/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

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 */

package javax.swing.plaf.nimbus;

import java.awt.AlphaComposite;

import java.awt.Graphics2D;

import java.awt.Transparency;

import java.awt.GraphicsConfiguration;

import java.awt.GraphicsEnvironment;

import java.awt.image.BufferedImage;

import java.awt.image.Raster;

import java.awt.image.WritableRaster;

import java.awt.image.ColorModel;

/**

 * EffectUtils

 *

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

 */

class EffectUtils {

    /**

     * Clear a transparent image to 100% transparent

     *

     * @param img The image to clear

     */

    static void clearImage(BufferedImage img) {

        Graphics2D g2 = img.createGraphics();

        g2.setComposite(AlphaComposite.Clear);

        g2.fillRect(0, 0, img.getWidth(), img.getHeight());

        g2.dispose();

    }

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

    // Blur

    /**

     * Apply Gaussian Blur to Image

     *

     * @param src    The image tp

     * @param dst    The destination image to draw blured src image into, null if you want a new one created

     * @param radius The blur kernel radius

     * @return The blured image

     */

    static BufferedImage gaussianBlur(BufferedImage src, BufferedImage dst, int radius) {

        int width = src.getWidth();

        int height = src.getHeight();

        if (dst == null || dst.getWidth() != width || dst.getHeight() != height || src.getType() != dst.getType()) {

            dst = createColorModelCompatibleImage(src);

        }

        float[] kernel = createGaussianKernel(radius);

        if (src.getType() == BufferedImage.TYPE_INT_ARGB) {

            int[] srcPixels = new int[width * height];

            int[] dstPixels = new int[width * height];

            getPixels(src, 0, 0, width, height, srcPixels);

            // horizontal pass

            blur(srcPixels, dstPixels, width, height, kernel, radius);

            // vertical pass

            //noinspection SuspiciousNameCombination

            blur(dstPixels, srcPixels, height, width, kernel, radius);

            // the result is now stored in srcPixels due to the 2nd pass

            setPixels(dst, 0, 0, width, height, srcPixels);

        } else if (src.getType() == BufferedImage.TYPE_BYTE_GRAY) {

            byte[] srcPixels = new byte[width * height];

            byte[] dstPixels = new byte[width * height];

            getPixels(src, 0, 0, width, height, srcPixels);

            // horizontal pass

            blur(srcPixels, dstPixels, width, height, kernel, radius);

            // vertical pass

            //noinspection SuspiciousNameCombination

            blur(dstPixels, srcPixels, height, width, kernel, radius);

            // the result is now stored in srcPixels due to the 2nd pass

            setPixels(dst, 0, 0, width, height, srcPixels);

        } else {

            throw new IllegalArgumentException("EffectUtils.gaussianBlur() src image is not a supported type, type=[" +

                    src.getType() + "]");

        }

        return dst;

    }

    /**

     * <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by the radius which

     * must be greater than 0.</p> <p>The source and destination pixels arrays are expected to be in the INT_ARGB

     * format.</p> <p>After this method is executed, dstPixels contains a transposed and filtered copy of

     * srcPixels.</p>

     *

     * @param srcPixels the source pixels

     * @param dstPixels the destination pixels

     * @param width     the width of the source picture

     * @param height    the height of the source picture

     * @param kernel    the kernel of the blur effect

     * @param radius    the radius of the blur effect

     */

    private static void blur(int[] srcPixels, int[] dstPixels,

                             int width, int height,

                             float[] kernel, int radius) {

        float a;

        float r;

        float g;

        float b;

        int ca;

        int cr;

        int cg;

        int cb;

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

            int index = y;

            int offset = y * width;

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

                a = r = g = b = 0.0f;

                for (int i = -radius; i <= radius; i++) {

                    int subOffset = x + i;

                    if (subOffset < 0 || subOffset >= width) {

                        subOffset = (x + width) % width;

                    }

                    int pixel = srcPixels[offset + subOffset];

                    float blurFactor = kernel[radius + i];

                    a += blurFactor * ((pixel >> 24) & 0xFF);

                    r += blurFactor * ((pixel >> 16) & 0xFF);

                    g += blurFactor * ((pixel >> 8) & 0xFF);

                    b += blurFactor * ((pixel) & 0xFF);

                }

                ca = (int) (a + 0.5f);

                cr = (int) (r + 0.5f);

                cg = (int) (g + 0.5f);

                cb = (int) (b + 0.5f);

                dstPixels[index] = ((ca > 255 ? 255 : ca) << 24) |

                        ((cr > 255 ? 255 : cr) << 16) |

                        ((cg > 255 ? 255 : cg) << 8) |

                        (cb > 255 ? 255 : cb);

                index += height;

