org.eclipse.gmf.runtime.diagram.ui/src/org/eclipse/gmf/runtime/diagram/ui/preferences/RulerGridPreferencePage.java - gmf-runtime/org.eclipse.gmf-runtime - Git at Google

 /******************************************************************************
  * Copyright (c) 2002, 2007 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
  ****************************************************************************/


 package org.eclipse.gmf.runtime.diagram.ui.preferences;

 import java.text.ParseException;
 import java.text.ParsePosition;
 import java.util.Locale;

 import org.eclipse.gef.rulers.RulerProvider;
 import org.eclipse.gmf.runtime.common.ui.preferences.AbstractPreferencePage;
 import org.eclipse.gmf.runtime.common.ui.preferences.ComboFieldEditor;
 import org.eclipse.gmf.runtime.diagram.ui.l10n.DiagramUIMessages;
 import org.eclipse.jface.preference.BooleanFieldEditor;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.preference.StringFieldEditor;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Combo;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Group;
 import org.eclipse.swt.widgets.Text;

 import com.ibm.icu.text.NumberFormat;


 /**
  * Diagram Ruler & Grid preference page.
  *
  * @author jschofie
  */
 public class RulerGridPreferencePage
 	extends AbstractPreferencePage {

 	private class DoubleFieldEditor extends StringFieldEditor {

 		private double minValidValue = 00.009;
 		private double maxValidValue = 99.999;

 		public DoubleFieldEditor(String pref, String label, Composite parent ) {
 			super(pref,label,parent);
 		}

 		/* (non-Javadoc)
 		 * @see org.eclipse.jface.preference.StringFieldEditor#doCheckState()
 		 */
 		protected boolean doCheckState() {
 			Text text = getTextControl();

 			if (text == null)
 				return false;

 			try {
 				NumberFormat numberFormatter = NumberFormat.getInstance();
 				ParsePosition parsePosition = new ParsePosition(0);
 				Number parsedNumber = numberFormatter.parse(text.getText(), parsePosition);

 				if (parsedNumber == null) {
 					showErrorMessage();
 					return false;
 				}

 				Double pageHeight = forceDouble(parsedNumber);
 				double number = pageHeight.doubleValue();
 				number = convertToBase(number);
 				if (number >= minValidValue && number <= maxValidValue
 						&& parsePosition.getIndex() == text.getText().length()) {
 					clearErrorMessage();
 					return true;
 				} else {
 					showErrorMessage();
 					return false;
 				}
 			} catch (NumberFormatException e1) {
 				showErrorMessage();
 			}

 			return false;
 		}

 		/* (non-Javadoc)
 		 * @see org.eclipse.jface.preference.StringFieldEditor#doLoadDefault()
 		 */
 		protected void doLoadDefault() {
 			Text text = getTextControl();
 			if (text != null) {
 				double value = getPreferenceStore().getDefaultDouble(getPreferenceName());
 				NumberFormat numberFormatter = NumberFormat.getNumberInstance();
 				text.setText(numberFormatter.format(value));
 			}
 			valueChanged();
 		}

 		/* (non-Javadoc)
 		 * Method declared on FieldEditor.
 		 */
 		protected void doLoad() {
 			Text text = getTextControl();
 			if (text != null) {
 				double value = getPreferenceStore().getDouble(getPreferenceName());
 				NumberFormat numberFormatter = NumberFormat.getNumberInstance();
 				text.setText(numberFormatter.format(value));
 			}
 		}

 		protected void doStore() {
 			NumberFormat numberFormatter = NumberFormat.getInstance();
 			Double gridWidth;
 			try {
 				gridWidth = forceDouble(numberFormatter.parse(getTextControl().getText()));
 				getPreferenceStore().setValue(getPreferenceName(), gridWidth.doubleValue());
 			} catch (ParseException e) {
 				showErrorMessage();
 			}

 		}
 	}

 	private int oldUnits = -1;

 	private static final int INCHES = 0;
 	private static final int CENTIMETERS = 1;
 	private static final int PIXELS = 2;

