/*
 * $Id: DropShadowBorder.java,v 1.1 2007/01/16 18:31:49 gfx Exp $
 *
 * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.awt.image.ConvolveOp;
import java.awt.image.Kernel;
import java.util.HashMap;
import java.util.Map;

import javax.swing.UIManager;
import javax.swing.border.Border;

/**
 * Implements a DropShadow for components. In general, the DropShadowBorder will
 * work with any rectangular components that do not have a default border installed
 * as part of the look and feel, or otherwise. For example, DropShadowBorder works
 * wonderfully with JPanel, but horribly with JComboBox.
 *
 * @author rbair
 */
public class DropShadowBorder implements Border {
    private static enum Position {TOP, TOP_LEFT, LEFT, BOTTOM_LEFT,
                    BOTTOM, BOTTOM_RIGHT, RIGHT, TOP_RIGHT};
                    
    private static final Map<Integer,Map<Position,BufferedImage>> CACHE 
            = new HashMap<Integer,Map<Position,BufferedImage>>();
                        
    private final Color lineColor;
    private final int lineWidth;
    private final int shadowSize;
    private final float shadowOpacity;
    private final int cornerSize;
    private final boolean showTopShadow;
    private final boolean showLeftShadow;
    private final boolean showBottomShadow;
    private final boolean showRightShadow;
    
    public DropShadowBorder() {
        this(UIManager.getColor("Control"), 1, 5);
    }
    
    public DropShadowBorder(Color lineColor, int lineWidth, int shadowSize) {
        this(lineColor, lineWidth, shadowSize, .5f, 12, false, false, true, true);
    }
    
    public DropShadowBorder(Color lineColor, int lineWidth, boolean showLeftShadow) {
        this(lineColor, lineWidth, 5, .5f, 12, false, showLeftShadow, true, true);
    }
    
    public DropShadowBorder(Color lineColor, int lineWidth, int shadowSize,
            float shadowOpacity, int cornerSize, boolean showTopShadow,
            boolean showLeftShadow, boolean showBottomShadow, boolean showRightShadow) {
        this.lineColor = lineColor;
        this.lineWidth = lineWidth;
        this.shadowSize = shadowSize;
        this.shadowOpacity = shadowOpacity;
        this.cornerSize = cornerSize;
        this.showTopShadow = showTopShadow;
        this.showLeftShadow = showLeftShadow;
        this.showBottomShadow = showBottomShadow;
        this.showRightShadow = showRightShadow;
    }
    
    /**
     * @inheritDoc
     */
    public void paintBorder(Component c, Graphics graphics, int x, int y, int width, int height) {
        /*
         * 1) Get images for this border
         * 2) Paint the images for each side of the border that should be painted
         */
       	Map<Position,BufferedImage> images = getImages((Graphics2D)graphics);
        
        //compute the edges of the component -- not including the border
//        Insets borderInsets = getBorderInsets(c);
//        int leftEdge = x + borderInsets.left;
//        int rightEdge = x + width - borderInsets.right;
//        int topEdge = y + borderInsets.top;
//        int bottomEdge = y + height - borderInsets.bottom;
        Graphics2D g2 = (Graphics2D)graphics.create();
        g2.setColor(lineColor);
        
        //The location and size of the shadows depends on which shadows are being
        //drawn. For instance, if the left & bottom shadows are being drawn, then
        //the left shadow extends all the way down to the corner, a corner is drawn,
        //and then the bottom shadow begins at the corner. If, however, only the
        //bottom shadow is drawn, then the bottom-left corner is drawn to the
        //right of the corner, and the bottom shadow is somewhat shorter than before.
        
        Point topLeftShadowPoint = null;
        if (showLeftShadow || showTopShadow) {
            topLeftShadowPoint = new Point();
            if (showLeftShadow && !showTopShadow) {
                topLeftShadowPoint.setLocation(x, y + shadowSize);
            } else if (showLeftShadow && showTopShadow) {
                topLeftShadowPoint.setLocation(x, y);
            } else if (!showLeftShadow && showTopShadow) {
                topLeftShadowPoint.setLocation(x + shadowSize, y);
            }
        }
  
        Point bottomLeftShadowPoint = null;
        if (showLeftShadow || showBottomShadow) {
            bottomLeftShadowPoint = new Point();
            if (showLeftShadow && !showBottomShadow) {
                bottomLeftShadowPoint.setLocation(x, y + height - shadowSize - shadowSize);
            } else if (showLeftShadow && showBottomShadow) {
                bottomLeftShadowPoint.setLocation(x, y + height - shadowSize);
            } else if (!showLeftShadow && showBottomShadow) {
                bottomLeftShadowPoint.setLocation(x + shadowSize, y + height - shadowSize);
            }
        }
        