            }

        }

    }

    /**

     * <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by the radius which

     * must be greater than 0.</p> <p>The source and destination pixels arrays are expected to be in the BYTE_GREY

     * format.</p> <p>After this method is executed, dstPixels contains a transposed and filtered copy of

     * srcPixels.</p>

     *

     * @param srcPixels the source pixels

     * @param dstPixels the destination pixels

     * @param width     the width of the source picture

     * @param height    the height of the source picture

     * @param kernel    the kernel of the blur effect

     * @param radius    the radius of the blur effect

     */

    static void blur(byte[] srcPixels, byte[] dstPixels,

                            int width, int height,

                            float[] kernel, int radius) {

        float p;

        int cp;

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

            int index = y;

            int offset = y * width;

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

                p = 0.0f;

                for (int i = -radius; i <= radius; i++) {

                    int subOffset = x + i;

//                    if (subOffset < 0) subOffset = 0;

//                    if (subOffset >= width) subOffset = width-1;

                    if (subOffset < 0 || subOffset >= width) {

                        subOffset = (x + width) % width;

                    }

                    int pixel = srcPixels[offset + subOffset] & 0xFF;

                    float blurFactor = kernel[radius + i];

                    p += blurFactor * pixel;

                }

                cp = (int) (p + 0.5f);

                dstPixels[index] = (byte) (cp > 255 ? 255 : cp);

                index += height;

            }

        }

    }

    static float[] createGaussianKernel(int radius) {

        if (radius < 1) {

            throw new IllegalArgumentException("Radius must be >= 1");

        }

        float[] data = new float[radius * 2 + 1];

        float sigma = radius / 3.0f;

        float twoSigmaSquare = 2.0f * sigma * sigma;

        float sigmaRoot = (float) Math.sqrt(twoSigmaSquare * Math.PI);

        float total = 0.0f;

        for (int i = -radius; i <= radius; i++) {

            float distance = i * i;

            int index = i + radius;

            data[index] = (float) Math.exp(-distance / twoSigmaSquare) / sigmaRoot;

            total += data[index];

        }

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

            data[i] /= total;

        }

        return data;

    }

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

    // Get/Set Pixels helper methods

    /**

     * <p>Returns an array of pixels, stored as integers, from a <code>BufferedImage</code>. The pixels are grabbed from

     * a rectangular area defined by a location and two dimensions. Calling this method on an image of type different

     * from <code>BufferedImage.TYPE_INT_ARGB</code> and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the

     * image.</p>

     *

     * @param img    the source image

     * @param x      the x location at which to start grabbing pixels

     * @param y      the y location at which to start grabbing pixels

     * @param w      the width of the rectangle of pixels to grab

     * @param h      the height of the rectangle of pixels to grab

     * @param pixels a pre-allocated array of pixels of size w*h; can be null

     * @return <code>pixels</code> if non-null, a new array of integers otherwise

     * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h

     */

    static byte[] getPixels(BufferedImage img,

                                   int x, int y, int w, int h, byte[] pixels) {

        if (w == 0 || h == 0) {

            return new byte[0];

        }

        if (pixels == null) {

            pixels = new byte[w * h];

        } else if (pixels.length < w * h) {

            throw new IllegalArgumentException("pixels array must have a length >= w*h");

        }

        int imageType = img.getType();

        if (imageType == BufferedImage.TYPE_BYTE_GRAY) {

            Raster raster = img.getRaster();

            return (byte[]) raster.getDataElements(x, y, w, h, pixels);

        } else {

            throw new IllegalArgumentException("Only type BYTE_GRAY is supported");

        }

    }

    /**

     * <p>Writes a rectangular area of pixels in the destination <code>BufferedImage</code>. Calling this method on an

     * image of type different from <code>BufferedImage.TYPE_INT_ARGB</code> and <code>BufferedImage.TYPE_INT_RGB</code>

     * will unmanage the image.</p>

     *

     * @param img    the destination image

     * @param x      the x location at which to start storing pixels

     * @param y      the y location at which to start storing pixels

     * @param w      the width of the rectangle of pixels to store

     * @param h      the height of the rectangle of pixels to store

     * @param pixels an array of pixels, stored as integers

     * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h

     */

    static void setPixels(BufferedImage img,

                                 int x, int y, int w, int h, byte[] pixels) {

        if (pixels == null || w == 0 || h == 0) {

            return;

        } else if (pixels.length < w * h) {

            throw new IllegalArgumentException("pixels array must have a length >= w*h");

        }

        int imageType = img.getType();

        if (imageType == BufferedImage.TYPE_BYTE_GRAY) {

            WritableRaster raster = img.getRaster();

            raster.setDataElements(x, y, w, h, pixels);

