org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/Histogram.java

   1 /*******************************************************************************
   2  * Copyright (c) 2011, 2012 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Francois Chouinard - Initial API and implementation
  11  *   Bernd Hufmann - Changed to updated histogram data model
  12  *   Francois Chouinard - Reformat histogram labels on format change
  13  *******************************************************************************/
  14
  15 package org.eclipse.linuxtools.tmf.ui.views.histogram;
  16
  17 import org.eclipse.linuxtools.tmf.core.event.ITmfTimestamp;
  18 import org.eclipse.linuxtools.tmf.core.event.TmfTimestamp;
  19 import org.eclipse.linuxtools.tmf.core.event.TmfTimestampFormat;
  20 import org.eclipse.linuxtools.tmf.core.signal.TmfSignalHandler;
  21 import org.eclipse.linuxtools.tmf.core.signal.TmfSignalManager;
  22 import org.eclipse.linuxtools.tmf.core.signal.TmfTimestampFormatUpdateSignal;
  23 import org.eclipse.linuxtools.tmf.ui.views.TmfView;
  24 import org.eclipse.swt.SWT;
  25 import org.eclipse.swt.events.ControlEvent;
  26 import org.eclipse.swt.events.ControlListener;
  27 import org.eclipse.swt.events.KeyEvent;
  28 import org.eclipse.swt.events.KeyListener;
  29 import org.eclipse.swt.events.MouseEvent;
  30 import org.eclipse.swt.events.MouseListener;
  31 import org.eclipse.swt.events.MouseTrackListener;
  32 import org.eclipse.swt.events.PaintEvent;
  33 import org.eclipse.swt.events.PaintListener;
  34 import org.eclipse.swt.graphics.Color;
  35 import org.eclipse.swt.graphics.Font;
  36 import org.eclipse.swt.graphics.FontData;
  37 import org.eclipse.swt.graphics.GC;
  38 import org.eclipse.swt.graphics.Image;
  39 import org.eclipse.swt.graphics.Point;
  40 import org.eclipse.swt.graphics.Rectangle;
  41 import org.eclipse.swt.layout.FillLayout;
  42 import org.eclipse.swt.layout.GridData;
  43 import org.eclipse.swt.layout.GridLayout;
  44 import org.eclipse.swt.widgets.Canvas;
  45 import org.eclipse.swt.widgets.Composite;
  46 import org.eclipse.swt.widgets.Display;
  47 import org.eclipse.swt.widgets.Text;
  48
  49 /**
  50  * Re-usable histogram widget.
  51  *
  52  * It has the following features:
  53  * <ul>
  54  * <li>Y-axis labels displaying min/max count values
  55  * <li>X-axis labels displaying time range
  56  * <li>a histogram displaying the distribution of values over time (note that
  57  * the histogram might not necessarily fill the whole canvas)
  58  * </ul>
  59  * The widget also has 2 'markers' to identify:
  60  * <ul>
  61  * <li>a red dashed line over the bar that contains the currently selected event
  62  * <li>a dark red dashed line that delimits the right end of the histogram (if
  63  * it doesn't fill the canvas)
  64  * </ul>
  65  * Clicking on the histogram will select the current event at the mouse
  66  * location.