 	// Conversion from inch to centimeter
 	private static final double INCH2CM = 2.54;

 	private String RULER_GROUP_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerGroup_label;
 	private String SHOW_RULERS_LABEL = DiagramUIMessages.GridRulerPreferencePage_showRulers_label;
 	private String RULER_UNITS_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_label;
 	private String RULER_UNITS_IN_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_inch_label;
 	private String RULER_UNITS_CM_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_cm_label;
 	private String RULER_UNITS_PIXEL_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_pixel_label;

 	private String GRID_GROUP_LABEL = DiagramUIMessages.GridRulerPreferencePage_gridGroup_label;
 	private String SHOW_GRID_LABEL = DiagramUIMessages.GridRulerPreferencePage_showGrid_label;
 	private String SNAP_TO_GRID_LABEL = DiagramUIMessages.GridRulerPreferencePage_snapToGrid_label;
 	private String SNAP_TO_GEOMETRY_LABEL = DiagramUIMessages.GridRulerPreferencePage_snapToGeometry_label;
 	private String GRID_SPACING_LABEL_INCHES = DiagramUIMessages.GridRulerPreferencePage_gridSpacing_label_inches;
     private String GRID_SPACING_LABEL_CM = DiagramUIMessages.GridRulerPreferencePage_gridSpacing_label_cm;
     private String GRID_SPACING_LABEL_PIXELS = DiagramUIMessages.GridRulerPreferencePage_gridSpacing_label_pixels;


 	// Ruler Field Editors
 	private BooleanFieldEditor showRulers = null;
     private ComboFieldEditor rulerUnits;

     // Grid Field Editors
     private BooleanFieldEditor showGrid = null;
 	private BooleanFieldEditor snapToGrid = null;
 	private BooleanFieldEditor snapToGeometry = null;
 	private DoubleFieldEditor gridSpacing = null;
     private Composite dblGroup = null;

 	private String convertUnits(int fromUnits, int toUnits ) {
 		String valueStr = gridSpacing.getStringValue();
 		if( fromUnits == toUnits ) {
 			return valueStr;
 		}

 		//Double value = Double.valueOf( valueStr );
 		NumberFormat numberFormatter = NumberFormat.getInstance();
 		Double value = new Double(0.125);
 		try {
 			value = forceDouble(numberFormatter.parse(valueStr));
 		} catch (ParseException e) {
 			// Use the default
 		}
 		double pixelValue = 0;

 		Display display = getControl().getDisplay();

 		switch( fromUnits ) {
 			case INCHES:
 				pixelValue = value.doubleValue() * display.getDPI().x;
 				break;
 			case CENTIMETERS:
 				pixelValue = value.doubleValue() * display.getDPI().x / INCH2CM;
 				break;
 			case PIXELS:
 				pixelValue = value.intValue();
 		}

 		double returnValue = 0;

 		switch( toUnits ) {
 			case INCHES:
 				returnValue = pixelValue / display.getDPI().x;
 				break;
 			case CENTIMETERS:
 				returnValue = pixelValue * INCH2CM / display.getDPI().x;
 				break;
 			case PIXELS:
 				returnValue = pixelValue;
 		}

 		return numberFormatter.format(returnValue);
 	}


 	/**
 	 *
 	 * converts the current units used to a base unit value to be used (e.g. in validation)
 	 *
 	 * @param number Units to be converted to the base unit
 	 * @return
 	 */
 	private double convertToBase(double number) {

 		double returnValue = 0;
 		switch( getUnits() ) {
 			case INCHES:
 				returnValue = number;
 				break;
 			case CENTIMETERS:
 				returnValue = number / INCH2CM;
 				break;
 			case PIXELS:
 				returnValue = number / getControl().getDisplay().getDPI().x;
 		}
 		return returnValue;
 	}

 	private void updateUnits() {

 		int units = getUnits();

 		switch( units )
 		{
 			case INCHES:
                 gridSpacing.setLabelText(GRID_SPACING_LABEL_INCHES);
 				break;

 			case CENTIMETERS:
                 gridSpacing.setLabelText(GRID_SPACING_LABEL_CM);
 				break;

 			case PIXELS:
                 gridSpacing.setLabelText(GRID_SPACING_LABEL_PIXELS);
 				break;
 		}

 		gridSpacing.setStringValue( convertUnits( oldUnits, units ) );
 		oldUnits = units;

         dblGroup.layout();

