RenderContext


1   /*
2    * @(#)RenderContext.java   1.16 04/05/18
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   /* ********************************************************************
9    **********************************************************************
10   **********************************************************************
11   *** COPYRIGHT (c) Eastman Kodak Company, 1997                      ***
12   *** As  an unpublished  work pursuant to Title 17 of the United    ***
13   *** States Code.  All rights reserved.                             ***
14   **********************************************************************
15   **********************************************************************
16   **********************************************************************/
17  
18  package java.awt.image.renderable;
19  import java.util.*;
20  import java.awt.geom.*;
21  import java.awt.*;
22  import java.awt.image.*;
23  
24  /**
25   * A RenderContext encapsulates the information needed to produce a
26   * specific rendering from a RenderableImage.  It contains the area to
27   * be rendered specified in rendering-independent terms, the
28   * resolution at which the rendering is to be performed, and hints
29   * used to control the rendering process.
30   * 
31   * <p> Users create RenderContexts and pass them to the
32   * RenderableImage via the createRendering method.  Most of the methods of
33   * RenderContexts are not meant to be used directly by applications,
34   * but by the RenderableImage and operator classes to which it is
35   * passed.
36   *
37   * <p> The AffineTransform parameter passed into and out of this class
38   * are cloned.  The RenderingHints and Shape parameters are not
39   * necessarily cloneable and are therefore only reference copied.
40   * Altering RenderingHints or Shape instances that are in use by
41   * instances of RenderContext may have undesired side effects.
42   */
43  public class RenderContext implements Cloneable   {
44      
45      /** Table of hints. May be null. */
46      RenderingHints hints;
47      
48      /** Transform to convert user coordinates to device coordinates.  */
49      AffineTransform usr2dev;
50      
51      /** The area of interest.  May be null. */
52      Shape aoi;
53      
54      // Various constructors that allow different levels of
55      // specificity. If the Shape is missing the whole renderable area
56      // is assumed. If hints is missing no hints are assumed.  
57  
58      /**
59       * Constructs a RenderContext with a given transform.
60       * The area of interest is supplied as a Shape,
61       * and the rendering hints are supplied as a RenderingHints object.
62       *
63       * @param usr2dev an AffineTransform.
64       * @param aoi a Shape representing the area of interest.
65       * @param hints a RenderingHints object containing rendering hints.
66       */
67      public RenderContext(AffineTransform usr2dev,
68                           Shape aoi,
69                           RenderingHints hints) {
70          this.hints = hints;
71          this.aoi = aoi;
72          this.usr2dev = (AffineTransform)usr2dev.clone();
73      }
74      
75      /**
76       * Constructs a RenderContext with a given transform.
77       * The area of interest is taken to be the entire renderable area.
78       * No rendering hints are used.
79       *
80       * @param usr2dev an AffineTransform.
81       */
82      public RenderContext(AffineTransform usr2dev) {
83          this(usr2dev, null, null);
84      }
85      
86      /**
87       * Constructs a RenderContext with a given transform and rendering hints.
88       * The area of interest is taken to be the entire renderable area.
89       *
90       * @param usr2dev an AffineTransform.
91       * @param hints a RenderingHints object containing rendering hints.
92       */
93      public RenderContext(AffineTransform usr2dev, RenderingHints hints) {
94          this(usr2dev, null, hints);
95      }
96      
97      /**
98       * Constructs a RenderContext with a given transform and area of interest.
99       * The area of interest is supplied as a Shape.
100      * No rendering hints are used.
101      *
102      * @param usr2dev an AffineTransform.
103      * @param aoi a Shape representing the area of interest.
104      */
105     public RenderContext(AffineTransform usr2dev, Shape aoi) {
106         this(usr2dev, aoi, null);
107     }
108 
109     /**
110      * Gets the rendering hints of this <code>RenderContext</code>.
111      * @return a <code>RenderingHints</code> object that represents
112      * the rendering hints of this <code>RenderContext</code>.
113      * @see #setRenderingHints(RenderingHints)
114      */
115     public RenderingHints getRenderingHints() {
116         return hints;
117     }
118 
119     /**
120      * Sets the rendering hints of this <code>RenderContext</code>.
