Support for large images (> 2GB)

[haraldk]

There is need for reading larger images than what can be created using the normal BufferedImage class and supporting Java2D classes. Currently, SampleModel (used by WritableRaster) has a restriction that width * height <= Integer.MAX_VALUE (as it uses int for index into the DataBuffer). Also, the most common type of images (TYPE_nBYTE_xxx) has a restriction that width * height * n <= Integer.MAX_VALUE, which further restricts the size of the images.

The RenderedImage (and WritableRenderedImage) interface that BufferedImage implements, has support for tiling. But there is no implementation of this tiling mechanism in the standard Java2D classes (TiledImage which is a subclass of PlanarImage does exist in Java Advanced Imaging, JAI). Further, as there is support for reading Rasters directly, it would be useful to have tiling for Rasters as well.

Because of the mentioned limitation of SampleModel, we should use the SampleModel only to control the tile size, and keep the full size of the image data in the Raster subclass.

-- Harald K