 	}

 	private int getUnits() {
 		int units = rulerUnits.getComboControl().getSelectionIndex();

 		// IF no selection has been made
 		if( units == -1 ) {
 			// Read the preference store
 			units = getPreferenceStore().getInt(IPreferenceConstants.PREF_RULER_UNITS);
 			oldUnits = units;
 		}
 		return units;
 	}

 	private void addRulerFields( Composite parent ) {

 		// Create a Group to hold the ruler fields
     	Group group = new Group(parent, SWT.NONE);
 		group.setText(RULER_GROUP_LABEL);

 		GridLayout gridLayout = new GridLayout(2, false);
 		GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
 		gridData.grabExcessHorizontalSpace = true;
 		gridData.horizontalSpan = 2;

         // Add the fields to the group
 		showRulers = new BooleanFieldEditor(
 			IPreferenceConstants.PREF_SHOW_RULERS,
 			SHOW_RULERS_LABEL, group);
 		addField(showRulers);

     	rulerUnits = new ComboFieldEditor(
     		IPreferenceConstants.PREF_RULER_UNITS,
         	RULER_UNITS_LABEL,
 			group,
 			ComboFieldEditor.INT_TYPE,
 			false,
 			0,
 			0,
 			true);
     	addField(rulerUnits);

     	Combo rulerUnitsCombo;
     	rulerUnitsCombo = rulerUnits.getComboControl();
     	rulerUnitsCombo.add(RULER_UNITS_IN_LABEL);
     	rulerUnitsCombo.add(RULER_UNITS_CM_LABEL);
     	rulerUnitsCombo.add(RULER_UNITS_PIXEL_LABEL);

     	rulerUnitsCombo.addSelectionListener( new SelectionListener() {
     		public void widgetDefaultSelected(SelectionEvent e){
     			//do nothing
     			}
     		public void widgetSelected(SelectionEvent e){
     			updateUnits();
     		}
     	});

 		group.setLayoutData(gridData);
 		group.setLayout(gridLayout);
 	}

 	private void addGridFields( Composite parent ) {

 		// Create a Group to hold the grid fields
     	Group group = new Group(parent, SWT.NONE);
 		group.setText(GRID_GROUP_LABEL);

 		GridLayout gridLayout = new GridLayout(2, false);

 		GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
 		gridData.grabExcessHorizontalSpace = true;
 		gridData.horizontalSpan = 2;

 		showGrid = new BooleanFieldEditor(
 			IPreferenceConstants.PREF_SHOW_GRID,
 			SHOW_GRID_LABEL, group);
 		addField(showGrid);

 		snapToGrid = new BooleanFieldEditor(
 			IPreferenceConstants.PREF_SNAP_TO_GRID,
 			SNAP_TO_GRID_LABEL, group);
 		addField(snapToGrid);

 		snapToGeometry = new BooleanFieldEditor(
 				IPreferenceConstants.PREF_SNAP_TO_GEOMETRY,
 				SNAP_TO_GEOMETRY_LABEL, group);
 			addField(snapToGeometry);

 		addGridSpacing( group );

 		group.setLayoutData(gridData);
 		group.setLayout(gridLayout);
 	}

 	private void addGridSpacing( Composite parent ) {

 		dblGroup = new Composite(parent, SWT.NONE);

 		GridLayout gridLayout = new GridLayout(2, false);

