org.eclipse.tracecompass.tmf.ui/src/org/eclipse/linuxtools/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.linuxtools.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  * @since 3.0
  25  */
  26 public class TmfMouseWheelZoomProvider extends TmfBaseProvider implements MouseWheelListener {
  27
  28     // ------------------------------------------------------------------------
  29     // Constants
  30     // ------------------------------------------------------------------------
  31     private final static double ZOOM_FACTOR = 0.8;
  32     private final static long MIN_WINDOW_SIZE = 1;
  33
  34     // ------------------------------------------------------------------------
  35     // Constructors
  36     // ------------------------------------------------------------------------
  37     /**
  38      * Standard constructor.
  39      *
  40      * @param tmfChartViewer
  41      *            The parent histogram object
  42      */
  43     public TmfMouseWheelZoomProvider(ITmfChartTimeProvider tmfChartViewer) {
  44         super(tmfChartViewer);
  45         register();
  46     }
  47
  48     // ------------------------------------------------------------------------
  49     // TmfBaseProvider
  50     // ------------------------------------------------------------------------
  51     @Override
  52     public void register() {
  53         getChart().getPlotArea().addMouseWheelListener(this);
  54     }
  55
  56     @Override
  57     public void deregister() {
  58         if ((getChartViewer().getControl() != null) && !getChartViewer().getControl().isDisposed()) {
  59             getChart().getPlotArea().removeMouseWheelListener(this);
  60         }
  61     }
  62
  63     @Override
  64     public void refresh() {
  65         // nothing to do
  66     }
  67
  68     // ------------------------------------------------------------------------
  69     // MouseWheelListener
  70     // ------------------------------------------------------------------------
  71     @Override
  72     public synchronized void mouseScrolled(MouseEvent event) {
  73         ITmfChartTimeProvider viewer = getChartViewer();
  74
  75         long oldDuration = viewer.getWindowDuration();
  76
  77         if (oldDuration == 0) {
  78             return;
  79         }
  80
  81         // Compute the new time range
  82         long newDuration = oldDuration;
  83         double ratio = 1.0;
  84         if (event.count > 0) {
  85             ratio = ZOOM_FACTOR;
  86             newDuration = Math.round(ZOOM_FACTOR * oldDuration);
  87         } else {
  88             ratio = 1.0 / ZOOM_FACTOR;
  89             newDuration = (long) Math.ceil(oldDuration * ratio);
  90         }
  91         newDuration = Math.max(MIN_WINDOW_SIZE, newDuration);
  92
  93         // Center the zoom on mouse position, distribute new duration and adjust for boundaries.
  94         IAxis xAxis = getChart().getAxisSet().getXAxis(0);
  95         long timeAtXPos = limitXDataCoordinate(xAxis.getDataCoordinate(event.x)) + viewer.getTimeOffset();
  96         // Note: ratio = newDuration/oldDuration
  97         long newWindowStartTime = timeAtXPos - Math.round(ratio * (timeAtXPos - viewer.getWindowStartTime()));
  98         long newWindowEndTime = validateWindowEndTime(newWindowStartTime, newWindowStartTime + newDuration);
  99         newWindowStartTime = validateWindowStartTime(newWindowStartTime);
 100         viewer.updateWindow(newWindowStartTime, newWindowEndTime);
 101     }
 102
 103     // ------------------------------------------------------------------------
 104     // Helper methods
 105     // ------------------------------------------------------------------------
 106     private long validateWindowStartTime(long start) {
 107         ITmfChartTimeProvider viewer = getChartViewer();
 108         long realStart = start;
 109
 110         long startTime = viewer.getStartTime();
 111         long endTime = viewer.getEndTime();
 112
 113         if (realStart < startTime) {
 114             realStart = startTime;
 115         }
 116         if (realStart > endTime) {
 117             realStart = endTime;
 118         }
 119         return realStart;
 120     }
 121
 122     private long validateWindowEndTime(long start, long end) {
 123         ITmfChartTimeProvider viewer = getChartViewer();
 124         long realEnd = end;
 125         long endTime = viewer.getEndTime();
 126
 127         if (realEnd > endTime) {
 128             realEnd = endTime;
 129         }
 130         if (realEnd < start + MIN_WINDOW_SIZE) {
 131             realEnd = start + MIN_WINDOW_SIZE;
 132         }
 133         return realEnd;
 134     }
 135 }