ltk/org.eclipse.statet.ltk.ui/src/org/eclipse/statet/ecommons/text/ui/TextViewerCustomCaretSupport.java - statet/org.eclipse.statet-ltk - Git at Google

 /*=============================================================================#
  # Copyright (c) 2000, 2020 Stephan Wahlbrink and others.
  #
  # This program and the accompanying materials are made available under the
  # terms of the Eclipse Public License 2.0 which is available at
  # https://www.eclipse.org/legal/epl-2.0.
  #
  # SPDX-License-Identifier: EPL-2.0
  #
  # Contributors:
  #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
  #     IBM Corporation - org.eclipse.platform: initial implementation of AbstractTextEditor
  #=============================================================================*/

 package org.eclipse.statet.ecommons.text.ui;

 import org.eclipse.core.commands.AbstractHandler;
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.jface.text.TextViewer;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.ST;
 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.ImageData;
 import org.eclipse.swt.graphics.PaletteData;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.widgets.Caret;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.ui.handlers.IHandlerService;
 import org.eclipse.ui.texteditor.AbstractTextEditor;
 import org.eclipse.ui.texteditor.ITextEditorActionDefinitionIds;
 import org.eclipse.ui.texteditor.ITextEditorExtension3;
 import org.eclipse.ui.texteditor.ITextEditorExtension3.InsertMode;


 public class TextViewerCustomCaretSupport {


 	/**
 	 * The caret width for the wide (double) caret.
 	 * Value: {@value}
 	 */
 	private static final int WIDE_CARET_WIDTH= 2;

 	/**
 	 * The caret width for the narrow (single) caret.
 	 * Value: {@value}
 	 */
 	private static final int SINGLE_CARET_WIDTH= 1;


 	private class ToggleOverwriteHandler extends AbstractHandler {

 		@Override
 		public Object execute(final ExecutionEvent event) throws ExecutionException {
 			toggleOverwriteMode();
 			return null;
 		}

 	}


 	private final TextViewer fTextViewer;

 	private final IPreferenceStore fPreferenceStore;

 	private final IPropertyChangeListener fPreferencePropertyListener= new IPropertyChangeListener() {
 		@Override
 		public void propertyChange(final PropertyChangeEvent event) {
 			final String property= event.getProperty();
 			if (AbstractTextEditor.PREFERENCE_USE_CUSTOM_CARETS.equals(property)
 					|| AbstractTextEditor.PREFERENCE_WIDE_CARET.equals(property) ) {
 				updateCaret();
 			}
 		}
 	};

 	private final IPropertyChangeListener fFontPropertyListener= new IPropertyChangeListener() {
 		@Override
 		public void propertyChange(final PropertyChangeEvent event) {
 			final String property= event.getProperty();
 			if (JFaceResources.TEXT_FONT.equals(property) ) {
 				updateCaret();
 			}
 		}
 	};

 	/**
 	 * Whether the overwrite mode is currently on.
 	 */
 	private boolean fIsOverwriting= false;

 	/**
 	 * The non-default caret.
 	 */
 	private Caret fNonDefaultCaret;

 	/**
 	 * The image used in non-default caret.
 	 */
 	private Image fNonDefaultCaretImage;

 	/**
 	 * The styled text's initial caret.
 	 */
 	private Caret fInitialCaret;


 	public TextViewerCustomCaretSupport(final TextViewer textViewer, final IPreferenceStore preferences) {
 		if (textViewer == null || preferences == null) {
 			throw new NullPointerException();
 		}
 		this.fTextViewer= textViewer;
 		this.fPreferenceStore= preferences;

 		this.fTextViewer.getTextWidget().addDisposeListener(new DisposeListener() {
 			@Override
 			public void widgetDisposed(final DisposeEvent e) {
 				dispose();
 			}
 		});

 		this.fPreferenceStore.addPropertyChangeListener(this.fPreferencePropertyListener);
 		JFaceResources.getFontRegistry().addListener(this.fFontPropertyListener);

 		updateCaret();
 	}


 	public void initActions(final IHandlerService handlerService) {
 		this.fTextViewer.getTextWidget().setKeyBinding(SWT.INSERT, SWT.NULL);
 		handlerService.activateHandler(ITextEditorActionDefinitionIds.TOGGLE_OVERWRITE,
 				new ToggleOverwriteHandler());
 	}

 	private void toggleOverwriteMode() {
 		if (isOverwriteEnabled()) {
 			this.fIsOverwriting= !this.fIsOverwriting;
 			this.fTextViewer.getTextWidget().invokeAction(ST.TOGGLE_OVERWRITE);
 			updateCaret();
 		}
 	}

