org.eclipse.tips.ui/src/org/eclipse/tips/ui/internal/Slider.java - platform/eclipse.platform.ua - Git at Google

 /*******************************************************************************
  * Copyright (c) 2018 Remain Software
  * 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:
  *     wim.jongman@remainsoftware.com - initial API and implementation
  *******************************************************************************/
 package org.eclipse.tips.ui.internal;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.ImageData;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.tips.core.TipImage;
 import org.eclipse.tips.core.TipManager;
 import org.eclipse.tips.core.TipProvider;
 import org.eclipse.tips.core.TipProviderListener;
 import org.eclipse.tips.core.internal.LogUtil;
 import org.eclipse.tips.ui.internal.util.ImageUtil;
 import org.eclipse.tips.ui.internal.util.ResourceManager;
 import org.eclipse.tips.ui.internal.util.SWTResourceManager;

 @SuppressWarnings("restriction")
 public class Slider extends Composite {

 	private Composite fScroller;
 	private TipProvider fSelectedProvider;
 	private int fSpacing = 5;
 	private int fSliderIndex = 0;
 	private List<ProviderSelectionListener> fListeners = new ArrayList<>();
 	private TipManager fTipManager;
 	private Button fLeftButton;
 	private Button fRightButton;
 	private TipProviderListener fProviderListener;
 	private Composite fSelectedProviderButton;
 	private HashMap<String, Image> fProviderImageCache = new HashMap<>();
 	private int fIconSize = 48;

 	/**
 	 * Constructor for the Slider widget.
 	 *
 	 * @param parent
 	 *            the parent
 	 * @param style
 	 *            the SWT style bits
 	 */
 	public Slider(Composite parent, int style) {
 		super(parent, style);

 		GridLayout layout = new GridLayout(3, false);
 		layout.marginHeight = 0;
 		setLayout(layout);

 		fLeftButton = new Button(this, SWT.FLAT);
 		GridData gd_leftButton = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);
 		gd_leftButton.widthHint = fIconSize / 2 + 8;
 		gd_leftButton.heightHint = fIconSize;
 		fLeftButton.setLayoutData(gd_leftButton);
 		fLeftButton.setImage(getImage("icons/" + fIconSize + "/aleft.png"));
 		fLeftButton.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				scrollLeft();
 			}
 		});

 		fScroller = new Composite(this, SWT.DOUBLE_BUFFERED);
 		GridData layoutData = new GridData(SWT.FILL, SWT.FILL, true, true, 1, 1);
 		layoutData.heightHint = fIconSize + 4;
 		fScroller.setLayoutData(layoutData);

 		fRightButton = new Button(this, SWT.FLAT);
 		GridData gd_rightButton = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);
 		gd_rightButton.widthHint = fIconSize / 2 + 8;
 		gd_rightButton.heightHint = fIconSize;
 		fRightButton.setLayoutData(gd_rightButton);
 		fRightButton.setImage(getImage("icons/" + fIconSize + "/aright.png"));
 		fRightButton.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				scrollRight();
 			}
 		});

 		setupDisposeListener();
 		setupProviderListener();
 	}

 	private void setupDisposeListener() {
 		addListener(SWT.Dispose, event -> {
 			fTipManager.getListenerManager().removeProviderListener(fProviderListener);
 			fProviderImageCache.values().forEach(img -> {
 				if (!img.isDisposed()) {
 					img.dispose();
 				}
 			});
 		});
 	}

 	private void setupProviderListener() {
 		fProviderListener = provider -> getDisplay().asyncExec(() -> load());
 	}

 	private static Image getImage(String icon) {
 		return ResourceManager.getPluginImage("org.eclipse.tips.ui", icon);
 	}

