/*
 * Copyright (c) 1996, 2014, 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 sun.awt.image;

import java.awt.Component;
import java.awt.Color;
import java.awt.SystemColor;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.awt.image.ImageProducer;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.ImageObserver;
import java.awt.image.WritableRaster;
import sun.java2d.SunGraphics2D;
import sun.java2d.loops.SurfaceType;

/**
 * This is a special variant of BufferedImage that keeps a reference to
 * a Component.  The Component's foreground and background colors and
 * default font are used as the defaults for this image.
 */
public class OffScreenImage extends BufferedImage {

    protected Component c;
    private OffScreenImageSource osis;
    private Font defaultFont;
    
    // The layout size of the image.
    private int width;
    private int height;
    
    // The scale factor which determines the physical size of the raster.
    private int scale = 1;
    
    // Affects the value returned by the size methods.
    // When {@code true}, the returned size value matches
    // the layout size of the image, otherwise the returned
    // size value matches the physical size of the raster,
    // which is determined by the scale factor.
    private boolean returnLayoutSize;
    
    /**
     * Constructs an OffScreenImage given a color model and tile,
     * for offscreen rendering to be used with a given component.
     * The component is used to obtain the foreground color, background
     * color and font.
     */
    public OffScreenImage(Component c, ColorModel cm, WritableRaster raster,
                          boolean isRasterPremultiplied)
    {
        super(cm, raster, isRasterPremultiplied, null);
        this.c = c;
        initSurface(raster.getWidth(), raster.getHeight());
    }
    
    private OffScreenImage(Component c, ColorModel cm, WritableRaster raster,
                           boolean isRasterPremultiplied,
                           int width, int height,
                           int scale)
    {
        this(c, cm, raster, isRasterPremultiplied);
        this.width = width;
        this.height = height;
        this.scale = scale;
    }
    
    /**
     * Constructs an OffScreenImage with the {@code scale} factor.
     * The scale determines the physical size of the raster, compared
     * to the layout {@code width/height} size of the image.
     */
    public OffScreenImage(Component c, int width, int height,
                          int imageType,
                          int scale)
    {
         super(width * scale, height * scale, imageType);
         this.c = c;
         this.width = width;
         this.height = height;
         this.scale = scale;
    }  
    
    /**
     * Constructs an OffScreenImage with the {@code scale} factor.
     * The scale determines the physical size of the raster, compared
     * to the layout {@code width/height} size of the image.
     */
    public static OffScreenImage create(Component c, GraphicsConfiguration gc,
                                        int width, int height,
                                        int transparency,
                                        int scale)
    {
        ColorModel cm = gc.getColorModel(transparency);
        WritableRaster wr = cm.createCompatibleWritableRaster(width * scale, height * scale);
        return new OffScreenImage(c, cm, wr, cm.isAlphaPremultiplied(),
                                  width, height, scale);        
    }
    
    /**
     * Sets whether the {@code getWidth/Height} methods should
     * return the layout or physical size of the image.
     * @param value 
     */
    public void setReturnLayoutSize(boolean value) {
        returnLayoutSize = value;
    }
    
    /**
     * Gets whether the {@code getWidth/Height} methods should
     * return the layout or physical size of the image.
     * @param value 
     */
    public boolean isReturnLayoutSize() {
        return returnLayoutSize;
    }
    
    @Override
    public int getWidth() {
        return returnLayoutSize ? width : super.getWidth();
    }
    
    @Override
    public int getWidth(ImageObserver o) {
        return getWidth();
    }
    
    @Override
    public int getHeight() {
        return returnLayoutSize ? height : super.getHeight();
    }
    
    @Override
    public int getHeight(ImageObserver o) {
        return getHeight();
    }
    
    /**
     * Gets the layout width of the image.
     * 
     * @return the layout width of the image
     */
    public int getLayoutWidth() {
        return width;
    }
    
    /**
     * Gets the layout height of the image.
     * 
     * @return the layout height of the image
     */
    public int getLayoutHeight() {
        return height;
    }
    
    /**
     * Gets the scale factor used to scale the image on HiDPI devices
     * 
     * @return the HiDPI scale factor
     */
    public int getHiDPIScale() {
        return scale;
    }
    
    public Graphics getGraphics() {
        return createGraphics();
    }

    public Graphics2D createGraphics() {
        if (c == null) {
            GraphicsEnvironment env =
                GraphicsEnvironment.getLocalGraphicsEnvironment();
            return env.createGraphics(this);
        }

        Color bg = c.getBackground();
        if (bg == null) {
            bg = SystemColor.window;
        }

        Color fg = c.getForeground();
        if (fg == null) {
            fg = SystemColor.windowText;
        }

        Font font = c.getFont();
        if (font == null) {
            if (defaultFont == null) {
                defaultFont = new Font("Dialog", Font.PLAIN, 12);
            }
            font = defaultFont;
        }

        return new SunGraphics2D(SurfaceData.getPrimarySurfaceData(this),
                                 fg, bg, font);
    }

    private void initSurface(int width, int height) {
        Graphics2D g2 = createGraphics();
        try {
            g2.clearRect(0, 0, width, height);
        } finally {
            g2.dispose();
        }
    }

    public ImageProducer getSource() {
        if (osis == null) {
            osis = new OffScreenImageSource(this);
        }
        return osis;
    }
    
    /**
     * Creates a scaled OffScreenImage.
     */
    public class GraphicsConfig extends BufferedImageGraphicsConfig {
        public GraphicsConfig() {
            super(OffScreenImage.this, null);
        }
        
        public BufferedImage createCompatibleHiDPIImage(int width, int height, int transparency) {
            return OffScreenImage.create(null, this,
                                         width, height,
                                         transparency,
                                         OffScreenImage.this.getHiDPIScale());
        }
    }
    
    /**
     * Returns correct physical bounds and the scale factor.
     */
    public class SurfaceData extends BufImgSurfaceData {
        public SurfaceData(DataBuffer db, SurfaceType sType) {
            super(db, OffScreenImage.this, sType);
        }
        
        @Override
        public Rectangle getBounds() {
            return new Rectangle(OffScreenImage.this.getRaster().getWidth(),
                                 OffScreenImage.this.getRaster().getHeight());
        }
        
        @Override
        public int getDefaultScale() {
            return OffScreenImage.this.getHiDPIScale();
        }
    }
    
    /**
     * Backed by a scaled OffScreenImage.
     */
    public static class VolatileImage extends SunVolatileImage {
        public VolatileImage(OffScreenImage.GraphicsConfig graphicsConfig,
                             int width, int height,
                             int transparency)
        {
            super(graphicsConfig, width, height, transparency, null);
        }
        
        @Override
        public BufferedImage getBackupImage() {
            OffScreenImage img = (OffScreenImage)
                ((OffScreenImage.GraphicsConfig)getGraphicsConfig()).
                createCompatibleHiDPIImage(getWidth(), getHeight(), transparency);
            img.setReturnLayoutSize(true);
            return img;
        }
    }
    
}