 	private boolean isOverwriteEnabled() {
 		return true;
 	}

 	private int getCaretWidthPreference() {
 		return (this.fPreferenceStore.getBoolean(AbstractTextEditor.PREFERENCE_WIDE_CARET)) ?
 				WIDE_CARET_WIDTH : SINGLE_CARET_WIDTH;
 	}

 	private void updateCaret() {
 		if (this.fTextViewer == null) {
 			return;
 		}
 		final StyledText styledText= this.fTextViewer.getTextWidget();

 		final InsertMode mode= ITextEditorExtension3.SMART_INSERT;

 		styledText.setCaret(null);
 		disposeNonDefaultCaret();

 		if (!this.fPreferenceStore.getBoolean(AbstractTextEditor.PREFERENCE_USE_CUSTOM_CARETS)) {
 			assert (this.fNonDefaultCaret == null);
 		}
 		else if (this.fIsOverwriting) {
 			this.fNonDefaultCaret= createOverwriteCaret(styledText);
 		}
 		else if (mode == ITextEditorExtension3.SMART_INSERT) {
 			this.fNonDefaultCaret= createInsertCaret(styledText);
 		}
 		else if (mode == ITextEditorExtension3.INSERT) {
 			this.fNonDefaultCaret= createRawInsertModeCaret(styledText);
 		}

 		if (this.fNonDefaultCaret != null) {
 			styledText.setCaret(this.fNonDefaultCaret);
 			this.fNonDefaultCaretImage= this.fNonDefaultCaret.getImage();
 		}
 		else if (this.fInitialCaret != styledText.getCaret()) {
 			styledText.setCaret(this.fInitialCaret);
 		}
 	}

 	private Caret createInsertCaret(final StyledText styledText) {
 		final Caret caret= new Caret(styledText, SWT.NULL);

 		caret.setSize(getCaretWidthPreference(), styledText.getLineHeight());
 		caret.setFont(styledText.getFont());

 		return caret;
 	}

 	private Caret createRawInsertModeCaret(final StyledText styledText) {
 //		// don't draw special raw caret if no smart mode is enabled
 //		if (!getLegalInsertModes().contains(SMART_INSERT)) {
 //			return createInsertCaret(styledText);
 //		}
 		final Caret caret= new Caret(styledText, SWT.NULL);
 		final Image image= createRawInsertModeCaretImage(styledText);
 		if (image != null) {
 			caret.setImage(image);
 		}
 		else {
 			caret.setSize(getCaretWidthPreference(), styledText.getLineHeight());
 		}

 		caret.setFont(styledText.getFont());

 		return caret;
 	}

 	private Image createRawInsertModeCaretImage(final StyledText styledText) {
 		final PaletteData caretPalette= new PaletteData(new RGB[] {new RGB (0,0,0), new RGB (255,255,255)});
 		final int width= getCaretWidthPreference();
 		final int widthOffset= width - 1;

 		final ImageData imageData= new ImageData(4 + widthOffset, styledText.getLineHeight(), 1, caretPalette);

 		final Display display= styledText.getDisplay();
 		final Image bracketImage= new Image(display, imageData);
 		final GC gc= new GC (bracketImage);
 		gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
 		gc.setLineWidth(0); // NOTE: 0 means width is 1 but with optimized performance
 		final int height= imageData.height / 3;
 		for (int i= 0; i < width ; i++) {
 			gc.drawLine(i, 0, i, height - 1);
 			gc.drawLine(i, imageData.height - height, i, imageData.height - 1);
 		}

 		gc.dispose();

 		return bracketImage;
 	}

 	private Caret createOverwriteCaret(final StyledText styledText) {
 		final Caret caret= new Caret(styledText, SWT.NULL);
 		final GC gc= new GC(styledText);
 		// this overwrite box is not proportional-font aware
 		// take 'a' as a medium sized character
 		final Point charSize= gc.stringExtent("a"); //$NON-NLS-1$

 		caret.setSize(charSize.x, styledText.getLineHeight());
 		caret.setFont(styledText.getFont());

 		gc.dispose();

 		return caret;
 	}

 	private void disposeNonDefaultCaret() {
 		if (this.fNonDefaultCaretImage != null) {
 			this.fNonDefaultCaretImage.dispose();
 			this.fNonDefaultCaretImage= null;
 		}

 		if (this.fNonDefaultCaret != null) {
 			this.fNonDefaultCaret.dispose();
 			this.fNonDefaultCaret= null;
 		}
 	}

 	private void dispose() {
 		this.fPreferenceStore.removePropertyChangeListener(this.fPreferencePropertyListener);
 		JFaceResources.getFontRegistry().removeListener(this.fFontPropertyListener);
 		disposeNonDefaultCaret();
 		this.fInitialCaret= null;
 	}

