01: /*
02: * @(#)GeometryProvider.java 1.12 06/10/10
03: *
04: * Copyright 1990-2006 Sun Microsystems, Inc. All Rights Reserved.
05: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
06: *
07: * This program is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU General Public License version
09: * 2 only, as published by the Free Software Foundation.
10: *
11: * This program 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 version 2 for more details (a copy is
15: * included at /legal/license.txt).
16: *
17: * You should have received a copy of the GNU General Public License
18: * version 2 along with this work; if not, write to the Free Software
19: * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20: * 02110-1301 USA
21: *
22: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
23: * Clara, CA 95054 or visit www.sun.com if you need additional
24: * information or have any questions.
25: *
26: */
27:
28: package sun.porting.graphicssystem;
29:
30: /**
31: * The <code>GeometryProvider</code> interface is what allows a Graphics
32: * object to clip to a window. Each time a <code>Graphics</code> object is used for
33: * a draw, it is required to consult its associated <code>GeometryProvider</code> in
34: * order to first lock the drawing surface, and then obtain the
35: * current transformation and clipping information for the operation.
36: * If the drawing surface is an offscreen image, the implementation of
37: * the <code>GeometryProvider</code> interface is trivial; if it is a window, the
38: * window system lock, window's onscreen location, current clip area
39: * and background are made available via this interface.
40: *
41: * @version 1.7, 08/19/02
42: */
43: public interface GeometryProvider extends sun.awt.DrawingSurfaceInfo {
44: /**
45: * Get the lock object associated with the
46: * <code>GeometryProvider</code>. <em>All operations must acquire
47: * this lock <strong>as the first thing they do</strong>, and hold
48: * the lock until the draw has been completed.</em> If the object
49: * being drawn is a window, this can prevent the windows from
50: * being moved during the draw; in any case it also prevents more
51: * than one thread from drawing to the same object at the same
52: * time.
53: * @return An Object to be used as the lock for the current draw
54: * operation.
55: */
56: Object getLock();
57:
58: /**
59: * Get the validation identifier. This is the same number that is
60: * returned by lock(); if it has not changed since the previous
61: * acquisition of the lock, the clipping information can be assumed
62: * not to have changed.
63: * @return The change identifier.
64: */
65: int getValidationID();
66:
67: /**
68: * Get the background color, if any, that this object is
69: * supposed to have. This allows surfaces to stack in either
70: * an opaque or a transparent manner (a return value of null
71: * indicates that the object is transparent).
72: * @return A <code>java.awt.Color</code> object describing the
73: * background color for the drawing surface.
74: */
75: java.awt.Color getBackgroundColor();
76: }
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