LayoutPath


1   /*
2    * @(#)LayoutPath.java  1.2 05/11/17
3    *
4    * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   /*
8    * (C) Copyright IBM Corp. 2005, All Rights Reserved.
9    */
10  package java.awt.font;
11  
12  import java.awt.geom.Point2D  ;
13  
14  /**
15   * LayoutPath provides a mapping between locations relative to the
16   * baseline and points in user space.  Locations consist of an advance
17   * along the baseline, and an offset perpendicular to the baseline at
18   * the advance.  Positive values along the perpendicular are in the
19   * direction that is 90 degrees clockwise from the baseline vector.
20   * Locations are represented as a <code>Point2D</code>, where x is the advance and 
21   * y is the offset.  
22   *
23   * @since 1.6
24   */
25  public abstract class LayoutPath {
26      /**
27       * Convert a point in user space to a location relative to the
28       * path. The location is chosen so as to minimize the distance
29       * from the point to the path (e.g., the magnitude of the offset
30       * will be smallest).  If there is more than one such location,
31       * the location with the smallest advance is chosen.
32       * @param point the point to convert.  If it is not the same
33       * object as location, point will remain unmodified by this call.
34       * @param location a <code>Point2D</code> to hold the returned location.  
35       * It can be the same object as point.
36       * @return true if the point is associated with the portion of the
37       * path preceding the location, false if it is associated with
38       * the portion following.  The default, if the location is not at
39       * a break or sharp bend in the path, is to return true.
40       * @throws NullPointerException if point or location is null
41       * @since 1.6
42       */
43      public abstract boolean pointToPath(Point2D   point, Point2D   location);
44  
45      /**
46       * Convert a location relative to the path to a point in user
47       * coordinates.  The path might bend abruptly or be disjoint at
48       * the location's advance.  If this is the case, the value of
49       * 'preceding' is used to disambiguate the portion of the path
50       * whose location and slope is to be used to interpret the offset.
51       * @param location a <code>Point2D</code> representing the advance (in x) and
52       * offset (in y) of a location relative to the path.  If location
53       * is not the same object as point, location will remain
54       * unmodified by this call.
55       * @param preceding if true, the portion preceding the advance
56       * should be used, if false the portion after should be used.
57       * This has no effect if the path does not break or bend sharply
58       * at the advance.
59       * @param point a <code>Point2D</code> to hold the returned point.  It can be 
60       * the same object as location.
61       * @throws NullPointerException if location or point is null
62       * @since 1.6
63       */
64      public abstract void pathToPoint(Point2D   location, boolean preceding, 
65                                       Point2D   point);
66  }
67  
68
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