Class ImageWriteParam
- java.lang.Object
-
- javax.imageio.IIOParam
-
- javax.imageio.ImageWriteParam
- Direct Known Subclasses:
-
BMPImageWriteParam
,JPEGImageWriteParam
public class ImageWriteParam extends IIOParam
A class describing how a stream is to be encoded. Instances of this class or its subclasses are used to supply prescriptive "how-to" information to instances of ImageWriter
.
A plug-in for a specific image format may define a subclass of this class, and return objects of that class from the getDefaultWriteParam
method of its ImageWriter
implementation. For example, the built-in JPEG writer plug-in will return instances of javax.imageio.plugins.jpeg.JPEGImageWriteParam
.
The region of the image to be written is determined by first intersecting the actual bounds of the image with the rectangle specified by IIOParam.setSourceRegion
, if any. If the resulting rectangle has a width or height of zero, the writer will throw an IIOException
. If the intersection is non-empty, writing will commence with the first subsampled pixel and include additional pixels within the intersected bounds according to the horizontal and vertical subsampling factors specified by IIOParam.setSourceSubsampling
.
Individual features such as tiling, progressive encoding, and compression may be set in one of four modes. MODE_DISABLED
disables the features; MODE_DEFAULT
enables the feature with writer-controlled parameter values; MODE_EXPLICIT
enables the feature and allows the use of a set
method to provide additional parameters; and MODE_COPY_FROM_METADATA
copies relevant parameter values from the stream and image metadata objects passed to the writer. The default for all features is MODE_COPY_FROM_METADATA
. Non-standard features supplied in subclasses are encouraged, but not required to use a similar scheme.
Plug-in writers may extend the functionality of ImageWriteParam
by providing a subclass that implements additional, plug-in specific interfaces. It is up to the plug-in to document what interfaces are available and how they are to be used. Writers will silently ignore any extended features of an ImageWriteParam
subclass of which they are not aware. Also, they may ignore any optional features that they normally disable when creating their own ImageWriteParam
instances via getDefaultWriteParam
.
Note that unless a query method exists for a capability, it must be supported by all ImageWriter
implementations (e.g. progressive encoding is optional, but subsampling must be supported).
- See Also:
ImageReadParam
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected boolean | canOffsetTiles | A |
protected boolean | canWriteCompressed | A |
protected boolean | canWriteProgressive | A |
protected boolean | canWriteTiles | A |
protected int | compressionMode | The mode controlling compression settings, which must be set to one of the four |
protected float | compressionQuality | A |
protected String | compressionType | A |
protected String[] | compressionTypes | An array of |
protected Locale | locale | A |
static int | MODE_COPY_FROM_METADATA | A constant value that may be passed into methods such as |
static int | MODE_DEFAULT | A constant value that may be passed into methods such as |
static int | MODE_DISABLED | A constant value that may be passed into methods such as |
static int | MODE_EXPLICIT | A constant value that may be passed into methods such as |
protected Dimension[] | preferredTileSizes | An array of preferred tile size range pairs. |
protected int | progressiveMode | The mode controlling progressive encoding, which must be set to one of the four |
protected int | tileGridXOffset | The amount by which the tile grid origin should be offset horizontally from the image origin if tiling has been set, or 0 otherwise. |
protected int | tileGridYOffset | The amount by which the tile grid origin should be offset vertically from the image origin if tiling has been set, or 0 otherwise. |
protected int | tileHeight | The height of each tile if tiling has been set, or 0 otherwise. |
protected int | tileWidth | The width of each tile if tiling has been set, or 0 otherwise. |
protected int | tilingMode | The mode controlling tiling settings, which Must be set to one of the four |
protected boolean | tilingSet | A |
Fields declared in class javax.imageio.IIOParam
controller, defaultController, destinationOffset, destinationType, sourceBands, sourceRegion, sourceXSubsampling, sourceYSubsampling, subsamplingXOffset, subsamplingYOffset
