Java tutorial
/* * Copyright (c) 1997, 2013, 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 * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing.text; import java.awt.*; import javax.swing.Icon; import javax.swing.event.*; /** * Icon decorator that implements the view interface. The * entire element is used to represent the icon. This acts * as a gateway from the display-only View implementations to * interactive lightweight icons (that is, it allows icons * to be embedded into the View hierarchy. The parent of the icon * is the container that is handed out by the associated view * factory. * * @author Timothy Prinzing */ public class IconView extends View { /** * Creates a new icon view that represents an element. * * @param elem the element to create a view for */ public IconView(Element elem) { super(elem); AttributeSet attr = elem.getAttributes(); c = StyleConstants.getIcon(attr); } // --- View methods --------------------------------------------- /** * Paints the icon. * The real paint behavior occurs naturally from the association * that the icon has with its parent container (the same * container hosting this view), so this simply allows us to * position the icon properly relative to the view. Since * the coordinate system for the view is simply the parent * containers, positioning the child icon is easy. * * @param g the rendering surface to use * @param a the allocated region to render into * @see View#paint */ public void paint(Graphics g, Shape a) { Rectangle alloc = a.getBounds(); c.paintIcon(getContainer(), g, alloc.x, alloc.y); } /** * Determines the preferred span for this view along an * axis. * * @param axis may be either View.X_AXIS or View.Y_AXIS * @return the span the view would like to be rendered into * Typically the view is told to render into the span * that is returned, although there is no guarantee. * The parent may choose to resize or break the view. * @exception IllegalArgumentException for an invalid axis */ public float getPreferredSpan(int axis) { switch (axis) { case View.X_AXIS: return c.getIconWidth(); case View.Y_AXIS: return c.getIconHeight(); default: throw new IllegalArgumentException("Invalid axis: " + axis); } } /** * Determines the desired alignment for this view along an * axis. This is implemented to give the alignment to the * bottom of the icon along the y axis, and the default * along the x axis. * * @param axis may be either View.X_AXIS or View.Y_AXIS * @return the desired alignment >= 0.0f && <= 1.0f. This should be * a value between 0.0 and 1.0 where 0 indicates alignment at the * origin and 1.0 indicates alignment to the full span * away from the origin. An alignment of 0.5 would be the * center of the view. */ public float getAlignment(int axis) { switch (axis) { case View.Y_AXIS: return 1; default: return super.getAlignment(axis); } } /** * Provides a mapping from the document model coordinate space * to the coordinate space of the view mapped to it. * * @param pos the position to convert >= 0 * @param a the allocated region to render into * @return the bounding box of the given position * @exception BadLocationException if the given position does not * represent a valid location in the associated document * @see View#modelToView */ public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException { int p0 = getStartOffset(); int p1 = getEndOffset(); if ((pos >= p0) && (pos <= p1)) { Rectangle r = a.getBounds(); if (pos == p1) { r.x += r.width; } r.width = 0; return r; } throw new BadLocationException(pos + " not in range " + p0 + "," + p1, pos); } /** * Provides a mapping from the view coordinate space to the logical * coordinate space of the model. * * @param x the X coordinate >= 0 * @param y the Y coordinate >= 0 * @param a the allocated region to render into * @return the location within the model that best represents the * given point of view >= 0 * @see View#viewToModel */ public int viewToModel(float x, float y, Shape a, Position.Bias[] bias) { Rectangle alloc = (Rectangle) a; if (x < alloc.x + (alloc.width / 2)) { bias[0] = Position.Bias.Forward; return getStartOffset(); } bias[0] = Position.Bias.Backward; return getEndOffset(); } // --- member variables ------------------------------------------------ private Icon c; }