org.eclipse.linuxtools.lttng.ui/src/org/eclipse/linuxtools/lttng/ui/views/histogram/HistogramCanvasPaintListener.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.events.PaintEvent;
  15 import org.eclipse.swt.events.PaintListener;
  16 import org.eclipse.swt.graphics.Rectangle;
  17
  18 /**
  19  * <b><u>HistogramCanvasPaintListener</u></b>
  20  * <p>
  21  * Implementation of a PaintListener for the need of the HistogramCanvas
  22  * <p>
  23  */
  24 public class HistogramCanvasPaintListener implements PaintListener
  25 {
  26         protected HistogramCanvas  parentCanvas = null;
  27
  28         /**
  29          * HistogramCanvasPaintListener constructor
  30          *
  31          * @param parentCanvas Related canvas
  32          */
  33         public HistogramCanvasPaintListener(HistogramCanvas newParentCanvas) {
  34                 parentCanvas = newParentCanvas;
  35         }
  36
  37         /**
  38          * Function called when the canvas need to redraw.<p>
  39          *
  40          * @param event  The generated paint event when redraw is called.
  41          */
  42         public void paintControl(PaintEvent event) {
  43
  44                 // First clear the whole canvas to have a clean section where to draw
  45                 clearDrawingSection(event);
  46
  47                 // If the content is null or has rady to draw we quit the function here
  48                 if ( (parentCanvas.getHistogramContent() == null) || (parentCanvas.getHistogramContent().getReadyUpToPosition() == 0) ) {
  49                         return;
  50                 }
  51
  52                 // Call the function that draw the bars
  53                 drawHistogram(event);
  54
  55                 // Pinpoint a position if set
  56                 if (parentCanvas.getHistogramContent().getSelectedEventTimeInWindow() > 0 ) {
  57                         drawSelectedEventInWindow(event);
  58                 }
  59
  60                 // If we have a selected window set to visible, call the function to draw it
  61                 if ( (parentCanvas.getCurrentWindow()  != null) && (parentCanvas.getCurrentWindow().getSelectedWindowVisible() == true) ) {
  62                         drawSelectedWindow(event);
  63                 }
  64         }
  65
  66         /**
  67          * Clear the drawing section of the canvas<p>
  68          * This paint the whole background in EMPTY_BACKGROUND_COLOR, so we have something clean to draw on.
  69          *
  70          * @param event The generated paint event when redraw is called.
  71          */
  72         public void clearDrawingSection(PaintEvent event) {
  73                 event.gc.setForeground(event.display.getSystemColor(HistogramConstant.EMPTY_BACKGROUND_COLOR));
  74                 event.gc.setBackground(event.display.getSystemColor(HistogramConstant.EMPTY_BACKGROUND_COLOR));
  75                 Rectangle allSection = new Rectangle(0, 0, event.width, event.height);
  76                 event.gc.fillRectangle(allSection);
  77                 event.gc.drawRectangle(allSection);
  78         }
  79
  80         // *** VERIFY ***
  81         // Is it good to put this synchronized?
  82         //
  83         /**
  84          * Draw the histogram bars in the canvas.<p>
  85          * Use existing elements in HistogramContent to draw bars on the cancas;
  86          *      the element table in content need to be populated and have consistent value.
  87          *
  88          * @param event The generated paint event when redraw is called.
  89          */
  90         public synchronized void drawHistogram(PaintEvent event) {
  91                 HistogramContent tmpContent = parentCanvas.getHistogramContent();
  92                 int tmpBarWidth = tmpContent.getBarsWidth();
  93
  94                 // This will be the color for all the bars that wil be draw below.
  95                 event.gc.setBackground(event.display.getSystemColor(HistogramConstant.HISTOGRAM_BARS_COLOR));
  96
  97                 // *** NOTE ***
  98                 // Y Position in a canvas is REVERSED, so "0" is on top of the screen and "MAX" is on bottom.
  99                 // Not very instinctive, isn't it?
 100
 101                 // Draw a bar from the left (pos X=0) until the pos=(NbBars*barWidth). If space is left, it will be blanked after.