 }
	/*=============================================================================#
	# Copyright (c) 2000, 2020 Stephan Wahlbrink and others.
	#
	# This program and the accompanying materials are made available under the
	# terms of the Eclipse Public License 2.0 which is available at
	# https://www.eclipse.org/legal/epl-2.0.
	#
	# SPDX-License-Identifier: EPL-2.0
	#
	# Contributors:
	# Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
	# IBM Corporation - org.eclipse.platform: initial implementation of AbstractTextEditor
	#=============================================================================*/

	package org.eclipse.statet.ecommons.text.ui;

	import org.eclipse.core.commands.AbstractHandler;
	import org.eclipse.core.commands.ExecutionEvent;
	import org.eclipse.core.commands.ExecutionException;
	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.jface.resource.JFaceResources;
	import org.eclipse.jface.text.TextViewer;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.jface.util.PropertyChangeEvent;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.ST;
	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.events.DisposeEvent;
	import org.eclipse.swt.events.DisposeListener;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.ImageData;
	import org.eclipse.swt.graphics.PaletteData;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.RGB;
	import org.eclipse.swt.widgets.Caret;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.ui.handlers.IHandlerService;
	import org.eclipse.ui.texteditor.AbstractTextEditor;
	import org.eclipse.ui.texteditor.ITextEditorActionDefinitionIds;
	import org.eclipse.ui.texteditor.ITextEditorExtension3;
	import org.eclipse.ui.texteditor.ITextEditorExtension3.InsertMode;


	public class TextViewerCustomCaretSupport {


	/**
	* The caret width for the wide (double) caret.
	* Value: {@value}
	*/
	private static final int WIDE_CARET_WIDTH= 2;

	/**
	* The caret width for the narrow (single) caret.
	* Value: {@value}
	*/
	private static final int SINGLE_CARET_WIDTH= 1;


	private class ToggleOverwriteHandler extends AbstractHandler {

	@Override
	public Object execute(final ExecutionEvent event) throws ExecutionException {
	toggleOverwriteMode();
	return null;
	}

	}


	private final TextViewer fTextViewer;

	private final IPreferenceStore fPreferenceStore;

	private final IPropertyChangeListener fPreferencePropertyListener= new IPropertyChangeListener() {
	@Override
	public void propertyChange(final PropertyChangeEvent event) {
	final String property= event.getProperty();
	if (AbstractTextEditor.PREFERENCE_USE_CUSTOM_CARETS.equals(property)
	\|\| AbstractTextEditor.PREFERENCE_WIDE_CARET.equals(property) ) {
	updateCaret();
	}
	}
	};

	private final IPropertyChangeListener fFontPropertyListener= new IPropertyChangeListener() {
	@Override
	public void propertyChange(final PropertyChangeEvent event) {
	final String property= event.getProperty();
	if (JFaceResources.TEXT_FONT.equals(property) ) {
	updateCaret();
	}
	}
	};

	/**
	* Whether the overwrite mode is currently on.
	*/
	private boolean fIsOverwriting= false;

	/**
	* The non-default caret.
	*/
	private Caret fNonDefaultCaret;

	/**
	* The image used in non-default caret.
	*/
	private Image fNonDefaultCaretImage;

	/**
	* The styled text's initial caret.
	*/
	private Caret fInitialCaret;


	public TextViewerCustomCaretSupport(final TextViewer textViewer, final IPreferenceStore preferences) {
	if (textViewer == null \|\| preferences == null) {
	throw new NullPointerException();
	}
	this.fTextViewer= textViewer;
	this.fPreferenceStore= preferences;

	this.fTextViewer.getTextWidget().addDisposeListener(new DisposeListener() {
	@Override
	public void widgetDisposed(final DisposeEvent e) {
	dispose();
	}
	});

	this.fPreferenceStore.addPropertyChangeListener(this.fPreferencePropertyListener);
	JFaceResources.getFontRegistry().addListener(this.fFontPropertyListener);

	updateCaret();
	}


	public void initActions(final IHandlerService handlerService) {
	this.fTextViewer.getTextWidget().setKeyBinding(SWT.INSERT, SWT.NULL);
	handlerService.activateHandler(ITextEditorActionDefinitionIds.TOGGLE_OVERWRITE,
	new ToggleOverwriteHandler());
	}

	private void toggleOverwriteMode() {
	if (isOverwriteEnabled()) {
	this.fIsOverwriting= !this.fIsOverwriting;
	this.fTextViewer.getTextWidget().invokeAction(ST.TOGGLE_OVERWRITE);
	updateCaret();
	}
	}

