org.eclipse.swt.snippets.Snippet212.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet212.java

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/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.snippets;

import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * StyledText snippet: embed images
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.2
 */
public class Snippet212 {

    static StyledText styledText;
    static String text = "This snippet shows how to embed images in a StyledText.\n"
            + "Here is one: \uFFFC, and here is another: \uFFFC."
            + "Use the add button to add an image from your filesystem to the StyledText at the current caret offset.";

    static void addImage(Image image, int offset) {
        StyleRange style = new StyleRange();
        style.start = offset;
        style.length = 1;
        style.data = image;
        Rectangle rect = image.getBounds();
        style.metrics = new GlyphMetrics(rect.height, 0, rect.width);
        styledText.setStyleRange(style);
    }

    public static void main(String[] args) {
        final Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setText("Snippet 212");
        shell.setLayout(new GridLayout());
        styledText = new StyledText(shell, SWT.WRAP | SWT.BORDER);
        styledText.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
        styledText.setText(text);
        int offset = text.indexOf("\uFFFC", 0);
        addImage(display.getSystemImage(SWT.ICON_QUESTION), offset);
        offset = text.indexOf("\uFFFC", offset + 1);
        addImage(display.getSystemImage(SWT.ICON_INFORMATION), offset);

        // use a verify listener to dispose the images
        styledText.addVerifyListener(event -> {
            if (event.start == event.end)
                return;
            String text = styledText.getText(event.start, event.end - 1);
            int index = text.indexOf('\uFFFC');
            while (index != -1) {
                StyleRange style = styledText.getStyleRangeAtOffset(event.start + index);
                if (style != null) {
                    Image image = (Image) style.data;
                    if (image != null)
                        image.dispose();
                }
                index = text.indexOf('\uFFFC', index + 1);
            }
        });
        // draw images on paint event
        styledText.addPaintObjectListener(event -> {
            StyleRange style = event.style;
            Image image = (Image) style.data;
            if (!image.isDisposed()) {
                int x = event.x;
                int y = event.y + event.ascent - style.metrics.ascent;
                event.gc.drawImage(image, x, y);
            }
        });
        styledText.addListener(SWT.Dispose, event -> {
            StyleRange[] styles = styledText.getStyleRanges();
            for (int i = 0; i < styles.length; i++) {
                StyleRange style = styles[i];
                if (style.data != null) {
                    Image image = (Image) style.data;
                    if (image != null)
                        image.dispose();
                }
            }
        });
        Button button = new Button(shell, SWT.PUSH);
        button.setText("Add Image");
        button.setLayoutData(new GridData(SWT.CENTER, SWT.CENTER, false, false));
        button.addListener(SWT.Selection, event -> {
            FileDialog dialog = new FileDialog(shell);
            String filename = dialog.open();
            if (filename != null) {
                try {
                    Image image = new Image(display, filename);
                    int offset1 = styledText.getCaretOffset();
                    styledText.replaceTextRange(offset1, 0, "\uFFFC");
                    addImage(image, offset1);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
        shell.setSize(400, 400);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}