eclient/org.eclipse.statet.rj.eclient.graphics/src/org/eclipse/statet/rj/eclient/graphics/RGraphicsPreferencePage.java - statet/org.eclipse.statet-rj - Git at Google

 /*=============================================================================#
  # Copyright (c) 2009, 2021 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, or the Apache License, Version 2.0
  # which is available at https://www.apache.org/licenses/LICENSE-2.0.
  #
  # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
  #
  # Contributors:
  #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
  #=============================================================================*/

 package org.eclipse.statet.rj.eclient.graphics;

 import java.util.ArrayList;
 import java.util.List;

 import org.osgi.service.prefs.BackingStoreException;

 import org.eclipse.core.databinding.AggregateValidationStatus;
 import org.eclipse.core.databinding.DataBindingContext;
 import org.eclipse.core.databinding.UpdateValueStrategy;
 import org.eclipse.core.databinding.observable.Realm;
 import org.eclipse.core.databinding.observable.value.IObservableValue;
 import org.eclipse.core.databinding.observable.value.IValueChangeListener;
 import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
 import org.eclipse.core.databinding.observable.value.WritableValue;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.preferences.DefaultScope;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
 import org.eclipse.core.runtime.preferences.IScopeContext;
 import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.jface.databinding.swt.typed.WidgetProperties;
 import org.eclipse.jface.preference.PreferencePage;
 import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.ComboViewer;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTError;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.FontData;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.FontDialog;
 import org.eclipse.swt.widgets.Group;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.Text;
 import org.eclipse.ui.IWorkbench;
 import org.eclipse.ui.IWorkbenchPreferencePage;
 import org.eclipse.ui.statushandlers.StatusManager;

 import org.eclipse.statet.jcommons.lang.Nullable;

 import org.eclipse.statet.ecommons.databinding.core.validation.DecimalValidator;
 import org.eclipse.statet.ecommons.ui.components.StatusInfo;
 import org.eclipse.statet.ecommons.ui.dialogs.DialogUtils;
 import org.eclipse.statet.ecommons.ui.util.LayoutUtils;


 /**
  * Preference page with options to configure R graphic options:
  * <ul>
  *    <li>Default font families ('serif', 'sans', 'mono')</li>
  * </ul>
  *
  * The page is not registered by this plug-in.
  */
 public class RGraphicsPreferencePage extends PreferencePage implements IWorkbenchPreferencePage {


 	public static double[] parseDPI(final String prefValue) {
 		if (prefValue != null) {
 			final String[] strings= prefValue.split(",");
 			if (strings.length == 2) {
 				try {
 					return new double[] {
 							Double.parseDouble(strings[0]),
 							Double.parseDouble(strings[1]),
 					};
 				}
 				catch (final Exception e) {}
 			}
 		}
 		return null;
 	}


 	private static class FontPref {

 		final String prefKey;

 		String defaultName;
 		String currentName;

 		Font currentFont;

 		Label valueLabel;


 		public FontPref(final String key) {
 			this.prefKey= key;
 		}


 		@Override
 		public int hashCode() {
 			return this.prefKey.hashCode();
 		}

 		@Override
 		public boolean equals(final @Nullable Object obj) {
 			return (this == obj
 					|| (obj instanceof FontPref
 							&& this.prefKey.equals(((FontPref) obj).prefKey) ));
 		}

 	}

 	private static class Encoding {

 		final String label;
 		final String prefValue;


 		public Encoding(final String label, final String prefValue) {
 			this.label= label;
 			this.prefValue= prefValue;
 		}


 		@Override
 		public int hashCode() {
 			return this.prefValue.hashCode();
 		}

 		@Override
 		public boolean equals(final @Nullable Object obj) {
 			return (this == obj
 					|| (obj instanceof Encoding
 							&& this.prefValue.equals(((Encoding) obj).prefValue) ));
 		}

 		@Override
 		public String toString() {
 			return this.label.toString();
 		}

 	}

 	private static final Encoding[] SYMBOL_ENCODINGS= new Encoding[] {
 			new Encoding("Unicode", "Unicode"),
 			new Encoding("Adobe Symbol", "AdobeSymbol"),
 	};

 	private static final Encoding SYMBOL_ENCODING_DEFAULT= SYMBOL_ENCODINGS[1];


 	private DataBindingContext dbc;

 	private FontPref serifPref;
 	private FontPref sansPref;
 	private FontPref monoPref;
 	private FontPref symbolFontPref;
 	private FontPref[] fontPrefs;
 	private Button symbolUseControl;
 	private ComboViewer symbolEncodingControl;
 	private Control[] symbolChildControls;

 	private final int size= 10;

 	private Button customDpiControl;
 	private Composite customDpiComposite;
 	private Text customHDpiControl;
 	private Text customVDpiControl;

 	private boolean customEnabled;
 	private IObservableValue<Double> customHDpiVisibleValue;
 	private IObservableValue<Double> customVDpiVisibleValue;
 	private double customHDpiUserValue;
 	private double customVDpiUserValue;


 	/**
 	 * Created via extension point
 	 */
 	public RGraphicsPreferencePage() {
 	}


