The short `s[off]` is written first, then the short `s[off + 1]`, and so on. The byte order of the stream is used to determine the order in which the individual bytes are written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Parameters:
  `s` - an array of `short`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `short`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `s.length`.
  `NullPointerException` - if `s` is `null`.
  `IOException` - if an I/O error occurs.

### writeChars

void writeChars(char[] c, int off, int len) throws IOException
Writes a sequence of chars to the stream at the current position. If `len` is 0, nothing is written. The char `c[off]` is written first, then the char `c[off + 1]`, and so on. The byte order of the stream is used to determine the order in which the individual bytes are written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Parameters:
  `c` - an array of `char`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `char`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `c.length`.
  `NullPointerException` - if `c` is `null`.
  `IOException` - if an I/O error occurs.

### writeInts

void writeInts(int[] i, int off, int len) throws IOException
Writes a sequence of ints to the stream at the current position. If `len` is 0, nothing is written. The int `i[off]` is written first, then the int `i[off + 1]`, and so on. The byte order of the stream is used to determine the order in which the individual bytes are written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Parameters:
  `i` - an array of `int`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `int`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `i.length`.
  `NullPointerException` - if `i` is `null`.
  `IOException` - if an I/O error occurs.

### writeLongs

void writeLongs(long[] l, int off, int len) throws IOException
Writes a sequence of longs to the stream at the current position. If `len` is 0, nothing is written. The long `l[off]` is written first, then the long `l[off + 1]`, and so on. The byte order of the stream is used to determine the order in which the individual bytes are written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Parameters:
  `l` - an array of `long`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `long`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `l.length`.
  `NullPointerException` - if `l` is `null`.
  `IOException` - if an I/O error occurs.

### writeFloats

void writeFloats(float[] f, int off, int len) throws IOException
Writes a sequence of floats to the stream at the current position. If `len` is 0, nothing is written. The float `f[off]` is written first, then the float `f[off + 1]`, and so on. The byte order of the stream is used to determine the order in which the individual bytes are written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Parameters:
  `f` - an array of `float`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `float`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `f.length`.
  `NullPointerException` - if `f` is `null`.
  `IOException` - if an I/O error occurs.

### writeDoubles

void writeDoubles(double[] d, int off, int len) throws IOException
Writes a sequence of doubles to the stream at the current position. If `len` is 0, nothing is written. The double `d[off]` is written first, then the double `d[off + 1]`, and so on. The byte order of the stream is used to determine the order in which the individual bytes are written.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write.

Parameters:
  `d` - an array of `doubles`s to be written.
  `off` - the start offset in the data.
  `len` - the number of `double`s to write.
Throws:
  `IndexOutOfBoundsException` - if `off` is negative, `len` is negative, or `off + len` is greater than `d.length`.
  `NullPointerException` - if `d` is `null`.
  `IOException` - if an I/O error occurs.

### writeBit

void writeBit(int bit) throws IOException
Writes a single bit, given by the least significant bit of the argument, to the stream at the current bit offset within the current byte position. The upper 31 bits of the argument are ignored. The given bit replaces the previous bit at that position. The bit offset is advanced by one and reduced modulo 8.

If any bits of a particular byte have never been set at the time the byte is flushed to the destination, those bits will be set to 0 automatically.

Parameters:
  `bit` - an `int` whose least significant bit is to be written to the stream.
Throws:
  `IOException` - if an I/O error occurs.

### writeBits

void writeBits(long bits, int numBits) throws IOException
Writes a sequence of bits, given by the `numBits` least significant bits of the `bits` argument in left-to-right order, to the stream at the current bit offset within the current byte position. The upper `64 - numBits` bits of the argument are ignored. The bit offset is advanced by `numBits` and reduced modulo 8. Note that a bit offset of 0 always indicates the most-significant bit of the byte, and bytes of bits are written out in sequence as they are encountered. Thus bit writes are always effectively in network byte order. The actual stream byte order setting is ignored.

Bit data may be accumulated in memory indefinitely, until `flushBefore` is called. At that time, all bit data prior to the flushed position will be written.

If any bits of a particular byte have never been set at the time the byte is flushed to the destination, those bits will be set to 0 automatically.

Parameters:
  `bits` - a `long` containing the bits to be written, starting with the bit in position `numBits - 1` down to the least significant bit.
  `numBits` - an `int` between 0 and 64, inclusive.
Throws:
  `IllegalArgumentException` - if `numBits` is not between 0 and 64, inclusive.
  `IOException` - if an I/O error occurs.

### flushBefore

void flushBefore(long pos) throws IOException
Flushes all data prior to the given position to the underlying destination, such as an `OutputStream` or `File`. Attempting to seek to the flushed portion of the stream will result in an `IndexOutOfBoundsException`.

Specified by:
  `flushBefore` in interface `ImageInputStream`
Parameters:
  `pos` - a `long` containing the length of the stream prefix that may be flushed to the destination.
Throws:
  `IndexOutOfBoundsException` - if `pos` lies in the flushed portion of the stream or past the current stream position.
  `IOException` - if an I/O error occurs.