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Préférences
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JavaTM 2 Platform Std. Ed. v1.6.0
javax.imageio.plugins.jpeg
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Field Summary |
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Fields inherited from class javax.imageio.ImageWriteParam |
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canOffsetTiles, canWriteCompressed, canWriteProgressive, canWriteTiles, compressionMode, compressionQuality, compressionType, compressionTypes, locale, MODE_COPY_FROM_METADATA, MODE_DEFAULT, MODE_DISABLED, MODE_EXPLICIT, preferredTileSizes, progressiveMode, tileGridXOffset, tileGridYOffset, tileHeight, tileWidth, tilingMode, tilingSet |
Fields inherited from class javax.imageio.IIOParam |
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controller, defaultController, destinationOffset, destinationType, sourceBands, sourceRegion, sourceXSubsampling, sourceYSubsampling, subsamplingXOffset, subsamplingYOffset |
Constructor Summary | |
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JPEGImageWriteParam(Locale locale)
Constructs a JPEGImageWriteParam . |
Method Summary | |
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boolean |
areTablesSet()
Returns true if tables are currently set. |
JPEGHuffmanTable[] |
getACHuffmanTables()
Returns a copy of the array of AC Huffman tables set on the most recent call to setEncodeTables , or
null if tables are not currently set. |
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. |
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. |
JPEGHuffmanTable[] |
getDCHuffmanTables()
Returns a copy of the array of DC Huffman tables set on the most recent call to setEncodeTables , or
null if tables are not currently set. |
boolean |
getOptimizeHuffmanTables()
Returns the value passed into the most recent call to setOptimizeHuffmanTables , or
false if setOptimizeHuffmanTables
has never been called. |
JPEGQTable[] |
getQTables()
Returns a copy of the array of quantization tables set on the most recent call to setEncodeTables , or
null if tables are not currently set. |
boolean |
isCompressionLossless()
Returns false since the JPEG plug-in only supports
lossy compression. |
void |
setEncodeTables(JPEGQTable[] qTables,
JPEGHuffmanTable[] DCHuffmanTables,
JPEGHuffmanTable[] ACHuffmanTables)
Sets the quantization and Huffman tables to use in encoding abbreviated streams. |
void |
setOptimizeHuffmanTables(boolean optimize)
Tells the writer to generate optimized Huffman tables for the image as part of the writing process. |
void |
unsetCompression()
Removes any previous compression quality setting. |
void |
unsetEncodeTables()
Removes any quantization and Huffman tables that are currently set. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public JPEGImageWriteParam(Locale locale)
JPEGImageWriteParam
. Tiling is not
supported. Progressive encoding is supported. The default
progressive mode is MODE_DISABLED. A single form of compression,
named "JPEG", is supported. The default compression quality is
0.75.
locale
- a Locale
to be used by the
superclass to localize compression type names and quality
descriptions, or null
.Method Detail |
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public void unsetCompression()
The default implementation resets the compression quality
to 0.75F
.
unsetCompression
in class ImageWriteParam
IllegalStateException
- if the compression mode is not
MODE_EXPLICIT
.ImageWriteParam.setCompressionType(java.lang.String)
,
ImageWriteParam.setCompressionQuality(float)
public boolean isCompressionLossless()
false
since the JPEG plug-in only supports
lossy compression.
isCompressionLossless
in class ImageWriteParam
false
.
IllegalStateException
- if the compression mode is not
MODE_EXPLICIT
.public String[] getCompressionQualityDescriptions()
ImageWriteParam
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
.
getCompressionQualityDescriptions
in class ImageWriteParam
String
s containing localized
descriptions of the compression quality levels.ImageWriteParam.getCompressionQualityValues()
public float[] getCompressionQualityValues()
ImageWriteParam
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
.
getCompressionQualityValues
in class ImageWriteParam
float
s indicating the
boundaries between the compression quality levels as described
by the String
s from
getCompressionQualityDescriptions
.ImageWriteParam.getCompressionQualityDescriptions()
public boolean areTablesSet()
true
if tables are currently set.
true
if tables are present.public void setEncodeTables(JPEGQTable[] qTables, JPEGHuffmanTable[] DCHuffmanTables, JPEGHuffmanTable[] ACHuffmanTables)
null
.
The two arrays of Huffman tables must have the same number of
elements. The table specifiers in the frame and scan headers
in the metadata are assumed to be equivalent to indices into
these arrays. The argument arrays are copied by this method.
qTables
- An array of quantization table objects.DCHuffmanTables
- An array of Huffman table objects.ACHuffmanTables
- An array of Huffman table objects.
IllegalArgumentException
- if any of the arguments
is null
or has more than 4 elements, or if the
numbers of DC and AC tables differ.unsetEncodeTables()
public void unsetEncodeTables()
public JPEGQTable[] getQTables()
setEncodeTables
, or
null
if tables are not currently set.
JPEGQTable
objects, or
null
.setEncodeTables(javax.imageio.plugins.jpeg.JPEGQTable[], javax.imageio.plugins.jpeg.JPEGHuffmanTable[], javax.imageio.plugins.jpeg.JPEGHuffmanTable[])
public JPEGHuffmanTable[] getDCHuffmanTables()
setEncodeTables
, or
null
if tables are not currently set.
JPEGHuffmanTable
objects, or
null
.setEncodeTables(javax.imageio.plugins.jpeg.JPEGQTable[], javax.imageio.plugins.jpeg.JPEGHuffmanTable[], javax.imageio.plugins.jpeg.JPEGHuffmanTable[])
public JPEGHuffmanTable[] getACHuffmanTables()
setEncodeTables
, or
null
if tables are not currently set.
JPEGHuffmanTable
objects, or
null
.setEncodeTables(javax.imageio.plugins.jpeg.JPEGQTable[], javax.imageio.plugins.jpeg.JPEGHuffmanTable[], javax.imageio.plugins.jpeg.JPEGHuffmanTable[])
public void setOptimizeHuffmanTables(boolean optimize)
false
. If this flag is set
to true
, it overrides any tables specified
in the metadata. Note that this means that any image
written with this flag set to true
will
always contain Huffman tables.
optimize
- A boolean indicating whether to generate
optimized Huffman tables when writing.getOptimizeHuffmanTables()
public boolean getOptimizeHuffmanTables()
setOptimizeHuffmanTables
, or
false
if setOptimizeHuffmanTables
has never been called.
true
if the writer will generate optimized
Huffman tables.setOptimizeHuffmanTables(boolean)