 	@Override
 	public void init(final IWorkbench workbench) {
 		this.serifPref= new FontPref(RGraphics.PREF_FONTS_SERIF_FONTNAME_KEY);
 		this.sansPref= new FontPref(RGraphics.PREF_FONTS_SANS_FONTNAME_KEY);
 		this.monoPref= new FontPref(RGraphics.PREF_FONTS_MONO_FONTNAME_KEY);
 		this.symbolFontPref= new FontPref(RGraphics.PREF_FONTS_SYMBOL_FONTNAME_KEY);
 		this.fontPrefs= new FontPref[] { this.serifPref, this.sansPref, this.monoPref, this.symbolFontPref };

 		final IEclipsePreferences node= DefaultScope.INSTANCE.getNode(RGraphics.FONTS_PREF_QUALIFIER);
 		for (final FontPref pref : this.fontPrefs) {
 			pref.defaultName= (node != null) ? node.get(pref.prefKey, "") : "";
 		}
 	}

 	@Override
 	protected Control createContents(final Composite parent) {
 		final Composite pageComposite= new Composite(parent, SWT.NONE);
 		pageComposite.setLayout(LayoutUtils.newCompositeGrid(1));

 		final Group displayGroup= createDisplayGroup(pageComposite);
 		displayGroup.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

 		final Group fontGroup= createFontGroup(pageComposite);
 		fontGroup.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

 		initBindings();
 		loadDisplayOptions();
 		loadFontOptions();

 		applyDialogFont(pageComposite);

 		return pageComposite;
 	}

 	protected Group createDisplayGroup(final Composite parent) {
 		final Group group= new Group(parent, SWT.NONE);
 		group.setText("Display:");
 		group.setLayout(LayoutUtils.newGroupGrid(2));

 		this.customDpiControl= new Button(group, SWT.CHECK);
 		this.customDpiControl.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
 		this.customDpiControl.setText("Use custom DPI (instead of system setting):");

 		this.customDpiComposite= new Composite(group, SWT.NONE);

 		{	final GridData gd= new GridData(SWT.FILL, SWT.FILL, true, false);
 			gd.horizontalIndent= LayoutUtils.defaultIndent();
 			this.customDpiComposite.setLayoutData(gd);
 			this.customDpiComposite.setLayout(LayoutUtils.newCompositeGrid(2));
 		}

 		{	final Label label= new Label(this.customDpiComposite, SWT.LEFT);
 			label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
 			label.setText("&Horizontal (x):");
 		}
 		{	final Text text= new Text(this.customDpiComposite, SWT.BORDER | SWT.RIGHT);
 			final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false);
 			gd.widthHint= LayoutUtils.hintWidth(text, 8);
 			text.setLayoutData(gd);
 			this.customHDpiControl= text;
 		}
 		{	final Label label= new Label(this.customDpiComposite, SWT.LEFT);
 			label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
 			label.setText("&Vertical (y):");
 		}
 		{	final Text text= new Text(this.customDpiComposite, SWT.BORDER | SWT.RIGHT);
 			final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false);
 			gd.widthHint= LayoutUtils.hintWidth(text, 8);
 			text.setLayoutData(gd);
 			this.customVDpiControl= text;
 		}

 		this.customDpiControl.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(final SelectionEvent e) {
 				updateDisplayGroup();
 			}
 		});

 		return group;
 	}

 	private void updateDisplayGroup() {
 		this.customEnabled= this.customDpiControl.getSelection();
 		DialogUtils.setEnabled(this.customDpiComposite, null, this.customEnabled);

 		final double hvalue;
 		final double vvalue;
 		if (!this.customEnabled || this.customHDpiUserValue <= 0 || this.customVDpiUserValue <= 0) {
 			final Point dpi= Display.getDefault().getDPI();
 			hvalue= dpi.x;
 			vvalue= dpi.y;
 			if (this.customEnabled) {
 				this.customHDpiUserValue= hvalue;
 				this.customVDpiUserValue= vvalue;
 			}
 		}
 		else {
 			hvalue= this.customHDpiUserValue;
 			vvalue= this.customVDpiUserValue;
 		}
 		this.customHDpiVisibleValue.setValue(hvalue);
 		this.customVDpiVisibleValue.setValue(vvalue);
 	}

 	protected Group createFontGroup(final Composite parent) {
 		final Group group= new Group(parent, SWT.NONE);
 		group.setText("Fonts:");
 		group.setLayout(LayoutUtils.newGroupGrid(3));

 		addFont(group, this.serifPref, "Default &Serif Font ('serif'):");
 		addFont(group, this.sansPref, "Default S&ansserif Font ('sans'):");
 		addFont(group, this.monoPref, "Default &Monospace Font ('mono'):");

 		LayoutUtils.addSmallFiller(group, false);

 		this.symbolUseControl= new Button(group, SWT.CHECK);
 		this.symbolUseControl.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false, 3, 1));
 		this.symbolUseControl.setText("Use special S&ymbol Font");
 		final List<Control> symbolControls= new ArrayList<>();
 		addFont(group, this.symbolFontPref, "Symbol &Font:",
 				LayoutUtils.defaultIndent(), symbolControls );
 		{	final Label label= new Label(group, SWT.NONE);
 			final GridData gd= new GridData(SWT.FILL, SWT.CENTER, false, false);
 			gd.horizontalIndent= LayoutUtils.defaultIndent();
 			label.setLayoutData(gd);
 			label.setText("Encoding:");
 			symbolControls.add(label);
 		}
 		{	this.symbolEncodingControl= new ComboViewer(group, SWT.DROP_DOWN | SWT.READ_ONLY);
 			final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false, 2, 1);
 			gd.widthHint= LayoutUtils.hintWidth(this.symbolEncodingControl.getCombo(), 15);
 			this.symbolEncodingControl.getControl().setLayoutData(gd);
 			this.symbolEncodingControl.setContentProvider(new ArrayContentProvider());
 			this.symbolEncodingControl.setInput(SYMBOL_ENCODINGS);
 			symbolControls.add(this.symbolEncodingControl.getControl());
 		}
 		this.symbolChildControls= symbolControls.toArray(new Control[symbolControls.size()]);
 		this.symbolUseControl.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(final SelectionEvent e) {
 				updateSymbolControls();
 			}
 		});