121      * @param hints a <code>RenderingHints</code> object that represents
122      * the rendering hints to assign to this <code>RenderContext</code>.
123      * @see #getRenderingHints
124      */
125     public void setRenderingHints(RenderingHints hints) {
126         this.hints = hints;
127     }
128     
129     /**
130      * Sets the current user-to-device AffineTransform contained
131      * in the RenderContext to a given transform.
132      *
133      * @param newTransform the new AffineTransform.
134      * @see #getTransform
135      */
136     public void setTransform(AffineTransform newTransform) {
137         usr2dev = (AffineTransform)newTransform.clone();
138     }
139         
140     /**
141      * Modifies the current user-to-device transform by prepending another
142      * transform.  In matrix notation the operation is:
143      * <pre>
144      * [this] = [modTransform] x [this]
145      * </pre>
146      *
147      * @param modTransform the AffineTransform to prepend to the
148      *        current usr2dev transform.
149      */
150     public void preConcatenateTransform(AffineTransform modTransform) {
151         this.preConcetenateTransform(modTransform);                
152     }
153     
154     /**
155      * Modifies the current user-to-device transform by prepending another
156      * transform.  In matrix notation the operation is:
157      * <pre>
158      * [this] = [modTransform] x [this]
159      * </pre>
160      * This method does the same thing as the preConcatenateTransform
161      * method.  It is here for backward compatibility with previous releases
162      * which misspelled the method name.
163      *
164      * @param modTransform the AffineTransform to prepend to the
165      *        current usr2dev transform.
166      * @deprecated     replaced by
167      *                 <code>preConcatenateTransform(AffineTransform)</code>.
168      */
169     @Deprecated  
170     public void preConcetenateTransform(AffineTransform modTransform) {
171         usr2dev.preConcatenate(modTransform);                
172     }
173 
174     /**
175      * Modifies the current user-to-device transform by appending another
176      * transform.  In matrix notation the operation is:
177      * <pre>
178      * [this] = [this] x [modTransform]
179      * </pre>
180      *
181      * @param modTransform the AffineTransform to append to the
182      *        current usr2dev transform.
183      */
184     public void concatenateTransform(AffineTransform modTransform) {
185         this.concetenateTransform(modTransform);                
186     }
187     
188     /**
189      * Modifies the current user-to-device transform by appending another
190      * transform.  In matrix notation the operation is:
191      * <pre>
192      * [this] = [this] x [modTransform]
193      * </pre>
194      * This method does the same thing as the concatenateTransform
195      * method.  It is here for backward compatibility with previous releases
196      * which misspelled the method name.
197      *
198      * @param modTransform the AffineTransform to append to the
199      *        current usr2dev transform.
200      * @deprecated     replaced by
201      *                 <code>concatenateTransform(AffineTransform)</code>.
202      */
203     @Deprecated  
204     public void concetenateTransform(AffineTransform modTransform) {
205         usr2dev.concatenate(modTransform);                
206     }
207     
208     /**
209      * Gets the current user-to-device AffineTransform.
210      *
211      * @return a reference to the current AffineTransform.
212      * @see #setTransform(AffineTransform)
213      */
214     public AffineTransform getTransform() {
215         return (AffineTransform)usr2dev.clone();
216     }
217 
218     /**
219      * Sets the current area of interest.  The old area is discarded.
220      *
221      * @param newAoi The new area of interest.
222      * @see #getAreaOfInterest
223      */
224     public void setAreaOfInterest(Shape newAoi) {
225         aoi = newAoi;
226     }
227 
228     /**
229      * Gets the ares of interest currently contained in the
230      * RenderContext.
231      * 
232      * @return a reference to the area of interest of the RenderContext, 
233      *         or null if none is specified.
234      * @see #setAreaOfInterest(Shape)
235      */
236     public Shape getAreaOfInterest() {
237         return aoi;
238     }
239 
240     /**
241      * Makes a copy of a RenderContext. The area of interest is copied
242      * by reference.  The usr2dev AffineTransform and hints are cloned,
243      * while the area of interest is copied by reference.
244      *
245      * @return the new cloned RenderContext.
246      */
247     public Object   clone() {
248         RenderContext   newRenderContext = new RenderContext  (usr2dev,
249                                                            aoi, hints);
250         return newRenderContext;
251     }
252 }
253
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