LabelView


1   /*
2    * @(#)LabelView.java   1.68 04/06/28
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   package javax.swing.text;
8   
9   import java.awt.*;
10  import javax.swing.event.*;
11  
12  /**
13   * A <code>LabelView</code> is a styled chunk of text
14   * that represents a view mapped over an element in the
15   * text model.  It caches the character level attributes
16   * used for rendering.
17   *
18   * @author Timothy Prinzing
19   * @version 1.68 06/28/04
20   */
21  public class LabelView extends GlyphView   implements TabableView   {
22  
23      /**
24       * Constructs a new view wrapped on an element.
25       *
26       * @param elem the element
27       */
28      public LabelView(Element   elem) {
29      super(elem);
30      }
31  
32      /**
33       * Synchronize the view's cached values with the model.
34       * This causes the font, metrics, color, etc to be 
35       * re-cached if the cache has been invalidated.
36       */
37      final void sync() {
38      if (font == null) {
39          setPropertiesFromAttributes();
40      }
41      }
42      
43      /**
44       * Sets whether or not the view is underlined.
45       * Note that this setter is protected and is really
46       * only meant if you need to update some additional
47       * state when set.
48       *
49       * @param u true if the view is underlined, otherwise
50       *          false
51       * @see #isUnderline
52       */
53      protected void setUnderline(boolean u) {
54      underline = u;
55      }
56  
57      /**
58       * Sets whether or not the view has a strike/line
59       * through it.
60       * Note that this setter is protected and is really
61       * only meant if you need to update some additional
62       * state when set.
63       *
64       * @param s true if the view has a strike/line
65       *          through it, otherwise false
66       * @see #isStrikeThrough
67       */
68      protected void setStrikeThrough(boolean s) {
69      strike = s;
70      }
71  
72  
73      /**
74       * Sets whether or not the view represents a 
75       * superscript.
76       * Note that this setter is protected and is really
77       * only meant if you need to update some additional
78       * state when set.
79       *
80       * @param s true if the view represents a
81       *          superscript, otherwise false
82       * @see #isSuperscript
83       */
84      protected void setSuperscript(boolean s) {
85      superscript = s;
86      }
87  
88      /**
89       * Sets whether or not the view represents a 
90       * subscript.
91       * Note that this setter is protected and is really
92       * only meant if you need to update some additional
93       * state when set.
94       *
95       * @param s true if the view represents a
96       *          subscript, otherwise false
97       * @see #isSubscript
98       */
99      protected void setSubscript(boolean s) {
100     subscript = s;
101     }
102 
103     /**
104      * Sets the background color for the view. This method is typically
105      * invoked as part of configuring this <code>View</code>. If you need
106      * to customize the background color you should override
107      * <code>setPropertiesFromAttributes</code> and invoke this method. A
108      * value of null indicates no background should be rendered, so that the
109      * background of the parent <code>View</code> will show through.
110      *
111      * @param bg background color, or null
112      * @see #setPropertiesFromAttributes
113      * @since 1.5
114      */
115     protected void setBackground(Color bg) {
116         this.bg = bg;
117     }
118     
119     /**
120      * Sets the cached properties from the attributes.
121      */
122     protected void setPropertiesFromAttributes() {
123     AttributeSet   attr = getAttributes();
124     if (attr != null) {
125             Document   d = getDocument();
126         if (d instanceof StyledDocument  ) {
127         StyledDocument   doc = (StyledDocument  ) d;
128         font = doc.getFont(attr);
129         fg = doc.getForeground(attr);
130         if (attr.isDefined(StyleConstants.Background)) {
131             bg = doc.getBackground(attr);
132         } else {
133             bg = null;
134         }
135         setUnderline(StyleConstants.isUnderline(attr));
136         setStrikeThrough(StyleConstants.isStrikeThrough(attr));
137         setSuperscript(StyleConstants.isSuperscript(attr));
138         setSubscript(StyleConstants.isSubscript(attr));
139         } else {
140         throw new StateInvariantError  ("LabelView needs StyledDocument");
141         }
142     }
143      }
144 
145     /**
146      * Fetches the <code>FontMetrics</code> used for this view.
147      * @deprecated FontMetrics are not used for glyph rendering
148      *  when running in the JDK.
