/*******************************************************************************
* Copyright (c) 2000, 2015 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Tom Eicher (Avaloq Evolution AG) - block selection mode
* Holger Voormann - Word Wrap - https://bugs.eclipse.org/bugs/show_bug.cgi?id=35779
* Florian Weßling <flo@cdhq.de> - Word Wrap - https://bugs.eclipse.org/bugs/show_bug.cgi?id=35779
*******************************************************************************/
package org.eclipse.jface.text;
import org.eclipse.swt.custom.LineBackgroundEvent;
import org.eclipse.swt.custom.LineBackgroundListener;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Point;
/**
* A painter the draws the background of the caret line in a configured color.
* <p>
* Clients usually instantiate and configure object of this class.</p>
* <p>
* This class is not intended to be subclassed.</p>
*
* @since 2.1
* @noextend This class is not intended to be subclassed by clients.
*/
public class CursorLinePainter implements IPainter, LineBackgroundListener {
/** The viewer the painter works on */
private final ITextViewer fViewer;
/** The cursor line back ground color */
private Color fHighlightColor;
/** The paint position manager for managing the line coordinates */
private IPaintPositionManager fPositionManager;
/** Keeps track of the line to be painted */
private Position fCurrentLine= new Position(0, 0);
/** Keeps track of the line to be cleared */
private Position fLastLine= new Position(0, 0);
/** Keeps track of the line number of the last painted line */
private int fLastLineNumber= -1;
/** Indicates whether this painter is active */
private boolean fIsActive;
/**
* Creates a new painter for the given source viewer.
*
* @param textViewer the source viewer for which to create a painter
*/
public CursorLinePainter(ITextViewer textViewer) {
fViewer= textViewer;
}
/**
* Sets the color in which to draw the background of the cursor line.
*
* @param highlightColor the color in which to draw the background of the cursor line
*/
public void setHighlightColor(Color highlightColor) {
fHighlightColor= highlightColor;
}
@Override
public void lineGetBackground(LineBackgroundEvent event) {
// don't use cached line information because of asynchronous painting
StyledText textWidget= fViewer.getTextWidget();
if (textWidget != null) {
int caret= textWidget.getCaretOffset();
int length= event.lineText.length();
if (event.lineOffset <= caret && caret <= event.lineOffset + length && !hasMultiLineSelection(textWidget))
event.lineBackground= fHighlightColor;
}
}
/**
* Updates all the cached information about the lines to be painted and to be cleared. Returns <code>true</code>
* if the line number of the cursor line has changed.
*
* @return <code>true</code> if cursor line changed
*/
private boolean updateHighlightLine() {
try {
IDocument document= fViewer.getDocument();
int modelCaret= getModelCaret();
int lineNumber= document.getLineOfOffset(modelCaret);
// redraw if the current line number is different from the last line number we painted
// initially fLastLineNumber is -1
if (lineNumber != fLastLineNumber || !fCurrentLine.overlapsWith(modelCaret, 0)) {
fLastLine.offset= fCurrentLine.offset;
fLastLine.length= fCurrentLine.length;
fLastLine.isDeleted= fCurrentLine.isDeleted;
if (fCurrentLine.isDeleted) {
fCurrentLine.isDeleted= false;
fPositionManager.managePosition(fCurrentLine);
}
fCurrentLine.offset= document.getLineOffset(lineNumber);
if (lineNumber == document.getNumberOfLines() - 1)
fCurrentLine.length= document.getLength() - fCurrentLine.offset;
else
fCurrentLine.length= document.getLineOffset(lineNumber + 1) - fCurrentLine.offset;
fLastLineNumber= lineNumber;
return true;
}
} catch (BadLocationException e) {
}
return false;
}
/**
* Returns the location of the caret as offset in the source viewer's
* input document.
