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