Class ResampledImage
- All Implemented Interfaces:
RenderedImage,Disposable
MathTransform (for example a map projection)
which converts pixel center coordinates from this image to pixel center coordinates
in the source image.
The converted coordinates usually contain fraction digits, in which case an interpolation is applied.
Usage note
This class should be used with non-linear transforms such as map projections. It is technically possible to use this class with linear transforms such asAffineTransform,
but there is more efficient alternatives for linear cases (for example
specifying the affine transform at rendering time).- Since:
- 1.1
- See Also:
Defined in the sis-feature module
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected final InterpolationThe object to use for performing interpolations.static final StringKey of a property providing an estimation of positional error for each pixel.protected final MathTransformConversion from pixel center coordinates of this image to pixel center coordinates of source image.Fields inherited from class ComputedImage
sampleModel, SOURCE_PADDING_KEYFields inherited from class PlanarImage
GRID_GEOMETRY_KEY, MASK_KEY, POSITIONAL_ACCURACY_KEY, SAMPLE_RESOLUTIONS_KEY, STATISTICS_KEY -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedResampledImage(RenderedImage source, SampleModel sampleModel, Point minTile, Rectangle bounds, MathTransform toSource, Interpolation interpolation, Number[] fillValues, Quantity<?>[] accuracy) Creates a new image which will resample the given image. -
Method Summary
Modifier and TypeMethodDescriptionprotected RastercomputeTile(int tileX, int tileY, WritableRaster tile) Invoked when a tile need to be computed or updated.booleanCompares the given object with this image for equality.Returns the color model of this resampled image.final intReturns the number of rows in this image.final intReturns the minimum tile index in the x direction.final intReturns the minimum tile index in the y direction.final intReturns the minimum x coordinate (inclusive) of this image.final intReturns the minimum y coordinate (inclusive) of this image.getProperty(String key) Gets a property from this image.String[]Returns the names of all recognized properties, ornullif this image has no properties.final intReturns the number of columns in this image.intReturns a hash code value for this image.protected DisposableNotifies the source image that tiles will be computed soon in the given region.verify()Verifies whether image layout information are consistent.Methods inherited from class ComputedImage
clearErrorFlags, createTile, dispose, getSampleModel, getSource, getSources, getTile, getTileHeight, getTileWidth, getWritableTileIndices, hasTileWriters, isTileWritable, markDirtyTiles, markTileWritable, sourceTileChangedMethods inherited from class PlanarImage
copyData, getBounds, getData, getData, getNumXTiles, getNumYTiles, getTileGridXOffset, getTileGridYOffset, toString
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Field Details
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POSITIONAL_CONSISTENCY_KEY
Key of a property providing an estimation of positional error for each pixel. Values shall be instances ofRenderedImagewith same size and origin than this image. The image should contain a single band where all sample values are error estimations in pixel units (relative to pixels of this image). The value should be small, for example between 0 and 0.2.The default implementation transforms all pixel coordinates to source, then convert them back to pixel coordinates in this image. The result is compared with expected coordinates and the distance is stored in the image.
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toSource
Conversion from pixel center coordinates of this image to pixel center coordinates of source image. This transform should be an instance ofMathTransform2D, but this is not required by this class (a future version may allow interpolations in a n-dimensional cube).- See Also:
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interpolation
The object to use for performing interpolations.
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Constructor Details
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ResampledImage
protected ResampledImage(RenderedImage source, SampleModel sampleModel, Point minTile, Rectangle bounds, MathTransform toSource, Interpolation interpolation, Number[] fillValues, Quantity<?>[] accuracy) Creates a new image which will resample the given image. The resampling operation is defined by a potentially non-linear transform from this image to the specified source image. That transform should map pixel centers.The
sampleModeldetermines the tile size and the target data type. This is often the same sample model than the one used by thesourceimage, but may also be different for forcing a different tile size or a different data type (e.g.byteversusfloat) for storing resampled values. If the specified sample model is not the same than the one used by the source image, then subclass should overridegetColorModel()for returning a color model which is compatible with the sample model.If a pixel in this image cannot be mapped to a pixel in the source image, then the sample values are set to
fillValues. If the given array isnull, or if any element in the given array isnull, then the default fill value is NaN for floating point data types or zero for integer data types. If the array is shorter than the number of bands, then above-cited default values are used for missing values. If longer than the number of bands, extraneous values are ignored.- Parameters:
source- the image to be resampled.sampleModel- the sample model shared by all tiles in this resampled image.minTile- indices of the first tile (minTileX,minTileY), ornullfor (0,0).bounds- domain of pixel coordinates of this resampled image.toSource- conversion of pixel coordinates of this image to pixel coordinates ofsourceimage.interpolation- the object to use for performing interpolations.fillValues- the values to use for pixels in this image that cannot be mapped to pixels in source image. May benullor containnullelements, and may have any length (see above for more details).accuracy- values of "org.apache.sis.PositionalAccuracy" property, ornullif none. This constructor may retain only a subset of specified values or replace some of them. If an accuracy is specified in pixel units, then a value such as 0.125 pixel may enable the use of a slightly faster algorithm at the expense of accuracy. This is only a hint honored on a best-effort basis.- See Also:
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Method Details
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verify
Verifies whether image layout information are consistent. This method verifies that source coordinates required by this image (computed by converting this image bounds using thetoSourcetransform) intersects the bounds of the source image. If this is not the case, then this method returns"toSource"for signaling that the transform may have a problem. Otherwise this method completes the check with all verifications documented in parent class- Overrides:
verifyin classPlanarImage- Returns:
nullif image layout information are consistent, or the name of inconsistent attribute if a problem is found.