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | ImageWriteParam() | Constructs an empty |
ImageWriteParam(Locale locale) | Constructs an |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
boolean | canOffsetTiles() | Returns |
boolean | canWriteCompressed() | Returns |
boolean | canWriteProgressive() | Returns |
boolean | canWriteTiles() | Returns |
float | getBitRate(float quality) | Returns a |
int | getCompressionMode() | Returns the current compression mode, if compression is supported. |
float | getCompressionQuality() | Returns the current compression quality setting. |
String[] | getCompressionQualityDescriptions() | Returns an array of |
float[] | getCompressionQualityValues() | Returns an array of |
String | getCompressionType() | Returns the currently set compression type, or |
String[] | getCompressionTypes() | Returns a list of available compression types, as an array or |
Locale | getLocale() | Returns the currently set |
String | getLocalizedCompressionTypeName() | Returns a localized version of the name of the current compression type, using the |
Dimension[] | getPreferredTileSizes() | Returns an array of |
int | getProgressiveMode() | Returns the current mode for writing the stream in a progressive manner. |
int | getTileGridXOffset() | Returns the horizontal tile grid offset of an image as it will be written to the output stream. |
int | getTileGridYOffset() | Returns the vertical tile grid offset of an image as it will be written to the output stream. |
int | getTileHeight() | Returns the height of each tile in an image as it will be written to the output stream. |
int | getTileWidth() | Returns the width of each tile in an image as it will be written to the output stream. |
int | getTilingMode() | Returns the current tiling mode, if tiling is supported. |
boolean | isCompressionLossless() | Returns |
void | setCompressionMode(int mode) | Specifies whether compression is to be performed, and if so how compression parameters are to be determined. |
void | setCompressionQuality(float quality) | Sets the compression quality to a value between |
void | setCompressionType(String compressionType) | Sets the compression type to one of the values indicated by |
void | setProgressiveMode(int mode) | Specifies that the writer is to write the image out in a progressive mode such that the stream will contain a series of scans of increasing quality. |
void | setTiling(int tileWidth,
int tileHeight,
int tileGridXOffset,
int tileGridYOffset) | Specifies that the image should be tiled in the output stream. |
void | setTilingMode(int mode) | Determines whether the image will be tiled in the output stream and, if it will, how the tiling parameters will be determined. |
void | unsetCompression() | Removes any previous compression type and quality settings. |
void | unsetTiling() | Removes any previous tile grid parameters specified by calls to |
Methods declared in class javax.imageio.IIOParam
activateController, getController, getDefaultController, getDestinationOffset, getDestinationType, getSourceBands, getSourceRegion, getSourceXSubsampling, getSourceYSubsampling, getSubsamplingXOffset, getSubsamplingYOffset, hasController, setController, setDestinationOffset, setDestinationType, setSourceBands, setSourceRegion, setSourceSubsampling
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Field Detail
MODE_DISABLED
public static final int MODE_DISABLED
A constant value that may be passed into methods such as setTilingMode
, setProgressiveMode
, and setCompressionMode
to disable a feature for future writes. That is, when this mode is set the stream will not be tiled, progressive, or compressed, and the relevant accessor methods will throw an IllegalStateException
.
- See Also:
-
MODE_EXPLICIT
,MODE_COPY_FROM_METADATA
,MODE_DEFAULT
,setProgressiveMode(int)
,getProgressiveMode()
,setTilingMode(int)
,getTilingMode()
,setCompressionMode(int)
,getCompressionMode()
, Constant Field Values
MODE_DEFAULT
public static final int MODE_DEFAULT
A constant value that may be passed into methods such as setTilingMode
, setProgressiveMode
, and setCompressionMode
to enable that feature for future writes. That is, when this mode is enabled the stream will be tiled, progressive, or compressed according to a sensible default chosen internally by the writer in a plug-in dependent way, and the relevant accessor methods will throw an IllegalStateException
.
