tmf/org.eclipse.tracecompass.tmf.ui/src/org/eclipse/tracecompass/tmf/ui/viewers/xycharts/TmfMouseWheelZoomProvider.java

   1 /*******************************************************************************
   2  * Copyright (c) 2013, 2014 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  *   Bernd Hufmann - Initial API and implementation
  11  *******************************************************************************/
  12
  13 package org.eclipse.tracecompass.tmf.ui.viewers.xycharts;
  14
  15 import org.eclipse.swt.events.MouseEvent;
  16 import org.eclipse.swt.events.MouseWheelListener;
  17 import org.swtchart.IAxis;
  18
  19 /**
  20  * Class for providing zooming based on mouse wheel. It centers the zoom on
  21  * mouse position. It also notifies the viewer about a change of range.
  22  *
  23  * @author Bernd Hufmann
  24  */
  25 public class TmfMouseWheelZoomProvider extends TmfBaseProvider implements MouseWheelListener {
  26
  27     // ------------------------------------------------------------------------
  28     // Constants
  29     // ------------------------------------------------------------------------
  30     private static final double ZOOM_FACTOR = 0.8;
  31     private static final long MIN_WINDOW_SIZE = 1;
  32
  33     // ------------------------------------------------------------------------
  34     // Constructors
  35     // ------------------------------------------------------------------------
  36     /**
  37      * Standard constructor.
  38      *
  39      * @param tmfChartViewer
  40      *            The parent histogram object
  41      */
  42     public TmfMouseWheelZoomProvider(ITmfChartTimeProvider tmfChartViewer) {
  43         super(tmfChartViewer);
  44         register();
  45     }
  46
  47     // ------------------------------------------------------------------------
  48     // TmfBaseProvider
  49     // ------------------------------------------------------------------------
  50     @Override
  51     public void register() {
  52         getChart().getPlotArea().addMouseWheelListener(this);
  53     }
  54
  55     @Override
  56     public void deregister() {
  57         if ((getChartViewer().getControl() != null) && !getChartViewer().getControl().isDisposed()) {
  58             getChart().getPlotArea().removeMouseWheelListener(this);
  59         }
  60     }
  61
  62     @Override
  63     public void refresh() {
  64         // nothing to do
  65     }
  66
  67     // ------------------------------------------------------------------------
  68     // MouseWheelListener
  69     // ------------------------------------------------------------------------
  70     @Override
  71     public synchronized void mouseScrolled(MouseEvent event) {
  72         ITmfChartTimeProvider viewer = getChartViewer();
  73
  74         long oldDuration = viewer.getWindowDuration();
  75
  76         if (oldDuration == 0) {
  77             return;
  78         }
  79
  80         // Compute the new time range
  81         long newDuration = oldDuration;
  82         double ratio = 1.0;
  83         if (event.count > 0) {
  84             ratio = ZOOM_FACTOR;
  85             newDuration = Math.round(ZOOM_FACTOR * oldDuration);
  86         } else {
  87             ratio = 1.0 / ZOOM_FACTOR;
  88             newDuration = (long) Math.ceil(oldDuration * ratio);
  89         }
  90         newDuration = Math.max(MIN_WINDOW_SIZE, newDuration);
  91
  92         // Center the zoom on mouse position, distribute new duration and adjust for boundaries.
  93         IAxis xAxis = getChart().getAxisSet().getXAxis(0);
  94         long timeAtXPos = limitXDataCoordinate(xAxis.getDataCoordinate(event.x)) + viewer.getTimeOffset();
  95         // Note: ratio = newDuration/oldDuration
  96         long newWindowStartTime = timeAtXPos - Math.round(ratio * (timeAtXPos - viewer.getWindowStartTime()));
  97         long newWindowEndTime = validateWindowEndTime(newWindowStartTime, newWindowStartTime + newDuration);
  98         newWindowStartTime = validateWindowStartTime(newWindowStartTime);
  99         viewer.updateWindow(newWindowStartTime, newWindowEndTime);
 100     }
 101
 102     // ------------------------------------------------------------------------
 103     // Helper methods
 104     // ------------------------------------------------------------------------
 105     private long validateWindowStartTime(long start) {
 106         ITmfChartTimeProvider viewer = getChartViewer();
 107         long realStart = start;
 108
 109         long startTime = viewer.getStartTime();
 110         long endTime = viewer.getEndTime();
 111
 112         if (realStart < startTime) {
 113             realStart = startTime;
 114         }
 115         if (realStart > endTime) {
 116             realStart = endTime;
 117         }
 118         return realStart;
 119     }
 120
 121     private long validateWindowEndTime(long start, long end) {
 122         ITmfChartTimeProvider viewer = getChartViewer();
 123         long realEnd = end;
 124         long endTime = viewer.getEndTime();
 125
 126         if (realEnd > endTime) {
 127             realEnd = endTime;
 128         }
 129         if (realEnd < start + MIN_WINDOW_SIZE) {
 130             realEnd = start + MIN_WINDOW_SIZE;
 131         }
 132         return realEnd;
 133     }
 134 }