 		return group;
 	}

 	private void addFont(final Group group, final FontPref pref, final String text) {
 		addFont(group, pref, text, 0, null);
 	}

 	private void addFont(final Group group, final FontPref pref, final String text,
 			final int indent, final List<Control> controls) {
 		final Label label= new Label(group, SWT.NONE);
 		final GridData gd= new GridData(SWT.FILL, SWT.CENTER, false, false);
 		gd.horizontalIndent= indent;
 		label.setLayoutData(gd);
 		label.setText(text);

 		pref.valueLabel= new Label(group, SWT.BORDER);
 		pref.valueLabel.setBackground(label.getDisplay().getSystemColor(SWT.COLOR_WHITE));
 		pref.valueLabel.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));

 		final Button button= new Button(group, SWT.PUSH);
 		button.setText("Edit...");
 		button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
 		button.addSelectionListener(new SelectionListener() {
 			@Override
 			public void widgetSelected(final SelectionEvent e) {
 				final FontDialog dialog= new FontDialog(button.getShell(), SWT.NONE);
 				dialog.setFontList((pref.currentFont != null) ? pref.currentFont.getFontData() : null);
 				final FontData result= dialog.open();
 				if (result != null) {
 					set(pref, result.getName());
 				}
 			}
 			@Override
 			public void widgetDefaultSelected(final SelectionEvent e) {
 			}
 		});

 		if (controls != null) {
 			controls.add(label);
 			controls.add(pref.valueLabel);
 			controls.add(button);
 		}
 	}

 	protected void initBindings() {
 		final Realm realm= Realm.getDefault();
 		this.dbc= new DataBindingContext(realm);
 		addBindings(this.dbc, realm);

 		final AggregateValidationStatus validationStatus= new AggregateValidationStatus(this.dbc,
 				AggregateValidationStatus.MAX_SEVERITY );
 		validationStatus.addValueChangeListener(new IValueChangeListener<IStatus>() {
 			@Override
 			public void handleValueChange(final ValueChangeEvent<? extends IStatus> event) {
 				final IStatus currentStatus= event.diff.getNewValue();
 				updateStatus(currentStatus);
 			}
 		});
 	}

 	protected void addBindings(final DataBindingContext dbc, final Realm realm) {
 		this.customHDpiVisibleValue= new WritableValue<>(realm, 96.0, Double.class);
 		this.customVDpiVisibleValue= new WritableValue<>(realm, 96.0, Double.class);

 		dbc.bindValue(
 				WidgetProperties.text(SWT.Modify)
 						.observe(this.customHDpiControl),
 				this.customHDpiVisibleValue,
 				new UpdateValueStrategy<String, Double>()
 						.setAfterGetValidator(new DecimalValidator(10.0, 10000.0,
 								"The value for Horizontal (x) DPI is invalid (10-10000)." )),
 				null );
 		dbc.bindValue(
 				WidgetProperties.text(SWT.Modify)
 						.observe(this.customVDpiControl),
 				this.customVDpiVisibleValue,
 				new UpdateValueStrategy<String, Double>()
 						.setAfterGetValidator(new DecimalValidator(10.0, 10000.0,
 								"The value for Vertical (x) DPI is invalid (10-10000)." )),
 				null );

 		this.customHDpiVisibleValue.addValueChangeListener(new IValueChangeListener<Double>() {
 			@Override
 			public void handleValueChange(final ValueChangeEvent<? extends Double> event) {
 				if (RGraphicsPreferencePage.this.customEnabled) {
 					RGraphicsPreferencePage.this.customHDpiUserValue= RGraphicsPreferencePage.this.customHDpiVisibleValue.getValue();
 				}
 			}
 		});
 		this.customVDpiVisibleValue.addValueChangeListener(new IValueChangeListener<Double>() {
 			@Override
 			public void handleValueChange(final ValueChangeEvent<? extends Double> event) {
 				if (RGraphicsPreferencePage.this.customEnabled) {
 					RGraphicsPreferencePage.this.customVDpiUserValue= RGraphicsPreferencePage.this.customVDpiVisibleValue.getValue();
 				}
 			}
 		});
 	}

 	protected void updateStatus(final IStatus status) {
 		setValid(!status.matches(IStatus.ERROR));
 		StatusInfo.applyToStatusLine(this, status);
 	}

 	protected void setCustomDpi(final String prefValue) {
 		final double[] dpi= parseDPI(prefValue);
 		if (dpi != null) {
 			this.customHDpiUserValue= dpi[0];
 			this.customVDpiUserValue= dpi[1];
 			this.customDpiControl.setSelection(true);
 		}
 		else {
 			this.customDpiControl.setSelection(false);
 		}
 		updateDisplayGroup();
 	}