  67  * <p>
  68  * Once the histogram is selected, there is some limited keyboard support:
  69  * <ul>
  70  * <li>Home: go to the first histogram bar
  71  * <li>End: go to the last histogram bar
  72  * <li>Left: go to the previous histogram
  73  * <li>Right: go to the next histogram bar
  74  * </ul>
  75  * Finally, when the mouse hovers over the histogram, a tool tip showing the
  76  * following information about the corresponding histogram bar time range:
  77  * <ul>
  78  * <li>start of the time range
  79  * <li>end of the time range
  80  * <li>number of events in that time range
  81  * </ul>
  82  *
  83  * @version 1.1
  84  * @author Francois Chouinard
  85  */
  86 public abstract class Histogram implements ControlListener, PaintListener, KeyListener, MouseListener, MouseTrackListener, IHistogramModelListener {
  87
  88     // ------------------------------------------------------------------------
  89     // Constants
  90     // ------------------------------------------------------------------------
  91
  92     // Histogram colors
  93     private final Color fBackgroundColor = Display.getCurrent().getSystemColor(SWT.COLOR_WHITE);
  94     private final Color fCurrentEventColor = Display.getCurrent().getSystemColor(SWT.COLOR_RED);
  95     private final Color fLastEventColor = Display.getCurrent().getSystemColor(SWT.COLOR_DARK_RED);
  96     private final Color fHistoBarColor = new Color(Display.getDefault(), 74, 112, 139);
  97
  98     // ------------------------------------------------------------------------
  99     // Attributes
 100     // ------------------------------------------------------------------------
 101
 102     /**
 103      * The parent TMF view.
 104      */
 105     protected TmfView fParentView;
 106
 107     private Composite fParent;
 108     private Font fFont;
 109
 110     // Histogram text fields
 111     private Text fMaxNbEventsText;
 112     private Text fMinNbEventsText;
 113     private Text fTimeRangeStartText;
 114     private Text fTimeRangeEndText;
 115
 116     /**
 117      *  Histogram drawing area
 118      */
 119     protected Canvas fCanvas;
 120
 121     /**
 122      *  The histogram data model.
 123      */
 124     protected final HistogramDataModel fDataModel;
 125
 126     /**
 127      * The histogram data model scaled to current resolution and screen width.
 128      */
 129     protected HistogramScaledData fScaledData;
 130
 131     /**
 132      * The current event value
 133      */
 134     protected long fCurrentEventTime = 0L;
 135
 136     // ------------------------------------------------------------------------
 137     // Construction
 138     // ------------------------------------------------------------------------
 139
 140     /**
 141      * Full constructor.
 142      *
 143      * @param view A reference to the parent TMF view.
 144      * @param parent A parent composite
 145      */
 146     public Histogram(final TmfView view, final Composite parent) {
 147         fParentView = view;
 148         fParent = parent;
 149
 150         createWidget(parent);
 151         fDataModel = new HistogramDataModel();
 152         fDataModel.addHistogramListener(this);
 153         clear();
 154
 155         fCanvas.addControlListener(this);
 156         fCanvas.addPaintListener(this);
 157         fCanvas.addKeyListener(this);
 158         fCanvas.addMouseListener(this);
 159         fCanvas.addMouseTrackListener(this);
 160
 161         TmfSignalManager.register(this);
 162     }
 163
 164     /**
 165      * Dispose resources and unregisters listeners.
 166      */
 167     public void dispose() {
 168         TmfSignalManager.deregister(this);
 169
 170         fHistoBarColor.dispose();
 171         fDataModel.removeHistogramListener(this);
 172     }
 173
 174     private void createWidget(final Composite parent) {
 175
 176         final Color labelColor = parent.getBackground();
 177         fFont = adjustFont(parent);
 178
 179         final int initalWidth = 10;
 180
 181         // --------------------------------------------------------------------
 182         // Define the histogram
 183         // --------------------------------------------------------------------
 184
 185         final GridLayout gridLayout = new GridLayout();
 186         gridLayout.numColumns = 3;
 187         gridLayout.marginHeight = 0;
 188         gridLayout.marginWidth = 0;
 189         gridLayout.marginTop = 0;
 190         gridLayout.horizontalSpacing = 0;
