HRuleView


1   /*
2    * @(#)HRuleView.java   1.32 03/12/19
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.html;
8   
9   import java.awt.*;
10  import javax.swing.event.DocumentEvent  ;
11  import javax.swing.text.*;
12  import java.util.Enumeration  ;
13  import java.lang.Integer  ;
14  
15  /**
16   * A view implementation to display an html horizontal
17   * rule.
18   *
19   * @author  Timothy Prinzing
20   * @author  Sara Swanson
21   * @version 1.32 12/19/03
22   */
23  class HRuleView extends View  {
24  
25      /**
26       * Creates a new view that represents an &lt;hr&gt; element.
27       *
28       * @param elem the element to create a view for
29       */
30      public HRuleView(Element elem) {
31      super(elem);
32      setPropertiesFromAttributes();
33      }
34  
35      /**
36       * Update any cached values that come from attributes.
37       */
38      protected void setPropertiesFromAttributes() {
39      StyleSheet   sheet = ((HTMLDocument  )getDocument()).getStyleSheet();
40      AttributeSet eAttr = getElement().getAttributes();
41      attr = sheet.getViewAttributes(this);
42  
43      alignment = StyleConstants.ALIGN_CENTER;
44      size = 0;
45      noshade = null;
46      widthValue = null;
47  
48      if (attr != null) {
49              // getAlignment() returns ALIGN_LEFT by default, and HR should
50              // use ALIGN_CENTER by default, so we check if the alignment
51              // attribute is actually defined
52              if (attr.getAttribute(StyleConstants.Alignment) != null) {
53              alignment = StyleConstants.getAlignment(attr);
54              }
55  
56          noshade = (String  )eAttr.getAttribute(HTML.Attribute.NOSHADE);
57          Object   value = eAttr.getAttribute(HTML.Attribute.SIZE);
58          if (value != null && (value instanceof String  ))
59          size = Integer.parseInt((String  )value);
60          value = attr.getAttribute(CSS.Attribute.WIDTH);
61          if (value != null && (value instanceof CSS.LengthValue  )) {
62          widthValue = (CSS.LengthValue  )value;
63          }
64          topMargin = getLength(CSS.Attribute.MARGIN_TOP, attr);
65          bottomMargin = getLength(CSS.Attribute.MARGIN_BOTTOM, attr);
66          leftMargin = getLength(CSS.Attribute.MARGIN_LEFT, attr);
67          rightMargin = getLength(CSS.Attribute.MARGIN_RIGHT, attr);
68      }
69      else {
70          topMargin = bottomMargin = leftMargin = rightMargin = 0;
71      }
72          size = Math.max(2, size);
73      }
74  
75      // This will be removed and centralized at some point, need to unify this
76      // and avoid private classes.
77      private float getLength(CSS.Attribute   key, AttributeSet a) {
78      CSS.LengthValue   lv = (CSS.LengthValue  ) a.getAttribute(key);
79      float len = (lv != null) ? lv.getValue() : 0;
80      return len;
81      }
82  
83      // --- View methods ---------------------------------------------
84  
85      /**
86       * Paints the view.
87       *
88       * @param g the graphics context
89       * @param a the allocation region for the view
90       * @see View#paint
91       */
92      public void paint(Graphics g, Shape a) {
93      Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a :
94                            a.getBounds();
95      int x = 0;
96      int y = alloc.y + SPACE_ABOVE + (int)topMargin;
97      int width = alloc.width - (int)(leftMargin + rightMargin);
98      if (widthValue != null) {
99          width = (int)widthValue.getValue((float)width);
100     }
101     int height = alloc.height - (SPACE_ABOVE + SPACE_BELOW +
102                      (int)topMargin + (int)bottomMargin);
103     if (size > 0)
104         height = size;
105 
106     // Align the rule horizontally.
107         switch (alignment) {
108         case StyleConstants.ALIGN_CENTER:
109             x = alloc.x + (alloc.width / 2) - (width / 2);
110         break;
111         case StyleConstants.ALIGN_RIGHT:
112             x = alloc.x + alloc.width - width - (int)rightMargin;
113         break;
114         case StyleConstants.ALIGN_LEFT:
115         default:
116             x = alloc.x + (int)leftMargin;
117         break;
118         }
119 
120     // Paint either a shaded rule or a solid line.
121     if (noshade != null) {
122             g.setColor(Color.black);
123         g.fillRect(x, y, width, height);
124         }
125     else {
126             Color bg = getContainer().getBackground();
127             Color bottom, top;
128             if (bg == null || bg.equals(Color.white)) {
129                 top = Color.darkGray;
130                 bottom = Color.lightGray;
131             }
132             else {
133                 top = Color.darkGray;
134                 bottom = Color.white;
135             }
136             g.setColor(bottom);
137             g.drawLine(x + width - 1, y, x + width - 1, y + height - 1);
138             g.drawLine(x, y + height - 1, x + width - 1, y + height - 1);
139             g.setColor(top);
140             g.drawLine(x, y, x + width - 1, y);
141             g.drawLine(x, y, x, y + height - 1);
142         }
143 
144     }
145 
146 
147     /**
148      * Calculates the desired shape of the rule... this is
149      * basically the preferred size of the border.