 	/**
 	 * Loads or reloads the provider list. If you want to update the read count of
 	 * the current button or all buttons then check the {@link #updateButton()} and
 	 * {@link #updateButtons()} methods.
 	 *
 	 */
 	public void load() {
 		if (isDisposed() || fScroller.isDisposed()) {
 			return;
 		}
 		Arrays.stream(fScroller.getChildren()).filter(control -> !control.isDisposed())
 				.forEach(control -> control.dispose());
 		List<TipProvider> providers = fTipManager.getProviders();
 		int spaceCount = Math.floorDiv(fScroller.getBounds().width, (fIconSize + fSpacing));
 		int providerCount = providers.size();

 		if (fSliderIndex > 0 && spaceCount >= providerCount) {
 			fSliderIndex = 0;
 		}

 		if (spaceCount >= providerCount) {
 			if (fRightButton.isEnabled()) {
 				fRightButton.setEnabled(false);
 				fLeftButton.setEnabled(false);
 				fLeftButton.setImage(getImage("icons/" + fIconSize + "/aright.png"));
 				fRightButton.setImage(getImage("icons/" + fIconSize + "/aleft.png"));
 			}
 		} else {
 			if (!fRightButton.isEnabled()) {
 				fRightButton.setEnabled(true);
 				fLeftButton.setEnabled(true);
 				fLeftButton.setImage(getImage("icons/" + fIconSize + "/aleft.png"));
 				fRightButton.setImage(getImage("icons/" + fIconSize + "/aright.png"));
 			}
 		}

 		int emptyPixelsLeft = Math.floorMod(fScroller.getBounds().width, (fIconSize + fSpacing));
 		int newSpacing = fSpacing + (emptyPixelsLeft / (spaceCount + 1));
 		for (int i = 0; i < Math.min(providerCount - fSliderIndex, spaceCount); i++) {
 			TipProvider provider = providers.get(i + fSliderIndex);
 			if (fSelectedProvider == null && !provider.getTips(true).isEmpty()) {
 				fSelectedProvider = provider;
 				notifyListeners(fSelectedProvider);
 			}
 			createProviderButton(providers.get(i + fSliderIndex), newSpacing, i);
 		}
 	}

 	private Composite createProviderButton(TipProvider provider, int spacing, int index) {
 		Composite button = new Composite(fScroller, SWT.DOUBLE_BUFFERED);
 		button.setToolTipText(provider.getDescription());
 		button.setBackground(fScroller.getBackground());
 		button.setSize(fIconSize + 4, fIconSize + 4);
 		button.setLocation((index * (fIconSize + spacing) + spacing - fSpacing), 2);
 		button.addPaintListener(e -> {
 			if (fSelectedProvider == provider) {
 				fSelectedProviderButton = button;
 			}
 			paintButton(e.gc, button, provider);
 		});
 		button.addListener(SWT.MouseEnter, event -> button.redraw());
 		button.addListener(SWT.MouseExit, event -> button.redraw());
 		button.addListener(SWT.MouseUp, event -> {
 			if (fSelectedProvider == provider) {
 				return;
 			}
 			fSelectedProvider = provider;
 			if (fSelectedProviderButton != null && !fSelectedProviderButton.isDisposed()) {
 				fSelectedProviderButton.redraw();
 			}
 			fSelectedProviderButton = button;
 			fSelectedProviderButton.redraw();
 			notifyListeners(provider);
 		});
 		if (fSelectedProvider == provider) {
 			fSelectedProviderButton = button;
 		}
 		return button;
 	}

 	/**
 	 * Updates the read count of the currently selected button.
 	 */
 	public void updateButton() {
 		if (fSelectedProviderButton != null && !fSelectedProviderButton.isDisposed()) {
 			getDisplay().asyncExec(() -> fSelectedProviderButton.redraw());
 		}
 	}

 	/**
 	 * Calls redraw on all buttons to update the badge counter.
 	 */
 	public void updateButtons() {
 		if (!isDisposed()) {
 			getDisplay().asyncExec(() -> {
 				if (!fScroller.isDisposed()) {
 					for (Control control : fScroller.getChildren()) {
 						if (control instanceof Composite && !control.isDisposed()) {
 							control.redraw();
 						}
 					}
 				}
 			});
 		}
 	}

