/*

 * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package javax.swing.plaf.nimbus;

import java.awt.image.BufferedImage;

import java.awt.image.Raster;

import java.awt.image.WritableRaster;

import java.util.Arrays;

/**

 * DropShadowEffect - This effect currently only works with ARGB type buffered

 * images.

 *

 * @author Created by Jasper Potts (Jun 18, 2007)

 */

class DropShadowEffect extends ShadowEffect {

    // =================================================================================================================

    // Effect Methods

    /**

     * Get the type of this effect, one of UNDER,BLENDED,OVER. UNDER means the result of apply effect should be painted

     * under the src image. BLENDED means the result of apply sffect contains a modified src image so just it should be

     * painted. OVER means the result of apply effect should be painted over the src image.

     *

     * @return The effect type

     */

    @Override

    EffectType getEffectType() {

        return EffectType.UNDER;

    }

    /**

     * Apply the effect to the src image generating the result . The result image may or may not contain the source

     * image depending on what the effect type is.

     *

     * @param src The source image for applying the effect to

     * @param dst The destination image to paint effect result into. If this is null then a new image will be created

     * @param w   The width of the src image to apply effect to, this allow the src and dst buffers to be bigger than

     *            the area the need effect applied to it

     * @param h   The height of the src image to apply effect to, this allow the src and dst buffers to be bigger than

     *            the area the need effect applied to it

     * @return Image with the result of the effect

     */

    @Override

    BufferedImage applyEffect(BufferedImage src, BufferedImage dst, int w, int h) {

        if (src == null || src.getType() != BufferedImage.TYPE_INT_ARGB){

            throw new IllegalArgumentException("Effect only works with " +

                    "source images of type BufferedImage.TYPE_INT_ARGB.");

        }

        if (dst != null && dst.getType() != BufferedImage.TYPE_INT_ARGB){

            throw new IllegalArgumentException("Effect only works with " +

                    "destination images of type BufferedImage.TYPE_INT_ARGB.");

        }

        // calculate offset

        double trangleAngle = Math.toRadians(angle - 90);

        int offsetX = (int) (Math.sin(trangleAngle) * distance);

        int offsetY = (int) (Math.cos(trangleAngle) * distance);

        // clac expanded size

        int tmpOffX = offsetX + size;

        int tmpOffY = offsetX + size;

        int tmpW = w + offsetX + size + size;

        int tmpH = h + offsetX + size;

        // create tmp buffers

        int[] lineBuf = getArrayCache().getTmpIntArray(w);

        byte[] tmpBuf1 = getArrayCache().getTmpByteArray1(tmpW * tmpH);

        Arrays.fill(tmpBuf1, (byte) 0x00);

        byte[] tmpBuf2 = getArrayCache().getTmpByteArray2(tmpW * tmpH);

        // extract src image alpha channel and inverse and offset

        Raster srcRaster = src.getRaster();

        for (int y = 0; y < h; y++) {

            int dy = (y + tmpOffY);

            int offset = dy * tmpW;

            srcRaster.getDataElements(0, y, w, 1, lineBuf);

            for (int x = 0; x < w; x++) {

                int dx = x + tmpOffX;

                tmpBuf1[offset + dx] = (byte) ((lineBuf[x] & 0xFF000000) >>> 24);

            }

        }

        // blur

        float[] kernel = EffectUtils.createGaussianKernel(size);

        EffectUtils.blur(tmpBuf1, tmpBuf2, tmpW, tmpH, kernel, size); // horizontal pass

        EffectUtils.blur(tmpBuf2, tmpBuf1, tmpH, tmpW, kernel, size);// vertical pass

        //rescale

        float spread = Math.min(1 / (1 - (0.01f * this.spread)), 255);

        for (int i = 0; i < tmpBuf1.length; i++) {

            int val = (int) (((int) tmpBuf1[i] & 0xFF) * spread);

            tmpBuf1[i] = (val > 255) ? (byte) 0xFF : (byte) val;

        }

        // create color image with shadow color and greyscale image as alpha

        if (dst == null) dst = new BufferedImage(w, h,

                BufferedImage.TYPE_INT_ARGB);

        WritableRaster shadowRaster = dst.getRaster();

        int red = color.getRed(), green = color.getGreen(), blue = color.getBlue();

        for (int y = 0; y < h; y++) {

            int srcY = y + tmpOffY;

            int shadowOffset = (srcY - offsetY) * tmpW;

            for (int x = 0; x < w; x++) {

                int srcX = x + tmpOffX;

                lineBuf[x] = tmpBuf1[shadowOffset + (srcX - offsetX)] << 24 | red << 16 | green << 8 | blue;

            }

            shadowRaster.setDataElements(0, y, w, 1, lineBuf);

        }

        return dst;

    }

}