- See Also:
-
MODE_DISABLED
,MODE_EXPLICIT
,MODE_COPY_FROM_METADATA
,setProgressiveMode(int)
,getProgressiveMode()
,setTilingMode(int)
,getTilingMode()
,setCompressionMode(int)
,getCompressionMode()
, Constant Field Values
MODE_EXPLICIT
public static final int MODE_EXPLICIT
A constant value that may be passed into methods such as setTilingMode
or setCompressionMode
to enable a feature for future writes. That is, when this mode is set the stream will be tiled or compressed according to additional information supplied to the corresponding set
methods in this class and retrievable from the corresponding get
methods. Note that this mode is not supported for progressive output.
- See Also:
-
MODE_DISABLED
,MODE_COPY_FROM_METADATA
,MODE_DEFAULT
,setProgressiveMode(int)
,getProgressiveMode()
,setTilingMode(int)
,getTilingMode()
,setCompressionMode(int)
,getCompressionMode()
, Constant Field Values
MODE_COPY_FROM_METADATA
public static final int MODE_COPY_FROM_METADATA
A constant value that may be passed into methods such as setTilingMode
, setProgressiveMode
, or setCompressionMode
to enable that feature for future writes. That is, when this mode is enabled the stream will be tiled, progressive, or compressed based on the contents of stream and/or image metadata passed into the write operation, and any relevant accessor methods will throw an IllegalStateException
.
This is the default mode for all features, so that a read including metadata followed by a write including metadata will preserve as much information as possible.
- See Also:
-
MODE_DISABLED
,MODE_EXPLICIT
,MODE_DEFAULT
,setProgressiveMode(int)
,getProgressiveMode()
,setTilingMode(int)
,getTilingMode()
,setCompressionMode(int)
,getCompressionMode()
, Constant Field Values
canWriteTiles
protected boolean canWriteTiles
A boolean
that is true
if this ImageWriteParam
allows tile width and tile height parameters to be set. By default, the value is false
. Subclasses must set the value manually.
Subclasses that do not support writing tiles should ensure that this value is set to false
.
tilingMode
protected int tilingMode
The mode controlling tiling settings, which Must be set to one of the four MODE_*
values. The default is MODE_COPY_FROM_METADATA
.
Subclasses that do not writing tiles may ignore this value.
- See Also:
-
MODE_DISABLED
,MODE_EXPLICIT
,MODE_COPY_FROM_METADATA
,MODE_DEFAULT
,setTilingMode(int)
,getTilingMode()
preferredTileSizes
protected Dimension[] preferredTileSizes
An array of preferred tile size range pairs. The default value is null
, which indicates that there are no preferred sizes. If the value is non-null
, it must have an even length of at least two.
Subclasses that do not support writing tiles may ignore this value.
- See Also:
getPreferredTileSizes()
tilingSet
protected boolean tilingSet
A boolean
that is true
if tiling parameters have been specified.
Subclasses that do not support writing tiles may ignore this value.
tileWidth
protected int tileWidth
The width of each tile if tiling has been set, or 0 otherwise.
Subclasses that do not support tiling may ignore this value.
tileHeight
protected int tileHeight
The height of each tile if tiling has been set, or 0 otherwise. The initial value is 0
.
Subclasses that do not support tiling may ignore this value.
canOffsetTiles
protected boolean canOffsetTiles
A boolean
that is true
if this ImageWriteParam
allows tiling grid offset parameters to be set. By default, the value is false
. Subclasses must set the value manually.
Subclasses that do not support writing tiles, or that support writing but not offsetting tiles must ensure that this value is set to false
.
tileGridXOffset
protected int tileGridXOffset
The amount by which the tile grid origin should be offset horizontally from the image origin if tiling has been set, or 0 otherwise. The initial value is 0
.
Subclasses that do not support offsetting tiles may ignore this value.
tileGridYOffset
protected int tileGridYOffset
The amount by which the tile grid origin should be offset vertically from the image origin if tiling has been set, or 0 otherwise. The initial value is 0
.
Subclasses that do not support offsetting tiles may ignore this value.
canWriteProgressive
protected boolean canWriteProgressive
A boolean
that is true
if this ImageWriteParam
allows images to be written as a progressive sequence of increasing quality passes. By default, the value is false
. Subclasses must set the value manually.
