/*
*

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 to change the brightness and contrast of an image.
 */
public class ContrastFilter extends TransferFilter  implements DynFiltering {

	private float brightness = 1.0f;
	private float contrast = 1.0f;
	
	protected float transferFunction( float f ) {
		f = f*brightness;
		f = (f-0.5f)*contrast+0.5f;
		return f;
	}

    /**
     * Set the filter brightness.
     * @param brightness the brightness in the range 0 to 1
     * @min-value 0
     * @max-value 0
     * @see #getBrightness
     */
	public void setBrightness(float brightness) {
		this.brightness = brightness;
		initialized = false;
	}
	
    /**
     * Get the filter brightness.
     * @return the brightness in the range 0 to 1
     * @see #setBrightness
     */
	public float getBrightness() {
		return brightness;
	}

    /**
     * Set the filter contrast.
     * @param contrast the contrast in the range 0 to 1
     * @min-value 0
     * @max-value 0
     * @see #getContrast
     */
	public void setContrast(float contrast) {
		this.contrast = contrast;
		initialized = false;
	}
	
    /**
     * Get the filter contrast.
     * @return the contrast in the range 0 to 1
     * @see #setContrast
     */
	public float getContrast() {
		return contrast;
	}

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

	public BufferedImage filter(BufferedImage src, Struct parameters) throws PageException {BufferedImage dst=ImageUtil.createBufferedImage(src);
		Object o;
		if((o=parameters.removeEL(KeyImpl.init("Brightness")))!=null)setBrightness(ImageFilterUtil.toFloatValue(o,"Brightness"));
		if((o=parameters.removeEL(KeyImpl.init("Contrast")))!=null)setContrast(ImageFilterUtil.toFloatValue(o,"Contrast"));
		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 [Brightness, Contrast, Dimensions]");
		}

		return filter(src, dst);
	}
}