Added latency analysis feature (bug 331467)

[deliverable/tracecompass.git] / org.eclipse.linuxtools.lttng.ui / src / org / eclipse / linuxtools / lttng / ui / views / latency / listeners / ZoomListener.java

/*******************************************************************************\r
 * Copyright (c) 2011 Ericsson\r
 * \r
 * All rights reserved. This program and the accompanying materials are\r
 * made available under the terms of the Eclipse Public License v1.0 which\r
 * accompanies this distribution, and is available at\r
 * http://www.eclipse.org/legal/epl-v10.html\r
 * \r
 * Contributors:\r
 *   Philippe Sawicki (INF4990.A2010@gmail.com)   - Initial API and implementation\r
 *   Mathieu Denis    (mathieu.denis55@gmail.com) - Refactored code\r
 *******************************************************************************/\r
package org.eclipse.linuxtools.lttng.ui.views.latency.listeners;\r
\r
import org.eclipse.linuxtools.lttng.ui.views.latency.AbstractViewer;\r
import org.eclipse.swt.SWT;\r
import org.eclipse.swt.widgets.Canvas;\r
import org.eclipse.swt.widgets.Event;\r
import org.eclipse.swt.widgets.Listener;\r
\r
/**\r
 * <b><u>ZoomListener</u></b>\r
 * <p>\r
 * \r
 * Canvas zoom listener.\r
 * \r
 * @author Philippe Sawicki\r
 */\r
public class ZoomListener implements Listener {\r
\r
    // ------------------------------------------------------------------------\r
    // Attributes\r
    // ------------------------------------------------------------------------\r
\r
    /**\r
     * A reference to the observed view.\r
     */\r
    protected AbstractViewer fView;\r
    /**\r
     * Default zoom factor.\r
     */\r
    protected int fZoomFactor;\r
    /**\r
     * Zoom increment.\r
     */\r
    protected int fZoomIncrement = 30;\r
\r
    // ------------------------------------------------------------------------\r
    // Constructors\r
    // ------------------------------------------------------------------------\r
\r
    /**\r
     * Constructor.\r
     * @param view\r
     *            A reference to the observed view.\r
     * @param defaultZoomFactor\r
     *            Default zoom factor.\r
     */\r
    public ZoomListener(AbstractViewer view, int defaultZoomFactor) {\r
        fView = view;\r
        fZoomFactor = defaultZoomFactor;\r
    }\r
\r
    /**\r
     * Constructor.\r
     * @param view\r
     *            A reference to the observed view.\r
     */\r
    public ZoomListener(AbstractViewer view) {\r
        this(view, 1);\r
    }\r
\r
    // ------------------------------------------------------------------------\r
    // Accessors\r
    // ------------------------------------------------------------------------\r
\r
    /**\r
     * Returns the zoom factor.\r
     * @return The zoom factor.\r
     */\r
    public int getZoomFactor() {\r
        if (fZoomFactor < 1)\r
            return 1;\r
        else\r
            return fZoomFactor;\r
    }\r
\r
    /**\r
     * Returns the zoom increment.\r
     * @return The zoom increment.\r
     */\r
    public int getZoomIncrement() {\r
        return fZoomIncrement;\r
    }\r
    \r
    // ------------------------------------------------------------------------\r
    // Operations\r
    // ------------------------------------------------------------------------\r
    \r
    /*\r
     * (non-Javadoc)\r
     * @see org.eclipse.swt.widgets.Listener#handleEvent(org.eclipse.swt.widgets.Event)\r
     */\r
    @Override\r
    public void handleEvent(Event event) {\r
        switch (event.type) {\r
            case SWT.MouseWheel:\r
                boolean scrollDown = (event.count == 0 ? false : (event.count > 0 ? false : true));\r
                int zoomStep = fZoomIncrement;\r
                if (scrollDown)\r
                    zoomStep = -fZoomIncrement;\r
                fZoomFactor = Math.max(0, fZoomFactor + zoomStep);\r
\r
                Canvas canvas = (Canvas) event.widget;\r
                if (fView != null) {\r
                    // clear the background to allow redraw of values of the vertical axis.\r
                    fView.clearBackground();\r
                    fView.redrawTitle();\r
                    fView.askForRedraw();\r
                }\r
                canvas.redraw();\r
                break;\r
        }\r
    }\r
\r
    /**\r
     * Sets the zoom increment.\r
     * @param zoomIncrement\r
     *            The new zoom increment.\r
     */\r
    public void setZoomIncrement(int zoomIncrement) {\r
        fZoomIncrement = zoomIncrement;\r
    }\r
}