Java Doc for GeometricOpImage.java in  » 6.0-JDK-Modules » Java-Advanced-Imaging » javax » media » jai » Java Source Code / Java DocumentationJava Source Code and Java Documentation

The geometric relationship between the source and destination images will be determined by the specific behavior of the methods backwardMapRect() and forwardMapRect() the implementations of which must be provided by a subclass.

The location of the source pixel corresponding to a given destination pixel is determined by the aforementioned backward mapping transformation. The value of the destination pixel is then calculated by interpolating the values of a set of source pixels at locations in the vicinity of the backward mapped destination pixel location according to the requirements of a specified interpolation algorithm. In particular, a given destination pixel value may be interpolated from the neighborhood of source pixels beginning at (sx - leftPadding, sy - topPadding) and extending to (sx + rightPadding, sy + bottomPadding), inclusive, where (sx, sy) is the truncated backward mapped location of the destination pixel. The actual amount of padding required is determined by a supplied Interpolation object.

Since this operator might need a region around each source pixel in order to compute the destination pixel value, the border destination pixels might not be able to be computed without any source extension mechanism. The source extension method can be specified by supplying a BorderExtender object that will define the pixel values of the source outside the actual source area as a function of the actual source pixel values. If no extension is specified, the destination samples that cannot be computed will be written in the destination as the user-specified background values.
See Also:   BorderExtender
See Also:   Interpolation
See Also:   InterpolationNearest
See Also:   OpImage
since:
   JAI 1.1

The integral destination rectangle coordinates should be considered pixel indices.

The integral source rectangle coordinates should be considered pixel indices.

The GeometricOpImage constructor sets the computable bounds to the image bounds. Subclasses should set this value to values reasonable for the operation in question.

Additional control over the image bounds, tile grid layout, SampleModel, and ColorModel may be obtained by specifying an ImageLayout parameter. This parameter will be passed to the superclass constructor unchanged.
Parameters:
  layout - An ImageLayout containing the sourcebounds before padding, and optionally containing thetile grid layout, SampleModel, andColorModel.
Parameters:
  sources - The immediate sources of this image.
Parameters:
  configuration - Configurable attributes of the image includingconfiguration variables indexed byRenderingHints.Keys and image properties indexedby Strings or CaselessStringKeys.This is simply forwarded to the superclass constructor.
Parameters:
  cobbleSources - A boolean indicating whethercomputeRect() expects contiguous sources.
Parameters:
  extender - A BorderExtender, or null.
Parameters:
  interp - an Interpolation object to use forinterpolation of the backward mapped pixel values atfractional positions. If the supplied parameter isnull the corresponding instance variablewill be initialized to an instance ofInterpolationNearest.
throws:
  IllegalArgumentException - if sourcesis null.
throws:
  IllegalArgumentException - If sourcesis non-null and any object insources is null.
throws:
  IllegalArgumentException - if combining the intersectedsource bounds with the layout parameter results in negativeoutput width or height.

Additional control over the image bounds, tile grid layout, SampleModel, and ColorModel may be obtained by specifying an ImageLayout parameter. This parameter will be passed to the superclass constructor unchanged.