        Point bottomRightShadowPoint = null;
        if (showRightShadow || showBottomShadow) {
            bottomRightShadowPoint = new Point();
            if (showRightShadow && !showBottomShadow) {
                bottomRightShadowPoint.setLocation(x + width - shadowSize, y + height - shadowSize - shadowSize);
            } else if (showRightShadow && showBottomShadow) {
                bottomRightShadowPoint.setLocation(x + width - shadowSize, y + height - shadowSize);
            } else if (!showRightShadow && showBottomShadow) {
                bottomRightShadowPoint.setLocation(x + width - shadowSize - shadowSize, y + height - shadowSize);
            }
        }
        
        Point topRightShadowPoint = null;
        if (showRightShadow || showTopShadow) {
            topRightShadowPoint = new Point();
            if (showRightShadow && !showTopShadow) {
                topRightShadowPoint.setLocation(x + width - shadowSize, y + shadowSize);
            } else if (showRightShadow && showTopShadow) {
                topRightShadowPoint.setLocation(x + width - shadowSize, y);
            } else if (!showRightShadow && showTopShadow) {
                topRightShadowPoint.setLocation(x + width - shadowSize - shadowSize, y);
            }
        }
 
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BILINEAR);
        g2.setRenderingHint(RenderingHints.KEY_RENDERING,
                            RenderingHints.VALUE_RENDER_SPEED);
        
        if (showLeftShadow) {
            Rectangle leftShadowRect =
                new Rectangle(x,
                              topLeftShadowPoint.y + shadowSize,
                              shadowSize,
                              bottomLeftShadowPoint.y - topLeftShadowPoint.y - shadowSize);
            g2.drawImage(images.get(Position.LEFT),
                         leftShadowRect.x, leftShadowRect.y,
                         leftShadowRect.width, leftShadowRect.height, null);
        }

        if (showBottomShadow) {
            Rectangle bottomShadowRect =
                new Rectangle(bottomLeftShadowPoint.x + shadowSize,
                              y + height - shadowSize,
                              bottomRightShadowPoint.x - bottomLeftShadowPoint.x - shadowSize,
                              shadowSize);
            g2.drawImage(images.get(Position.BOTTOM),
                         bottomShadowRect.x, bottomShadowRect.y,
                         bottomShadowRect.width, bottomShadowRect.height, null);
        }
        
        if (showRightShadow) {
            Rectangle rightShadowRect =
                new Rectangle(x + width - shadowSize,
                              topRightShadowPoint.y + shadowSize,
                              shadowSize,
                              bottomRightShadowPoint.y - topRightShadowPoint.y - shadowSize);
            g2.drawImage(images.get(Position.RIGHT),
                         rightShadowRect.x, rightShadowRect.y,
                         rightShadowRect.width, rightShadowRect.height, null);
        }
        
        if (showTopShadow) {
            Rectangle topShadowRect =
                new Rectangle(topLeftShadowPoint.x + shadowSize,
                              y,
                              topRightShadowPoint.x - topLeftShadowPoint.x - shadowSize,
                              shadowSize);
            g2.drawImage(images.get(Position.TOP),
                         topShadowRect.x, topShadowRect.y,
                         topShadowRect.width, topShadowRect.height, null);
        }
        
        if (showLeftShadow || showTopShadow) {
            g2.drawImage(images.get(Position.TOP_LEFT),
                         topLeftShadowPoint.x, topLeftShadowPoint.y, null);
        }
        if (showLeftShadow || showBottomShadow) {
            g2.drawImage(images.get(Position.BOTTOM_LEFT),
                         bottomLeftShadowPoint.x, bottomLeftShadowPoint.y, null);
        }
        if (showRightShadow || showBottomShadow) {
            g2.drawImage(images.get(Position.BOTTOM_RIGHT),
                         bottomRightShadowPoint.x, bottomRightShadowPoint.y, null);
        }
        if (showRightShadow || showTopShadow) {
            g2.drawImage(images.get(Position.TOP_RIGHT),
                         topRightShadowPoint.x, topRightShadowPoint.y, null);
        }
        
        g2.dispose();
    }
    
    private Map<Position,BufferedImage> getImages(Graphics2D g2) {
        //first, check to see if an image for this size has already been rendered
        //if so, use the cache. Else, draw and save
        Map<Position,BufferedImage> images = CACHE.get(shadowSize);
        if (images == null) {
            images = new HashMap<Position,BufferedImage>();

