/*
*

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;import java.awt.image.BufferedImage;

import railo.runtime.engine.ThreadLocalPageContext;
import railo.runtime.exp.FunctionException;
import railo.runtime.exp.PageException;
import railo.runtime.img.ImageUtil;
import railo.runtime.type.KeyImpl;
import railo.runtime.type.Struct;
import railo.runtime.type.util.CollectionUtil;



/**
 * A filter which changes the exposure of an image.
 */
public class ExposureFilter extends TransferFilter  implements DynFiltering {

	private float exposure = 1.0f;

	protected float transferFunction( float f ) {
		return 1 - (float)Math.exp(-f * exposure);
	}

    /**
     * Set the exposure level.
     * @param exposure the exposure level
     * @min-value 0
     * @max-value 5+
     * @see #getExposure
     */
	public void setExposure(float exposure) {
		this.exposure = exposure;
		initialized = false;
	}
	
    /**
     * Get the exposure level.
     * @return the exposure level
     * @see #setExposure
     */
	public float getExposure() {
		return exposure;
	}

	public String toString() {
		return "Colors/Exposure...";
	}

	public BufferedImage filter(BufferedImage src, Struct parameters) throws PageException {BufferedImage dst=ImageUtil.createBufferedImage(src);
		Object o;
		if((o=parameters.removeEL(KeyImpl.init("Exposure")))!=null)setExposure(ImageFilterUtil.toFloatValue(o,"Exposure"));
		if((o=parameters.removeEL(KeyImpl.init("Dimensions")))!=null){
			int[] dim=ImageFilterUtil.toDimensions(o,"Dimensions");
			setDimensions(dim[0],dim[1]);
		}

		// check for arguments not supported
		if(parameters.size()>0) {
			throw new FunctionException(ThreadLocalPageContext.get(), "ImageFilter", 3, "parameters", "the parameter"+(parameters.size()>1?"s":"")+" ["+CollectionUtil.getKeyList(parameters,", ")+"] "+(parameters.size()>1?"are":"is")+" not allowed, only the following parameters are supported [Exposure, Dimensions]");
		}

		return filter(src, dst);
	}
}