StyledTextEmbebControls.java Source code

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Here is the source code for StyledTextEmbebControls.java

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/*******************************************************************************
 * Copyright (c) 2000, 2005 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
//package org.eclipse.swt.snippets;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.PaintObjectEvent;
import org.eclipse.swt.custom.PaintObjectListener;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.events.VerifyEvent;
import org.eclipse.swt.events.VerifyListener;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GlyphMetrics;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

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

    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[] offsets;

    static Control[] controls;

    static int MARGIN = 5;

    static void addControl(Control control, int offset) {
        StyleRange style = new StyleRange();
        style.start = offset;
        style.length = 1;
        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", 32, SWT.NORMAL);
        final Shell shell = new Shell(display);
        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);
        controls = new Control[2];
        Button button = new Button(styledText, SWT.PUSH);
        button.setText("Button 1");
        controls[0] = button;
        Combo combo = new Combo(styledText, SWT.NONE);
        combo.add("item 1");
        combo.add("another item");
        controls[1] = combo;
        offsets = new int[controls.length];
        int lastOffset = 0;
        for (int i = 0; i < controls.length; i++) {
            int offset = text.indexOf("\uFFFC", lastOffset);
            offsets[i] = offset;
            addControl(controls[i], offsets[i]);
            lastOffset = offset + 1;
        }

        // use a verify listener to keep the offsets up to date
        styledText.addVerifyListener(new VerifyListener() {
            public void verifyText(VerifyEvent e) {
                int start = e.start;
                int replaceCharCount = e.end - e.start;
                int newCharCount = e.text.length();
                for (int i = 0; i < offsets.length; i++) {
                    int offset = offsets[i];
                    if (start <= offset && offset < start + replaceCharCount) {
                        // this widget is being deleted from the text
                        if (controls[i] != null && !controls[i].isDisposed()) {
                            controls[i].dispose();
                            controls[i] = null;
                        }
                        offset = -1;
                    }
                    if (offset != -1 && offset >= start)
                        offset += newCharCount - replaceCharCount;
                    offsets[i] = offset;
                }
            }
        });

        // reposition widgets on paint event
        styledText.addPaintObjectListener(new PaintObjectListener() {
            public void paintObject(PaintObjectEvent event) {
                StyleRange style = event.style;
                int start = style.start;
                for (int i = 0; i < offsets.length; i++) {
                    int offset = offsets[i];
                    if (start == offset) {
                        Point pt = controls[i].getSize();
                        int x = event.x + MARGIN;
                        int y = event.y + event.ascent - 2 * pt.y / 3;
                        controls[i].setLocation(x, y);
                        break;
                    }
                }
            }
        });

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