            /*
             * Do draw a drop shadow, I have to:
             *  1) Create a rounded rectangle
             *  2) Create a BufferedImage to draw the rounded rect in
             *  3) Translate the graphics for the image, so that the rectangle
             *     is centered in the drawn space. The border around the rectangle
             *     needs to be shadowWidth wide, so that there is space for the
             *     shadow to be drawn.
             *  4) Draw the rounded rect as black, with an opacity of 50%
             *  5) Create the BLUR_KERNEL
             *  6) Blur the image
             *  7) copy off the corners, sides, etc into images to be used for
             *     drawing the Border
             */
            int rectWidth = cornerSize + 1;
            RoundRectangle2D rect = new RoundRectangle2D.Double(0, 0, rectWidth, rectWidth, cornerSize, cornerSize);
            int imageWidth = rectWidth + shadowSize * 2;
            BufferedImage image = GraphicsUtilities.createCompatibleTranslucentImage(imageWidth, imageWidth);
            Graphics2D buffer = (Graphics2D)image.getGraphics();
            buffer.setColor(new Color(0.0f, 0.0f, 0.0f, shadowOpacity));
            buffer.translate(shadowSize, shadowSize);
            buffer.fill(rect);
            buffer.dispose();
            
            float blurry = 1.0f / (float)(shadowSize * shadowSize);
            float[] blurKernel = new float[shadowSize * shadowSize];
            for (int i=0; i<blurKernel.length; i++) {
                blurKernel[i] = blurry;
            }
            ConvolveOp blur = new ConvolveOp(new Kernel(shadowSize, shadowSize, blurKernel));
            BufferedImage targetImage = GraphicsUtilities.createCompatibleTranslucentImage(imageWidth, imageWidth);
            ((Graphics2D)targetImage.getGraphics()).drawImage(image, blur, -(shadowSize/2), -(shadowSize/2));

            int x = 1;
            int y = 1;
            int w = shadowSize;
            int h = shadowSize;
            images.put(Position.TOP_LEFT, getSubImage(targetImage, x, y, w, h));
            x = 1;
            y = h;
            w = shadowSize;
            h = 1;
            images.put(Position.LEFT, getSubImage(targetImage, x, y, w, h));
            x = 1;
            y = rectWidth;
            w = shadowSize;
            h = shadowSize;
            images.put(Position.BOTTOM_LEFT, getSubImage(targetImage, x, y, w, h));
            x = cornerSize + 1;
            y = rectWidth;
            w = 1;
            h = shadowSize;
            images.put(Position.BOTTOM, getSubImage(targetImage, x, y, w, h));
            x = rectWidth;
            y = x;
            w = shadowSize;
            h = shadowSize;
            images.put(Position.BOTTOM_RIGHT, getSubImage(targetImage, x, y, w, h));
            x = rectWidth;
            y = cornerSize + 1;
            w = shadowSize;
            h = 1;
            images.put(Position.RIGHT, getSubImage(targetImage, x, y, w, h));
            x = rectWidth;
            y = 1;
            w = shadowSize;
            h = shadowSize;
            images.put(Position.TOP_RIGHT, getSubImage(targetImage, x, y, w, h));
            x = shadowSize;
            y = 1;
            w = 1;
            h = shadowSize;
            images.put(Position.TOP, getSubImage(targetImage, x, y, w, h));

            image.flush();
            CACHE.put(shadowSize, images);
        }
        return images;
    }
    
    /**
     * Returns a new BufferedImage that represents a subregion of the given
     * BufferedImage.  (Note that this method does not use
     * BufferedImage.getSubimage(), which will defeat image acceleration
     * strategies on later JDKs.)
     */
    private BufferedImage getSubImage(BufferedImage img,
                                      int x, int y, int w, int h) {
        BufferedImage ret = GraphicsUtilities.createCompatibleTranslucentImage(w, h);
        Graphics2D g2 = ret.createGraphics();
        g2.drawImage(img,
                     0, 0, w, h,
                     x, y, x+w, y+h,
                     null);
        g2.dispose();
        return ret;
    }
    
    /**
     * @inheritDoc
     */
    public Insets getBorderInsets(Component c) {
        int top = showTopShadow ? lineWidth + shadowSize : lineWidth;
        int left = showLeftShadow ? lineWidth + shadowSize : lineWidth;
        int bottom = showBottomShadow ? lineWidth + shadowSize : lineWidth;
        int right = showRightShadow ? lineWidth + shadowSize : lineWidth;
        return new Insets(top, left, bottom, right);
    }
    
    /**
     * @inheritDoc
     */
    public boolean isBorderOpaque() {
        return false;
    }
    
    public boolean isShowTopShadow() {
        return showTopShadow;
    }
    
    public boolean isShowLeftShadow() {
        return showLeftShadow;
    }
    
    public boolean isShowRightShadow() {
        return showRightShadow;
    }
    
    public boolean isShowBottomShadow() {
        return showBottomShadow;
    }
    
    public int getLineWidth() {
        return lineWidth;
    }
    
    public Color getLineColor() {
        return lineColor;
    }
    
    public int getShadowSize() {
        return shadowSize;
    }
    
    public float getShadowOpacity() {
        return shadowOpacity;
    }
    
    public int getCornerSize() {
        return cornerSize;
    }
}