RemoteCLIDisplay.java

/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.motorola.studio.android.emulator.ui.controls;

import java.util.Timer;
import java.util.TimerTask;

import org.eclipse.sequoyah.vnc.vncviewer.graphics.swt.ISWTPainter;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;

import com.motorola.studio.android.emulator.core.model.IAndroidEmulatorInstance;

/**
 * DESCRIPTION:
 * This class implements the composite that displays the contents of the
 * CLI display, according to the provided painter object.
 *
 * RESPONSIBILITY:
 * - Display the contents of the CLI display at screen
 *
 * COLABORATORS:
 * None.
 *
 * USAGE:
 * Add the composite to a view or other equivalent SWT object for it to
 * display the result of the communication through VNC Protocol
 *
 */
public class RemoteCLIDisplay extends Composite
{
    private Canvas canvas;

    private Image screen = null;

    private ISWTPainter painter;

    private Timer refreshTimer;

    private static long FIRST_REFRESH_DELAY_MS = 500; /* Time in milliseconds for the first update */

    private static long REFRESH_DELAY_PERIOD_MS = 300; /* Time in milliseconds between 2 updates */

    private boolean active = false;

    private double zoomFactor = 1;

    /**
     * Creates a new RemoteCLIDisplay object.
     *
     * @param parent The parent composite
     * @param cliPainter The object where to retrieve pixels from
     */
    public RemoteCLIDisplay(Composite parent, ISWTPainter cliPainter)
    {
        super(parent, SWT.BACKGROUND);
        this.painter = cliPainter;
        this.setLayout(parent.getLayout());
        canvas = new Canvas(this, SWT.BACKGROUND);
    }

    /**
     * Starts the display refresh
     */
    synchronized public void start()
    {
        addRefreshTimer();
        setRunning(true);
    }

    /**
     * Stops the display refresh
     */
    synchronized public void stop()
    {
        setRunning(false);
        refreshTimer.cancel();

        if (!canvas.isDisposed())
        {
            GC gc = new GC(canvas);
            canvas.drawBackground(gc, 0, 0, canvas.getSize().x, canvas.getSize().y);
            gc.dispose();
        }
    }

    /**
     * Adds a timer that schedules the screen's update in a fixed period.
     */
    private void addRefreshTimer()
    {
        refreshTimer = new Timer();

        final IAndroidEmulatorInstance instance = UIHelper.getInstanceAssociatedToControl(this);

        refreshTimer.scheduleAtFixedRate(new TimerTask()
        {
            @Override
            public void run()
            {
                if (instance.getHasCli())
                {
                    // Request CLI Update here (when applicable)

                    getDisplay().syncExec(new Runnable()
                    {
                        public void run()
                        {
                            updateScreen();
                        }
                    });
                }
            }
        }, FIRST_REFRESH_DELAY_MS, REFRESH_DELAY_PERIOD_MS);
    }

    /**
     * Performs the screen update itself
     */
    private void updateScreen()
    {
        if (screen != null)
        {
            screen.dispose();
        }

        if ((!getDisplay().isDisposed()) && (isDisplayActive()))
        {
            if ((painter.getImageData() != null) && (!canvas.isDisposed()))
            {
                screen =
                        new Image(canvas.getDisplay(), painter.getImageData().scaledTo(
                                (int) (painter.getImageData().width * zoomFactor),
                                (int) (painter.getImageData().height * zoomFactor)));

                GC gc = new GC(canvas);
                gc.drawImage(screen, 0, 0);
                gc.dispose();
            }
        }
        else
        {
            stop();
        }
    }

    /**
     * Returns true if the component is running.
     */
    synchronized public boolean isDisplayActive()
    {
        return active;
    }

    /**
     * Gets the Canvas used to show the screen.
     *
     * @return the Canvas object.
     */
    public Canvas getCanvas()
    {
        return canvas;
    }

    /**
     * Retrieves the image being drawn at display
     *
     * @return The image being drawn at display
     */
    public Image getScreen()
    {
        return screen;
    }

    /**
     * Retrieves the display width
     *
     * @return The display width
     */
    public int getScreenWidth()
    {
        return painter.getWidth();
    }

    /**
     * Retrieves the display height
     *
     * @return The display height
     */
    public int getScreenHeight()
    {
        return painter.getHeight();
    }

    /**
     * Sets the current state of the display
     *
     * @param running true if the display is refreshing; false otherwise
     */
    synchronized private void setRunning(boolean running)
    {
        this.active = running;
    }

    /**
     * @see org.eclipse.swt.widgets.Widget#dispose()
     */
    @Override
    public void dispose()
    {
        if (isDisplayActive())
        {
            stop();
        }

        if (screen != null)
        {
            screen.dispose();
        }

        canvas.dispose();
        super.dispose();
    }

    /**
     * @see org.eclipse.swt.widgets.Control#setBackground(Color)
     */
    @Override
    public void setBackground(Color color)
    {
        super.setBackground(color);
        canvas.setBackground(color);
    }

    /**
     * Retrieves the current zoom factor being applied to the screen
     *
     * @return The current zoom factor
     */
    public double getZoomFactor()
    {
        return zoomFactor;
    }

    /**
     * Sets a new zoom factor to the screen
     *
     * @param zoomFactor The zoom factor to set to the screen
     */
    public void setZoomFactor(double zoomFactor)
    {
        this.zoomFactor = zoomFactor;

        IAndroidEmulatorInstance instance = UIHelper.getInstanceAssociatedToControl(this);
        if (instance.getHasCli())
        {
            updateScreen();
        }
    }
}