DrawLayer


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16   * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
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19  
20  package org.netbeans.editor;
21  
22  /** Draw layer applies changes to draw context during painting process.
23  * Each extended UI has its own set of layers.
24  * It can currently include changes to font bold and italic attributes,
25  * and foreground and background color (and probably more in future).
26  * These changes are made by draw layer to draw context
27  * in <CODE>updateContext()</CODE> method.
28  * Draw layers form double-linked lists. Renderer goes through
29  * this list every time it draws the tokens of the text.
30  * A layer can work either by returning the next-activity-change-offset
31  * or by being activated through the draw-marks that it places
32  * at the appropriate positions or it can mix these two approaches.
33  *
34  * @deprecated Please use Highlighting SPI instead, for details see
35  *   <a HREF="@org-netbeans-modules-editor-lib2@/overview-summary.html">Editor Library 2</a>.
36  * 
37  * @author Miloslav Metelka
38  * @version 1.00
39  */
40  
41  
42  public interface DrawLayer {
43  
44      /**
45       * Start of the next region with the frame.
46       */
47      public static final String   TEXT_FRAME_START_POSITION_COMPONENT_PROPERTY
48              = "text-frame-start-position"; // NOI18N
49      
50      /**
51       * End of the next region with the frame.
52       */
53      public static final String   TEXT_FRAME_END_POSITION_COMPONENT_PROPERTY
54              = "text-frame-end-position"; // NOI18N
55      
56      /** Get the name of the layer. The layers that should work together
57      * over one component must have the different names.
58      */
59      public String   getName();
60  
61      /** Whether the layer wants to use the last context's background
62      * till the end of the window or not.
63      */
64      public boolean extendsEOL();
65  
66      /** Whether the layer marks the empty line with the background by half
67      * of the character.
68      */
69      public boolean extendsEmptyLine();
70  
71      /** Get the next position at which the activity of the layer will change.
72      * It can return <tt>Integer.MAX_VALUE</tt> to mark that the activity
73      * will never change or if it will change only by draw-marks.
74      * When this position will be reached the <tt>isActive</tt> will be called.
75      */
76      public int getNextActivityChangeOffset(DrawContext ctx);
77  
78      /** Called each time the paint begins for all layers
79      * in the layer chain regardless whether they are currently active
80      * or not. It is intended to prepare the layer. It doesn't need
81      * to set the next-activity-change-offset because <tt>isActive()</tt>
82      * will be called at the begining of the drawing when this method
83      * finishes.
84      */
85      public void init(DrawContext ctx);
86  
87      /** Return whether the layer is active or not. This method
88      * is called at the begining of the drawing,
89      * then each time when the draw-mark is found at the current
90      * fragment offset or when drawing reaches the next-activity-change-offset
91      * of this layer (mark parameter is null in this case).
92      * The layer must return whether it wants to be active for the next drawing
93      * or not.
94      * The layer should also consider
95      * changing the next-activity-change-offset because the draw-engine
96      * will ask for it after this method finishes.
97      * If the mark is found at the same position like next-activity-change-offset
98      * is, then this method is called only once with the valid <tt>mark</tt> parameter.
99      * @param ctx current context with the information about the drawing
100     * @param mark draw-mark at the fragment-offset or null if called
101     * because of the next-activity-change-offset.
102     */
103     public boolean isActive(DrawContext ctx, MarkFactory.DrawMark mark);
104 
105     /** Update draw context by setting colors, fonts and possibly other draw
106     * properties.
107     * The method can use information from the context to find where the painting
108     * process is currently located. It is called only if the layer is active.
109     */
110     public void updateContext(DrawContext ctx);
111 
112     /** Update draw context related to the drawing of line number for the given
113     * line by setting colors, fonts and possibly other draw
114     * properties. The method can also change the current line number by returning
115     * the modified line-number than the original one. At the begining the first
116     * layer gets the line-number <tt>lineOffset + 1</tt> but some layers can
117     * change it. If the layer doesn't want to change the line-number it should
118     * return the same value as it gets.
119     * The context can be affected to change the font and colors for the line-number.
120     * The context's <tt>getFragmentOffset()</tt> returns the begining of the line.
121     * The following methods in the context return undefined values:
122     * <tt>isEOL(), getBuffer(), getTokenID(), getTokenOffset(), getTokenLength()</tt>.
123     * The process of calling this method is independent of the status
124     * of the layers and is called for each layer even if it's not active.
125     * @param lineNumber the number that will be drawn before the line's text.
126     *   The layer can change it by returning a different value.
127     * @param ctx the draw context
128     */
129     public int updateLineNumberContext(int lineNumber, DrawContext ctx);
130 
131     /** 
132      * Abstract implementation of the draw-layer. 
133      * 
134      * @deprecated Please use Highlighting SPI instead, for details see
135      *   <a HREF="@org-netbeans-modules-editor-lib2@/overview-summary.html">Editor Library 2</a>.
136      */
137     public static abstract class AbstractLayer implements DrawLayer {
138 
139         /** Name of this layer. The name of the layer must be unique among
140         * layers installed into EditorUI
141         */
142         private String   name;
143 
144         /** Next position where the layer should be notified
145         * to update its state.
146         */
147         int nextActivityChangeOffset = Integer.MAX_VALUE;
148 
149         /** Construct new abstract layer with the known name and visibility. */
150         public AbstractLayer(String   name) {
151             this.name = name;
152         }
153 
154         public String   getName() {
155             return name;
156         }
157 
158         public boolean extendsEOL() {
159             return false;
160         }
161 
162         public boolean extendsEmptyLine() {
163             return false;
164         }
165 
166         public int getNextActivityChangeOffset(DrawContext ctx) {
167             return nextActivityChangeOffset;
168         }
169 
170         public void setNextActivityChangeOffset(int nextActivityChangeOffset) {
171             this.nextActivityChangeOffset = nextActivityChangeOffset;
172         }
173 
174         public void init(DrawContext ctx) {
175         }
176 
177         public int updateLineNumberContext(int lineNumber, DrawContext ctx) {
178             return lineNumber;
179         }
180 
181         public String   toString() {
182             return "Layer " + getClass() + ", name='" + name; // NOI18N
183         }
184 
185     }
186 
187 }
188
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