BufferedImageOp
, RasterOp
public class RescaleOp extends Object implements BufferedImageOp, RasterOp
The pseudo code for the rescaling operation is as follows:
for each pixel from Source object { for each band/component of the pixel { dstElement = (srcElement*scaleFactor) + offset } }
For Rasters, rescaling operates on bands. The number of sets of scaling constants may be one, in which case the same constants are applied to all bands, or it must equal the number of Source Raster bands.
For BufferedImages, rescaling operates on color and alpha components. The number of sets of scaling constants may be one, in which case the same constants are applied to all color (but not alpha) components. Otherwise, the number of sets of scaling constants may equal the number of Source color components, in which case no rescaling of the alpha component (if present) is performed. If neither of these cases apply, the number of sets of scaling constants must equal the number of Source color components plus alpha components, in which case all color and alpha components are rescaled.
BufferedImage sources with premultiplied alpha data are treated in the same manner as non-premultiplied images for purposes of rescaling. That is, the rescaling is done per band on the raw data of the BufferedImage source without regard to whether the data is premultiplied. If a color conversion is required to the destination ColorModel, the premultiplied state of both source and destination will be taken into account for this step.
Images with an IndexColorModel cannot be rescaled.
If a RenderingHints object is specified in the constructor, the color rendering hint and the dithering hint may be used when color conversion is required.
Note that in-place operation is allowed (i.e. the source and destination can be the same object).
Constructor | Description |
---|---|
RescaleOp |
Constructs a new RescaleOp with the desired scale factors and offsets. |
RescaleOp |
Constructs a new RescaleOp with the desired scale factor and offset. |
Modifier and Type | Method | Description |
---|---|---|
BufferedImage |
createCompatibleDestImage |
Creates a zeroed destination image with the correct size and number of bands. |
WritableRaster |
createCompatibleDestRaster |
Creates a zeroed-destination Raster with the correct size and number of bands, given this source. |
final BufferedImage |
filter |
Rescales the source BufferedImage. |
final WritableRaster |
filter |
Rescales the pixel data in the source Raster. |
final Rectangle2D |
getBounds2D |
Returns the bounding box of the rescaled destination image. |
final Rectangle2D |
getBounds2D |
Returns the bounding box of the rescaled destination Raster. |
final int |
getNumFactors() |
Returns the number of scaling factors and offsets used in this RescaleOp. |
final float[] |
getOffsets |
Returns the offsets in the given array. |
final Point2D |
getPoint2D |
Returns the location of the destination point given a point in the source. |
final RenderingHints |
getRenderingHints() |
Returns the rendering hints for this op. |
final float[] |
getScaleFactors |
Returns the scale factors in the given array. |
public RescaleOp(float[] scaleFactors, float[] offsets, RenderingHints hints)
scaleFactors
- the specified scale factorsoffsets
- the specified offsetshints
- the specified RenderingHints
, or null
public RescaleOp(float scaleFactor, float offset, RenderingHints hints)
scaleFactor
- the specified scale factoroffset
- the specified offsethints
- the specified RenderingHints
, or null
public final float[] getScaleFactors(float[] scaleFactors)
scaleFactors
- the array to contain the scale factors of this RescaleOp
RescaleOp
.public final float[] getOffsets(float[] offsets)
offsets
- the array to contain the offsets of this RescaleOp
RescaleOp
.public final int getNumFactors()
RescaleOp
.public final BufferedImage filter(BufferedImage src, BufferedImage dst)
filter
in interface BufferedImageOp
src
- the BufferedImage
to be filtereddst
- the destination for the filtering operation or null
BufferedImage
.IllegalArgumentException
- if the ColorModel
of src
is an IndexColorModel
, or if the number of scaling factors and offsets in this RescaleOp
do not meet the requirements stated in the class comments, or if the source and destination images differ in size.public final WritableRaster filter(Raster src, WritableRaster dst)
filter
in interface RasterOp
src
- the Raster
to be filtereddst
- the destination for the filtering operation or null
WritableRaster
.IllegalArgumentException
- if src
and dst
do not have the same number of bands, or if the number of scaling factors and offsets in this RescaleOp
do not meet the requirements stated in the class comments, or if the source and destination rasters differ in size.public final Rectangle2D getBounds2D(BufferedImage src)
getBounds2D
in interface BufferedImageOp
src
- The BufferedImage
to be filteredRectangle2D
representing the destination image's bounding box.public final Rectangle2D getBounds2D(Raster src)
getBounds2D
in interface RasterOp
src
- the rescaled destination Raster
Raster
.public BufferedImage createCompatibleDestImage(BufferedImage src, ColorModel destCM)
createCompatibleDestImage
in interface BufferedImageOp
src
- Source image for the filter operation.destCM
- ColorModel of the destination. If null, the ColorModel of the source will be used.public WritableRaster createCompatibleDestRaster(Raster src)
Raster
with the correct size and number of bands, given this source.createCompatibleDestRaster
in interface RasterOp
src
- the source Raster
Raster
.public final Point2D getPoint2D(Point2D srcPt, Point2D dstPt)
getPoint2D
in interface BufferedImageOp
getPoint2D
in interface RasterOp
srcPt
- a point in the source imagedstPt
- the destination point or null
public final RenderingHints getRenderingHints()
getRenderingHints
in interface BufferedImageOp
getRenderingHints
in interface RasterOp
RescaleOp
.
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Documentation extracted from Debian's OpenJDK Development Kit package.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/image/RescaleOp.html