150      *
151      * @param axis may be either X_AXIS or Y_AXIS
152      * @return the desired span
153      * @see View#getPreferredSpan
154      */
155     public float getPreferredSpan(int axis) {
156     switch (axis) {
157     case View.X_AXIS:
158         return 1;
159     case View.Y_AXIS:
160         if (size > 0) {
161             return size + SPACE_ABOVE + SPACE_BELOW + topMargin +
162             bottomMargin;
163         } else {
164         if (noshade != null) {
165             return 2 + SPACE_ABOVE + SPACE_BELOW + topMargin +
166             bottomMargin;
167         } else {
168             return SPACE_ABOVE + SPACE_BELOW + topMargin +bottomMargin;
169         }
170         }
171     default:
172         throw new IllegalArgumentException  ("Invalid axis: " + axis);
173     }
174     }
175 
176     /**
177      * Gets the resize weight for the axis.
178      * The rule is: rigid vertically and flexible horizontally.
179      *
180      * @param axis may be either X_AXIS or Y_AXIS
181      * @return the weight
182      */
183     public int getResizeWeight(int axis) {
184     if (axis == View.X_AXIS) {
185         return 1;
186     } else if (axis == View.Y_AXIS) {
187         return 0;
188     } else {
189         return 0;
190     }
191     }
192 
193     /**
194      * Determines how attractive a break opportunity in 
195      * this view is.  This is implemented to request a forced break.
196      *
197      * @param axis may be either View.X_AXIS or View.Y_AXIS
198      * @param pos the potential location of the start of the 
199      *   broken view (greater than or equal to zero).
200      *   This may be useful for calculating tab
201      *   positions.
202      * @param len specifies the relative length from <em>pos</em>
203      *   where a potential break is desired. The value must be greater
204      *   than or equal to zero.
205      * @return the weight, which should be a value between
206      *   ForcedBreakWeight and BadBreakWeight.
207      */
208     public int getBreakWeight(int axis, float pos, float len) {
209     if (axis == X_AXIS) {
210         return ForcedBreakWeight;
211     }
212     return BadBreakWeight;
213     }
214 
215     public View breakView(int axis, int offset, float pos, float len) {
216     return null;
217     }
218 
219     /**
220      * Provides a mapping from the document model coordinate space
221      * to the coordinate space of the view mapped to it.
222      *
223      * @param pos the position to convert
224      * @param a the allocated region to render into
225      * @return the bounding box of the given position
226      * @exception BadLocationException  if the given position does not
227      * represent a valid location in the associated document
228      * @see View#modelToView
229      */
230     public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
231     int p0 = getStartOffset();
232     int p1 = getEndOffset();
233     if ((pos >= p0) && (pos <= p1)) {
234         Rectangle r = a.getBounds();
235         if (pos == p1) {
236         r.x += r.width;
237         }
238         r.width = 0;
239         return r;
240     }
241     return null;
242     }
243 
244     /**
245      * Provides a mapping from the view coordinate space to the logical
246      * coordinate space of the model.
247      *
248      * @param x the X coordinate
249      * @param y the Y coordinate
250      * @param a the allocated region to render into
251      * @return the location within the model that best represents the
252      *  given point of view
253      * @see View#viewToModel
254      */
255     public int viewToModel(float x, float y, Shape a, Position.Bias[] bias) {
256     Rectangle alloc = (Rectangle) a;
257     if (x < alloc.x + (alloc.width / 2)) {
258         bias[0] = Position.Bias.Forward;
259         return getStartOffset();
260     }
261     bias[0] = Position.Bias.Backward;
262     return getEndOffset();
263     }
264 
265     /**
266      * Fetches the attributes to use when rendering.  This is
267      * implemented to multiplex the attributes specified in the
268      * model with a StyleSheet.
269      */
270     public AttributeSet getAttributes() {
271     return attr;
272     }
273 
274     public void changedUpdate(DocumentEvent   changes, Shape a, ViewFactory f) {
275     super.changedUpdate(changes, a, f);
276     int pos = changes.getOffset();
277     if (pos <= getStartOffset() && (pos + changes.getLength()) >=
278         getEndOffset()) {
279         setPropertiesFromAttributes();
280     }
281     }
282 
283     // --- variables ------------------------------------------------
284 
285     private float topMargin;
286     private float bottomMargin;
287     private float leftMargin;
288     private float rightMargin;
289     private int alignment = StyleConstants.ALIGN_CENTER;
290     private String   noshade = null;
291     private int size = 0;
292     private CSS.LengthValue   widthValue;
293 
294     private static final int SPACE_ABOVE = 3;
295     private static final int SPACE_BELOW = 3;
296 
297     /** View Attributes. */
298     private AttributeSet attr;
299 }
300 
301
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