 191         gridLayout.verticalSpacing = 0;
 192         gridLayout.marginLeft = 0;
 193         gridLayout.marginRight = 0;
 194         final Composite composite = new Composite(parent, SWT.FILL);
 195         composite.setLayout(gridLayout);
 196
 197         // Use all the horizontal space
 198         GridData gridData = new GridData();
 199         gridData.horizontalAlignment = SWT.FILL;
 200         gridData.verticalAlignment = SWT.FILL;
 201         gridData.grabExcessHorizontalSpace = true;
 202         composite.setLayoutData(gridData);
 203
 204         // Y-axis max event
 205         gridData = new GridData();
 206         gridData.horizontalAlignment = SWT.RIGHT;
 207         gridData.verticalAlignment = SWT.TOP;
 208         fMaxNbEventsText = new Text(composite, SWT.READ_ONLY | SWT.RIGHT);
 209         fMaxNbEventsText.setFont(fFont);
 210         fMaxNbEventsText.setBackground(labelColor);
 211         fMaxNbEventsText.setEditable(false);
 212         fMaxNbEventsText.setText("0"); //$NON-NLS-1$
 213         fMaxNbEventsText.setLayoutData(gridData);
 214
 215         // Histogram itself
 216         Composite canvasComposite = new Composite(composite, SWT.BORDER);
 217         gridData = new GridData();
 218         gridData.horizontalSpan = 2;
 219         gridData.verticalSpan = 2;
 220         gridData.horizontalAlignment = SWT.FILL;
 221         gridData.verticalAlignment = SWT.FILL;
 222         gridData.grabExcessHorizontalSpace = true;
 223         canvasComposite.setLayoutData(gridData);
 224         canvasComposite.setLayout(new FillLayout());
 225         fCanvas = new Canvas(canvasComposite, SWT.DOUBLE_BUFFERED);
 226
 227         // Y-axis min event (always 0...)
 228         gridData = new GridData();
 229         gridData.horizontalAlignment = SWT.RIGHT;
 230         gridData.verticalAlignment = SWT.BOTTOM;
 231         fMinNbEventsText = new Text(composite, SWT.READ_ONLY | SWT.RIGHT);
 232         fMinNbEventsText.setFont(fFont);
 233         fMinNbEventsText.setBackground(labelColor);
 234         fMinNbEventsText.setEditable(false);
 235         fMinNbEventsText.setText("0"); //$NON-NLS-1$
 236         fMinNbEventsText.setLayoutData(gridData);
 237
 238         // Dummy cell
 239         gridData = new GridData(initalWidth, SWT.DEFAULT);
 240         gridData.horizontalAlignment = SWT.RIGHT;
 241         gridData.verticalAlignment = SWT.BOTTOM;
 242         final Text dummyText = new Text(composite, SWT.READ_ONLY);
 243         dummyText.setFont(fFont);
 244         dummyText.setBackground(labelColor);
 245         dummyText.setEditable(false);
 246         dummyText.setText(""); //$NON-NLS-1$
 247         dummyText.setLayoutData(gridData);
 248
 249         // Window range start time
 250         gridData = new GridData();
 251         gridData.horizontalAlignment = SWT.LEFT;
 252         gridData.verticalAlignment = SWT.BOTTOM;
 253         fTimeRangeStartText = new Text(composite, SWT.READ_ONLY);
 254         fTimeRangeStartText.setFont(fFont);
 255         fTimeRangeStartText.setBackground(labelColor);
 256         fTimeRangeStartText.setText(TmfTimestamp.ZERO.toString());
 257         fTimeRangeStartText.setLayoutData(gridData);
 258
 259         // Window range end time
 260         gridData = new GridData();
 261         gridData.horizontalAlignment = SWT.RIGHT;
 262         gridData.verticalAlignment = SWT.BOTTOM;
 263         fTimeRangeEndText = new Text(composite, SWT.READ_ONLY);
 264         fTimeRangeEndText.setFont(fFont);
 265         fTimeRangeEndText.setBackground(labelColor);
 266         fTimeRangeEndText.setText(TmfTimestamp.ZERO.toString());
 267         fTimeRangeEndText.setLayoutData(gridData);
 268     }
 269
 270     private static Font adjustFont(final Composite composite) {
 271         // Reduce font size for a more pleasing rendering
 272         final int fontSizeAdjustment = -2;
 273         final Font font = composite.getFont();
 274         final FontData fontData = font.getFontData()[0];
 275         return new Font(font.getDevice(), fontData.getName(), fontData.getHeight() + fontSizeAdjustment, fontData.getStyle());
 276     }
 277
 278     // ------------------------------------------------------------------------
 279     // Accessors
 280     // ------------------------------------------------------------------------
 281
 282     /**
 283      * Returns the start time (equal first bucket time)
 284      * @return the start time.