Subclasses that do not support progressive encoding must ensure that this value is set to false
.
progressiveMode
protected int progressiveMode
The mode controlling progressive encoding, which must be set to one of the four MODE_*
values, except MODE_EXPLICIT
. The default is MODE_COPY_FROM_METADATA
.
Subclasses that do not support progressive encoding may ignore this value.
- See Also:
-
MODE_DISABLED
,MODE_EXPLICIT
,MODE_COPY_FROM_METADATA
,MODE_DEFAULT
,setProgressiveMode(int)
,getProgressiveMode()
canWriteCompressed
protected boolean canWriteCompressed
A boolean
that is true
if this writer can write images using compression. By default, the value is false
. Subclasses must set the value manually.
Subclasses that do not support compression must ensure that this value is set to false
.
compressionMode
protected int compressionMode
The mode controlling compression settings, which must be set to one of the four MODE_*
values. The default is MODE_COPY_FROM_METADATA
.
Subclasses that do not support compression may ignore this value.
- See Also:
-
MODE_DISABLED
,MODE_EXPLICIT
,MODE_COPY_FROM_METADATA
,MODE_DEFAULT
,setCompressionMode(int)
,getCompressionMode()
compressionTypes
protected String[] compressionTypes
An array of String
s containing the names of the available compression types. Subclasses must set the value manually.
Subclasses that do not support compression may ignore this value.
compressionType
protected String compressionType
A String
containing the name of the current compression type, or null
if none is set.
Subclasses that do not support compression may ignore this value.
compressionQuality
protected float compressionQuality
A float
containing the current compression quality setting. The initial value is 1.0F
.
Subclasses that do not support compression may ignore this value.
locale
protected Locale locale
A Locale
to be used to localize compression type names and quality descriptions, or null
to use a default Locale
. Subclasses must set the value manually.
Constructor Detail
ImageWriteParam
protected ImageWriteParam()
Constructs an empty ImageWriteParam
. It is up to the subclass to set up the instance variables properly.
ImageWriteParam
public ImageWriteParam(Locale locale)
Constructs an ImageWriteParam
set to use a given Locale
.
- Parameters:
-
locale
- aLocale
to be used to localize compression type names and quality descriptions, ornull
.
Method Detail
getLocale
public Locale getLocale()
Returns the currently set Locale
, or null
if only a default Locale
is supported.
- Returns:
- the current
Locale
, ornull
.
canWriteTiles
public boolean canWriteTiles()
Returns true
if the writer can perform tiling while writing. If this method returns false
, then setTiling
will throw an UnsupportedOperationException
.
- Returns:
-
true
if the writer supports tiling. - See Also:
-
canOffsetTiles()
,setTiling(int, int, int, int)
canOffsetTiles
public boolean canOffsetTiles()
Returns true
if the writer can perform tiling with non-zero grid offsets while writing. If this method returns false
, then setTiling
will throw an UnsupportedOperationException
if the grid offset arguments are not both zero. If canWriteTiles
returns false
, this method will return false
as well.
- Returns:
-
true
if the writer supports non-zero tile offsets. - See Also:
-
canWriteTiles()
,setTiling(int, int, int, int)
setTilingMode
public void setTilingMode(int mode)
Determines whether the image will be tiled in the output stream and, if it will, how the tiling parameters will be determined. The modes are interpreted as follows:
-
MODE_DISABLED
- The image will not be tiled.setTiling
will throw anIllegalStateException
. -
MODE_DEFAULT
- The image will be tiled using default parameters.setTiling
will throw anIllegalStateException
. -
MODE_EXPLICIT
- The image will be tiled according to parameters given in thesetTiling
method. Any previously set tiling parameters are discarded. -
MODE_COPY_FROM_METADATA
- The image will conform to the metadata object passed in to a write.setTiling
will throw anIllegalStateException
.