 		GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
 		gridData.grabExcessHorizontalSpace = true;
 		gridData.horizontalSpan = 2;

 		gridSpacing = new DoubleFieldEditor(
 			IPreferenceConstants.PREF_GRID_SPACING,
 			GRID_SPACING_LABEL_INCHES, dblGroup);
 		gridSpacing.setTextLimit(10);
 		addField(gridSpacing);

 		updateUnits();

         dblGroup.setLayoutData(gridData);
         dblGroup.setLayout(gridLayout);
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.gmf.runtime.common.ui.preferences.AbstractPreferencePage#addFields(org.eclipse.swt.widgets.Composite)
 	 */
 	protected void addFields(Composite parent) {
 		addRulerFields( parent );
 		addGridFields( parent );
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.gmf.runtime.common.ui.preferences.AbstractPreferencePage#initHelp()
 	 */
 	protected void initHelp() {
 		// TODO: Implement to support context help
 	}

 	/**
 	 * Initializes the default preference values for the preferences.
 	 *
 	 * @param IPreferenceStore preferences
 	 */
 	public static void initDefaults(IPreferenceStore preferenceStore) {
 		preferenceStore.setDefault(IPreferenceConstants.PREF_SHOW_RULERS, false);
 		String defaultCountry = Locale.getDefault().getCountry();
 		if (defaultCountry == null
 				|| defaultCountry.equals(Locale.US.getCountry())
 				|| defaultCountry.equals(Locale.CANADA.getCountry())) {
 			preferenceStore.setDefault(IPreferenceConstants.PREF_RULER_UNITS,
 					RulerProvider.UNIT_INCHES);
 		} else {
 			preferenceStore.setDefault(IPreferenceConstants.PREF_RULER_UNITS,
 					RulerProvider.UNIT_CENTIMETERS);
 		}
 		preferenceStore.setDefault(IPreferenceConstants.PREF_SHOW_GRID, false);
 		preferenceStore.setDefault(IPreferenceConstants.PREF_SNAP_TO_GRID, true);
 		preferenceStore.setDefault(IPreferenceConstants.PREF_SNAP_TO_GEOMETRY, false);
 		preferenceStore.setDefault(IPreferenceConstants.PREF_GRID_SPACING, 0.125);
 	}

 	/**
 	 * The NumberFormatter.parse() could return a Long or Double
 	 * We are storing all values related to the page setup as doubles
 	 * so we call this function when ever we are getting values from
 	 * the dialog.
 	 * @param number
 	 * @return
 	 */
 	private Double forceDouble(Number number) {
 		if (!(number instanceof Double))
 			return new Double(number.doubleValue());
 		return (Double) number;
 	}

 }
	/******************************************************************************
	* Copyright (c) 2002, 2007 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
	****************************************************************************/


	package org.eclipse.gmf.runtime.diagram.ui.preferences;

	import java.text.ParseException;
	import java.text.ParsePosition;
	import java.util.Locale;

	import org.eclipse.gef.rulers.RulerProvider;
	import org.eclipse.gmf.runtime.common.ui.preferences.AbstractPreferencePage;
	import org.eclipse.gmf.runtime.common.ui.preferences.ComboFieldEditor;
	import org.eclipse.gmf.runtime.diagram.ui.l10n.DiagramUIMessages;
	import org.eclipse.jface.preference.BooleanFieldEditor;
	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.jface.preference.StringFieldEditor;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Combo;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Group;
	import org.eclipse.swt.widgets.Text;

	import com.ibm.icu.text.NumberFormat;


	/**
	* Diagram Ruler & Grid preference page.
	*
	* @author jschofie
	*/
	public class RulerGridPreferencePage
	extends AbstractPreferencePage {

	private class DoubleFieldEditor extends StringFieldEditor {

	private double minValidValue = 00.009;
	private double maxValidValue = 99.999;

	public DoubleFieldEditor(String pref, String label, Composite parent ) {
	super(pref,label,parent);
	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.preference.StringFieldEditor#doCheckState()
	*/
	protected boolean doCheckState() {
	Text text = getTextControl();

	if (text == null)
	return false;