 	protected void updateSymbolControls() {
 		DialogUtils.setEnabled(this.symbolChildControls, null, this.symbolUseControl.getSelection());
 	}

 	protected void set(final FontPref pref, final String value) {
 		if (value.equals(pref.currentName)) {
 			return;
 		}
 		pref.valueLabel.setText("");
 		Font font;
 		try {
 			font= new Font(pref.valueLabel.getDisplay(), value, this.size, SWT.NONE);
 			if (pref != this.symbolFontPref) {
 				pref.valueLabel.setFont(font);
 			}
 			pref.valueLabel.setText(value);
 		}
 		catch (final SWTError e) {
 			font= JFaceResources.getDialogFont();
 			pref.valueLabel.setFont(font);
 			pref.valueLabel.setText(value + " (not available)");
 		}
 		if (pref.currentFont != null && !pref.currentFont.isDisposed()) {
 			pref.currentFont.dispose();
 		}
 		pref.currentName= value;
 		pref.currentFont= font;
 	}

 	@Override
 	protected void performDefaults() {
 		setCustomDpi(null);
 		this.symbolUseControl.setSelection(true);
 		this.symbolEncodingControl.setSelection(new StructuredSelection(SYMBOL_ENCODING_DEFAULT));
 		for (final FontPref pref : this.fontPrefs) {
 			set(pref, pref.defaultName);
 		}
 		updateSymbolControls();
 		super.performDefaults();
 	}

 	@Override
 	protected void performApply() {
 		saveDisplayOptions(true);
 		saveFontOptions(true);
 	}

 	@Override
 	public boolean performOk() {
 		saveDisplayOptions(false);
 		saveFontOptions(false);
 		return true;
 	}


 	protected IScopeContext getScope() {
 		return InstanceScope.INSTANCE;
 	}

 	protected void loadDisplayOptions() {
 		final IEclipsePreferences node= getScope().getNode(RGraphics.PREF_DISPLAY_QUALIFIER);
 		setCustomDpi(node.get(RGraphics.PREF_DISPLAY_CUSTOM_DPI_KEY, null));
 	}

 	protected void saveDisplayOptions(final boolean flush) {
 		final IEclipsePreferences node= getScope().getNode(RGraphics.PREF_DISPLAY_QUALIFIER);
 		if (this.customEnabled) {
 			node.put(RGraphics.PREF_DISPLAY_CUSTOM_DPI_KEY,
 					Double.toString(this.customHDpiUserValue) + "," + Double.toString(this.customVDpiUserValue));
 		}
 		else {
 			node.remove(RGraphics.PREF_DISPLAY_CUSTOM_DPI_KEY);
 		}
 		if (flush) {
 			try {
 				node.flush();
 			}
 			catch (final BackingStoreException e) {
 				StatusManager.getManager().handle(new Status(IStatus.ERROR, RGraphics.BUNDLE_ID, -1,
 						"An error occurred when storing R graphics display preferences.", e));
 			}
 		}
 	}

 	protected void loadFontOptions() {
 		if (this.fontPrefs != null) {
 			final IEclipsePreferences node= getScope().getNode(RGraphics.FONTS_PREF_QUALIFIER);
 			this.symbolUseControl.setSelection(node.getBoolean(RGraphics.PREF_FONTS_SYMBOL_USE_KEY, true));
 			final String s= node.get(RGraphics.PREF_FONTS_SYMBOL_ENCODING_KEY, (String) null);
 			this.symbolEncodingControl.setSelection(new StructuredSelection((s != null) ?
 					new Encoding(null, s) : SYMBOL_ENCODING_DEFAULT ));
 			for (final FontPref pref : this.fontPrefs) {
 				final String value= node.get(pref.prefKey, ""); //$NON-NLS-1$
 				set(pref, (value.length() > 0) ? value : pref.defaultName);
 			}
 			updateSymbolControls();
 		}
 	}

 	protected void saveFontOptions(final boolean flush) {
 		if (this.fontPrefs != null) {
 			final IEclipsePreferences node= getScope().getNode(RGraphics.FONTS_PREF_QUALIFIER);
 			node.putBoolean(RGraphics.PREF_FONTS_SYMBOL_USE_KEY, this.symbolUseControl.getSelection());
 			final IStructuredSelection selection= (IStructuredSelection) this.symbolEncodingControl.getSelection();
 			if (selection.getFirstElement() instanceof Encoding
 					&& !SYMBOL_ENCODING_DEFAULT.equals(selection.getFirstElement())) {
 				node.put(RGraphics.PREF_FONTS_SYMBOL_ENCODING_KEY,
 						((Encoding) selection.getFirstElement()).prefValue );
 			}
 			else {
 				node.remove(RGraphics.PREF_FONTS_SYMBOL_ENCODING_KEY);
 			}
 			for (final FontPref pref : this.fontPrefs) {
 				if (pref.currentName == null || pref.currentName.equals(pref.defaultName)) {
 					node.remove(pref.prefKey);
 				}
 				else {
 					node.put(pref.prefKey, pref.currentName);
 				}
 			}
 			updateSymbolControls();
 			if (flush) {
 				try {
 					node.flush();
 				}
 				catch (final BackingStoreException e) {
 					StatusManager.getManager().handle(new Status(IStatus.ERROR, RGraphics.BUNDLE_ID, -1,
 							"An error occurred when storing R graphics font preferences.", e));
 				}
 			}
 		}
 	}

