The java.awt.image.RGBImageFilter class is an abstract
subclass of java.awt.image.ImageFilter. It allows you
to write image filters modify a single pixel at a time. It's used
when each pixel's filtering is independent of the other pixels. On
the other hand you would not use it for filters where the filtering
depended on neighboring pixels such as a filter that averaged the
surrounding pixels.
The only method you need to override in this class is
filterRGB()
public abstract int filterRGB(int x, int y, int rgb)
For performance reasons you may also wish to override filterRGBPixels() and set the
canFilterIndexColorModel field to true. This
field determines whether or not the filter depends on the position
of the pixel. If it's true, then instead of filtering every pixel
in the image, the limited number of entries is the image's color
map are filtered instead. This is much faster. By default, it is
assumed that the filter does depend on position and the value of
the field is false.
public void filterRGBPixels(int x, int y, int width, int height,
int[] pixel, int offset, int scan)
The filterRGBPixels() method passes each pixel in the
pixels array to the filterRGB() method one at a time.
However you may be able to improve performance in some cases by
avoiding unnecessary method calls and filtering each pixel
directly, especially if canFilterIndexColorModel is
false.