 102             for ( int x=0; x<tmpContent.getReadyUpToPosition(); x++) {
 103                 Rectangle rect = new Rectangle(tmpBarWidth*x, event.height - tmpContent.getElementByIndex(x).intervalHeight, tmpBarWidth, tmpContent.getElementByIndex(x).intervalHeight);
 104                 event.gc.fillRectangle(rect);
 105             }
 106
 107             // Clear the remaining space in the canvas (if any) so it appears clean.
 108             event.gc.setBackground(event.display.getSystemColor(HistogramConstant.EMPTY_BACKGROUND_COLOR));
 109             Rectangle rect = new Rectangle(tmpBarWidth*tmpContent.getNbElement(), 0, event.width, event.height);
 110             event.gc.fillRectangle(rect);
 111         }
 112
 113         /**
 114          * Draw a certain event selected in the window.<p>
 115          *
 116          * @param event The generated paint event when redraw is called.
 117          */
 118         public synchronized void drawSelectedEventInWindow(PaintEvent event) {
 119                 HistogramContent tmpContent = parentCanvas.getHistogramContent();
 120                 int tmpBarWidth = tmpContent.getBarsWidth();
 121
 122                 // This will be the color for all the bars that wil be draw below.
 123                 event.gc.setBackground(event.display.getSystemColor(HistogramConstant.SELECTED_EVENT_COLOR));
 124
 125                 int position = tmpContent.getClosestXPositionFromTimestamp(tmpContent.getSelectedEventTimeInWindow());
 126
 127                 Rectangle rect = new Rectangle(tmpBarWidth*position, 0, tmpBarWidth, event.height);
 128                 event.gc.fillRectangle(rect);
 129         }
 130
 131         /**
 132          * Draw the selection window in the canvas.<p>
 133          * This draw a square around the selected section with a crosshair in the middle.
 134          * The square cannot be smaller than "MINIMUM_WINDOW_WIDTH"
 135          *
 136          * @param event The generated paint event when redraw is called.
 137          */
 138         public void drawSelectedWindow(PaintEvent event) {
 139                 HistogramSelectedWindow tmpWindow = parentCanvas.getCurrentWindow();
 140
 141                 // Attributes (color and width) of the lines
 142                 event.gc.setForeground(event.display.getSystemColor(HistogramConstant.SELECTION_WINDOW_COLOR));
 143                 event.gc.setLineWidth(HistogramConstant.SELECTION_LINE_WIDTH);
 144
 145                 // Get the window position... this would fail if the window is not initialized yet
 146                 int positionCenter = tmpWindow.getWindowXPositionCenter();
 147                 int positionLeft = tmpWindow.getWindowXPositionLeft();
 148                 int positionRight = tmpWindow.getWindowXPositionRight();
 149
 150                 // Minimal size verification.
 151                 if ( (positionRight - positionLeft) < HistogramConstant.MINIMUM_WINDOW_WIDTH ) {
 152                         positionLeft  = positionCenter - (HistogramConstant.MINIMUM_WINDOW_WIDTH/2);
 153                         positionRight = positionCenter + (HistogramConstant.MINIMUM_WINDOW_WIDTH/2);
 154                 }
 155
 156                 // Draw the selection window square
 157                 event.gc.drawLine(positionLeft , 0               , positionLeft , event.height);
 158                 event.gc.drawLine(positionLeft , event.height, positionRight, event.height);
 159                 event.gc.drawLine(positionRight, event.height, positionRight, 0);
 160                 event.gc.drawLine(positionLeft , 0               , positionRight, 0);
 161
 162                 // Draw the crosshair section
 163                 event.gc.drawLine(positionCenter + HistogramConstant.SELECTION_CROSSHAIR_LENGTH, event.height/2, positionCenter - HistogramConstant.SELECTION_CROSSHAIR_LENGTH, event.height/2);
 164                 event.gc.drawLine(positionCenter, (event.height/2) + HistogramConstant.SELECTION_CROSSHAIR_LENGTH, positionCenter, (event.height/2) - HistogramConstant.SELECTION_CROSSHAIR_LENGTH);
 165         }
 166
 167 }