| java.lang.Object
 javax.imageio.IIOParam
All known Subclasses: javax.imageio.ImageReadParam, javax.imageio.ImageWriteParam,
| IIOParam | | abstract public class IIOParam (Code) | | A superclass of all classes describing how streams should be
decoded or encoded. This class contains all the variables and
methods that are shared by ImageReadParam and
ImageWriteParam.
This class provides mechanisms to specify a source region and a
destination region. When reading, the source is the stream and
the in-memory image is the destination. When writing, these are
reversed. In the case of writing, destination regions may be used
only with a writer that supports pixel replacement.
Decimation subsampling may be specified for both readers
and writers, using a movable subsampling grid.
Subsets of the source and destination bands may be selected.
version:
0.5 |
| Field Summary | |
| protected IIOParamController | controller
The IIOParamController that will be
used to provide settings for this IIOParam
object when the activateController method
is called. | | protected IIOParamController | defaultController
The default IIOParamController that will be
used to provide settings for this IIOParam
object when the activateController method
is called. | | protected Point | destinationOffset
The offset in the destination where the upper-left decoded
pixel should be placed. | | protected ImageTypeSpecifier | destinationType
An ImageTypeSpecifier to be used to generate a
destination image when reading, or to set the output color type
when writing. | | protected int[] | sourceBands
An array of ints indicating which source bands
will be used, or null. | | protected Rectangle | sourceRegion
The source region, on null if none is set. | | protected int | sourceXSubsampling
The decimation subsampling to be applied in the horizontal
direction. | | protected int | sourceYSubsampling
The decimation subsampling to be applied in the vertical
direction. | | protected int | subsamplingXOffset
A horizontal offset to be applied to the subsampling grid before
subsampling. | | protected int | subsamplingYOffset
A vertical offset to be applied to the subsampling grid before
subsampling. |
| Constructor Summary | |
| protected | IIOParam()
Protected constructor may be called only by subclasses. |
| Method Summary | |
| public boolean | activateController()
Activates the installed IIOParamController for
this IIOParam object and returns the resulting
value. | | public IIOParamController | getController()
Returns whatever IIOParamController is currently
installed. | | public IIOParamController | getDefaultController()
Returns the default IIOParamController, if there
is one, regardless of the currently installed controller. | | public Point | getDestinationOffset()
Returns the offset in the destination image at which pixels are
to be placed. | | public ImageTypeSpecifier | getDestinationType()
Returns the type of image to be returned by the read, if one
was set by a call to
setDestination(ImageTypeSpecifier), as an
ImageTypeSpecifier. | | public int[] | getSourceBands()
Returns the set of of source bands to be used. | | public Rectangle | getSourceRegion()
Returns the source region to be used. | | public int | getSourceXSubsampling()
Returns the number of source columns to advance for each pixel. | | public int | getSourceYSubsampling()
Returns the number of rows to advance for each pixel. | | public int | getSubsamplingXOffset()
Returns the horizontal offset of the subsampling grid. | | public int | getSubsamplingYOffset()
Returns the vertical offset of the subsampling grid. | | public boolean | hasController()
Returns true if there is a controller installed
for this IIOParam object. | | public void | setController(IIOParamController controller)
Sets the IIOParamController to be used
to provide settings for this IIOParam
object when the activateController method
is called, overriding any default controller. | | public void | setDestinationOffset(Point destinationOffset)
Specifies the offset in the destination image at which future
decoded pixels are to be placed, when reading, or where a
region will be written, when writing.
When reading, the region to be written within the
destination BufferedImage will start at this
offset and have a width and height determined by the source
region of interest, the subsampling parameters, and the
destination bounds.
Normal writes are not affected by this method, only writes
performed using ImageWriter.replacePixels. | | public void | setDestinationType(ImageTypeSpecifier destinationType)
Sets the desired image type for the destination image, using an
ImageTypeSpecifier.
When reading, if the layout of the destination has been set
using this method, each call to an ImageReader
read method will return a new
BufferedImage using the format specified by the
supplied type specifier. | | public void | setSourceBands(int[] sourceBands)
Sets the indices of the source bands to be used. | | public void | setSourceRegion(Rectangle sourceRegion)
Sets the source region of interest. | | public void | setSourceSubsampling(int sourceXSubsampling, int sourceYSubsampling, int subsamplingXOffset, int subsamplingYOffset)
Specifies a decimation subsampling to apply on I/O. |
| destinationOffset | | protected Point destinationOffset(Code) | | The offset in the destination where the upper-left decoded
pixel should be placed. By default, the value is (0, 0).
|
| destinationType | | protected ImageTypeSpecifier destinationType(Code) | | An ImageTypeSpecifier to be used to generate a
destination image when reading, or to set the output color type
when writing. If non has been setm the value will be
null. By default, the value is null.
|
| sourceBands | | protected int[] sourceBands(Code) | | An array of ints indicating which source bands
will be used, or null. If null, the
set of source bands to be used is as described in the comment
for the setSourceBands method. No value should
be allowed to be negative.
|
| sourceRegion | | protected Rectangle sourceRegion(Code) | | The source region, on null if none is set.
|
| sourceXSubsampling | | protected int sourceXSubsampling(Code) | | The decimation subsampling to be applied in the horizontal
direction. By default, the value is 1.
