/*
Copyright 2006 Jerry Huxtable

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 org.meteoinfo.image.filter;

import org.meteoinfo.image.math.Noise;

import java.awt.image.BufferedImage;

/**
 * This filter applies a marbling effect to an image, displacing pixels by
 * random amounts.
 */
public class MarbleFilter extends TransformFilter {

    private float[] sinTable, cosTable;
    private float xScale = 4;
    private float yScale = 4;
    private float amount = 1;
    private float turbulence = 1;

    public MarbleFilter() {
        setEdgeAction(CLAMP);
    }

    /**
     * Set the X scale of the effect.
     *
     * @param xScale the scale.
     * @see #getXScale
     */
    public void setXScale(float xScale) {
        this.xScale = xScale;
    }

    /**
     * Get the X scale of the effect.
     *
     * @return the scale.
     * @see #setXScale
     */
    public float getXScale() {
        return xScale;
    }

    /**
     * Set the Y scale of the effect.
     *
     * @param yScale the scale.
     * @see #getYScale
     */
    public void setYScale(float yScale) {
        this.yScale = yScale;
    }

    /**
     * Get the Y scale of the effect.
     *
     * @return the scale.
     * @see #setYScale
     */
    public float getYScale() {
        return yScale;
    }

    /**
     * Set the amount of effect.
     *
     * @param amount the amount
     * min-value 0
     * max-value 1
     * @see #getAmount
     */
    public void setAmount(float amount) {
        this.amount = amount;
    }

    /**
     * Get the amount of effect.
     *
     * @return the amount
     * @see #setAmount
     */
    public float getAmount() {
        return amount;
    }

    /**
     * Specifies the turbulence of the effect.
     *
     * @param turbulence the turbulence of the effect.
     * min-value 0
     * max-value 1
     * @see #getTurbulence
     */
    public void setTurbulence(float turbulence) {
        this.turbulence = turbulence;
    }

    /**
     * Returns the turbulence of the effect.
     *
     * @return the turbulence of the effect.
     * @see #setTurbulence
     */
    public float getTurbulence() {
        return turbulence;
    }

    private void initialize() {
        sinTable = new float[256];
        cosTable = new float[256];
        for (int i = 0; i < 256; i++) {
            float angle = ImageMath.TWO_PI * i / 256f * turbulence;
            sinTable[i] = (float) (-yScale * Math.sin(angle));
            cosTable[i] = (float) (yScale * Math.cos(angle));
        }
    }

    private int displacementMap(int x, int y) {
        return PixelUtils.clamp((int) (127 * (1 + Noise.noise2(x / xScale, y / xScale))));
    }

    @Override
    protected void transformInverse(int x, int y, float[] out) {
        int displacement = displacementMap(x, y);
        out[0] = x + sinTable[displacement];
        out[1] = y + cosTable[displacement];
    }

    @Override
    public BufferedImage filter(BufferedImage src, BufferedImage dst) {
        initialize();
        return super.filter(src, dst);
    }

    @Override
    public String toString() {
        return "Distort/Marble...";
    }
}
