net.sourceforge.phpeclipse/src/net/sourceforge/phpeclipse/phpeditor/LinePainter.java

   1 package net.sourceforge.phpeclipse.phpeditor;
   2
   3 /*
   4  * (c) Copyright IBM Corp. 2000, 2001.
   5  * All Rights Reserved.
   6  */
   7
   8 import org.eclipse.jface.text.BadLocationException;
   9 import org.eclipse.jface.text.IDocument;
  10 import org.eclipse.jface.text.Position;
  11 import org.eclipse.jface.text.source.ISourceViewer;
  12 import org.eclipse.swt.custom.LineBackgroundEvent;
  13 import org.eclipse.swt.custom.LineBackgroundListener;
  14 import org.eclipse.swt.custom.StyledText;
  15 import org.eclipse.swt.graphics.Color;
  16 import org.eclipse.swt.graphics.Point;
  17
  18 public class LinePainter implements IPainter, LineBackgroundListener {
  19
  20         private final ISourceViewer fViewer;
  21
  22         private Color fHighlightColor;
  23
  24         private IPositionManager fPositionManager;
  25
  26         // positions to keep track of beginning and end of line to be painted or
  27         // cleared
  28         private Position fCurrentLine = new Position(0, 0);
  29
  30         private Position fLastLine = new Position(0, 0);
  31
  32         // used to keep track of the last line painted
  33         private int fLastLineNumber = -1;
  34
  35         private boolean fIsActive;
  36
  37         public LinePainter(ISourceViewer sourceViewer) {
  38                 fViewer = sourceViewer;
  39         }
  40
  41         public void setHighlightColor(Color highlightColor) {
  42                 fHighlightColor = highlightColor;
  43         }
  44
  45         /*
  46          * @see LineBackgroundListener#lineGetBackground(LineBackgroundEvent)
  47          */
  48         public void lineGetBackground(LineBackgroundEvent event) {
  49                 // don't use cached line information because of asynch painting
  50
  51                 StyledText textWidget = fViewer.getTextWidget();
  52                 if (textWidget != null) {
  53
  54                         int caret = textWidget.getCaretOffset();
  55                         int length = event.lineText.length();
  56
  57                         if (event.lineOffset <= caret && caret <= event.lineOffset + length)
  58                                 event.lineBackground = fHighlightColor;
  59                         else
  60                                 event.lineBackground = textWidget.getBackground();
  61                 }
  62         }
  63
  64         private boolean updateHighlightLine() {
  65                 try {
  66
  67                         IDocument document = fViewer.getDocument();
  68
  69                         int offset = fViewer.getTextWidget().getCaretOffset()
  70                                         + fViewer.getVisibleRegion().getOffset();
  71                         int lineNumber = document.getLineOfOffset(offset);
  72
  73                         // redraw if the current line number is different from the last line
  74                         // number we painted
  75                         // initially fLastLineNumber is -1
  76                         if (lineNumber != fLastLineNumber) {
  77
  78                                 fLastLine.offset = fCurrentLine.offset;
  79                                 fLastLine.length = fCurrentLine.length;
  80                                 fLastLine.isDeleted = fCurrentLine.isDeleted;
  81
  82                                 fCurrentLine.isDeleted = false;
  83                                 fCurrentLine.offset = document.getLineOffset(lineNumber);
  84                                 if (lineNumber == document.getNumberOfLines() - 1)
  85                                         fCurrentLine.length = document.getLength()
  86                                                         - fCurrentLine.offset;
  87                                 else
  88                                         fCurrentLine.length = document
  89                                                         .getLineOffset(lineNumber + 1)
  90                                                         - fCurrentLine.offset;
  91
  92                                 fLastLineNumber = lineNumber;
  93                                 return true;
  94
  95                         }
  96
  97                 } catch (BadLocationException e) {
  98                 }
  99
 100                 return false;
 101         }
 102
 103         private void drawHighlightLine(Position position, int visibleOffset) {
 104                 StyledText textWidget = fViewer.getTextWidget();
 105
 106                 // if the position that is about to be drawn was deleted then we can't
 107                 if (position.isDeleted())
 108                         return;
 109
 110                 int delta = position.offset - visibleOffset;
 111                 if (0 <= delta && delta <= fViewer.getVisibleRegion().getLength()) {
 112                         Point upperLeft = textWidget.getLocationAtOffset(delta);
 113                         int width = textWidget.getClientArea().width
 114                                         + textWidget.getHorizontalPixel();
 115                         int height = textWidget.getLineHeight();
 116                         textWidget.redraw(upperLeft.x, upperLeft.y, width, height, false);
 117                 }
 118         }
 119
 120         /*
 121          * @see IPainter#deactivate(boolean)
 122          */
 123         public void deactivate(boolean redraw) {
 124                 if (fIsActive) {
 125                         fIsActive = false;
 126
 127                         /*
 128                          * on turning off the feature one has to paint the currently
 129                          * highlighted line with the standard background color
 130                          */
 131                         if (redraw)
 132                                 drawHighlightLine(fCurrentLine, fViewer.getVisibleRegion()
 133                                                 .getOffset());
 134
 135                         fViewer.getTextWidget().removeLineBackgroundListener(this);
 136
 137                         if (fPositionManager != null)
 138                                 fPositionManager.removeManagedPosition(fCurrentLine);
 139
 140                         fLastLineNumber = -1;
 141                 }
 142         }
 143
 144         /*
 145          * @see IPainter#dispose()
 146          */
 147         public void dispose() {
 148         }
 149
 150         /*
 151          * @see IPainter#paint(int)
 152          */
 153         public void paint(int reason) {
 154
 155                 // check selection
 156                 Point selection = fViewer.getTextWidget().getSelectionRange();
 157                 if (selection.y > 0) {
 158                         deactivate(true);
 159                         return;
 160                 }
 161
 162                 // initialization
 163                 if (!fIsActive) {
 164                         fViewer.getTextWidget().addLineBackgroundListener(this);
 165                         fPositionManager.addManagedPosition(fCurrentLine);
 166                         fIsActive = true;
 167                 }
 168
 169                 // redraw line highlight only if it hasn't been drawn yet on the
 170                 // respective line
 171                 if (updateHighlightLine()) {
 172                         // used to handle segmented view of source files
 173                         int visibleRegionOffset = fViewer.getVisibleRegion().getOffset();
 174                         // clear last line
 175                         drawHighlightLine(fLastLine, visibleRegionOffset);
 176                         // draw new line
 177                         drawHighlightLine(fCurrentLine, visibleRegionOffset);
 178                 }
 179         }
 180
 181         /*
 182          * @see IPainter#setPositionManager(IPositionManager)
 183          */
 184         public void setPositionManager(IPositionManager manager) {
 185                 fPositionManager = manager;
 186         }
 187 }