        } else {

            throw new IllegalArgumentException("Only type BYTE_GRAY is supported");

        }

    }

    /**

     * <p>Returns an array of pixels, stored as integers, from a

     * <code>BufferedImage</code>. The pixels are grabbed from a rectangular

     * area defined by a location and two dimensions. Calling this method on

     * an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>

     * and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>

     *

     * @param img the source image

     * @param x the x location at which to start grabbing pixels

     * @param y the y location at which to start grabbing pixels

     * @param w the width of the rectangle of pixels to grab

     * @param h the height of the rectangle of pixels to grab

     * @param pixels a pre-allocated array of pixels of size w*h; can be null

     * @return <code>pixels</code> if non-null, a new array of integers

     *   otherwise

     * @throws IllegalArgumentException is <code>pixels</code> is non-null and

     *   of length < w*h

     */

    public static int[] getPixels(BufferedImage img,

                                  int x, int y, int w, int h, int[] pixels) {

        if (w == 0 || h == 0) {

            return new int[0];

        }

        if (pixels == null) {

            pixels = new int[w * h];

        } else if (pixels.length < w * h) {

            throw new IllegalArgumentException("pixels array must have a length" +

                                               " >= w*h");

        }

        int imageType = img.getType();

        if (imageType == BufferedImage.TYPE_INT_ARGB ||

            imageType == BufferedImage.TYPE_INT_RGB) {

            Raster raster = img.getRaster();

            return (int[]) raster.getDataElements(x, y, w, h, pixels);

        }

        // Unmanages the image

        return img.getRGB(x, y, w, h, pixels, 0, w);

    }

    /**

     * <p>Writes a rectangular area of pixels in the destination

     * <code>BufferedImage</code>. Calling this method on

     * an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>

     * and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>

     *

     * @param img the destination image

     * @param x the x location at which to start storing pixels

     * @param y the y location at which to start storing pixels

     * @param w the width of the rectangle of pixels to store

     * @param h the height of the rectangle of pixels to store

     * @param pixels an array of pixels, stored as integers

     * @throws IllegalArgumentException is <code>pixels</code> is non-null and

     *   of length < w*h

     */

    public static void setPixels(BufferedImage img,

                                 int x, int y, int w, int h, int[] pixels) {

        if (pixels == null || w == 0 || h == 0) {

            return;

        } else if (pixels.length < w * h) {

            throw new IllegalArgumentException("pixels array must have a length" +

                                               " >= w*h");

        }

        int imageType = img.getType();

        if (imageType == BufferedImage.TYPE_INT_ARGB ||

            imageType == BufferedImage.TYPE_INT_RGB) {

            WritableRaster raster = img.getRaster();

            raster.setDataElements(x, y, w, h, pixels);

        } else {

            // Unmanages the image

            img.setRGB(x, y, w, h, pixels, 0, w);

        }

    }

    /**

     * <p>Returns a new <code>BufferedImage</code> using the same color model

     * as the image passed as a parameter. The returned image is only compatible

     * with the image passed as a parameter. This does not mean the returned

     * image is compatible with the hardware.</p>

     *

     * @param image the reference image from which the color model of the new

     *   image is obtained

     * @return a new <code>BufferedImage</code>, compatible with the color model

     *   of <code>image</code>

     */

    public static BufferedImage createColorModelCompatibleImage(BufferedImage image) {

        ColorModel cm = image.getColorModel();

        return new BufferedImage(cm,

            cm.createCompatibleWritableRaster(image.getWidth(),

                                              image.getHeight()),

            cm.isAlphaPremultiplied(), null);

    }

    /**

     * <p>Returns a new translucent compatible image of the specified width and

     * height. That is, the returned <code>BufferedImage</code> is compatible with

     * the graphics hardware. If the method is called in a headless

     * environment, then the returned BufferedImage will be compatible with

     * the source image.</p>

     *

     * @param width the width of the new image

     * @param height the height of the new image

     * @return a new translucent compatible <code>BufferedImage</code> of the

     *   specified width and height

     */

    public static BufferedImage createCompatibleTranslucentImage(int width,

                                                                 int height) {

        return isHeadless() ?

                new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB) :

                getGraphicsConfiguration().createCompatibleImage(width, height,

                                                   Transparency.TRANSLUCENT);

    }

    private static boolean isHeadless() {

        return GraphicsEnvironment.isHeadless();

    }

    // Returns the graphics configuration for the primary screen

    private static GraphicsConfiguration getGraphicsConfiguration() {

        return GraphicsEnvironment.getLocalGraphicsEnvironment().

                    getDefaultScreenDevice().getDefaultConfiguration();

    }

}