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

   1 /*******************************************************************************
   2  * Copyright (c) 2009 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  *   William Bourque - Initial API and implementation
  11  *******************************************************************************/
  12 package org.eclipse.linuxtools.lttng.ui.views.histogram;
  13
  14 import org.eclipse.swt.SWT;
  15 import org.eclipse.swt.events.KeyEvent;
  16 import org.eclipse.swt.events.KeyListener;
  17
  18 /**
  19  * <b><u>HistogramCanvasKeyListener</u></b>
  20  * <p>
  21  * Implementation of a KeyListener for the need of the HistogramCanvas
  22  * <p>
  23  */
  24 public class HistogramCanvasKeyListener implements KeyListener
  25 {
  26         protected HistogramCanvas parentCanvas = null;
  27         protected boolean isShiftPressed = false;
  28
  29         /**
  30          * HistogramCanvasKeyListener constructor
  31          *
  32          * @param newCanvas Related canvas
  33          */
  34         public HistogramCanvasKeyListener(HistogramCanvas newCanvas) {
  35                 parentCanvas = newCanvas;
  36         }
  37
  38         /**
  39          * Function that is called when a key is pressed.<p>
  40          * Possible actions :
  41          * - Left arrow  : move the selection window left.<p>
  42          * - Right arrow : move the selection window right.<p>
  43          * - Shift       : turn on "fast move" mode.<p>
  44          *
  45          * @param event  The KeyEvent generated when the key was pressed.
  46          */
  47         public void keyPressed(KeyEvent event) {
  48                 switch (event.keyCode) {
  49                         case SWT.SHIFT:
  50                                 isShiftPressed = true;
  51                                 break;
  52                         case SWT.ARROW_LEFT:
  53                                 moveWindowPosition(HistogramConstant.BASIC_DISPLACEMENT_FACTOR * -1);
  54                                 break;
  55                         case SWT.ARROW_RIGHT:
  56                                 moveWindowPosition(HistogramConstant.BASIC_DISPLACEMENT_FACTOR);
  57                                 break;
  58                         default:
  59                                 break;
  60                 }
  61         }
  62
  63         /**
  64          * Function that is called when a key is released.<p>
  65          * Possible actions :
  66          * - Shift  : turn off "fast move" mode.
  67          *
  68          * @param event  The KeyEvent generated when the key was pressed.
  69          */
  70         public void keyReleased(KeyEvent event) {
  71                 switch (event.keyCode) {
  72                         case SWT.SHIFT:
  73                                 isShiftPressed = false;
  74                                 break;
  75                         default:
  76                                 break;
  77                 }
  78         }
  79
  80         /**
  81          * Function to move the window position of a given displacemnt.<p>
  82          *
  83          * @param displacementFactor    The basic displacement to perform (positive or negative value)
  84          */
  85         public void moveWindowPosition(int displacementFactor) {
  86
  87                 // If we are in "fast move mode", multiply the basic displacement by a factor
  88                 if ( isShiftPressed == true ) {
  89                         displacementFactor = (int)((double)displacementFactor * HistogramConstant.FAST_DISPLACEMENT_MULTIPLE);
  90                 }
  91
  92                 parentCanvas.moveWindow(displacementFactor);
  93         }
  94
  95 }