 285      */
 286     public long getStartTime() {
 287         return fDataModel.getFirstBucketTime();
 288     }
 289
 290     /**
 291      * Returns the end time.
 292      * @return the end time.
 293      */
 294     public long getEndTime() {
 295         return fDataModel.getEndTime();
 296     }
 297
 298     /**
 299      * Returns the time limit (end of last bucket)
 300      * @return the time limit.
 301      */
 302     public long getTimeLimit() {
 303         return fDataModel.getTimeLimit();
 304     }
 305
 306     /**
 307      * Returns a data model reference.
 308      * @return data model.
 309      */
 310     public HistogramDataModel getDataModel() {
 311         return fDataModel;
 312     }
 313
 314     // ------------------------------------------------------------------------
 315     // Operations
 316     // ------------------------------------------------------------------------
 317     /**
 318      * Updates the time range.
 319      * @param startTime A start time
 320      * @param endTime A end time.
 321      */
 322     public abstract void updateTimeRange(long startTime, long endTime);
 323
 324     /**
 325      * Clear the histogram and reset the data
 326      */
 327     public void clear() {
 328         fDataModel.clear();
 329         fScaledData = null;
 330     }
 331
 332     /**
 333      * Increase the histogram bucket corresponding to [timestamp]
 334      *
 335      * @param eventCount
 336      *            The new event count
 337      * @param timestamp
 338      *            The latest timestamp
 339      */
 340     public void countEvent(final long eventCount, final long timestamp) {
 341         fDataModel.countEvent(eventCount, timestamp);
 342     }
 343
 344     /**
 345      * Sets the current event time and refresh the display
 346      *
 347      * @param timestamp
 348      *            The time of the current event
 349      */
 350     public void setCurrentEvent(final long timestamp) {
 351         fCurrentEventTime = (timestamp > 0) ? timestamp : 0;
 352         fDataModel.setCurrentEventNotifyListeners(timestamp);
 353     }
 354
 355     /**
 356      * Computes the timestamp of the bucket at [offset]
 357      *
 358      * @param offset offset from the left on the histogram
 359      * @return the start timestamp of the corresponding bucket
 360      */
 361     public synchronized long getTimestamp(final int offset) {
 362         assert offset > 0 && offset < fScaledData.fWidth;
 363         try {
 364             return fDataModel.getFirstBucketTime() + fScaledData.fBucketDuration * offset;
 365         } catch (final Exception e) {
 366             return 0; // TODO: Fix that racing condition (NPE)
 367         }
 368     }
 369
 370     /**
 371      * Computes the offset of the timestamp in the histogram
 372      *
 373      * @param timestamp the timestamp
 374      * @return the offset of the corresponding bucket (-1 if invalid)
 375      */
 376     public synchronized int getOffset(final long timestamp) {
 377         if (timestamp < fDataModel.getFirstBucketTime() || timestamp > fDataModel.getEndTime()) {
 378             return -1;
 379         }
 380         return (int) ((timestamp - fDataModel.getFirstBucketTime()) / fScaledData.fBucketDuration);
 381     }
 382
 383     /**
 384      * Move the currently selected bar cursor to a non-empty bucket.