 	/**
 	 * Sets the {@link TipManager}.
 	 *
 	 * @param tipManager
 	 *            the {@link TipManager}
 	 * @return this
 	 */
 	public Slider setTipManager(TipManager tipManager) {
 		fTipManager = tipManager;
 		fTipManager.getListenerManager().addProviderListener(fProviderListener);
 		fIconSize = 48;
 		load();
 		return this;
 	}

 	private void notifyListeners(TipProvider provider) {
 		fListeners.forEach(listener -> {
 			try {
 				listener.selected(provider);
 			} catch (Exception e) {
 				fTipManager.log(LogUtil.error(getClass(), e));
 			}
 		});
 	}

 	@Override
 	public Point computeSize(int wHint, int hHint, boolean changed) {
 		Point point = new Point(fIconSize * 3, fIconSize + fSpacing + fSpacing);
 		return point;
 	}

 	protected void scrollRight() {
 		if (fSliderIndex < fTipManager.getProviders().size() - 1) {
 			fSliderIndex++;
 			load();
 		}
 	}

 	protected void scrollLeft() {
 		if (fSliderIndex > 0) {
 			fSliderIndex--;
 			load();
 		}
 	}

 	/**
 	 * @return the current selected {@link TipProvider}.
 	 */
 	public TipProvider getTipProvider() {
 		return fSelectedProvider;
 	}

 	/**
 	 * Sets the passed provider as the selected provider in the slider.
 	 *
 	 * @param provider
 	 *            the new provider for the slider.
 	 *
 	 * @return this
 	 */
 	public Slider setTipProvider(TipProvider provider) {
 		fSelectedProvider = provider;
 		updateButtons();
 		return this;
 	}

 	/**
 	 * Adds the listener to the list of listeners to be called when an event with a
 	 * {@link TipProvider} occurs.
 	 *
 	 * @param listener
 	 *            the {@link ProviderSelectionListener}
 	 * @return this
 	 */
 	public Slider addTipProviderListener(ProviderSelectionListener listener) {
 		fListeners.add(listener);
 		return this;
 	}

 	/**
 	 * Removes the listener from the list.
 	 *
 	 * @param listener
 	 *            the {@link ProviderSelectionListener}
 	 * @return this
 	 */
 	public Slider removeTipProviderListener(ProviderSelectionListener listener) {
 		fListeners.remove(listener);
 		return this;
 	}

 	private void paintButton(GC gc, Composite providerButton, TipProvider provider) {
 		gc.setAdvanced(true);
 		if (fSelectedProvider.equals(provider)) {
 			gc.setForeground(getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT));
 			gc.setBackground(getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION));
 			gc.drawRectangle(0, 0, fIconSize + 3, fIconSize + 3);
 		} else {
 			gc.setForeground(fLeftButton.getForeground());
 			gc.setBackground(fLeftButton.getBackground());
 			boolean mouseIn = getDisplay().getCursorControl() == providerButton;
 			if (mouseIn) {
 				gc.drawRectangle(0, 0, fIconSize + 3, fIconSize + 3);
 			} else {
 				gc.setBackground(fScroller.getBackground());
 			}
 		}
 		gc.fillRectangle(2, 2, fIconSize, fIconSize);
 		Image overlay = getUnreadOverlay(providerButton, provider);
 		gc.drawImage(overlay, 2, 2);
 		if (overlay != getProviderImage(provider, selectProviderImage(provider))) {
 			overlay.dispose();
 		}
 	}

 	private TipImage selectProviderImage(TipProvider provider) {
 		return provider.getImage();
 	}