149      */
150     @Deprecated  
151     protected FontMetrics getFontMetrics() {
152     sync();
153         Container c = getContainer();
154         return (c != null) ? c.getFontMetrics(font) :
155             Toolkit.getDefaultToolkit().getFontMetrics(font);
156     }
157 
158     /**
159      * Fetches the background color to use to render the glyphs.
160      * This is implemented to return a cached background color,
161      * which defaults to <code>null</code>.
162      *
163      * @return the cached background color
164      */
165     public Color getBackground() {
166     sync();
167     return bg;
168     }
169 
170     /**
171      * Fetches the foreground color to use to render the glyphs.
172      * This is implemented to return a cached foreground color,
173      * which defaults to <code>null</code>.
174      *
175      * @return the cached foreground color
176      */
177     public Color getForeground() {
178     sync();
179     return fg;
180     }
181 
182     /**
183      * Fetches the font that the glyphs should be based upon.
184      * This is implemented to return a cached font.
185      *
186      * @return the cached font
187      */
188      public Font getFont() {
189     sync();
190     return font;
191     }
192 
193     /**
194      * Determines if the glyphs should be underlined.  If true,
195      * an underline should be drawn through the baseline.  This
196      * is implemented to return the cached underline property.
197      *
198      * <p>When you request this property, <code>LabelView</code>
199      * re-syncs its state with the properties of the
200      * <code>Element</code>'s <code>AttributeSet</code>.
201      * If <code>Element</code>'s <code>AttributeSet</code>
202      * does not have this property set, it will revert to false.
203      *
204      * @return the value of the cached
205      *     <code>underline</code> property
206      */
207     public boolean isUnderline() {
208     sync();
209     return underline;
210     }
211 
212     /**
213      * Determines if the glyphs should have a strikethrough
214      * line.  If true, a line should be drawn through the center
215      * of the glyphs.  This is implemented to return the
216      * cached <code>strikeThrough</code> property.
217      *
218      * <p>When you request this property, <code>LabelView</code>
219      * re-syncs its state with the properties of the
220      * <code>Element</code>'s <code>AttributeSet</code>.
221      * If <code>Element</code>'s <code>AttributeSet</code>
222      * does not have this property set, it will revert to false.
223      *
224      * @return the value of the cached
225      *     <code>strikeThrough</code> property
226      */
227     public boolean isStrikeThrough() {
228     sync();
229     return strike;
230     }
231 
232     /**
233      * Determines if the glyphs should be rendered as superscript.
234      * @return the value of the cached subscript property
235      *
236      * <p>When you request this property, <code>LabelView</code>
237      * re-syncs its state with the properties of the
238      * <code>Element</code>'s <code>AttributeSet</code>.
239      * If <code>Element</code>'s <code>AttributeSet</code>
240      * does not have this property set, it will revert to false.
241      *
242      * @return the value of the cached
243      *     <code>subscript</code> property
244      */
245     public boolean isSubscript() {
246     sync();
247     return subscript;
248     }
249 
250     /**
251      * Determines if the glyphs should be rendered as subscript.
252      *
253      * <p>When you request this property, <code>LabelView</code>
254      * re-syncs its state with the properties of the
255      * <code>Element</code>'s <code>AttributeSet</code>.
256      * If <code>Element</code>'s <code>AttributeSet</code>
257      * does not have this property set, it will revert to false.
258      *
259      * @return the value of the cached
260      *     <code>superscript</code> property
261      */
262     public boolean isSuperscript() {
263     sync();
264     return superscript;
265     }
266 
267     // --- View methods ---------------------------------------------
268 
269     /**
270      * Gives notification from the document that attributes were changed
271      * in a location that this view is responsible for.
272      *
273      * @param e the change information from the associated document
274      * @param a the current allocation of the view
275      * @param f the factory to use to rebuild if the view has children
276      * @see View#changedUpdate
277      */
278     public void changedUpdate(DocumentEvent e, Shape a, ViewFactory   f) {
279     font = null;
280         super.changedUpdate(e, a, f);
281     }
282 
283     // --- variables ------------------------------------------------
284 
285     private Font font;
286     private Color fg;
287     private Color bg;
288     private boolean underline;
289     private boolean strike;
290     private boolean superscript;
291     private boolean subscript;
292 
293 }
294 
295
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