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

   1 /*******************************************************************************
   2  * Copyright (c) 2011, 2013 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  *   Francois Chouinard - Moved from LTTng to TMF
  12  *******************************************************************************/
  13
  14 package org.eclipse.linuxtools.tmf.ui.views.histogram;
  15
  16 import org.eclipse.swt.events.MouseEvent;
  17 import org.eclipse.swt.events.MouseWheelListener;
  18 import org.eclipse.swt.widgets.Canvas;
  19
  20 /**
  21  * Class to handle zooming within histogram windows..
  22  *
  23  * @version 1.0
  24  * @author Francois Chouinard
  25  * <p>
  26  */
  27 public class HistogramZoom implements MouseWheelListener {
  28
  29     // ------------------------------------------------------------------------
  30     // Constants
  31     // ------------------------------------------------------------------------
  32
  33     private final static double ZOOM_FACTOR = 0.8;
  34
  35     // ------------------------------------------------------------------------
  36     // Attributes
  37     // ------------------------------------------------------------------------
  38
  39     private final Histogram fHistogram;
  40     private final Canvas fCanvas;
  41
  42     private long fAbsoluteStartTime;
  43     private long fAbsoluteEndTime;
  44     private final long fMinWindowSize;
  45
  46     private long fRangeStartTime;
  47     private long fRangeDuration;
  48
  49     // ------------------------------------------------------------------------
  50     // Constructors
  51     // ------------------------------------------------------------------------
  52
  53     /**
  54      * Standard constructor.
  55      *
  56      * @param histogram
  57      *            The parent histogram object
  58      * @param canvas
  59      *            The canvas
  60      * @param start
  61      *            The start time of the zoom area
  62      * @param end
  63      *            The end time of the zoom area
  64      */
  65     public HistogramZoom(Histogram histogram, Canvas canvas, long start,
  66             long end) {
  67         fHistogram = histogram;
  68         fCanvas = canvas;
  69         fAbsoluteStartTime = start;
  70         fAbsoluteEndTime = end;
  71         fMinWindowSize = fCanvas.getBounds().x;
  72
  73         fRangeStartTime = fAbsoluteStartTime;
  74         fRangeDuration = fAbsoluteStartTime + fMinWindowSize;
  75
  76         canvas.addMouseWheelListener(this);
  77     }
  78
  79     // ------------------------------------------------------------------------
  80     // Accessors
  81     // ------------------------------------------------------------------------
  82
  83     /**
  84      * Get start time of the zoom window.
  85      * @return the start time.
  86      */
  87     public synchronized long getStartTime() {
  88         return fRangeStartTime;
  89     }
  90
  91     /**
  92      * Get the end time of the zoom window.
  93      * @return the end time
  94      */
  95     public synchronized long getEndTime() {
  96         return fRangeStartTime + fRangeDuration;
  97     }
  98
  99     /**
 100      * Get the duration of the zoom window.
 101      * @return the duration of the zoom window.
 102      */
 103     public synchronized long getDuration() {
 104         return fRangeDuration;
 105     }
 106
 107     // ------------------------------------------------------------------------
 108     // Operations
 109     // ------------------------------------------------------------------------
 110
 111     /**
 112      * The the full time range of the histogram
 113      *
 114      * @param startTime the start time the histogram
 115      * @param endTime the end time of the histogram
 116      */
 117     public synchronized void setFullRange(long startTime, long endTime) {
 118         fAbsoluteStartTime = startTime;
 119         fAbsoluteEndTime = endTime;
 120     }
 121
 122     /**
 123      * Sets the new zoom window
 124      * @param startTime the start time
 125      * @param duration the duration
 126      */
 127     public synchronized void setNewRange(long startTime, long duration) {
 128         long realStart = startTime;
 129
 130         if (realStart < fAbsoluteStartTime) {
 131             realStart = fAbsoluteStartTime;
 132         }
 133
 134         long endTime = realStart + duration;
 135         if (endTime > fAbsoluteEndTime) {
 136             endTime = fAbsoluteEndTime;
 137             if (endTime - duration > fAbsoluteStartTime) {
 138                 realStart = endTime - duration;
 139             } else {
 140                 realStart = fAbsoluteStartTime;
 141             }
 142         }
 143
 144         fRangeStartTime = realStart;
 145         fRangeDuration = endTime - realStart;
 146     }
 147
 148     // ------------------------------------------------------------------------
 149     // MouseWheelListener
 150     // ------------------------------------------------------------------------
 151
 152     @Override
 153     public synchronized void mouseScrolled(MouseEvent event) {
 154         zoom(event.count);
 155     }
 156
 157     private synchronized void zoom(int nbClicks) {
 158         // Compute the new time range
 159         long requestedRange = (nbClicks > 0) ? Math.round(ZOOM_FACTOR * fRangeDuration) : (long) Math.ceil(fRangeDuration * (1.0 / ZOOM_FACTOR));
 160
 161         // Distribute delta and adjust for boundaries
 162         long requestedStart = validateStart(fRangeStartTime + (fRangeDuration - requestedRange) / 2);
 163         long requestedEnd = validateEnd(requestedStart, requestedStart + requestedRange);
 164         requestedStart = validateStart(requestedEnd - requestedRange);
 165
 166         fHistogram.updateTimeRange(requestedStart, requestedEnd);
 167     }
 168
 169     private long validateStart(long start) {
 170         long realStart = start;
 171
 172         if (realStart < fAbsoluteStartTime) {
 173             realStart = fAbsoluteStartTime;
 174         }
 175         if (realStart > fAbsoluteEndTime) {
 176             realStart = fAbsoluteEndTime - fMinWindowSize;
 177         }
 178         return realStart;
 179     }
 180
 181     private long validateEnd(long start, long end) {
 182         long realEnd = end;
 183
 184         if (realEnd > fAbsoluteEndTime) {
 185             realEnd = fAbsoluteEndTime;
 186         }
 187         if (realEnd < start + fMinWindowSize) {
 188             realEnd = start + fMinWindowSize;
 189         }
 190         return realEnd;
 191     }
 192 }