 	private Image getProviderImage(TipProvider provider, TipImage image) {
 		if (!fProviderImageCache.containsKey(provider.getID())) {
 			try {
 				fProviderImageCache.put(provider.getID(),
 						new Image(getDisplay(), ImageUtil.decodeToImage(image.getBase64Image())));
 			} catch (Exception e) {
 				fTipManager.log(LogUtil.error(getClass(), e));
 				return null;
 			}
 		}
 		return fProviderImageCache.get(provider.getID());
 	}

 	private Image getUnreadOverlay(Composite providerButton, TipProvider provider) {
 		if (provider.getTips(true).isEmpty()) {
 			return getProviderImage(provider, selectProviderImage(provider));
 		}
 		GC gc2 = new GC(providerButton);
 		gc2.setAdvanced(true);
 		gc2.setFont(SWTResourceManager.getBoldFont(gc2.getFont()));
 		int tipCount = provider.getTips(true).size();
 		Point textExtent = gc2.textExtent(tipCount + "");
 		gc2.dispose();

 		Image image = null;
 		if (tipCount > 9) {
 			image = new Image(getDisplay(), textExtent.x + 8, textExtent.y + 5);
 		} else {
 			image = new Image(getDisplay(), textExtent.x + 15, textExtent.y + 5);
 		}
 		ImageData data = image.getImageData();
 		data.transparentPixel = data.getPixel(0, 0);
 		image.dispose();
 		image = new Image(getDisplay(), data);
 		GC gc = new GC(image);
 		gc.setAdvanced(true);
 		if (fTipManager.mustServeReadTips()) {
 			gc.setBackground(getDisplay().getSystemColor(SWT.COLOR_DARK_GREEN));
 		} else {
 			gc.setBackground(getDisplay().getSystemColor(SWT.COLOR_RED));
 		}
 		gc.setForeground(getDisplay().getSystemColor(SWT.COLOR_WHITE));
 		gc.setFont(SWTResourceManager.getBoldFont(gc.getFont()));
 		gc.setAlpha(210);
 		gc.setTextAntialias(SWT.ON);
 		if (tipCount > 9) {
 			gc.fillOval(0, 0, textExtent.x + 8, textExtent.y + 5);
 			gc.drawText(tipCount + "", 4, 2, true);
 		} else {
 			gc.fillOval(0, 0, textExtent.x + 15, textExtent.y + 5);
 			gc.drawText(tipCount + "", 8, 2, true);
 		}
 		Image result = ResourceManager.decorateImage(getProviderImage(provider, selectProviderImage(provider)), image,
 				SWTResourceManager.TOP_RIGHT);
 		image.dispose();
 		gc.dispose();
 		return result;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2018 Remain Software
	* 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:
	* wim.jongman@remainsoftware.com - initial API and implementation
	*******************************************************************************/
	package org.eclipse.tips.ui.internal;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.HashMap;
	import java.util.List;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.ImageData;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.tips.core.TipImage;
	import org.eclipse.tips.core.TipManager;
	import org.eclipse.tips.core.TipProvider;
	import org.eclipse.tips.core.TipProviderListener;
	import org.eclipse.tips.core.internal.LogUtil;
	import org.eclipse.tips.ui.internal.util.ImageUtil;
	import org.eclipse.tips.ui.internal.util.ResourceManager;
	import org.eclipse.tips.ui.internal.util.SWTResourceManager;

	@SuppressWarnings("restriction")
	public class Slider extends Composite {

	private Composite fScroller;
	private TipProvider fSelectedProvider;
	private int fSpacing = 5;
	private int fSliderIndex = 0;
	private List<ProviderSelectionListener> fListeners = new ArrayList<>();
	private TipManager fTipManager;
	private Button fLeftButton;
	private Button fRightButton;
	private TipProviderListener fProviderListener;
	private Composite fSelectedProviderButton;
	private HashMap<String, Image> fProviderImageCache = new HashMap<>();
	private int fIconSize = 48;

	/**
	* Constructor for the Slider widget.
	*
	* @param parent
	* the parent
	* @param style
	* the SWT style bits
	*/
	public Slider(Composite parent, int style) {
	super(parent, style);