- Parameters:
-
mode
- The mode to use for tiling. - Throws:
-
UnsupportedOperationException
- ifcanWriteTiles
returnsfalse
. -
IllegalArgumentException
- ifmode
is not one of the modes listed above. - See Also:
-
setTiling(int, int, int, int)
,getTilingMode()
getTilingMode
public int getTilingMode()
Returns the current tiling mode, if tiling is supported. Otherwise throws an UnsupportedOperationException
.
- Returns:
- the current tiling mode.
- Throws:
-
UnsupportedOperationException
- ifcanWriteTiles
returnsfalse
. - See Also:
setTilingMode(int)
getPreferredTileSizes
public Dimension[] getPreferredTileSizes()
Returns an array of Dimension
s indicating the legal size ranges for tiles as they will be encoded in the output file or stream. The returned array is a copy.
The information is returned as a set of pairs; the first element of a pair contains an (inclusive) minimum width and height, and the second element contains an (inclusive) maximum width and height. Together, each pair defines a valid range of sizes. To specify a fixed size, use the same width and height for both elements. To specify an arbitrary range, a value of null
is used in place of an actual array of Dimension
s.
If no array is specified on the constructor, but tiling is allowed, then this method returns null
.
- Returns:
- an array of
Dimension
s with an even length of at least two, ornull
. - Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling.
setTiling
public void setTiling(int tileWidth, int tileHeight, int tileGridXOffset, int tileGridYOffset)
Specifies that the image should be tiled in the output stream. The tileWidth
and tileHeight
parameters specify the width and height of the tiles in the file. If the tile width or height is greater than the width or height of the image, the image is not tiled in that dimension.
If canOffsetTiles
returns false
, then the tileGridXOffset
and tileGridYOffset
parameters must be zero.
- Parameters:
-
tileWidth
- the width of each tile. -
tileHeight
- the height of each tile. -
tileGridXOffset
- the horizontal offset of the tile grid. -
tileGridYOffset
- the vertical offset of the tile grid. - Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling. -
IllegalStateException
- if the tiling mode is notMODE_EXPLICIT
. -
UnsupportedOperationException
- if the plug-in does not support grid offsets, and the grid offsets are not both zero. -
IllegalArgumentException
- if the tile size is not within one of the allowable ranges returned bygetPreferredTileSizes
. -
IllegalArgumentException
- iftileWidth
ortileHeight
is less than or equal to 0. - See Also:
-
canWriteTiles
,canOffsetTiles
,getTileWidth()
,getTileHeight()
,getTileGridXOffset()
,getTileGridYOffset()
unsetTiling
public void unsetTiling()
Removes any previous tile grid parameters specified by calls to setTiling
.
The default implementation sets the instance variables tileWidth
, tileHeight
, tileGridXOffset
, and tileGridYOffset
to 0
.
- Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling. -
IllegalStateException
- if the tiling mode is notMODE_EXPLICIT
. - See Also:
setTiling(int, int, int, int)
getTileWidth
public int getTileWidth()
Returns the width of each tile in an image as it will be written to the output stream. If tiling parameters have not been set, an IllegalStateException
is thrown.
- Returns:
- the tile width to be used for encoding.
- Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling. -
IllegalStateException
- if the tiling mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the tiling parameters have not been set. - See Also:
-
setTiling(int, int, int, int)
,getTileHeight()
getTileHeight
public int getTileHeight()
Returns the height of each tile in an image as it will be written to the output stream. If tiling parameters have not been set, an IllegalStateException
is thrown.
- Returns:
- the tile height to be used for encoding.
- Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling. -
IllegalStateException
- if the tiling mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the tiling parameters have not been set. - See Also:
-
setTiling(int, int, int, int)
,getTileWidth()
getTileGridXOffset
public int getTileGridXOffset()
Returns the horizontal tile grid offset of an image as it will be written to the output stream. If tiling parameters have not been set, an IllegalStateException
is thrown.
- Returns:
- the tile grid X offset to be used for encoding.
- Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling. -
IllegalStateException
- if the tiling mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the tiling parameters have not been set. - See Also:
-
setTiling(int, int, int, int)
,getTileGridYOffset()
getTileGridYOffset
public int getTileGridYOffset()
Returns the vertical tile grid offset of an image as it will be written to the output stream. If tiling parameters have not been set, an IllegalStateException
is thrown.
