1 /*
   2  * Copyright (c) 1996, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.awt.image;
  27 
  28 import java.awt.Component;
  29 import java.awt.Color;
  30 import java.awt.SystemColor;
  31 import java.awt.Font;
  32 import java.awt.Graphics;
  33 import java.awt.Graphics2D;
  34 import java.awt.GraphicsEnvironment;
  35 import java.awt.image.BufferedImage;
  36 import java.awt.image.ImageProducer;
  37 import java.awt.image.ColorModel;
  38 import java.awt.image.WritableRaster;
  39 import sun.java2d.SunGraphics2D;
  40 import sun.java2d.SurfaceData;
  41 
  42 /**
  43  * This is a special variant of BufferedImage that keeps a reference to
  44  * a Component.  The Component's foreground and background colors and
  45  * default font are used as the defaults for this image.
  46  */
  47 public class OffScreenImage extends BufferedImage {
  48 
  49     protected Component c;
  50     private OffScreenImageSource osis;
  51     private Font defaultFont;
  52 
  53     /**
  54      * Constructs an OffScreenImage given a color model and tile,
  55      * for offscreen rendering to be used with a given component.
  56      * The component is used to obtain the foreground color, background
  57      * color and font.
  58      */
  59     public OffScreenImage(Component c, ColorModel cm, WritableRaster raster,
  60                           boolean isRasterPremultiplied)
  61     {
  62         super(cm, raster, isRasterPremultiplied, null);
  63         this.c = c;
  64         initSurface(raster.getWidth(), raster.getHeight());
  65     }
  66 
  67     public Graphics getGraphics() {
  68         return createGraphics();
  69     }
  70 
  71     public Graphics2D createGraphics() {
  72         if (c == null) {
  73             GraphicsEnvironment env =
  74                 GraphicsEnvironment.getLocalGraphicsEnvironment();
  75             return env.createGraphics(this);
  76         }
  77 
  78         Color bg = c.getBackground();
  79         if (bg == null) {
  80             bg = SystemColor.window;
  81         }
  82 
  83         Color fg = c.getForeground();
  84         if (fg == null) {
  85             fg = SystemColor.windowText;
  86         }
  87 
  88         Font font = c.getFont();
  89         if (font == null) {
  90             if (defaultFont == null) {
  91                 defaultFont = new Font("Dialog", Font.PLAIN, 12);
  92             }
  93             font = defaultFont;
  94         }
  95 
  96         return new SunGraphics2D(SurfaceData.getPrimarySurfaceData(this),
  97                                  fg, bg, font);
  98     }
  99 
 100     private void initSurface(int width, int height) {
 101         Graphics2D g2 = createGraphics();
 102         try {
 103             g2.clearRect(0, 0, width, height);
 104         } finally {
 105             g2.dispose();
 106         }
 107     }
 108 
 109     public ImageProducer getSource() {
 110         if (osis == null) {
 111             osis = new OffScreenImageSource(this);
 112         }
 113         return osis;
 114     }
 115 }