A RenderingHints for JAI.KEY_REPLACE_INDEX_COLOR_MODEL with the value of Boolean.TRUE is automatically added to the given configuration and passed up to the superclass constructor so that geometric operations are performed on the pixel values instead of being performed on the indices into the color map for those operations whose source(s) have an IndexColorModel. This addition will take place only if a value for the JAI.KEY_REPLACE_INDEX_COLOR_MODEL has not already been provided by the user. Note that the configuration Map is cloned before the new hint is added to it. Regarding the value for the JAI.KEY_REPLACE_INDEX_COLOR_MODEL RenderingHints, the operator itself can be smart based on the parameters, i.e. while the default value for the JAI.KEY_REPLACE_INDEX_COLOR_MODEL is Boolean.TRUE for operations that extend this class, in some cases the operator could set the default.
Parameters:
  layout - An ImageLayout containing the sourcebounds before padding, and optionally containing thetile grid layout, SampleModel, andColorModel.
Parameters:
  sources - The immediate sources of this image.
Parameters:
  configuration - Configurable attributes of the image includingconfiguration variables indexed byRenderingHints.Keys and image properties indexedby Strings or CaselessStringKeys.This is simply forwarded to the superclass constructor.
Parameters:
  cobbleSources - A boolean indicating whethercomputeRect() expects contiguous sources.
Parameters:
  extender - A BorderExtender, or null.
Parameters:
  interp - an Interpolation object to use forinterpolation of the backward mapped pixel values atfractional positions. If the supplied parameter isnull the corresponding instance variablewill be initialized to an instance ofInterpolationNearest.
Parameters:
  backgroundValues - The user-specified background values. If theprovided array length is smaller than the number of bands, allthe bands will be filled with the first element of the array.If the provided array is null, set it to new double[]{0.0}.
throws:
  IllegalArgumentException - if sourcesis null.
throws:
  IllegalArgumentException - If sourcesis non-null and any object insources is null.
throws:
  IllegalArgumentException - if combining the intersectedsource bounds with the layout parameter results in negativeoutput width or height.
since:
   JAI 1.1.2

The integral destination rectangle coordinates should be considered pixel indices. The "energy" of each pixel is defined to be concentrated in the continuous plane of pixels at an offset of (0.5, 0.5) from the index of the pixel. Backward mappings must take this (0.5, 0.5) pixel center into account. Thus given integral destination pixel indices as input, the fractional source location, as calculated by functions Xb(xDst, yDst), Yb(xDst, yDst), is given by:

 xSrc = Xb(xDst+0.5, yDst+0.5) - 0.5
 ySrc = Yb(xDst+0.5, yDst+0.5) - 0.5
 

Whether or not this method performs source cobbling is determined by the cobbleSources variable set at construction time. If cobbleSources is true, cobbling is performed on the source for areas that intersect multiple tiles, and computeRect(Raster[], WritableRaster, Rectangle) is called to perform the actual computation. Otherwise, computeRect(PlanarImage[], WritableRaster, Rectangle) is called to perform the actual computation.
Parameters:
  tileX - The X index of the tile.
Parameters:
  tileY - The Y index of the tile. The tile as a Raster.

The integral source rectangle coordinates should be considered pixel indices. The "energy" of each pixel is defined to be concentrated in the continuous plane of pixels at an offset of (0.5, 0.5) from the index of the pixel. Forward mappings must take this (0.5, 0.5) pixel center into account. Thus given integral source pixel indices as input, the fractional destination location, as calculated by functions Xf(xSrc, ySrc), Yf(xSrc, ySrc), is given by:

 xDst = Xf(xSrc+0.5, ySrc+0.5) - 0.5
 yDst = Yf(xSrc+0.5, ySrc+0.5) - 0.5
 

The implementation in this class returns the value of pt in the following code snippet:

 Rectangle destRect = new Rectangle((int)destPt.getX(),
 (int)destPt.getY(),
 1, 1);
 Rectangle sourceRect = backwardMapRect(destRect, sourceIndex);
 Point2D pt = (Point2D)destPt.clone();
 pt.setLocation(sourceRect.x + (sourceRect.width - 1.0)/2.0,
 sourceRect.y + (sourceRect.height - 1.0)/2.0);
 

The implementation in this class returns the value of pt in the following code snippet:

 Rectangle sourceRect = new Rectangle((int)sourcePt.getX(),
 (int)sourcePt.getY(),
 1, 1);
 Rectangle destRect = forwardMapRect(sourceRect, sourceIndex);
 Point2D pt = (Point2D)sourcePt.clone();
 pt.setLocation(destRect.x + (destRect.width - 1.0)/2.0,
 destRect.y + (destRect.height - 1.0)/2.0);