 	@Override
 	public void dispose() {
 		if (this.dbc != null) {
 			this.dbc.dispose();
 			this.dbc= null;
 		}
 		if (this.fontPrefs != null) {
 			for (final FontPref pref : this.fontPrefs) {
 				if (pref.currentFont != null && !pref.currentFont.isDisposed()) {
 					pref.currentFont.dispose();
 					pref.currentFont= null;
 				}
 			}
 		}
 		super.dispose();
 	}

 }
	/*=============================================================================#
	# Copyright (c) 2009, 2021 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, or the Apache License, Version 2.0
	# which is available at https://www.apache.org/licenses/LICENSE-2.0.
	#
	# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
	#
	# Contributors:
	# Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
	#=============================================================================*/

	package org.eclipse.statet.rj.eclient.graphics;

	import java.util.ArrayList;
	import java.util.List;

	import org.osgi.service.prefs.BackingStoreException;

	import org.eclipse.core.databinding.AggregateValidationStatus;
	import org.eclipse.core.databinding.DataBindingContext;
	import org.eclipse.core.databinding.UpdateValueStrategy;
	import org.eclipse.core.databinding.observable.Realm;
	import org.eclipse.core.databinding.observable.value.IObservableValue;
	import org.eclipse.core.databinding.observable.value.IValueChangeListener;
	import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
	import org.eclipse.core.databinding.observable.value.WritableValue;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.core.runtime.preferences.DefaultScope;
	import org.eclipse.core.runtime.preferences.IEclipsePreferences;
	import org.eclipse.core.runtime.preferences.IScopeContext;
	import org.eclipse.core.runtime.preferences.InstanceScope;
	import org.eclipse.jface.databinding.swt.typed.WidgetProperties;
	import org.eclipse.jface.preference.PreferencePage;
	import org.eclipse.jface.resource.JFaceResources;
	import org.eclipse.jface.viewers.ArrayContentProvider;
	import org.eclipse.jface.viewers.ComboViewer;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.StructuredSelection;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.SWTError;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.FontData;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.FontDialog;
	import org.eclipse.swt.widgets.Group;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.swt.widgets.Text;
	import org.eclipse.ui.IWorkbench;
	import org.eclipse.ui.IWorkbenchPreferencePage;
	import org.eclipse.ui.statushandlers.StatusManager;

	import org.eclipse.statet.jcommons.lang.Nullable;

	import org.eclipse.statet.ecommons.databinding.core.validation.DecimalValidator;
	import org.eclipse.statet.ecommons.ui.components.StatusInfo;
	import org.eclipse.statet.ecommons.ui.dialogs.DialogUtils;
	import org.eclipse.statet.ecommons.ui.util.LayoutUtils;


	/**
	* Preference page with options to configure R graphic options:
	* <ul>
	* <li>Default font families ('serif', 'sans', 'mono')</li>
	* </ul>
	*
	* The page is not registered by this plug-in.
	*/
	public class RGraphicsPreferencePage extends PreferencePage implements IWorkbenchPreferencePage {


	public static double[] parseDPI(final String prefValue) {
	if (prefValue != null) {
	final String[] strings= prefValue.split(",");
	if (strings.length == 2) {
	try {
	return new double[] {
	Double.parseDouble(strings[0]),
	Double.parseDouble(strings[1]),
	};
	}
	catch (final Exception e) {}
	}
	}
	return null;
	}


	private static class FontPref {

	final String prefKey;

	String defaultName;
	String currentName;

	Font currentFont;

	Label valueLabel;


	public FontPref(final String key) {
	this.prefKey= key;
	}


	@Override
	public int hashCode() {
	return this.prefKey.hashCode();
	}

	@Override
	public boolean equals(final @Nullable Object obj) {
	return (this == obj
	\|\| (obj instanceof FontPref
	&& this.prefKey.equals(((FontPref) obj).prefKey) ));
	}

	}

	private static class Encoding {

	final String label;
	final String prefValue;


	public Encoding(final String label, final String prefValue) {
	this.label= label;
	this.prefValue= prefValue;
	}


	@Override
	public int hashCode() {
	return this.prefValue.hashCode();
	}

	@Override
	public boolean equals(final @Nullable Object obj) {
	return (this == obj
	\|\| (obj instanceof Encoding
	&& this.prefValue.equals(((Encoding) obj).prefValue) ));
	}

	@Override
	public String toString() {
	return this.label.toString();
	}

	}

	private static final Encoding[] SYMBOL_ENCODINGS= new Encoding[] {
	new Encoding("Unicode", "Unicode"),
	new Encoding("Adobe Symbol", "AdobeSymbol"),
	};

	private static final Encoding SYMBOL_ENCODING_DEFAULT= SYMBOL_ENCODINGS[1];


	private DataBindingContext dbc;

	private FontPref serifPref;
	private FontPref sansPref;
	private FontPref monoPref;
	private FontPref symbolFontPref;
	private FontPref[] fontPrefs;
	private Button symbolUseControl;
	private ComboViewer symbolEncodingControl;
	private Control[] symbolChildControls;

	private final int size= 10;

	private Button customDpiControl;
	private Composite customDpiComposite;
	private Text customHDpiControl;
	private Text customVDpiControl;

	private boolean customEnabled;
	private IObservableValue<Double> customHDpiVisibleValue;
	private IObservableValue<Double> customVDpiVisibleValue;
	private double customHDpiUserValue;
	private double customVDpiUserValue;