	try {
	NumberFormat numberFormatter = NumberFormat.getInstance();
	ParsePosition parsePosition = new ParsePosition(0);
	Number parsedNumber = numberFormatter.parse(text.getText(), parsePosition);

	if (parsedNumber == null) {
	showErrorMessage();
	return false;
	}

	Double pageHeight = forceDouble(parsedNumber);
	double number = pageHeight.doubleValue();
	number = convertToBase(number);
	if (number >= minValidValue && number <= maxValidValue
	&& parsePosition.getIndex() == text.getText().length()) {
	clearErrorMessage();
	return true;
	} else {
	showErrorMessage();
	return false;
	}
	} catch (NumberFormatException e1) {
	showErrorMessage();
	}

	return false;
	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.preference.StringFieldEditor#doLoadDefault()
	*/
	protected void doLoadDefault() {
	Text text = getTextControl();
	if (text != null) {
	double value = getPreferenceStore().getDefaultDouble(getPreferenceName());
	NumberFormat numberFormatter = NumberFormat.getNumberInstance();
	text.setText(numberFormatter.format(value));
	}
	valueChanged();
	}

	/* (non-Javadoc)
	* Method declared on FieldEditor.
	*/
	protected void doLoad() {
	Text text = getTextControl();
	if (text != null) {
	double value = getPreferenceStore().getDouble(getPreferenceName());
	NumberFormat numberFormatter = NumberFormat.getNumberInstance();
	text.setText(numberFormatter.format(value));
	}
	}

	protected void doStore() {
	NumberFormat numberFormatter = NumberFormat.getInstance();
	Double gridWidth;
	try {
	gridWidth = forceDouble(numberFormatter.parse(getTextControl().getText()));
	getPreferenceStore().setValue(getPreferenceName(), gridWidth.doubleValue());
	} catch (ParseException e) {
	showErrorMessage();
	}

	}
	}

	private int oldUnits = -1;

	private static final int INCHES = 0;
	private static final int CENTIMETERS = 1;
	private static final int PIXELS = 2;

	// Conversion from inch to centimeter
	private static final double INCH2CM = 2.54;

	private String RULER_GROUP_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerGroup_label;
	private String SHOW_RULERS_LABEL = DiagramUIMessages.GridRulerPreferencePage_showRulers_label;
	private String RULER_UNITS_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_label;
	private String RULER_UNITS_IN_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_inch_label;
	private String RULER_UNITS_CM_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_cm_label;
	private String RULER_UNITS_PIXEL_LABEL = DiagramUIMessages.GridRulerPreferencePage_rulerUnits_pixel_label;

	private String GRID_GROUP_LABEL = DiagramUIMessages.GridRulerPreferencePage_gridGroup_label;
	private String SHOW_GRID_LABEL = DiagramUIMessages.GridRulerPreferencePage_showGrid_label;
	private String SNAP_TO_GRID_LABEL = DiagramUIMessages.GridRulerPreferencePage_snapToGrid_label;
	private String SNAP_TO_GEOMETRY_LABEL = DiagramUIMessages.GridRulerPreferencePage_snapToGeometry_label;
	private String GRID_SPACING_LABEL_INCHES = DiagramUIMessages.GridRulerPreferencePage_gridSpacing_label_inches;
	private String GRID_SPACING_LABEL_CM = DiagramUIMessages.GridRulerPreferencePage_gridSpacing_label_cm;
	private String GRID_SPACING_LABEL_PIXELS = DiagramUIMessages.GridRulerPreferencePage_gridSpacing_label_pixels;


	// Ruler Field Editors
	private BooleanFieldEditor showRulers = null;
	private ComboFieldEditor rulerUnits;

	// Grid Field Editors
	private BooleanFieldEditor showGrid = null;
	private BooleanFieldEditor snapToGrid = null;
	private BooleanFieldEditor snapToGeometry = null;
	private DoubleFieldEditor gridSpacing = null;
	private Composite dblGroup = null;

	private String convertUnits(int fromUnits, int toUnits ) {
	String valueStr = gridSpacing.getStringValue();
	if( fromUnits == toUnits ) {
	return valueStr;
	}