 385      *
 386      * @param keyCode the SWT key code
 387      */
 388     protected void moveCursor(final int keyCode) {
 389
 390         if (fScaledData.fCurrentBucket == HistogramScaledData.OUT_OF_RANGE_BUCKET) {
 391             return;
 392         }
 393
 394         int index;
 395         switch (keyCode) {
 396
 397             case SWT.HOME:
 398                 index = 0;
 399                 while (index < fScaledData.fLastBucket && fScaledData.fData[index] == 0) {
 400                     index++;
 401                 }
 402                 if (index < fScaledData.fLastBucket) {
 403                     fScaledData.fCurrentBucket = index;
 404                 }
 405                 break;
 406
 407             case SWT.ARROW_RIGHT:
 408                 index = fScaledData.fCurrentBucket + 1;
 409                 while (index < fScaledData.fWidth && fScaledData.fData[index] == 0) {
 410                     index++;
 411                 }
 412                 if (index < fScaledData.fLastBucket) {
 413                     fScaledData.fCurrentBucket = index;
 414                 }
 415                 break;
 416
 417             case SWT.END:
 418                 index = fScaledData.fLastBucket;
 419                 while (index >= 0 && fScaledData.fData[index] == 0) {
 420                     index--;
 421                 }
 422                 if (index >= 0) {
 423                     fScaledData.fCurrentBucket = index;
 424                 }
 425                 break;
 426
 427             case SWT.ARROW_LEFT:
 428                 index = fScaledData.fCurrentBucket - 1;
 429                 while (index >= 0 && fScaledData.fData[index] == 0) {
 430                     index--;
 431                 }
 432                 if (index >= 0) {
 433                     fScaledData.fCurrentBucket = index;
 434                 }
 435                 break;
 436
 437             default:
 438                 return;
 439         }
 440
 441         updateCurrentEventTime();
 442     }
 443
 444     /**
 445      * Refresh the histogram display
 446      */
 447     @Override
 448     public void modelUpdated() {
 449         if (!fCanvas.isDisposed() && fCanvas.getDisplay() != null) {
 450             fCanvas.getDisplay().asyncExec(new Runnable() {
 451                 @Override
 452                 public void run() {
 453                     if (!fCanvas.isDisposed()) {
 454                         // Retrieve and normalize the data
 455                         final int canvasWidth = fCanvas.getBounds().width;
 456                         final int canvasHeight = fCanvas.getBounds().height;
 457                         if (canvasWidth <= 0 || canvasHeight <= 0) {
 458                             return;
 459                         }
 460                         fDataModel.setCurrentEvent(fCurrentEventTime);
 461                         fScaledData = fDataModel.scaleTo(canvasWidth, canvasHeight, 1);
 462                         synchronized(fScaledData) {
 463                             if (fScaledData != null) {
 464                                 fCanvas.redraw();
 465                                 // Display histogram and update X-,Y-axis labels
 466                                 fTimeRangeStartText.setText(TmfTimestampFormat.getDefaulTimeFormat().format(fDataModel.getFirstBucketTime()));
 467                                 fTimeRangeEndText.setText(TmfTimestampFormat.getDefaulTimeFormat().format(fDataModel.getEndTime()));
 468                                 fMaxNbEventsText.setText(Long.toString(fScaledData.fMaxValue));
 469                                 // The Y-axis area might need to be re-sized
 470                                 fMaxNbEventsText.getParent().layout();
 471                             }
 472                         }
 473                     }
 474                 }
 475             });
 476         }
 477     }
 478
 479     // ------------------------------------------------------------------------
 480     // Helper functions
 481     // ------------------------------------------------------------------------
 482
 483     private void updateCurrentEventTime() {
 484         final long bucketStartTime = getTimestamp(fScaledData.fCurrentBucket);
 485         ((HistogramView) fParentView).updateCurrentEventTime(bucketStartTime);
 486     }
 487
 488     // ------------------------------------------------------------------------
 489     // PaintListener
 490     // ------------------------------------------------------------------------
 491     /**
 492      * Image key string for the canvas.
