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1: /* EmptyBorder.java -- 2: Copyright (C) 2003 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package javax.swing.border; 40: 41: import java.awt.Component; 42: import java.awt.Graphics; 43: import java.awt.Insets; 44: 45: 46: /** 47: * A border for leaving a specifiable number of pixels empty around 48: * the enclosed component. An EmptyBorder requires some space on each 49: * edge, but does not perform any drawing. 50: * 51: * <p><img src="EmptyBorder-1.png" width="290" height="200" 52: * alt="[An illustration of EmptyBorder]" /> 53: * 54: * @author Sascha Brawer (brawer@dandelis.ch) 55: */ 56: public class EmptyBorder extends AbstractBorder 57: { 58: /** 59: * Determined using the <code>serialver</code> tool 60: * of Apple/Sun JDK 1.3.1 on MacOS X 10.1.5. 61: */ 62: static final long serialVersionUID = -8116076291731988694L; 63: 64: 65: /** 66: * The number of pixels required at the left edge. 67: */ 68: protected int left; 69: 70: 71: /** 72: * The number of pixels required at the right edge. 73: */ 74: protected int right; 75: 76: 77: /** 78: * The number of pixels required at the top edge. 79: */ 80: protected int top; 81: 82: 83: /** 84: * The number of pixels required at the bottom edge. 85: */ 86: protected int bottom; 87: 88: 89: /** 90: * Constructs an empty border given the number of pixels required 91: * on each side. 92: * 93: * @param top the number of pixels that the border will need 94: * for its top edge. 95: * 96: * @param left the number of pixels that the border will need 97: * for its left edge. 98: * 99: * @param bottom the number of pixels that the border will need 100: * for its bottom edge. 101: * 102: * @param right the number of pixels that the border will need 103: * for its right edge. 104: */ 105: public EmptyBorder(int top, int left, int bottom, int right) 106: { 107: this.top = top; 108: this.left = left; 109: this.bottom = bottom; 110: this.right = right; 111: } 112: 113: 114: /** 115: * Constructs an empty border given the number of pixels required 116: * on each side, passed in an Insets object. 117: * 118: * @param borderInsets the Insets for the new border. 119: */ 120: public EmptyBorder(Insets borderInsets) 121: { 122: this(borderInsets.top, borderInsets.left, 123: borderInsets.bottom, borderInsets.right); 124: } 125: 126: 127: /** 128: * Performs nothing because an EmptyBorder does not paint any 129: * pixels. While the inherited implementation provided by 130: * {@link AbstractBorder#paintBorder} is a no-op as well, 131: * it is overwritten in order to match the API of the Sun 132: * reference implementation. 133: * 134: * @param c the component whose border is to be painted. 135: * @param g the graphics for painting. 136: * @param x the horizontal position for painting the border. 137: * @param y the vertical position for painting the border. 138: * @param width the width of the available area for painting the border. 139: * @param height the height of the available area for painting the border. 140: */ 141: public void paintBorder(Component c, Graphics g, 142: int x, int y, int width, int height) 143: { 144: // Nothing to do here. 145: } 146: 147: 148: /** 149: * Measures the width of this border. 150: * 151: * @param c the component whose border is to be measured. 152: * 153: * @return an Insets object whose <code>left</code>, <code>right</code>, 154: * <code>top</code> and <code>bottom</code> fields indicate the 155: * width of the border at the respective edge. 156: * 157: * @see #getBorderInsets(java.awt.Component, java.awt.Insets) 158: */ 159: public Insets getBorderInsets(Component c) 160: { 161: return getBorderInsets(c, null); 162: } 163: 164: 165: /** 166: * Measures the width of this border, storing the results into a 167: * pre-existing Insets object. 168: * 169: * @param insets an Insets object for holding the result values. 170: * After invoking this method, the <code>left</code>, 171: * <code>right</code>, <code>top</code> and 172: * <code>bottom</code> fields indicate the width of the 173: * border at the respective edge. 174: * 175: * @return the same object that was passed for <code>insets</code>. 176: * 177: * @see #getBorderInsets() 178: */ 179: public Insets getBorderInsets(Component c, Insets insets) 180: { 181: if (insets == null) 182: insets = new Insets(0, 0, 0, 0); 183: 184: insets.left = left; 185: insets.right = right; 186: insets.top = top; 187: insets.bottom = bottom; 188: return insets; 189: } 190: 191: 192: /** 193: * Measures the width of this border. 194: * 195: * @return an Insets object whose <code>left</code>, <code>right</code>, 196: * <code>top</code> and <code>bottom</code> fields indicate the 197: * width of the border at the respective edge. 198: * 199: * @see #getBorderInsets(java.awt.Component, java.awt.Insets) 200: */ 201: public Insets getBorderInsets() 202: { 203: return getBorderInsets(null, null); 204: } 205: 206: 207: /** 208: * Determines whether this border fills every pixel in its area 209: * when painting. Since an empty border does not paint any pixels 210: * whatsoever, the result is <code>false</code>. 211: * 212: * @return <code>false</code>. 213: */ 214: public boolean isBorderOpaque() 215: { 216: /* The inherited implementation of AbstractBorder.isBorderOpaque() 217: * would also return false. It is not clear why this is overriden 218: * in the Sun implementation, at least not from just reading the 219: * JavaDoc. 220: */ 221: return false; 222: } 223: }