org.eclipse.linuxtools.lttng.ui/src/org/eclipse/linuxtools/lttng/ui/views/histogram/ParentHistogramCanvasControlListener.java

   1 /*******************************************************************************
   2  * Copyright (c) 2009, 2010 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  *   2010-06-20 Yuriy Vashchuk - Initial API and implementation
  11  *
  12  * Modifications:
  13  * 2010-07-16 Yuriy Vashchuk - Base class simplification.
  14  *******************************************************************************/
  15
  16 package org.eclipse.linuxtools.lttng.ui.views.histogram;
  17
  18 import org.eclipse.swt.events.ControlEvent;
  19
  20 /**
  21  * <b><u>ParentHistogramCanvasControlListener</u></b>
  22  * <p>
  23  * Implementation of a ControlListener for the need of the ParentHistogramCanvas
  24  * <p>
  25  */
  26 public class ParentHistogramCanvasControlListener extends HistogramCanvasControlListener {
  27
  28         private ParentHistogramCanvas ourCanvas = null;
  29
  30         /**
  31          * ParentHistogramCanvasControlListenerl constructor
  32          *
  33          * @param newCanvas Related canvas
  34          */
  35         public ParentHistogramCanvasControlListener(ParentHistogramCanvas newCanvas) {
  36                 ourCanvas = newCanvas;
  37         }
  38
  39
  40         /**
  41          * Method called when the canvas is resized.<p>
  42          *
  43          * We need to tell the content that the canvas size changed and to recenter the windows
  44          *
  45          * @param event         The control event generated by the resize.
  46          */
  47         @Override
  48         public void controlResized(ControlEvent event) {
  49
  50                 if ( (ourCanvas != null) && (ourCanvas.getHistogramContent() != null) ) {
  51                         int newSize = ourCanvas.getSize().x;
  52                         int oldSize = ourCanvas.getHistogramContent().getCanvasWindowSize();
  53
  54                         // Set the new canvas size
  55                         ourCanvas.getHistogramContent().setCanvasWindowSize(newSize);
  56
  57                         // Try to recenter to window at the same place it was
  58                         // Note : this is a best hope approach and is not intended to be precise;
  59                         //              the idea is to avoid issuing a (maybe) long request fo the selection window;
  60                         // There WILL be slight discrepancy between the "window values" (timestamp, etc...) showed
  61                         //              and what it really points to. The user should reclick by himself to refresh it.
  62                         int oldWindowCenter = ourCanvas.getCurrentWindow().getWindowXPositionCenter();
  63                         int newWindowCenter = (int)Math.ceil((double)newSize * ((double)oldWindowCenter / (double)oldSize));
  64                         ourCanvas.setWindowCenterPosition(newWindowCenter);
  65                 }
  66         }
  67 }