	/**
	* Created via extension point
	*/
	public RGraphicsPreferencePage() {
	}


	@Override
	public void init(final IWorkbench workbench) {
	this.serifPref= new FontPref(RGraphics.PREF_FONTS_SERIF_FONTNAME_KEY);
	this.sansPref= new FontPref(RGraphics.PREF_FONTS_SANS_FONTNAME_KEY);
	this.monoPref= new FontPref(RGraphics.PREF_FONTS_MONO_FONTNAME_KEY);
	this.symbolFontPref= new FontPref(RGraphics.PREF_FONTS_SYMBOL_FONTNAME_KEY);
	this.fontPrefs= new FontPref[] { this.serifPref, this.sansPref, this.monoPref, this.symbolFontPref };

	final IEclipsePreferences node= DefaultScope.INSTANCE.getNode(RGraphics.FONTS_PREF_QUALIFIER);
	for (final FontPref pref : this.fontPrefs) {
	pref.defaultName= (node != null) ? node.get(pref.prefKey, "") : "";
	}
	}

	@Override
	protected Control createContents(final Composite parent) {
	final Composite pageComposite= new Composite(parent, SWT.NONE);
	pageComposite.setLayout(LayoutUtils.newCompositeGrid(1));

	final Group displayGroup= createDisplayGroup(pageComposite);
	displayGroup.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

	final Group fontGroup= createFontGroup(pageComposite);
	fontGroup.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

	initBindings();
	loadDisplayOptions();
	loadFontOptions();

	applyDialogFont(pageComposite);

	return pageComposite;
	}

	protected Group createDisplayGroup(final Composite parent) {
	final Group group= new Group(parent, SWT.NONE);
	group.setText("Display:");
	group.setLayout(LayoutUtils.newGroupGrid(2));

	this.customDpiControl= new Button(group, SWT.CHECK);
	this.customDpiControl.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
	this.customDpiControl.setText("Use custom DPI (instead of system setting):");

	this.customDpiComposite= new Composite(group, SWT.NONE);

	{ final GridData gd= new GridData(SWT.FILL, SWT.FILL, true, false);
	gd.horizontalIndent= LayoutUtils.defaultIndent();
	this.customDpiComposite.setLayoutData(gd);
	this.customDpiComposite.setLayout(LayoutUtils.newCompositeGrid(2));
	}

	{ final Label label= new Label(this.customDpiComposite, SWT.LEFT);
	label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
	label.setText("&Horizontal (x):");
	}
	{ final Text text= new Text(this.customDpiComposite, SWT.BORDER \| SWT.RIGHT);
	final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false);
	gd.widthHint= LayoutUtils.hintWidth(text, 8);
	text.setLayoutData(gd);
	this.customHDpiControl= text;
	}
	{ final Label label= new Label(this.customDpiComposite, SWT.LEFT);
	label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
	label.setText("&Vertical (y):");
	}
	{ final Text text= new Text(this.customDpiComposite, SWT.BORDER \| SWT.RIGHT);
	final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false);
	gd.widthHint= LayoutUtils.hintWidth(text, 8);
	text.setLayoutData(gd);
	this.customVDpiControl= text;
	}

	this.customDpiControl.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(final SelectionEvent e) {
	updateDisplayGroup();
	}
	});

	return group;
	}

	private void updateDisplayGroup() {
	this.customEnabled= this.customDpiControl.getSelection();
	DialogUtils.setEnabled(this.customDpiComposite, null, this.customEnabled);

	final double hvalue;
	final double vvalue;
	if (!this.customEnabled \|\| this.customHDpiUserValue <= 0 \|\| this.customVDpiUserValue <= 0) {
	final Point dpi= Display.getDefault().getDPI();
	hvalue= dpi.x;
	vvalue= dpi.y;
	if (this.customEnabled) {
	this.customHDpiUserValue= hvalue;
	this.customVDpiUserValue= vvalue;
	}
	}
	else {
	hvalue= this.customHDpiUserValue;
	vvalue= this.customVDpiUserValue;
	}
	this.customHDpiVisibleValue.setValue(hvalue);
	this.customVDpiVisibleValue.setValue(vvalue);
	}

	protected Group createFontGroup(final Composite parent) {
	final Group group= new Group(parent, SWT.NONE);
	group.setText("Fonts:");
	group.setLayout(LayoutUtils.newGroupGrid(3));

	addFont(group, this.serifPref, "Default &Serif Font ('serif'):");
	addFont(group, this.sansPref, "Default S&ansserif Font ('sans'):");
	addFont(group, this.monoPref, "Default &Monospace Font ('mono'):");