The value must not be negative or 0.
|
| sourceYSubsampling | | protected int sourceYSubsampling(Code) | | The decimation subsampling to be applied in the vertical
direction. By default, the value is 1.
The value must not be negative or 0.
|
| subsamplingXOffset | | protected int subsamplingXOffset(Code) | | A horizontal offset to be applied to the subsampling grid before
subsampling. The first pixel to be used will be offset this
amount from the origin of the region, or of the image if no
region is specified.
|
| subsamplingYOffset | | protected int subsamplingYOffset(Code) | | A vertical offset to be applied to the subsampling grid before
subsampling. The first pixel to be used will be offset this
amount from the origin of the region, or of the image if no
region is specified.
|
| IIOParam | | protected IIOParam()(Code) | | Protected constructor may be called only by subclasses.
|
| activateController | | public boolean activateController()(Code) | | Activates the installed IIOParamController for
this IIOParam object and returns the resulting
value. When this method returns true, all values
for this IIOParam object will be ready for the
next read or write operation. If false is
returned, no settings in this object will have been disturbed
(i.e., the user canceled the operation).
Ordinarily, the controller will be a GUI providing a user
interface for a subclass of IIOParam for a
particular plug-in. Controllers need not be GUIs, however.
true if the controller completed normally.
exception:
IllegalStateException - if there is no controllercurrently installed.
See Also: IIOParamController
See Also: IIOParam.setController(IIOParamController)
See Also: IIOParam.getController
See Also: IIOParam.getDefaultController
See Also: IIOParam.hasController |
| getDestinationOffset | | public Point getDestinationOffset()(Code) | | Returns the offset in the destination image at which pixels are
to be placed.
If setDestinationOffsets has not been called,
a Point with zero X and Y values is returned
(which is the correct value).
the destination offset as a Point.
See Also: IIOParam.setDestinationOffset |
| getDestinationType | | public ImageTypeSpecifier getDestinationType()(Code) | | Returns the type of image to be returned by the read, if one
was set by a call to
setDestination(ImageTypeSpecifier), as an
ImageTypeSpecifier. If none was set,
null is returned.
an ImageTypeSpecifier describing thedestination type, or null.
See Also: IIOParam.setDestinationType |
| getSourceBands | | public int[] getSourceBands()(Code) | | Returns the set of of source bands to be used. The returned
value is that set by the most recent call to
setSourceBands, or null if there have
been no calls to setSourceBands.
Semantically, the array returned is a copy; changes to
array contents subsequent to this call have no effect on this
IIOParam.
the set of source bands to be used, ornull.
See Also: IIOParam.setSourceBands |
| getSourceRegion | | public Rectangle getSourceRegion()(Code) | | Returns the source region to be used. The returned value is
that set by the most recent call to
setSourceRegion, and will be null if
there is no region set.
the source region of interest as aRectangle, or null.
See Also: IIOParam.setSourceRegion |
| getSourceXSubsampling | | public int getSourceXSubsampling()(Code) | | Returns the number of source columns to advance for each pixel.
If setSourceSubsampling has not been called, 1
is returned (which is the correct value).
the source subsampling X period.
See Also: IIOParam.setSourceSubsampling
See Also: IIOParam.getSourceYSubsampling |
| setDestinationOffset | | public void setDestinationOffset(Point destinationOffset)(Code) | | Specifies the offset in the destination image at which future
decoded pixels are to be placed, when reading, or where a
region will be written, when writing.
When reading, the region to be written within the
destination BufferedImage will start at this
offset and have a width and height determined by the source
region of interest, the subsampling parameters, and the
destination bounds.
Normal writes are not affected by this method, only writes
performed using ImageWriter.replacePixels. For
such writes, the offset specified is within the output stream
image whose pixels are being modified.
There is no unsetDestinationOffset method;
simply call setDestinationOffset(new Point(0, 0)) to
restore default values.
Parameters:
destinationOffset - the offset in the destination, as aPoint.
exception:
IllegalArgumentException - ifdestinationOffset is null.
See Also: IIOParam.getDestinationOffset
See Also: ImageWriter.replacePixels |
| setDestinationType | | public void setDestinationType(ImageTypeSpecifier destinationType)(Code) | | Sets the desired image type for the destination image, using an
ImageTypeSpecifier.
When reading, if the layout of the destination has been set
using this method, each call to an ImageReader
read method will return a new
BufferedImage using the format specified by the
supplied type specifier. As a side effect, any destination
BufferedImage set by
ImageReadParam.setDestination(BufferedImage) will
no longer be set as the destination. In other words, this
method may be thought of as calling
setDestination((BufferedImage)null).
When writing, the destination type maybe used to determine
the color type of the image. The SampleModel
information will be ignored, and may be null. For
example, a 4-banded image could represent either CMYK or RGBA
data. If a destination type is set, its
ColorModel will override any
ColorModel on the image itself. This is crucial
when setSourceBands is used since the image's
ColorModel will refer to the entire image rather
than to the subset of bands being written.