- Returns:
- the tile grid Y offset to be used for encoding.
- Throws:
-
UnsupportedOperationException
- if the plug-in does not support tiling. -
IllegalStateException
- if the tiling mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the tiling parameters have not been set. - See Also:
-
setTiling(int, int, int, int)
,getTileGridXOffset()
canWriteProgressive
public boolean canWriteProgressive()
Returns true
if the writer can write out images as a series of passes of progressively increasing quality.
- Returns:
-
true
if the writer supports progressive encoding. - See Also:
-
setProgressiveMode(int)
,getProgressiveMode()
setProgressiveMode
public void setProgressiveMode(int mode)
Specifies that the writer is to write the image out in a progressive mode such that the stream will contain a series of scans of increasing quality. If progressive encoding is not supported, an UnsupportedOperationException
will be thrown.
The mode argument determines how the progression parameters are chosen, and must be either MODE_DISABLED
, MODE_COPY_FROM_METADATA
, or MODE_DEFAULT
. Otherwise an IllegalArgumentException
is thrown.
The modes are interpreted as follows:
-
MODE_DISABLED
- No progression. Use this to turn off progression. -
MODE_COPY_FROM_METADATA
- The output image will use whatever progression parameters are found in the metadata objects passed into the writer. -
MODE_DEFAULT
- The image will be written progressively, with parameters chosen by the writer.
The default is MODE_COPY_FROM_METADATA
.
- Parameters:
-
mode
- The mode for setting progression in the output stream. - Throws:
-
UnsupportedOperationException
- if the writer does not support progressive encoding. -
IllegalArgumentException
- ifmode
is not one of the modes listed above. - See Also:
getProgressiveMode()
getProgressiveMode
public int getProgressiveMode()
Returns the current mode for writing the stream in a progressive manner.
- Returns:
- the current mode for progressive encoding.
- Throws:
-
UnsupportedOperationException
- if the writer does not support progressive encoding. - See Also:
setProgressiveMode(int)
canWriteCompressed
public boolean canWriteCompressed()
Returns true
if this writer supports compression.
- Returns:
-
true
if the writer supports compression.
setCompressionMode
public void setCompressionMode(int mode)
Specifies whether compression is to be performed, and if so how compression parameters are to be determined. The mode
argument must be one of the four modes, interpreted as follows:
-
MODE_DISABLED
- If the mode is set toMODE_DISABLED
, methods that query or modify the compression type or parameters will throw anIllegalStateException
(if compression is normally supported by the plug-in). Some writers, such as JPEG, do not normally offer uncompressed output. In this case, attempting to set the mode toMODE_DISABLED
will throw anUnsupportedOperationException
and the mode will not be changed. -
MODE_EXPLICIT
- Compress using the compression type and quality settings specified in thisImageWriteParam
. Any previously set compression parameters are discarded. -
MODE_COPY_FROM_METADATA
- Use whatever compression parameters are specified in metadata objects passed in to the writer. -
MODE_DEFAULT
- Use default compression parameters.
The default is MODE_COPY_FROM_METADATA
.
- Parameters:
-
mode
- The mode for setting compression in the output stream. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression, or does not support the requested mode. -
IllegalArgumentException
- ifmode
is not one of the modes listed above. - See Also:
getCompressionMode()
getCompressionMode
public int getCompressionMode()
Returns the current compression mode, if compression is supported.
- Returns:
- the current compression mode.
- Throws:
-
UnsupportedOperationException
- if the writer does not support compression. - See Also:
setCompressionMode(int)
getCompressionTypes
public String[] getCompressionTypes()
Returns a list of available compression types, as an array or String
s, or null
if a compression type may not be chosen using these interfaces. The array returned is a copy.
If the writer only offers a single, mandatory form of compression, it is not necessary to provide any named compression types. Named compression types should only be used where the user is able to make a meaningful choice between different schemes.