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getColorModel
Returns the color model of this resampled image. Default implementation assumes that this image has the same color model than the source image.- Returns:
- the color model, or
nullif unspecified.
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getProperty
Gets a property from this image. Current default implementation supports the following keys (more properties may be added to this list in future Apache SIS versions):- "org.apache.sis.PositionalAccuracy"
- "org.apache.sis.PositionalConsistency"
- "org.apache.sis.SampleResolution" (forwarded to the source image)
- "org.apache.sis.Mask" if the image uses floating point numbers.
Note: the sample resolutions are retained because they should have approximately the same values before and after resampling. Statistics are not in this list because, while minimum and maximum values should stay approximately the same, the average value and standard deviation may be quite different.- Specified by:
getPropertyin interfaceRenderedImage- Overrides:
getPropertyin classPlanarImage- Parameters:
key- the name of the property to get.- Returns:
- the property value, or
Image.UndefinedPropertyif none.
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getPropertyNames
Returns the names of all recognized properties, ornullif this image has no properties. The returned array contains the properties listed ingetProperty(String)if the source image has those properties.- Specified by:
getPropertyNamesin interfaceRenderedImage- Overrides:
getPropertyNamesin classPlanarImage- Returns:
- names of all recognized properties, or
nullif none.
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getMinTileX
public final int getMinTileX()Returns the minimum tile index in the x direction. This is often 0.- Specified by:
getMinTileXin interfaceRenderedImage- Overrides:
getMinTileXin classPlanarImage- Returns:
- the minimum tile index in the x direction.
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getMinTileY
public final int getMinTileY()Returns the minimum tile index in the y direction. This is often 0.- Specified by:
getMinTileYin interfaceRenderedImage- Overrides:
getMinTileYin classPlanarImage- Returns:
- the minimum tile index in the y direction.
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getMinX
public final int getMinX()Returns the minimum x coordinate (inclusive) of this image. This is theRectangle.xvalue of theboundsspecified at construction time.- Specified by:
getMinXin interfaceRenderedImage- Overrides:
getMinXin classPlanarImage- Returns:
- the minimum x coordinate (column) of this image.
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getMinY
public final int getMinY()Returns the minimum y coordinate (inclusive) of this image. This is theRectangle.yvalue of theboundsspecified at construction time.- Specified by:
getMinYin interfaceRenderedImage- Overrides:
getMinYin classPlanarImage- Returns:
- the minimum y coordinate (row) of this image.
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getWidth
public final int getWidth()Returns the number of columns in this image. This is theRectangle.widthvalue of theboundsspecified at construction time.- Returns:
- number of columns in this image.
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getHeight
public final int getHeight()Returns the number of rows in this image. This is theRectangle.heightvalue of theboundsspecified at construction time.- Returns:
- number of rows in this image.
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computeTile
Invoked when a tile need to be computed or updated. This method fills all pixel values of the tile with values interpolated from the source image. It may be invoked concurrently in different threads.- Specified by:
computeTilein classComputedImage- Parameters:
tileX- the column index of the tile to compute.tileY- the row index of the tile to compute.tile- if the tile already exists but needs to be updated, the tile to update. Otherwisenull.- Returns:
- computed tile for the given indices.
- Throws:
TransformException- if an error occurred while computing pixel coordinates.
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prefetch
Notifies the source image that tiles will be computed soon in the given region. If the source image is an instance ofComputedImage, then this method forwards the notification to it. Otherwise default implementation does nothing.- Overrides:
prefetchin classComputedImage- Parameters:
tiles- indices of the tiles which will be prefetched.- Returns:
- handler on which to invoke
dispose()after the prefetch operation completed (successfully or not), ornullif none. - Since:
- 1.2
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equals
Compares the given object with this image for equality. This method returnstrueif the given object is non-null, is an instance of the exact same class than this image, has equal sources and do the same resampling operation (same interpolation method, same fill values, same coordinates). -
hashCode
public int hashCode()Returns a hash code value for this image.
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