	GridLayout layout = new GridLayout(3, false);
	layout.marginHeight = 0;
	setLayout(layout);

	fLeftButton = new Button(this, SWT.FLAT);
	GridData gd_leftButton = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);
	gd_leftButton.widthHint = fIconSize / 2 + 8;
	gd_leftButton.heightHint = fIconSize;
	fLeftButton.setLayoutData(gd_leftButton);
	fLeftButton.setImage(getImage("icons/" + fIconSize + "/aleft.png"));
	fLeftButton.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	scrollLeft();
	}
	});

	fScroller = new Composite(this, SWT.DOUBLE_BUFFERED);
	GridData layoutData = new GridData(SWT.FILL, SWT.FILL, true, true, 1, 1);
	layoutData.heightHint = fIconSize + 4;
	fScroller.setLayoutData(layoutData);

	fRightButton = new Button(this, SWT.FLAT);
	GridData gd_rightButton = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);
	gd_rightButton.widthHint = fIconSize / 2 + 8;
	gd_rightButton.heightHint = fIconSize;
	fRightButton.setLayoutData(gd_rightButton);
	fRightButton.setImage(getImage("icons/" + fIconSize + "/aright.png"));
	fRightButton.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	scrollRight();
	}
	});

	setupDisposeListener();
	setupProviderListener();
	}

	private void setupDisposeListener() {
	addListener(SWT.Dispose, event -> {
	fTipManager.getListenerManager().removeProviderListener(fProviderListener);
	fProviderImageCache.values().forEach(img -> {
	if (!img.isDisposed()) {
	img.dispose();
	}
	});
	});
	}

	private void setupProviderListener() {
	fProviderListener = provider -> getDisplay().asyncExec(() -> load());
	}

	private static Image getImage(String icon) {
	return ResourceManager.getPluginImage("org.eclipse.tips.ui", icon);
	}

	/**
	* Loads or reloads the provider list. If you want to update the read count of
	* the current button or all buttons then check the {@link #updateButton()} and
	* {@link #updateButtons()} methods.
	*
	*/
	public void load() {
	if (isDisposed() \|\| fScroller.isDisposed()) {
	return;
	}
	Arrays.stream(fScroller.getChildren()).filter(control -> !control.isDisposed())
	.forEach(control -> control.dispose());
	List<TipProvider> providers = fTipManager.getProviders();
	int spaceCount = Math.floorDiv(fScroller.getBounds().width, (fIconSize + fSpacing));
	int providerCount = providers.size();

	if (fSliderIndex > 0 && spaceCount >= providerCount) {
	fSliderIndex = 0;
	}

	if (spaceCount >= providerCount) {
	if (fRightButton.isEnabled()) {
	fRightButton.setEnabled(false);
	fLeftButton.setEnabled(false);
	fLeftButton.setImage(getImage("icons/" + fIconSize + "/aright.png"));
	fRightButton.setImage(getImage("icons/" + fIconSize + "/aleft.png"));
	}
	} else {
	if (!fRightButton.isEnabled()) {
	fRightButton.setEnabled(true);
	fLeftButton.setEnabled(true);
	fLeftButton.setImage(getImage("icons/" + fIconSize + "/aleft.png"));
	fRightButton.setImage(getImage("icons/" + fIconSize + "/aright.png"));
	}
	}

	int emptyPixelsLeft = Math.floorMod(fScroller.getBounds().width, (fIconSize + fSpacing));
	int newSpacing = fSpacing + (emptyPixelsLeft / (spaceCount + 1));
	for (int i = 0; i < Math.min(providerCount - fSliderIndex, spaceCount); i++) {
	TipProvider provider = providers.get(i + fSliderIndex);
	if (fSelectedProvider == null && !provider.getTips(true).isEmpty()) {
	fSelectedProvider = provider;
	notifyListeners(fSelectedProvider);
	}
	createProviderButton(providers.get(i + fSliderIndex), newSpacing, i);
	}
	}