The default implementation checks if compression is supported and throws an UnsupportedOperationException
if not. Otherwise, it returns a clone of the compressionTypes
instance variable if it is non-null
, or else returns null
.
- Returns:
- an array of
String
s containing the (non-localized) names of available compression types, ornull
. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression.
setCompressionType
public void setCompressionType(String compressionType)
Sets the compression type to one of the values indicated by getCompressionTypes
. If a value of null
is passed in, any previous setting is removed.
The default implementation checks whether compression is supported and the compression mode is MODE_EXPLICIT
. If so, it calls getCompressionTypes
and checks if compressionType
is one of the legal values. If it is, the compressionType
instance variable is set. If compressionType
is null
, the instance variable is set without performing any checking.
- Parameters:
-
compressionType
- one of theString
s returned bygetCompressionTypes
, ornull
to remove any previous setting. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
UnsupportedOperationException
- if there are no settable compression types. -
IllegalArgumentException
- ifcompressionType
is non-null
but is not one of the values returned bygetCompressionTypes
. - See Also:
-
getCompressionTypes()
,getCompressionType()
,unsetCompression()
getCompressionType
public String getCompressionType()
Returns the currently set compression type, or null
if none has been set. The type is returned as a String
from among those returned by getCompressionTypes
. If no compression type has been set, null
is returned.
The default implementation checks whether compression is supported and the compression mode is MODE_EXPLICIT
. If so, it returns the value of the compressionType
instance variable.
- Returns:
- the current compression type as a
String
, ornull
if no type is set. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. - See Also:
setCompressionType(java.lang.String)
unsetCompression
public void unsetCompression()
Removes any previous compression type and quality settings.
The default implementation sets the instance variable compressionType
to null
, and the instance variable compressionQuality
to 1.0F
.
- Throws:
-
UnsupportedOperationException
- if the plug-in does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. - See Also:
-
setCompressionType(java.lang.String)
,setCompressionQuality(float)
getLocalizedCompressionTypeName
public String getLocalizedCompressionTypeName()
Returns a localized version of the name of the current compression type, using the Locale
returned by getLocale
.
The default implementation checks whether compression is supported and the compression mode is MODE_EXPLICIT
. If so, if compressionType
is non-null
the value of getCompressionType
is returned as a convenience.
- Returns:
- a
String
containing a localized version of the name of the current compression type. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if no compression type is set.
isCompressionLossless
public boolean isCompressionLossless()
Returns true
if the current compression type provides lossless compression. If a plug-in provides only one mandatory compression type, then this method may be called without calling setCompressionType
first.
If there are multiple compression types but none has been set, an IllegalStateException
is thrown.
The default implementation checks whether compression is supported and the compression mode is MODE_EXPLICIT
. If so, if getCompressionTypes()
is null
or getCompressionType()
is non-null
true
is returned as a convenience.
- Returns:
-
true
if the current compression type is lossless. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the set of legal compression types is non-null
and the current compression type isnull
.
setCompressionQuality
public void setCompressionQuality(float quality)
Sets the compression quality to a value between 0
and 1
. Only a single compression quality setting is supported by default; writers can provide extended versions of ImageWriteParam
that offer more control. For lossy compression schemes, the compression quality should control the tradeoff between file size and image quality (for example, by choosing quantization tables when writing JPEG images). For lossless schemes, the compression quality may be used to control the tradeoff between file size and time taken to perform the compression (for example, by optimizing row filters and setting the ZLIB compression level when writing PNG images).
A compression quality setting of 0.0 is most generically interpreted as "high compression is important," while a setting of 1.0 is most generically interpreted as "high image quality is important."
If there are multiple compression types but none has been set, an IllegalStateException
is thrown.
The default implementation checks that compression is supported, and that the compression mode is MODE_EXPLICIT
. If so, if getCompressionTypes()
returns null
or compressionType
is non-null
it sets the compressionQuality
instance variable.