 493      */
 494     protected final String IMAGE_KEY = "double-buffer-image"; //$NON-NLS-1$
 495
 496     @Override
 497     public void paintControl(final PaintEvent event) {
 498
 499         // Get the geometry
 500         final int canvasWidth = fCanvas.getBounds().width;
 501         final int canvasHeight = fCanvas.getBounds().height;
 502
 503         // Make sure we have something to draw upon
 504         if (canvasWidth <= 0 || canvasHeight <= 0) {
 505             return;
 506         }
 507
 508         // Retrieve image; re-create only if necessary
 509         Image image = (Image) fCanvas.getData(IMAGE_KEY);
 510         if (image == null || image.getBounds().width != canvasWidth || image.getBounds().height != canvasHeight) {
 511             image = new Image(event.display, canvasWidth, canvasHeight);
 512             fCanvas.setData(IMAGE_KEY, image);
 513         }
 514
 515         // Draw the histogram on its canvas
 516         final GC imageGC = new GC(image);
 517         formatImage(imageGC, image);
 518         event.gc.drawImage(image, 0, 0);
 519         imageGC.dispose();
 520     }
 521
 522     private void formatImage(final GC imageGC, final Image image) {
 523
 524         if (fScaledData == null) {
 525             return;
 526         }
 527
 528         final HistogramScaledData scaledData = new HistogramScaledData(fScaledData);
 529
 530         try {
 531             // Get drawing boundaries
 532             final int width = image.getBounds().width;
 533             final int height = image.getBounds().height;
 534
 535             // Clear the drawing area
 536             imageGC.setBackground(fBackgroundColor);
 537             imageGC.fillRectangle(0, 0, image.getBounds().width + 1, image.getBounds().height + 1);
 538
 539             // Draw the histogram bars
 540             imageGC.setBackground(fHistoBarColor);
 541             final int limit = width < scaledData.fWidth ? width : scaledData.fWidth;
 542             for (int i = 0; i < limit; i++) {
 543                 final int value = (int) Math.ceil(scaledData.fData[i] * scaledData.fScalingFactor);
 544                 imageGC.fillRectangle(i, height - value, 1, value);
 545             }
 546
 547             // Draw the current event bar
 548             final int currentBucket = scaledData.fCurrentBucket;
 549             if (currentBucket >= 0 && currentBucket < limit) {
 550                 drawDelimiter(imageGC, fCurrentEventColor, height, currentBucket);
 551             }
 552
 553             // Add a dashed line as a delimiter (at the right of the last bar)
 554             int lastEventIndex = limit - 1;
 555             while (lastEventIndex >= 0 && scaledData.fData[lastEventIndex] == 0) {
 556                 lastEventIndex--;
 557             }
 558             lastEventIndex += (lastEventIndex < limit - 1) ? 1 : 0;
 559             drawDelimiter(imageGC, fLastEventColor, height, lastEventIndex);
 560         } catch (final Exception e) {
 561             // Do nothing
 562         }
 563     }
 564
 565     private static void drawDelimiter(final GC imageGC, final Color color,
 566             final int height, final int index) {
 567         imageGC.setBackground(color);
 568         final int dash = height / 4;
 569         imageGC.fillRectangle(index, 0 * dash, 1, dash - 1);
 570         imageGC.fillRectangle(index, 1 * dash, 1, dash - 1);
 571         imageGC.fillRectangle(index, 2 * dash, 1, dash - 1);
 572         imageGC.fillRectangle(index, 3 * dash, 1, height - 3 * dash);
 573     }
 574
 575     // ------------------------------------------------------------------------
 576     // KeyListener
 577     // ------------------------------------------------------------------------
 578
 579     @Override
 580     public void keyPressed(final KeyEvent event) {
 581         moveCursor(event.keyCode);
 582     }
 583
 584     @Override
 585     public void keyReleased(final KeyEvent event) {
 586     }
 587
 588     // ------------------------------------------------------------------------
 589     // MouseListener
 590     // ------------------------------------------------------------------------
 591
 592     @Override
 593     public void mouseDoubleClick(final MouseEvent event) {
 594     }
 595
 596     @Override
 597     public void mouseDown(final MouseEvent event) {
