public abstract WritableRaster copyData (WritableRaster raster)

Computes an arbitrary rectangular region of the RenderedImage and copies it into a caller-supplied WritableRaster. The region to be computed is determined from the bounds of the supplied WritableRaster. The supplied WritableRaster must have a SampleModel that is compatible with this image. If raster is null, an appropriate WritableRaster is created.

Parameters:
raster    a WritableRaster to hold the returned portion of the image, or null.

Returns:  a reference to the supplied or created WritableRaster.