*
* @return the caret location
*/
private int getModelCaret() {
int widgetCaret= fViewer.getTextWidget().getCaretOffset();
if (fViewer instanceof ITextViewerExtension5) {
ITextViewerExtension5 extension= (ITextViewerExtension5) fViewer;
return extension.widgetOffset2ModelOffset(widgetCaret);
}
IRegion visible= fViewer.getVisibleRegion();
return widgetCaret + visible.getOffset();
}
/**
* Assumes the given position to specify offset and length of a line to be painted.
*
* @param position the specification of the line to be painted
*/
private void drawHighlightLine(Position position) {
// if the position that is about to be drawn was deleted then we can't
if (position.isDeleted())
return;
int widgetOffset= 0;
if (fViewer instanceof ITextViewerExtension5) {
ITextViewerExtension5 extension= (ITextViewerExtension5) fViewer;
widgetOffset= extension.modelOffset2WidgetOffset(position.getOffset());
if (widgetOffset == -1)
return;
} else {
IRegion visible= fViewer.getVisibleRegion();
widgetOffset= position.getOffset() - visible.getOffset();
if (widgetOffset < 0 || visible.getLength() < widgetOffset )
return;
}
StyledText textWidget= fViewer.getTextWidget();
// check for https://bugs.eclipse.org/bugs/show_bug.cgi?id=64898
// this is a guard against the symptoms but not the actual solution
int charCount= textWidget.getCharCount();
if (widgetOffset > charCount) {
return;
}
Point upperLeft= textWidget.getLocationAtOffset(widgetOffset);
int width= textWidget.getClientArea().width + textWidget.getHorizontalPixel();
// different height if word wrap is activated and line is not empty
int height;
if (position.length == 0 || !textWidget.getWordWrap()) {
height= textWidget.getLineHeight(widgetOffset);
} else {
int offsetEnd= widgetOffset + position.length - 1;
if (offsetEnd >= charCount) {
offsetEnd= charCount - 1;
}
height= textWidget.getTextBounds(widgetOffset, offsetEnd).height;
}
textWidget.redraw(0, upperLeft.y, width, height, false);
}
@Override
public void deactivate(boolean redraw) {
if (fIsActive) {
fIsActive= false;
/* on turning off the feature one has to paint the currently
* highlighted line with the standard background color
*/
if (redraw)
drawHighlightLine(fCurrentLine);
fViewer.getTextWidget().removeLineBackgroundListener(this);
if (fPositionManager != null)
fPositionManager.unmanagePosition(fCurrentLine);
fLastLineNumber= -1;
fCurrentLine.offset= 0;
fCurrentLine.length= 0;
}
}
@Override
public void dispose() {
}
@Override
public void paint(int reason) {
if (fViewer.getDocument() == null) {
deactivate(false);
return;
}
StyledText textWidget= fViewer.getTextWidget();
// check selection
if (hasMultiLineSelection(textWidget)) {
deactivate(true);
return;
}
// initialization
if (!fIsActive) {
textWidget.addLineBackgroundListener(this);
fPositionManager.managePosition(fCurrentLine);
fIsActive= true;
}
//redraw line highlight only if it hasn't been drawn yet on the respective line
if (updateHighlightLine()) {
// clear last line
drawHighlightLine(fLastLine);
// draw new line
drawHighlightLine(fCurrentLine);
}
}
/**
* Returns <code>true</code> if the widget has a selection spanning multiple lines,
* <code>false</code> otherwise.
*
* @param textWidget the text widget to check
* @return <code>true</code> if <code>textWidget</code> has a multiline selection,
* <code>false</code> otherwise
* @since 3.5
*/
private boolean hasMultiLineSelection(StyledText textWidget) {
Point selection= textWidget.getSelection();
try {
int startLine= textWidget.getLineAtOffset(selection.x);
int endLine= textWidget.getLineAtOffset(selection.y);
return startLine != endLine;
} catch (IllegalArgumentException e) {
// ignore - apparently, the widget has a stale selection
// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=273721
return false;
}
}
@Override
public void setPositionManager(IPaintPositionManager manager) {
fPositionManager = manager;
}
}