	//Double value = Double.valueOf( valueStr );
	NumberFormat numberFormatter = NumberFormat.getInstance();
	Double value = new Double(0.125);
	try {
	value = forceDouble(numberFormatter.parse(valueStr));
	} catch (ParseException e) {
	// Use the default
	}
	double pixelValue = 0;

	Display display = getControl().getDisplay();

	switch( fromUnits ) {
	case INCHES:
	pixelValue = value.doubleValue() * display.getDPI().x;
	break;
	case CENTIMETERS:
	pixelValue = value.doubleValue() * display.getDPI().x / INCH2CM;
	break;
	case PIXELS:
	pixelValue = value.intValue();
	}

	double returnValue = 0;

	switch( toUnits ) {
	case INCHES:
	returnValue = pixelValue / display.getDPI().x;
	break;
	case CENTIMETERS:
	returnValue = pixelValue * INCH2CM / display.getDPI().x;
	break;
	case PIXELS:
	returnValue = pixelValue;
	}

	return numberFormatter.format(returnValue);
	}


	/**
	*
	* converts the current units used to a base unit value to be used (e.g. in validation)
	*
	* @param number Units to be converted to the base unit
	* @return
	*/
	private double convertToBase(double number) {

	double returnValue = 0;
	switch( getUnits() ) {
	case INCHES:
	returnValue = number;
	break;
	case CENTIMETERS:
	returnValue = number / INCH2CM;
	break;
	case PIXELS:
	returnValue = number / getControl().getDisplay().getDPI().x;
	}
	return returnValue;
	}

	private void updateUnits() {

	int units = getUnits();

	switch( units )
	{
	case INCHES:
	gridSpacing.setLabelText(GRID_SPACING_LABEL_INCHES);
	break;

	case CENTIMETERS:
	gridSpacing.setLabelText(GRID_SPACING_LABEL_CM);
	break;

	case PIXELS:
	gridSpacing.setLabelText(GRID_SPACING_LABEL_PIXELS);
	break;
	}

	gridSpacing.setStringValue( convertUnits( oldUnits, units ) );
	oldUnits = units;

	dblGroup.layout();

	}

	private int getUnits() {
	int units = rulerUnits.getComboControl().getSelectionIndex();

	// IF no selection has been made
	if( units == -1 ) {
	// Read the preference store
	units = getPreferenceStore().getInt(IPreferenceConstants.PREF_RULER_UNITS);
	oldUnits = units;
	}
	return units;
	}

	private void addRulerFields( Composite parent ) {

	// Create a Group to hold the ruler fields
	Group group = new Group(parent, SWT.NONE);
	group.setText(RULER_GROUP_LABEL);

	GridLayout gridLayout = new GridLayout(2, false);
	GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
	gridData.grabExcessHorizontalSpace = true;
	gridData.horizontalSpan = 2;

	// Add the fields to the group
	showRulers = new BooleanFieldEditor(
	IPreferenceConstants.PREF_SHOW_RULERS,
	SHOW_RULERS_LABEL, group);
	addField(showRulers);

	rulerUnits = new ComboFieldEditor(
	IPreferenceConstants.PREF_RULER_UNITS,
	RULER_UNITS_LABEL,
	group,
	ComboFieldEditor.INT_TYPE,
	false,
	0,
	0,
	true);
	addField(rulerUnits);

	Combo rulerUnitsCombo;
	rulerUnitsCombo = rulerUnits.getComboControl();
	rulerUnitsCombo.add(RULER_UNITS_IN_LABEL);
	rulerUnitsCombo.add(RULER_UNITS_CM_LABEL);
	rulerUnitsCombo.add(RULER_UNITS_PIXEL_LABEL);

	rulerUnitsCombo.addSelectionListener( new SelectionListener() {
	public void widgetDefaultSelected(SelectionEvent e){
	//do nothing
	}
	public void widgetSelected(SelectionEvent e){
	updateUnits();
	}
	});

	group.setLayoutData(gridData);
	group.setLayout(gridLayout);
	}

	private void addGridFields( Composite parent ) {

	// Create a Group to hold the grid fields
	Group group = new Group(parent, SWT.NONE);
	group.setText(GRID_GROUP_LABEL);