 598         if (fDataModel.getNbEvents() > 0 && fScaledData.fLastBucket >= event.x) {
 599             fScaledData.fCurrentBucket = event.x;
 600             updateCurrentEventTime();
 601         }
 602     }
 603
 604     @Override
 605     public void mouseUp(final MouseEvent event) {
 606     }
 607
 608     // ------------------------------------------------------------------------
 609     // MouseTrackListener
 610     // ------------------------------------------------------------------------
 611
 612     @Override
 613     public void mouseEnter(final MouseEvent event) {
 614     }
 615
 616     @Override
 617     public void mouseExit(final MouseEvent event) {
 618     }
 619
 620     @Override
 621     public void mouseHover(final MouseEvent event) {
 622         if (fDataModel.getNbEvents() > 0 && fScaledData != null && fScaledData.fLastBucket >= event.x) {
 623             final String tooltip = formatToolTipLabel(event.x);
 624             fCanvas.setToolTipText(tooltip);
 625         }
 626     }
 627
 628     private String formatToolTipLabel(final int index) {
 629         long startTime = fScaledData.getBucketStartTime(index);
 630         // negative values are possible if time values came into the model in decreasing order
 631         if (startTime < 0) {
 632             startTime = 0;
 633         }
 634         final long endTime = fScaledData.getBucketEndTime(index);
 635         final int nbEvents = (index >= 0) ? fScaledData.fData[index] : 0;
 636
 637         final StringBuffer buffer = new StringBuffer();
 638         buffer.append("Range = ["); //$NON-NLS-1$
 639         buffer.append(new TmfTimestamp(startTime, ITmfTimestamp.NANOSECOND_SCALE).toString());
 640         buffer.append(","); //$NON-NLS-1$
 641         buffer.append(new TmfTimestamp(endTime, ITmfTimestamp.NANOSECOND_SCALE).toString());
 642         buffer.append(")\n"); //$NON-NLS-1$
 643         buffer.append("Event count = "); //$NON-NLS-1$
 644         buffer.append(nbEvents);
 645         return buffer.toString();
 646     }
 647
 648     // ------------------------------------------------------------------------
 649     // ControlListener
 650     // ------------------------------------------------------------------------
 651
 652     @Override
 653     public void controlMoved(final ControlEvent event) {
 654         fDataModel.complete();
 655     }
 656
 657     @Override
 658     public void controlResized(final ControlEvent event) {
 659         fDataModel.complete();
 660     }
 661
 662     // ------------------------------------------------------------------------
 663     // Signal Handlers
 664     // ------------------------------------------------------------------------
 665
 666     /**
 667      * Format the timestamp and update the display
 668      *
 669      * @param signal the incoming signal
 670      * @since 2.0
 671      */
 672     @TmfSignalHandler
 673     public void timestampFormatUpdated(TmfTimestampFormatUpdateSignal signal) {
 674         Point size = fTimeRangeStartText.getSize();
 675         String newTS = TmfTimestampFormat.getDefaulTimeFormat().format(fDataModel.getFirstBucketTime());
 676         size.x = getTextSize(newTS);
 677         fTimeRangeStartText.setSize(size);
 678         fTimeRangeStartText.setText(newTS);
 679
 680         newTS = TmfTimestampFormat.getDefaulTimeFormat().format(fDataModel.getEndTime());
 681         Rectangle rect = fTimeRangeEndText.getBounds();
 682         int newWidth = getTextSize(newTS);
 683         rect.x += rect.width - newWidth;
 684         rect.width = newWidth;
 685         fTimeRangeEndText.setBounds(rect);
 686         fTimeRangeEndText.setText(newTS);
 687     }
 688
 689     /**
 690      * Compute the width of a String.
 691      *
 692      * @param text the Text to measure
 693      * @return The result size
 694      * @since 2.0
 695      */
 696     private int getTextSize(final String text) {
 697         GC controlGC = new GC(fParent);
 698         controlGC.setFont(fFont);
 699
 700         int textSize = 0;
 701         for (int pos = 0; pos < text.length(); pos++) {
 702             textSize += controlGC.getAdvanceWidth(text.charAt(pos));
 703         }
 704         // Add an extra space
 705         textSize += controlGC.getAdvanceWidth(' ');
 706
 707         controlGC.dispose();
 708
 709         return textSize;
 710     }
 711
 712 }