	LayoutUtils.addSmallFiller(group, false);

	this.symbolUseControl= new Button(group, SWT.CHECK);
	this.symbolUseControl.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false, 3, 1));
	this.symbolUseControl.setText("Use special S&ymbol Font");
	final List<Control> symbolControls= new ArrayList<>();
	addFont(group, this.symbolFontPref, "Symbol &Font:",
	LayoutUtils.defaultIndent(), symbolControls );
	{ final Label label= new Label(group, SWT.NONE);
	final GridData gd= new GridData(SWT.FILL, SWT.CENTER, false, false);
	gd.horizontalIndent= LayoutUtils.defaultIndent();
	label.setLayoutData(gd);
	label.setText("Encoding:");
	symbolControls.add(label);
	}
	{ this.symbolEncodingControl= new ComboViewer(group, SWT.DROP_DOWN \| SWT.READ_ONLY);
	final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false, 2, 1);
	gd.widthHint= LayoutUtils.hintWidth(this.symbolEncodingControl.getCombo(), 15);
	this.symbolEncodingControl.getControl().setLayoutData(gd);
	this.symbolEncodingControl.setContentProvider(new ArrayContentProvider());
	this.symbolEncodingControl.setInput(SYMBOL_ENCODINGS);
	symbolControls.add(this.symbolEncodingControl.getControl());
	}
	this.symbolChildControls= symbolControls.toArray(new Control[symbolControls.size()]);
	this.symbolUseControl.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(final SelectionEvent e) {
	updateSymbolControls();
	}
	});

	return group;
	}

	private void addFont(final Group group, final FontPref pref, final String text) {
	addFont(group, pref, text, 0, null);
	}

	private void addFont(final Group group, final FontPref pref, final String text,
	final int indent, final List<Control> controls) {
	final Label label= new Label(group, SWT.NONE);
	final GridData gd= new GridData(SWT.FILL, SWT.CENTER, false, false);
	gd.horizontalIndent= indent;
	label.setLayoutData(gd);
	label.setText(text);

	pref.valueLabel= new Label(group, SWT.BORDER);
	pref.valueLabel.setBackground(label.getDisplay().getSystemColor(SWT.COLOR_WHITE));
	pref.valueLabel.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));

	final Button button= new Button(group, SWT.PUSH);
	button.setText("Edit...");
	button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
	button.addSelectionListener(new SelectionListener() {
	@Override
	public void widgetSelected(final SelectionEvent e) {
	final FontDialog dialog= new FontDialog(button.getShell(), SWT.NONE);
	dialog.setFontList((pref.currentFont != null) ? pref.currentFont.getFontData() : null);
	final FontData result= dialog.open();
	if (result != null) {
	set(pref, result.getName());
	}
	}
	@Override
	public void widgetDefaultSelected(final SelectionEvent e) {
	}
	});

	if (controls != null) {
	controls.add(label);
	controls.add(pref.valueLabel);
	controls.add(button);
	}
	}

	protected void initBindings() {
	final Realm realm= Realm.getDefault();
	this.dbc= new DataBindingContext(realm);
	addBindings(this.dbc, realm);

	final AggregateValidationStatus validationStatus= new AggregateValidationStatus(this.dbc,
	AggregateValidationStatus.MAX_SEVERITY );
	validationStatus.addValueChangeListener(new IValueChangeListener<IStatus>() {
	@Override
	public void handleValueChange(final ValueChangeEvent<? extends IStatus> event) {
	final IStatus currentStatus= event.diff.getNewValue();
	updateStatus(currentStatus);
	}
	});
	}

	protected void addBindings(final DataBindingContext dbc, final Realm realm) {
	this.customHDpiVisibleValue= new WritableValue<>(realm, 96.0, Double.class);
	this.customVDpiVisibleValue= new WritableValue<>(realm, 96.0, Double.class);

	dbc.bindValue(
	WidgetProperties.text(SWT.Modify)
	.observe(this.customHDpiControl),
	this.customHDpiVisibleValue,
	new UpdateValueStrategy<String, Double>()
	.setAfterGetValidator(new DecimalValidator(10.0, 10000.0,
	"The value for Horizontal (x) DPI is invalid (10-10000)." )),
	null );
	dbc.bindValue(
	WidgetProperties.text(SWT.Modify)
	.observe(this.customVDpiControl),
	this.customVDpiVisibleValue,
	new UpdateValueStrategy<String, Double>()
	.setAfterGetValidator(new DecimalValidator(10.0, 10000.0,
	"The value for Vertical (x) DPI is invalid (10-10000)." )),
	null );

	this.customHDpiVisibleValue.addValueChangeListener(new IValueChangeListener<Double>() {
	@Override
	public void handleValueChange(final ValueChangeEvent<? extends Double> event) {
	if (RGraphicsPreferencePage.this.customEnabled) {
	RGraphicsPreferencePage.this.customHDpiUserValue= RGraphicsPreferencePage.this.customHDpiVisibleValue.getValue();
	}
	}
	});
	this.customVDpiVisibleValue.addValueChangeListener(new IValueChangeListener<Double>() {
	@Override
	public void handleValueChange(final ValueChangeEvent<? extends Double> event) {
	if (RGraphicsPreferencePage.this.customEnabled) {
	RGraphicsPreferencePage.this.customVDpiUserValue= RGraphicsPreferencePage.this.customVDpiVisibleValue.getValue();
	}
	}
	});
	}

	protected void updateStatus(final IStatus status) {
	setValid(!status.matches(IStatus.ERROR));
	StatusInfo.applyToStatusLine(this, status);
	}

	protected void setCustomDpi(final String prefValue) {
	final double[] dpi= parseDPI(prefValue);
	if (dpi != null) {
	this.customHDpiUserValue= dpi[0];
	this.customVDpiUserValue= dpi[1];
	this.customDpiControl.setSelection(true);
	}
	else {
	this.customDpiControl.setSelection(false);
	}
	updateDisplayGroup();
	}

	protected void updateSymbolControls() {
	DialogUtils.setEnabled(this.symbolChildControls, null, this.symbolUseControl.getSelection());
	}

	protected void set(final FontPref pref, final String value) {
	if (value.equals(pref.currentName)) {
	return;
	}
	pref.valueLabel.setText("");
	Font font;
	try {
	font= new Font(pref.valueLabel.getDisplay(), value, this.size, SWT.NONE);
	if (pref != this.symbolFontPref) {
	pref.valueLabel.setFont(font);
	}
	pref.valueLabel.setText(value);
	}
	catch (final SWTError e) {
	font= JFaceResources.getDialogFont();
	pref.valueLabel.setFont(font);
	pref.valueLabel.setText(value + " (not available)");
	}
	if (pref.currentFont != null && !pref.currentFont.isDisposed()) {
	pref.currentFont.dispose();
	}
	pref.currentName= value;
	pref.currentFont= font;
	}

