SubsampleAverage throws ArrayIndexOutOfBoundsException when run the attached code with a paremetr 0.4.  It is okay for 0.5.

N/A

  xxxxx@xxxxx   2004-09-02

SubsampleAverageOpImage.backwardMapRect() creates a Rectangle which includes area outside the bounds of the source image and GeometricOpImage.mapDestRect() does not clip this Rectangle so that as there is no BorderExtender the getData() call applied to the source throws an Exception.

  xxxxx@xxxxx   2004-09-03

The implementation of SubsampleAverageOpImage.backwardMapRect() is incorrect. It ends up including area to the right and below that which is really necessary in the source. This is due to calculating the width and height of the backward mapped rectangle directly instead of calculating the difference between the backward mapped positions of the upper left and lower right corners. As the JAI portion of the mediaLib implementation is a subclass this problem affects both native and Java implementations.

A secondary problem is that GeometricOpImage.computeTile() does not clip the result of mapDestRect() to the source bounds when there is no BorderExtender (as is always the case for SubsampleAverage) and the rectangle returned by mapDestRect() includes area outside the source bounds.

Same error with different xFactor/yFactor