- Parameters:
-
quality
- afloat
between0
and1
indicating the desired quality level. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the set of legal compression types is non-null
and the current compression type isnull
. -
IllegalArgumentException
- ifquality
is not between0
and1
, inclusive. - See Also:
getCompressionQuality()
getCompressionQuality
public float getCompressionQuality()
Returns the current compression quality setting.
If there are multiple compression types but none has been set, an IllegalStateException
is thrown.
The default implementation checks that compression is supported and that the compression mode is MODE_EXPLICIT
. If so, if getCompressionTypes()
is null
or getCompressionType()
is non-null
, it returns the value of the compressionQuality
instance variable.
- Returns:
- the current compression quality setting.
- Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the set of legal compression types is non-null
and the current compression type isnull
. - See Also:
setCompressionQuality(float)
getBitRate
public float getBitRate(float quality)
Returns a float
indicating an estimate of the number of bits of output data for each bit of input image data at the given quality level. The value will typically lie between 0
and 1
, with smaller values indicating more compression. A special value of -1.0F
is used to indicate that no estimate is available.
If there are multiple compression types but none has been set, an IllegalStateException
is thrown.
The default implementation checks that compression is supported and the compression mode is MODE_EXPLICIT
. If so, if getCompressionTypes()
is null
or getCompressionType()
is non-null
, and quality
is within bounds, it returns -1.0
.
- Parameters:
-
quality
- the quality setting whose bit rate is to be queried. - Returns:
- an estimate of the compressed bit rate, or
-1.0F
if no estimate is available. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the set of legal compression types is non-null
and the current compression type isnull
. -
IllegalArgumentException
- ifquality
is not between0
and1
, inclusive.
getCompressionQualityDescriptions
public String[] getCompressionQualityDescriptions()
Returns an array of String
s that may be used along with getCompressionQualityValues
as part of a user interface for setting or displaying the compression quality level. The String
with index i
provides a description of the range of quality levels between getCompressionQualityValues[i]
and getCompressionQualityValues[i + 1]
. Note that the length of the array returned from getCompressionQualityValues
will always be one greater than that returned from getCompressionQualityDescriptions
.
As an example, the strings "Good", "Better", and "Best" could be associated with the ranges [0, .33)
, [.33, .66)
, and [.66, 1.0]
. In this case, getCompressionQualityDescriptions
would return { "Good", "Better", "Best" }
and getCompressionQualityValues
would return { 0.0F, .33F, .66F, 1.0F }
.
If no descriptions are available, null
is returned. If null
is returned from getCompressionQualityValues
, this method must also return null
.
The descriptions should be localized for the Locale
returned by getLocale
, if it is non-null
.
If there are multiple compression types but none has been set, an IllegalStateException
is thrown.
The default implementation checks that compression is supported and that the compression mode is MODE_EXPLICIT
. If so, if getCompressionTypes()
is null
or getCompressionType()
is non-null
, it returns null
.
- Returns:
- an array of
String
s containing localized descriptions of the compression quality levels. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the set of legal compression types is non-null
and the current compression type isnull
. - See Also:
getCompressionQualityValues()
getCompressionQualityValues
public float[] getCompressionQualityValues()
Returns an array of float
s that may be used along with getCompressionQualityDescriptions
as part of a user interface for setting or displaying the compression quality level. See getCompressionQualityDescriptions
for more information.
If no descriptions are available, null
is returned. If null
is returned from getCompressionQualityDescriptions
, this method must also return null
.
If there are multiple compression types but none has been set, an IllegalStateException
is thrown.
The default implementation checks that compression is supported and that the compression mode is MODE_EXPLICIT
. If so, if getCompressionTypes()
is null
or getCompressionType()
is non-null
, it returns null
.
- Returns:
- an array of
float
s indicating the boundaries between the compression quality levels as described by theString
s fromgetCompressionQualityDescriptions
. - Throws:
-
UnsupportedOperationException
- if the writer does not support compression. -
IllegalStateException
- if the compression mode is notMODE_EXPLICIT
. -
IllegalStateException
- if the set of legal compression types is non-null
and the current compression type isnull
. - See Also:
getCompressionQualityDescriptions()