	private boolean isOverwriteEnabled() {
	return true;
	}

	private int getCaretWidthPreference() {
	return (this.fPreferenceStore.getBoolean(AbstractTextEditor.PREFERENCE_WIDE_CARET)) ?
	WIDE_CARET_WIDTH : SINGLE_CARET_WIDTH;
	}

	private void updateCaret() {
	if (this.fTextViewer == null) {
	return;
	}
	final StyledText styledText= this.fTextViewer.getTextWidget();

	final InsertMode mode= ITextEditorExtension3.SMART_INSERT;

	styledText.setCaret(null);
	disposeNonDefaultCaret();

	if (!this.fPreferenceStore.getBoolean(AbstractTextEditor.PREFERENCE_USE_CUSTOM_CARETS)) {
	assert (this.fNonDefaultCaret == null);
	}
	else if (this.fIsOverwriting) {
	this.fNonDefaultCaret= createOverwriteCaret(styledText);
	}
	else if (mode == ITextEditorExtension3.SMART_INSERT) {
	this.fNonDefaultCaret= createInsertCaret(styledText);
	}
	else if (mode == ITextEditorExtension3.INSERT) {
	this.fNonDefaultCaret= createRawInsertModeCaret(styledText);
	}

	if (this.fNonDefaultCaret != null) {
	styledText.setCaret(this.fNonDefaultCaret);
	this.fNonDefaultCaretImage= this.fNonDefaultCaret.getImage();
	}
	else if (this.fInitialCaret != styledText.getCaret()) {
	styledText.setCaret(this.fInitialCaret);
	}
	}

	private Caret createInsertCaret(final StyledText styledText) {
	final Caret caret= new Caret(styledText, SWT.NULL);

	caret.setSize(getCaretWidthPreference(), styledText.getLineHeight());
	caret.setFont(styledText.getFont());

	return caret;
	}

	private Caret createRawInsertModeCaret(final StyledText styledText) {
	// // don't draw special raw caret if no smart mode is enabled
	// if (!getLegalInsertModes().contains(SMART_INSERT)) {
	// return createInsertCaret(styledText);
	// }
	final Caret caret= new Caret(styledText, SWT.NULL);
	final Image image= createRawInsertModeCaretImage(styledText);
	if (image != null) {
	caret.setImage(image);
	}
	else {
	caret.setSize(getCaretWidthPreference(), styledText.getLineHeight());
	}

	caret.setFont(styledText.getFont());

	return caret;
	}

	private Image createRawInsertModeCaretImage(final StyledText styledText) {
	final PaletteData caretPalette= new PaletteData(new RGB[] {new RGB (0,0,0), new RGB (255,255,255)});
	final int width= getCaretWidthPreference();
	final int widthOffset= width - 1;

	final ImageData imageData= new ImageData(4 + widthOffset, styledText.getLineHeight(), 1, caretPalette);

	final Display display= styledText.getDisplay();
	final Image bracketImage= new Image(display, imageData);
	final GC gc= new GC (bracketImage);
	gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
	gc.setLineWidth(0); // NOTE: 0 means width is 1 but with optimized performance
	final int height= imageData.height / 3;
	for (int i= 0; i < width ; i++) {
	gc.drawLine(i, 0, i, height - 1);
	gc.drawLine(i, imageData.height - height, i, imageData.height - 1);
	}

	gc.dispose();

	return bracketImage;
	}

	private Caret createOverwriteCaret(final StyledText styledText) {
	final Caret caret= new Caret(styledText, SWT.NULL);
	final GC gc= new GC(styledText);
	// this overwrite box is not proportional-font aware
	// take 'a' as a medium sized character
	final Point charSize= gc.stringExtent("a"); //$NON-NLS-1$

	caret.setSize(charSize.x, styledText.getLineHeight());
	caret.setFont(styledText.getFont());

	gc.dispose();

	return caret;
	}

	private void disposeNonDefaultCaret() {
	if (this.fNonDefaultCaretImage != null) {
	this.fNonDefaultCaretImage.dispose();
	this.fNonDefaultCaretImage= null;
	}

	if (this.fNonDefaultCaret != null) {
	this.fNonDefaultCaret.dispose();
	this.fNonDefaultCaret= null;
	}
	}

	private void dispose() {
	this.fPreferenceStore.removePropertyChangeListener(this.fPreferencePropertyListener);
	JFaceResources.getFontRegistry().removeListener(this.fFontPropertyListener);
	disposeNonDefaultCaret();
	this.fInitialCaret= null;
	}

	}