/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You 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 org.apache.batik.ext.awt.image.renderable;

import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.RenderContext;

import org.apache.batik.ext.awt.image.GraphicsUtil;
import org.apache.batik.ext.awt.image.Light;
import org.apache.batik.ext.awt.image.PadMode;
import org.apache.batik.ext.awt.image.rendered.AffineRed;
import org.apache.batik.ext.awt.image.rendered.BumpMap;
import org.apache.batik.ext.awt.image.rendered.CachableRed;
import org.apache.batik.ext.awt.image.rendered.DiffuseLightingRed;
import org.apache.batik.ext.awt.image.rendered.PadRed;

/**
 * Implementation of the DiffuseLightRable interface.
 *
 * @author <a href="mailto:vincent.hardy@eng.sun.com">Vincent Hardy</a>
 * @version $Id$
 */
public class DiffuseLightingRable8Bit
    extends AbstractColorInterpolationRable
    implements DiffuseLightingRable {
    /**
     * Surface Scale
     */
    private double surfaceScale;

    /**
     * Diffuse constant
     */
    private double kd;

    /**
     * Light used for the diffuse lighting computations
     */
    private Light light;

    /**
     * Lit Area
     */
    private Rectangle2D litRegion;

    /**
     * The dx/dy to use in user space for the sobel gradient.
     */
    private float [] kernelUnitLength = null;

    public DiffuseLightingRable8Bit(Filter src,
                                    Rectangle2D litRegion,
                                    Light light,
                                    double kd,
                                    double surfaceScale,
                                    double [] kernelUnitLength) {
        super(src, null);
        setLight(light);
        setKd(kd);
        setSurfaceScale(surfaceScale);
        setLitRegion(litRegion);
        setKernelUnitLength(kernelUnitLength);
    }

    /**
     * Returns the source to be filtered
     */
    public Filter getSource(){
        return (Filter)getSources().get(0);
    }

    /**
     * Sets the source to be filtered
     */
    public void setSource(Filter src){
        init(src, null);
    }

    /**
     * Returns this filter's bounds
     */
    public Rectangle2D getBounds2D(){
        return (Rectangle2D)(litRegion.clone());
    }

    /**
     * Returns this filter's litRegion
     */
    public Rectangle2D getLitRegion(){
        return getBounds2D();
    }

    /**
     * Set this filter's litRegion
     */
    public void setLitRegion(Rectangle2D litRegion){
        touch();
        this.litRegion = litRegion;
    }

    /**
     * @return Light object used for the diffuse lighting
     */
    public Light getLight(){
        return light;
    }

    /**
     * @param light New Light object
     */
    public void setLight(Light light){
        touch();
        this.light = light;
    }

    /**
     * @return surfaceScale
     */
    public double getSurfaceScale(){
        return surfaceScale;
    }

    /**
     * Sets the surface scale
     */
    public void setSurfaceScale(double surfaceScale){
        touch();
        this.surfaceScale = surfaceScale;
    }

    /**
     * @return diffuse constant, or kd.
     */
    public double getKd(){
        return kd;
    }

    /**
     * Sets the diffuse constant, or kd
     */
    public void setKd(double kd){
        touch();
        this.kd = kd;
    }

    /**
     * Returns the min [dx,dy] distance in user space for evalutation of
     * the sobel gradient.
     */
    public double [] getKernelUnitLength() {
        if (kernelUnitLength == null)
            return null;

        double [] ret = new double[2];
        ret[0] = kernelUnitLength[0];
        ret[1] = kernelUnitLength[1];
        return ret;
    }

    /**
     * Sets the min [dx,dy] distance in user space for evaluation of the
     * sobel gradient. If set to zero or null then device space will be used.
     */
    public void setKernelUnitLength(double [] kernelUnitLength) {
        touch();
        if (kernelUnitLength == null) {
            this.kernelUnitLength = null;
            return;
        }

        if (this.kernelUnitLength == null)
            this.kernelUnitLength = new float[2];

        this.kernelUnitLength[0] = (float)kernelUnitLength[0];
        this.kernelUnitLength[1] = (float)kernelUnitLength[1];
    }

    public RenderedImage createRendering(RenderContext rc) {
        Shape aoi = rc.getAreaOfInterest();
        if (aoi == null)
            aoi = getBounds2D();

        Rectangle2D aoiR = aoi.getBounds2D();
        Rectangle2D.intersect(aoiR, getBounds2D(), aoiR);

        AffineTransform at = rc.getTransform();
        Rectangle devRect = at.createTransformedShape(aoiR).getBounds();

        if(devRect.width == 0 || devRect.height == 0){
            return null;
        }

        //
        // DiffuseLightingRed only operates on a scaled space.
        // The following extracts the scale portion of the
        // user to device transform
        //
        // The source is rendered with the scale-only transform
        // and the rendered result is used as a bumpMap for the
        // DiffuseLightingRed filter.
        //
        double sx = at.getScaleX();
        double sy = at.getScaleY();

        double shx = at.getShearX();
        double shy = at.getShearY();

        double tx = at.getTranslateX();
        double ty = at.getTranslateY();

         // The Scale is the "hypotonose" of the matrix vectors.
        double scaleX = Math.sqrt(sx*sx + shy*shy);
        double scaleY = Math.sqrt(sy*sy + shx*shx);

        if(scaleX == 0 || scaleY == 0){
            // Non invertible transform
            return null;
        }

        // These values represent the scale factor to the intermediate
        // coordinate system where we will apply our convolution.
        if (kernelUnitLength != null) {
            if ((kernelUnitLength[0] > 0) &&
                (scaleX > 1/kernelUnitLength[0]))
                scaleX = 1/kernelUnitLength[0];

            if ((kernelUnitLength[1] > 0) &&
                (scaleY > 1/kernelUnitLength[1]))
                scaleY = 1/kernelUnitLength[1];
        }

        AffineTransform scale =
            AffineTransform.getScaleInstance(scaleX, scaleY);

        devRect = scale.createTransformedShape(aoiR).getBounds();

        // Grow for surround needs of bump map.
        aoiR.setRect(aoiR.getX()     -(2/scaleX),
                     aoiR.getY()     -(2/scaleY),
                     aoiR.getWidth() +(4/scaleX),
                     aoiR.getHeight()+(4/scaleY));


        // Build texture from the source
        rc = (RenderContext)rc.clone();
        rc.setAreaOfInterest(aoiR);
        rc.setTransform(scale);

        // System.out.println("scaleX / scaleY : " + scaleX + "/" + scaleY);

        CachableRed cr;
        cr = GraphicsUtil.wrap(getSource().createRendering(rc));

        BumpMap bumpMap = new BumpMap(cr, surfaceScale, scaleX, scaleY);

        cr = new DiffuseLightingRed(kd, light, bumpMap,
                                    devRect, 1/scaleX, 1/scaleY,
                                    isColorSpaceLinear());

        // Return sheared/rotated tiled image
        AffineTransform shearAt =
            new AffineTransform(sx/scaleX, shy/scaleX,
                                shx/scaleY, sy/scaleY,
                                tx, ty);

        if(!shearAt.isIdentity()) {
            RenderingHints rh = rc.getRenderingHints();
            Rectangle padRect = new Rectangle(devRect.x-1, devRect.y-1,
                                              devRect.width+2,
                                              devRect.height+2);
            cr = new PadRed(cr, padRect, PadMode.REPLICATE, rh);

            cr = new AffineRed(cr, shearAt, rh);
        }

        return cr;
    }
}