	private Composite createProviderButton(TipProvider provider, int spacing, int index) {
	Composite button = new Composite(fScroller, SWT.DOUBLE_BUFFERED);
	button.setToolTipText(provider.getDescription());
	button.setBackground(fScroller.getBackground());
	button.setSize(fIconSize + 4, fIconSize + 4);
	button.setLocation((index * (fIconSize + spacing) + spacing - fSpacing), 2);
	button.addPaintListener(e -> {
	if (fSelectedProvider == provider) {
	fSelectedProviderButton = button;
	}
	paintButton(e.gc, button, provider);
	});
	button.addListener(SWT.MouseEnter, event -> button.redraw());
	button.addListener(SWT.MouseExit, event -> button.redraw());
	button.addListener(SWT.MouseUp, event -> {
	if (fSelectedProvider == provider) {
	return;
	}
	fSelectedProvider = provider;
	if (fSelectedProviderButton != null && !fSelectedProviderButton.isDisposed()) {
	fSelectedProviderButton.redraw();
	}
	fSelectedProviderButton = button;
	fSelectedProviderButton.redraw();
	notifyListeners(provider);
	});
	if (fSelectedProvider == provider) {
	fSelectedProviderButton = button;
	}
	return button;
	}

	/**
	* Updates the read count of the currently selected button.
	*/
	public void updateButton() {
	if (fSelectedProviderButton != null && !fSelectedProviderButton.isDisposed()) {
	getDisplay().asyncExec(() -> fSelectedProviderButton.redraw());
	}
	}

	/**
	* Calls redraw on all buttons to update the badge counter.
	*/
	public void updateButtons() {
	if (!isDisposed()) {
	getDisplay().asyncExec(() -> {
	if (!fScroller.isDisposed()) {
	for (Control control : fScroller.getChildren()) {
	if (control instanceof Composite && !control.isDisposed()) {
	control.redraw();
	}
	}
	}
	});
	}
	}

	/**
	* Sets the {@link TipManager}.
	*
	* @param tipManager
	* the {@link TipManager}
	* @return this
	*/
	public Slider setTipManager(TipManager tipManager) {
	fTipManager = tipManager;
	fTipManager.getListenerManager().addProviderListener(fProviderListener);
	fIconSize = 48;
	load();
	return this;
	}

	private void notifyListeners(TipProvider provider) {
	fListeners.forEach(listener -> {
	try {
	listener.selected(provider);
	} catch (Exception e) {
	fTipManager.log(LogUtil.error(getClass(), e));
	}
	});
	}

	@Override
	public Point computeSize(int wHint, int hHint, boolean changed) {
	Point point = new Point(fIconSize * 3, fIconSize + fSpacing + fSpacing);
	return point;
	}

	protected void scrollRight() {
	if (fSliderIndex < fTipManager.getProviders().size() - 1) {
	fSliderIndex++;
	load();
	}
	}

	protected void scrollLeft() {
	if (fSliderIndex > 0) {
	fSliderIndex--;
	load();
	}
	}

	/**
	* @return the current selected {@link TipProvider}.
	*/
	public TipProvider getTipProvider() {
	return fSelectedProvider;
	}

	/**
	* Sets the passed provider as the selected provider in the slider.
	*
	* @param provider
	* the new provider for the slider.
	*
	* @return this
	*/
	public Slider setTipProvider(TipProvider provider) {
	fSelectedProvider = provider;
	updateButtons();
	return this;
	}

	/**
	* Adds the listener to the list of listeners to be called when an event with a
	* {@link TipProvider} occurs.
	*
	* @param listener
	* the {@link ProviderSelectionListener}
	* @return this
	*/
	public Slider addTipProviderListener(ProviderSelectionListener listener) {
	fListeners.add(listener);
	return this;
	}

