Quantizer.java

/*
*

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package railo.runtime.img.filter;
/**
 * The interface for an image quantizer. The addColor method is called (repeatedly
 * if necessary) with all the image pixels. A color table can then be returned by 
 * calling the buildColorTable method.
 */
public interface Quantizer {
	/**
	 * Initialize the quantizer. This should be called before adding any pixels.
	 * @param numColors the number of colors we're quantizing to.
	 */
	public void setup(int numColors);
	
	/**
	 * Add pixels to the quantizer.
	 * @param pixels the array of ARGB pixels
	 * @param offset the offset into the array
	 * @param count the count of pixels
	 */
	public void addPixels(int[] pixels, int offset, int count);
	
	/**
	 * Build a color table from the added pixels.
	 * @return an array of ARGB pixels representing a color table
	 */
	public int[] buildColorTable();
	
	/**
	 * Using the previously-built color table, return the index into that table for a pixel.
	 * This is guaranteed to return a valid index - returning the index of a color closer
	 * to that requested if necessary. 
	 * @param rgb the pixel to find
	 * @return the pixel's index in the color table
	 */
	public int getIndexForColor(int rgb);
}