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1: /* AbstractBorder.java -- 2: Copyright (C) 2003, 2006, 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: import java.awt.Rectangle; 45: import java.io.Serializable; 46: 47: 48: /** 49: * An invisible zero-width border, serving as a base class for 50: * implementing more interesting borders. 51: * 52: * @author Sascha Brawer (brawer@dandelis.ch) 53: * @author Ronald Veldema (rveldema@cs.vu.nl) 54: */ 55: public abstract class AbstractBorder implements Border, Serializable 56: { 57: static final long serialVersionUID = -545885975315191844L; 58: 59: /** 60: * Constructs a new AbstractBorder. 61: */ 62: public AbstractBorder() 63: { 64: // Nothing to do here. 65: } 66: 67: /** 68: * Performs nothing, because the default implementation provided by 69: * this class is an invisible, zero-width border. Subclasses will 70: * likely want to override this method, but they are not required 71: * to do so. 72: * 73: * @param c the component whose border is to be painted. 74: * @param g the graphics for painting. 75: * @param x the horizontal position for painting the border. 76: * @param y the vertical position for painting the border. 77: * @param width the width of the available area for painting the border. 78: * @param height the height of the available area for painting the border. 79: */ 80: public void paintBorder(Component c, Graphics g, int x, int y, int width, 81: int height) 82: { 83: // A previous version of Classpath had emitted a warning when 84: // this method was called. The warning was removed because it is 85: // perfectly legal for a subclass to not override the paintBorder 86: // method. An example would be EmptyBorder. 87: } 88: 89: /** 90: * Returns the insets required for drawing this border around the specified 91: * component. 92: * 93: * @param c the component that the border applies to (ignored here, 94: * subclasses may use it). 95: * 96: * @return an Insets object whose <code>left</code>, <code>right</code>, 97: * <code>top</code> and <code>bottom</code> fields indicate the 98: * width of the border at the respective edge, which is zero 99: * for the default implementation provided by AbstractButton. 100: * 101: * @see #getBorderInsets(java.awt.Component, java.awt.Insets) 102: */ 103: public Insets getBorderInsets(Component c) 104: { 105: return new Insets(0, 0, 0, 0); 106: } 107: 108: /** 109: * Returns the insets required for drawing this border around the specified 110: * component. The default implementation provided here sets the 111: * <code>left</code>, <code>right</code>, <code>top</code> and 112: * <code>bottom</code> fields of the passed <code>insets</code> parameter to 113: * zero. 114: * 115: * @param c the component that the border applies to (ignored here, 116: * subclasses may use it). 117: * @param insets an instance that will be overwritten and returned as the 118: * result (<code>null</code> not permitted). 119: * 120: * @return The border insets (the same object that was passed as the 121: * <code>insets</code> argument). 122: * 123: * @see #getBorderInsets(Component) 124: * 125: * @throws NullPointerException if <code>insets</code> is <code>null</code>. 126: */ 127: public Insets getBorderInsets(Component c, Insets insets) 128: { 129: insets.left = insets.right = insets.top = insets.bottom = 0; 130: return insets; 131: } 132: 133: /** 134: * Determines whether or not this border is opaque. An opaque border 135: * fills every pixel in its area when painting. Partially 136: * translucent borders must return <code>false</code>, or ugly 137: * artifacts can appear on screen. The default implementation 138: * provided here always returns <code>false</code>. 139: * 140: * @return <code>false</code>. 141: */ 142: public boolean isBorderOpaque() 143: { 144: return false; 145: } 146: 147: /** 148: * Returns a rectangle that covers the specified area minus the insets 149: * required to draw this border. Components that wish to determine an area 150: * into which they can safely draw without intersecting with a border might 151: * want to use this helper method. 152: * 153: * @param c the component in the center of this border. 154: * @param x the horizontal position of the border. 155: * @param y the vertical position of the border. 156: * @param width the width of the available area for the border. 157: * @param height the height of the available area for the border. 158: * 159: * @return The interior rectangle. 160: */ 161: public Rectangle getInteriorRectangle(Component c, int x, int y, int width, 162: int height) 163: { 164: return getInteriorRectangle(c, this, x, y, width, height); 165: } 166: 167: /** 168: * Returns a rectangle that covers the specified area minus the insets 169: * required to draw the specified border (if the border is <code>null</code>, 170: * zero insets are assumed). Components that wish to determine an area into 171: * which they can safely draw without intersecting with a border might want 172: * to use this helper method. 173: * 174: * @param c the component in the center of this border. 175: * @param b the border (<code>null</code> permitted). 176: * @param x the horizontal position of the border. 177: * @param y the vertical position of the border. 178: * @param width the width of the available area for the border. 179: * @param height the height of the available area for the border. 180: * 181: * @return The interior rectangle. 182: */ 183: public static Rectangle getInteriorRectangle(Component c, Border b, int x, 184: int y, int width, int height) 185: { 186: Insets borderInsets; 187: 188: if (b != null) 189: { 190: borderInsets = b.getBorderInsets(c); 191: x += borderInsets.left; 192: y += borderInsets.top; 193: width -= borderInsets.left + borderInsets.right; 194: height -= borderInsets.top + borderInsets.bottom; 195: } 196: 197: return new Rectangle(x, y, width, height); 198: } 199: }