	@Override
	protected void performDefaults() {
	setCustomDpi(null);
	this.symbolUseControl.setSelection(true);
	this.symbolEncodingControl.setSelection(new StructuredSelection(SYMBOL_ENCODING_DEFAULT));
	for (final FontPref pref : this.fontPrefs) {
	set(pref, pref.defaultName);
	}
	updateSymbolControls();
	super.performDefaults();
	}

	@Override
	protected void performApply() {
	saveDisplayOptions(true);
	saveFontOptions(true);
	}

	@Override
	public boolean performOk() {
	saveDisplayOptions(false);
	saveFontOptions(false);
	return true;
	}


	protected IScopeContext getScope() {
	return InstanceScope.INSTANCE;
	}

	protected void loadDisplayOptions() {
	final IEclipsePreferences node= getScope().getNode(RGraphics.PREF_DISPLAY_QUALIFIER);
	setCustomDpi(node.get(RGraphics.PREF_DISPLAY_CUSTOM_DPI_KEY, null));
	}

	protected void saveDisplayOptions(final boolean flush) {
	final IEclipsePreferences node= getScope().getNode(RGraphics.PREF_DISPLAY_QUALIFIER);
	if (this.customEnabled) {
	node.put(RGraphics.PREF_DISPLAY_CUSTOM_DPI_KEY,
	Double.toString(this.customHDpiUserValue) + "," + Double.toString(this.customVDpiUserValue));
	}
	else {
	node.remove(RGraphics.PREF_DISPLAY_CUSTOM_DPI_KEY);
	}
	if (flush) {
	try {
	node.flush();
	}
	catch (final BackingStoreException e) {
	StatusManager.getManager().handle(new Status(IStatus.ERROR, RGraphics.BUNDLE_ID, -1,
	"An error occurred when storing R graphics display preferences.", e));
	}
	}
	}

	protected void loadFontOptions() {
	if (this.fontPrefs != null) {
	final IEclipsePreferences node= getScope().getNode(RGraphics.FONTS_PREF_QUALIFIER);
	this.symbolUseControl.setSelection(node.getBoolean(RGraphics.PREF_FONTS_SYMBOL_USE_KEY, true));
	final String s= node.get(RGraphics.PREF_FONTS_SYMBOL_ENCODING_KEY, (String) null);
	this.symbolEncodingControl.setSelection(new StructuredSelection((s != null) ?
	new Encoding(null, s) : SYMBOL_ENCODING_DEFAULT ));
	for (final FontPref pref : this.fontPrefs) {
	final String value= node.get(pref.prefKey, ""); //$NON-NLS-1$
	set(pref, (value.length() > 0) ? value : pref.defaultName);
	}
	updateSymbolControls();
	}
	}

	protected void saveFontOptions(final boolean flush) {
	if (this.fontPrefs != null) {
	final IEclipsePreferences node= getScope().getNode(RGraphics.FONTS_PREF_QUALIFIER);
	node.putBoolean(RGraphics.PREF_FONTS_SYMBOL_USE_KEY, this.symbolUseControl.getSelection());
	final IStructuredSelection selection= (IStructuredSelection) this.symbolEncodingControl.getSelection();
	if (selection.getFirstElement() instanceof Encoding
	&& !SYMBOL_ENCODING_DEFAULT.equals(selection.getFirstElement())) {
	node.put(RGraphics.PREF_FONTS_SYMBOL_ENCODING_KEY,
	((Encoding) selection.getFirstElement()).prefValue );
	}
	else {
	node.remove(RGraphics.PREF_FONTS_SYMBOL_ENCODING_KEY);
	}
	for (final FontPref pref : this.fontPrefs) {
	if (pref.currentName == null \|\| pref.currentName.equals(pref.defaultName)) {
	node.remove(pref.prefKey);
	}
	else {
	node.put(pref.prefKey, pref.currentName);
	}
	}
	updateSymbolControls();
	if (flush) {
	try {
	node.flush();
	}
	catch (final BackingStoreException e) {
	StatusManager.getManager().handle(new Status(IStatus.ERROR, RGraphics.BUNDLE_ID, -1,
	"An error occurred when storing R graphics font preferences.", e));
	}
	}
	}
	}

	@Override
	public void dispose() {
	if (this.dbc != null) {
	this.dbc.dispose();
	this.dbc= null;
	}
	if (this.fontPrefs != null) {
	for (final FontPref pref : this.fontPrefs) {
	if (pref.currentFont != null && !pref.currentFont.isDisposed()) {
	pref.currentFont.dispose();
	pref.currentFont= null;
	}
	}
	}
	super.dispose();
	}

	}