EmbeddedImageRefresh.java

package com.vaadin.tests.components.embedded;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;

import javax.imageio.ImageIO;

import com.vaadin.server.StreamResource;
import com.vaadin.tests.components.TestBase;
import com.vaadin.ui.Button;
import com.vaadin.ui.Button.ClickEvent;
import com.vaadin.ui.Embedded;

public class EmbeddedImageRefresh extends TestBase {
    @Override
    protected String getDescription() {
        return "Tests if requestRepaint() makes the browser reload a dynamic resource.";
    }

    @Override
    protected Integer getTicketNumber() {
        return 2470;
    }

    @Override
    protected void setup() {
        // Create the embedded.
        final Embedded embedded = new Embedded();
        embedded.setDescription("Click on the grid cells to switch them.");
        addComponent(embedded);

        // Attach it to a resource.
        final MyImageSource imageSource = new MyImageSource();
        final StreamResource imageResource = new StreamResource(imageSource,
                "testimage.png");
        imageResource.setCacheTime(0);
        embedded.setSource(imageResource);

        // The button requests repainting the embedded.
        Button button = new Button("refr");
        button.addClickListener(new Button.ClickListener() {
            @Override
            public void buttonClick(ClickEvent event) {
                embedded.markAsDirty();
            }
        });
        addComponent(button);
        button = new Button("refr name");
        button.addClickListener(new Button.ClickListener() {
            @Override
            public void buttonClick(ClickEvent event) {
                ((StreamResource) embedded.getSource())
                        .setFilename(new Date().getTime() + ".png");
                embedded.markAsDirty();
            }
        });
        addComponent(button);
        button = new Button("200x200");
        button.addClickListener(new Button.ClickListener() {
            @Override
            public void buttonClick(ClickEvent event) {
                embedded.setWidth("200px");
                embedded.setHeight("200px");
            }
        });
        addComponent(button);
        button = new Button("undef");
        button.addClickListener(new Button.ClickListener() {
            @Override
            public void buttonClick(ClickEvent event) {
                embedded.setSizeUndefined();
            }
        });
        addComponent(button);

    }

    public class MyImageSource implements StreamResource.StreamSource {
        public MyImageSource() {
        }

        int intervalPos(int pos, int resolution, int cells) {
            return (int) Math.round(pos * resolution / (cells * 1.0));
        }

        @Override
        public InputStream getStream() {
            // Create an image and draw some background on it.
            BufferedImage image = new BufferedImage(640, 480,
                    BufferedImage.TYPE_INT_RGB);
            Graphics drawable = image.getGraphics();

            // Background
            drawable.setColor(Color.white);
            drawable.fillRect(0, 0, 640, 480);

            final int rows = 10;
            final int cols = 10;

            // Grid
            for (int row = 0; row < rows; row++) {
                int gridy = intervalPos(row, 480, rows);
                int gridynext = intervalPos(row + 1, 480, rows);

                // Horizontal grid line
                if (row > 0) {
                    drawable.setColor(Color.lightGray);
                    drawable.drawLine(0, gridy, 640 - 1, gridy);
                }

                for (int col = 0; col < cols; col++) {
                    int gridx = intervalPos(col, 640, cols);
                    int gridxnext = intervalPos(col + 1, 640, cols);

                    // Vertical grid line
                    if (row == 0 && col > 0) {
                        drawable.setColor(Color.lightGray);
                        drawable.drawLine(gridx, 0, gridx, 480 - 1);
                    }

                    // Cell
                    if (Math.random() < 0.5f) {
                        drawable.setColor(Color.white);
                    } else {
                        drawable.setColor(Color.black);
                    }
                    drawable.fillRect(gridx + 1, gridy + 1,
                            gridxnext - gridx - 1, gridynext - gridy - 1);
                }
            }

            try {
                // Write the image to a buffer.
                ByteArrayOutputStream imagebuffer = new ByteArrayOutputStream();
                ImageIO.write(image, "png", imagebuffer);

                // Return a stream from the buffer.
                ByteArrayInputStream istream = new ByteArrayInputStream(
                        imagebuffer.toByteArray());
                return istream; // new DownloadStream (istream,null,null);
            } catch (IOException e) {
                return null;
            }
        }

    }
}