org.eclipse.swt.snippets.Snippet217.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet217.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 controls
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.2
 */
public class Snippet217 {

    static StyledText styledText;
    static String text = "This snippet shows how to embed widgets in a StyledText.\n"
            + "Here is one: \uFFFC, and here is another: \uFFFC.";
    static int MARGIN = 5;

    static void addControl(Control control, int offset) {
        StyleRange style = new StyleRange();
        style.start = offset;
        style.length = 1;
        style.data = control;
        control.pack();
        Rectangle rect = control.getBounds();
        int ascent = 2 * rect.height / 3;
        int descent = rect.height - ascent;
        style.metrics = new GlyphMetrics(ascent + MARGIN, descent + MARGIN, rect.width + 2 * MARGIN);
        styledText.setStyleRange(style);
    }

    public static void main(String[] args) {
        final Display display = new Display();
        Font font = new Font(display, "Tahoma", 16, SWT.NORMAL);
        final Shell shell = new Shell(display);
        shell.setText("Snippet 217");
        shell.setLayout(new GridLayout());
        styledText = new StyledText(shell, SWT.WRAP | SWT.BORDER);
        styledText.setFont(font);
        styledText.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
        styledText.setText(text);
        Button button = new Button(styledText, SWT.PUSH);
        button.setText("Button 1");
        int offset = text.indexOf('\uFFFC');
        addControl(button, offset);
        button.setLocation(styledText.getLocationAtOffset(offset));
        Combo combo = new Combo(styledText, SWT.NONE);
        combo.add("item 1");
        combo.add("another item");
        combo.setText(combo.getItem(0));
        offset = text.indexOf('\uFFFC', offset + 1);
        addControl(combo, offset);
        combo.setLocation(styledText.getLocationAtOffset(offset));

        // use a verify listener to dispose the controls
        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) {
                    Control control = (Control) style.data;
                    if (control != null)
                        control.dispose();
                }
                index = text.indexOf('\uFFFC', index + 1);
            }
        });

        // reposition widgets on paint event
        styledText.addPaintObjectListener(event -> {
            Control control = (Control) event.style.data;
            Point pt = control.getSize();
            int x = event.x + MARGIN;
            int y = event.y + event.ascent - 2 * pt.y / 3;
            control.setLocation(x, y);
        });

        shell.setSize(400, 400);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        font.dispose();
        display.dispose();
    }
}