ChartCanvas.java

/*******************************************************************************
 * Copyright (c) 2006, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Qi Liang (IBM Corporation)
 * 
 * Modified as explained in 
 *   http://www.eclipse.org/forums/index.php/mv/msg/171310/557779/#msg_557779
*******************************************************************************/
package net.sf.eclipsefp.haskell.profiler.internal.editors;

import net.sf.eclipsefp.haskell.profiler.ProfilerPlugin;
import net.sf.eclipsefp.haskell.profiler.internal.util.UITexts;

import org.eclipse.birt.chart.device.IDeviceRenderer;
import org.eclipse.birt.chart.exception.ChartException;
import org.eclipse.birt.chart.factory.GeneratedChartState;
import org.eclipse.birt.chart.factory.Generator;
import org.eclipse.birt.chart.model.Chart;
import org.eclipse.birt.chart.model.attribute.Bounds;
import org.eclipse.birt.chart.model.attribute.impl.BoundsImpl;
import org.eclipse.birt.chart.util.PluginSettings;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.swt.events.ControlAdapter;
import org.eclipse.swt.events.ControlEvent;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;

/**
 * The canvas to show chart.
 * 
 * @author Qi Liang
 */
public class ChartCanvas extends Canvas {

    /**
     * The device render for rendering chart.
     */
    protected IDeviceRenderer render = null;

    /**
     * The chart instantce.
     */
    protected Chart chart = null;

    /**
     * The chart state.
     */
    protected GeneratedChartState state = null;

    /**
     * The image which caches the chart image to improve drawing performance.
     */
    private Image cachedImage = null;

    /**
     * Constructs one canvas containing chart.
     * 
     * @param parent
     *            a composite control which will be the parent of the new
     *            instance (cannot be null)
     * @param style
     *            the style of control to construct
     */
    public ChartCanvas(Composite parent, int style) {
        super(parent, style);

        // initialize the SWT rendering device
        try {
            PluginSettings ps = PluginSettings.instance();
            render = ps.getDevice("dv.SWT");
            if (render!=null){
		        addPaintListener(new PaintListener() {
		
		            @Override
					public void paintControl(PaintEvent e) {
		
		                Composite co = (Composite) e.getSource();
		                final Rectangle rect = co.getClientArea();
		                
		                render.setProperty(IDeviceRenderer.GRAPHICS_CONTEXT, e.gc);
		
		                if (cachedImage == null) {
		                    buildChart();
		                    drawToCachedImage(rect);
		                }
		                e.gc.drawImage(cachedImage,
		                        0,
		                        0,
		                        cachedImage.getBounds().width,
		                        cachedImage.getBounds().height,
		                        0,
		                        0,
		                        rect.width,
		                        rect.height);
		
		            }
		        });
		
		        addControlListener(new ControlAdapter() {
		
		            @Override
					public void controlResized(ControlEvent e) {
		            	
		            	render.setProperty(IDeviceRenderer.GRAPHICS_CONTEXT, new GC(ChartCanvas.this));
		                buildChart();
		                cachedImage = null;
		            }
		        });
            }
        } catch (ChartException ex) {
            //ex.printStackTrace();
        	ProfilerPlugin.log(IStatus.ERROR, ex.getLocalizedMessage(), ex);
        }
    }
    

    public void rebuildChart() {
    	render.setProperty(IDeviceRenderer.GRAPHICS_CONTEXT, new GC(ChartCanvas.this));
        buildChart();
        cachedImage = null;
    }

    /**
     * Builds the chart state. This method should be call when data is changed.
     */
    private void buildChart() {
    	state=null;
        Point size = getSize();
        Bounds bo = BoundsImpl.create(0, 0, size.x, size.y);
        int resolution = render.getDisplayServer().getDpiResolution();
        bo.scale(72d / resolution);
        try {
        	Generator gr = Generator.instance();
            state = gr.build(render.getDisplayServer(),
                    chart,
                    bo,
                    null,null);
        } catch (ChartException ex) {
           ProfilerPlugin.log(IStatus.ERROR, UITexts.graph_generate_error, ex);
        }
    }

    /**
     * Draws the chart onto the cached image in the area of the given
     * <code>Rectangle</code>.
     * 
     * @param size
     *            the area to draw
     */
    public void drawToCachedImage(Rectangle size) {
        GC gc = null;
        try {
            if (cachedImage != null)
                cachedImage.dispose();
            cachedImage = new Image(Display.getCurrent(), size.width,
                    size.height);

            gc = new GC(cachedImage);
            render.setProperty(IDeviceRenderer.GRAPHICS_CONTEXT, gc);

            Generator gr = Generator.instance();
            if (state!=null){
            	gr.render(render, state);
            }
        } catch (ChartException ex) {
            ex.printStackTrace();
        } finally {
            if (gc != null)
                gc.dispose();
        }
    }

    /**
     * Returns the chart which is contained in this canvas.
     * 
     * @return the chart contained in this canvas.
     */
    public Chart getChart() {
        return chart;
    }

    /**
     * Sets the chart into this canvas. Note: When the chart is set, the cached
     * image will be dopped, but this method doesn't reset the flag
     * <code>cachedImage</code>.
     * 
     * @param chart
     *            the chart to set
     */
    public void setChart(Chart chart) {
        if (cachedImage != null)
            cachedImage.dispose();

        cachedImage = null;
        this.chart = chart;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.swt.widgets.Widget#dispose()
     */
    @Override
	public void dispose() {
        if (cachedImage != null)
            cachedImage.dispose();
        super.dispose();
    }

}