	/**
	* Removes the listener from the list.
	*
	* @param listener
	* the {@link ProviderSelectionListener}
	* @return this
	*/
	public Slider removeTipProviderListener(ProviderSelectionListener listener) {
	fListeners.remove(listener);
	return this;
	}

	private void paintButton(GC gc, Composite providerButton, TipProvider provider) {
	gc.setAdvanced(true);
	if (fSelectedProvider.equals(provider)) {
	gc.setForeground(getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT));
	gc.setBackground(getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION));
	gc.drawRectangle(0, 0, fIconSize + 3, fIconSize + 3);
	} else {
	gc.setForeground(fLeftButton.getForeground());
	gc.setBackground(fLeftButton.getBackground());
	boolean mouseIn = getDisplay().getCursorControl() == providerButton;
	if (mouseIn) {
	gc.drawRectangle(0, 0, fIconSize + 3, fIconSize + 3);
	} else {
	gc.setBackground(fScroller.getBackground());
	}
	}
	gc.fillRectangle(2, 2, fIconSize, fIconSize);
	Image overlay = getUnreadOverlay(providerButton, provider);
	gc.drawImage(overlay, 2, 2);
	if (overlay != getProviderImage(provider, selectProviderImage(provider))) {
	overlay.dispose();
	}
	}

	private TipImage selectProviderImage(TipProvider provider) {
	return provider.getImage();
	}

	private Image getProviderImage(TipProvider provider, TipImage image) {
	if (!fProviderImageCache.containsKey(provider.getID())) {
	try {
	fProviderImageCache.put(provider.getID(),
	new Image(getDisplay(), ImageUtil.decodeToImage(image.getBase64Image())));
	} catch (Exception e) {
	fTipManager.log(LogUtil.error(getClass(), e));
	return null;
	}
	}
	return fProviderImageCache.get(provider.getID());
	}

	private Image getUnreadOverlay(Composite providerButton, TipProvider provider) {
	if (provider.getTips(true).isEmpty()) {
	return getProviderImage(provider, selectProviderImage(provider));
	}
	GC gc2 = new GC(providerButton);
	gc2.setAdvanced(true);
	gc2.setFont(SWTResourceManager.getBoldFont(gc2.getFont()));
	int tipCount = provider.getTips(true).size();
	Point textExtent = gc2.textExtent(tipCount + "");
	gc2.dispose();

	Image image = null;
	if (tipCount > 9) {
	image = new Image(getDisplay(), textExtent.x + 8, textExtent.y + 5);
	} else {
	image = new Image(getDisplay(), textExtent.x + 15, textExtent.y + 5);
	}
	ImageData data = image.getImageData();
	data.transparentPixel = data.getPixel(0, 0);
	image.dispose();
	image = new Image(getDisplay(), data);
	GC gc = new GC(image);
	gc.setAdvanced(true);
	if (fTipManager.mustServeReadTips()) {
	gc.setBackground(getDisplay().getSystemColor(SWT.COLOR_DARK_GREEN));
	} else {
	gc.setBackground(getDisplay().getSystemColor(SWT.COLOR_RED));
	}
	gc.setForeground(getDisplay().getSystemColor(SWT.COLOR_WHITE));
	gc.setFont(SWTResourceManager.getBoldFont(gc.getFont()));
	gc.setAlpha(210);
	gc.setTextAntialias(SWT.ON);
	if (tipCount > 9) {
	gc.fillOval(0, 0, textExtent.x + 8, textExtent.y + 5);
	gc.drawText(tipCount + "", 4, 2, true);
	} else {
	gc.fillOval(0, 0, textExtent.x + 15, textExtent.y + 5);
	gc.drawText(tipCount + "", 8, 2, true);
	}
	Image result = ResourceManager.decorateImage(getProviderImage(provider, selectProviderImage(provider)), image,
	SWTResourceManager.TOP_RIGHT);
	image.dispose();
	gc.dispose();
	return result;
	}
	}