Parameters:
destinationType - the ImageTypeSpecifier tobe used to determine the destination layout and color type.
See Also: IIOParam.getDestinationType |
| setSourceBands | | public void setSourceBands(int[] sourceBands)(Code) | | Sets the indices of the source bands to be used. Duplicate
indices are not allowed.
A null value indicates that all source bands
will be used.
At the time of reading, an
IllegalArgumentException will be thrown by the
reader or writer if a value larger than the largest available
source band index has been specified or if the number of source
bands and destination bands to be used differ. The
ImageReader.checkReadParamBandSettings method may
be used to automate this test.
Semantically, a copy is made of the array; changes to the
array contents subsequent to this call have no effect on
this IIOParam.
Parameters:
sourceBands - an array of integer band indices to beused.
exception:
IllegalArgumentException - if sourceBandscontains a negative or duplicate value.
See Also: IIOParam.getSourceBands
See Also: ImageReadParam.setDestinationBands
See Also: ImageReader.checkReadParamBandSettings |
| setSourceRegion | | public void setSourceRegion(Rectangle sourceRegion)(Code) | | Sets the source region of interest. The region of interest is
described as a rectangle, with the upper-left corner of the
source image as pixel (0, 0) and increasing values down and to
the right. The actual number of pixels used will depend on
the subsampling factors set by setSourceSubsampling.
If subsampling has been set such that this number is zero,
an IllegalStateException will be thrown.
The source region of interest specified by this method will
be clipped as needed to fit within the source bounds, as well
as the destination offsets, width, and height at the time of
actual I/O.
A value of null for sourceRegion
will remove any region specification, causing the entire image
to be used.
Parameters:
sourceRegion - a Rectangle specifying thesource region of interest, or null.
exception:
IllegalArgumentException - ifsourceRegion is non-null and eithersourceRegion.x or sourceRegion.y isnegative.
exception:
IllegalArgumentException - ifsourceRegion is non-null and eithersourceRegion.width orsourceRegion.height is negative or 0.
exception:
IllegalStateException - if subsampling is such thatthis region will have a subsampled width or height of zero.
See Also: IIOParam.getSourceRegion
See Also: IIOParam.setSourceSubsampling
See Also: ImageReadParam.setDestinationOffset
See Also: ImageReadParam.getDestinationOffset |
| setSourceSubsampling | | public void setSourceSubsampling(int sourceXSubsampling, int sourceYSubsampling, int subsamplingXOffset, int subsamplingYOffset)(Code) | | Specifies a decimation subsampling to apply on I/O. The
sourceXSubsampling and
sourceYSubsampling parameters specify the
subsampling period (i.e., the number of rows and columns
to advance after every source pixel). Specifically, a period of
1 will use every row or column; a period of 2 will use every
other row or column. The subsamplingXOffset and
subsamplingYOffset parameters specify an offset
from the region (or image) origin for the first subsampled pixel.
Adjusting the origin of the subsample grid is useful for avoiding
seams when subsampling a very large source image into destination
regions that will be assembled into a complete subsampled image.
Most users will want to simply leave these parameters at 0.
The number of pixels and scanlines to be used are calculated
as follows.
The number of subsampled pixels in a scanline is given by
truncate[(width - subsamplingXOffset + sourceXSubsampling - 1)
/ sourceXSubsampling].
If the region is such that this width is zero, an
IllegalStateException is thrown.
The number of scanlines to be used can be computed similarly.
The ability to set the subsampling grid to start somewhere
other than the source region origin is useful if the
region is being used to create subsampled tiles of a large image,
where the tile width and height are not multiples of the
subsampling periods. If the subsampling grid does not remain
consistent from tile to tile, there will be artifacts at the tile
boundaries. By adjusting the subsampling grid offset for each
tile to compensate, these artifacts can be avoided. The tradeoff
is that in order to avoid these artifacts, the tiles are not all
the same size. The grid offset to use in this case is given by:
grid offset = [period - (region offset modulo period)] modulo period)
If either sourceXSubsampling or
sourceYSubsampling is 0 or negative, an
IllegalArgumentException will be thrown.
If either subsamplingXOffset or
subsamplingYOffset is negative or greater than or
equal to the corresponding period, an
IllegalArgumentException will be thrown.
There is no unsetSourceSubsampling method;
simply call setSourceSubsampling(1, 1, 0, 0) to
restore default values.
Parameters:
sourceXSubsampling - the number of columns to advancebetween pixels.
Parameters:
sourceYSubsampling - the number of rows to advance betweenpixels.
Parameters:
subsamplingXOffset - the horizontal offset of the first subsamplewithin the region, or within the image if no region is set.
Parameters:
subsamplingYOffset - the horizontal offset of the first subsamplewithin the region, or within the image if no region is set.
exception:
IllegalArgumentException - if either period isnegative or 0, or if either grid offset is negative or greater thanthe corresponding period.
exception:
IllegalStateException - if the source region is such thatthe subsampled output would contain no pixels. |
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