	GridLayout gridLayout = new GridLayout(2, false);

	GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
	gridData.grabExcessHorizontalSpace = true;
	gridData.horizontalSpan = 2;

	showGrid = new BooleanFieldEditor(
	IPreferenceConstants.PREF_SHOW_GRID,
	SHOW_GRID_LABEL, group);
	addField(showGrid);

	snapToGrid = new BooleanFieldEditor(
	IPreferenceConstants.PREF_SNAP_TO_GRID,
	SNAP_TO_GRID_LABEL, group);
	addField(snapToGrid);

	snapToGeometry = new BooleanFieldEditor(
	IPreferenceConstants.PREF_SNAP_TO_GEOMETRY,
	SNAP_TO_GEOMETRY_LABEL, group);
	addField(snapToGeometry);

	addGridSpacing( group );

	group.setLayoutData(gridData);
	group.setLayout(gridLayout);
	}

	private void addGridSpacing( Composite parent ) {

	dblGroup = new Composite(parent, SWT.NONE);

	GridLayout gridLayout = new GridLayout(2, false);

	GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
	gridData.grabExcessHorizontalSpace = true;
	gridData.horizontalSpan = 2;

	gridSpacing = new DoubleFieldEditor(
	IPreferenceConstants.PREF_GRID_SPACING,
	GRID_SPACING_LABEL_INCHES, dblGroup);
	gridSpacing.setTextLimit(10);
	addField(gridSpacing);

	updateUnits();

	dblGroup.setLayoutData(gridData);
	dblGroup.setLayout(gridLayout);
	}

	/* (non-Javadoc)
	* @see org.eclipse.gmf.runtime.common.ui.preferences.AbstractPreferencePage#addFields(org.eclipse.swt.widgets.Composite)
	*/
	protected void addFields(Composite parent) {
	addRulerFields( parent );
	addGridFields( parent );
	}

	/* (non-Javadoc)
	* @see org.eclipse.gmf.runtime.common.ui.preferences.AbstractPreferencePage#initHelp()
	*/
	protected void initHelp() {
	// TODO: Implement to support context help
	}

	/**
	* Initializes the default preference values for the preferences.
	*
	* @param IPreferenceStore preferences
	*/
	public static void initDefaults(IPreferenceStore preferenceStore) {
	preferenceStore.setDefault(IPreferenceConstants.PREF_SHOW_RULERS, false);
	String defaultCountry = Locale.getDefault().getCountry();
	if (defaultCountry == null
	\|\| defaultCountry.equals(Locale.US.getCountry())
	\|\| defaultCountry.equals(Locale.CANADA.getCountry())) {
	preferenceStore.setDefault(IPreferenceConstants.PREF_RULER_UNITS,
	RulerProvider.UNIT_INCHES);
	} else {
	preferenceStore.setDefault(IPreferenceConstants.PREF_RULER_UNITS,
	RulerProvider.UNIT_CENTIMETERS);
	}
	preferenceStore.setDefault(IPreferenceConstants.PREF_SHOW_GRID, false);
	preferenceStore.setDefault(IPreferenceConstants.PREF_SNAP_TO_GRID, true);
	preferenceStore.setDefault(IPreferenceConstants.PREF_SNAP_TO_GEOMETRY, false);
	preferenceStore.setDefault(IPreferenceConstants.PREF_GRID_SPACING, 0.125);
	}

	/**
	* The NumberFormatter.parse() could return a Long or Double
	* We are storing all values related to the page setup as doubles
	* so we call this function when ever we are getting values from
	* the dialog.
	* @param number
	* @return
	*/
	private Double forceDouble(Number number) {
	if (!(number instanceof Double))
	return new Double(number.doubleValue());
	return (Double) number;
	}

	}