edu.harvard.i2b2.eclipse.plugins.querytool.ui.utils.table.EmulatedNativeCheckboxLabelProvider.java Source code

Introduction

Here is the source code for edu.harvard.i2b2.eclipse.plugins.querytool.ui.utils.table.EmulatedNativeCheckboxLabelProvider.java

Source

/*
 * Copyright (c) 2006-2015 Partners Healthcare 
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the i2b2 Software License v2.1 
 * which accompanies this distribution. 
 * 
 * This source code was developed as part of i2b2 for the 
 * Medical Imaging Informatics Bench to Beside project (mi2b2).
 * 
 * Contributors: Taowei David Wang 
 */

package edu.harvard.i2b2.eclipse.plugins.querytool.ui.utils.table;

import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.viewers.ColumnLabelProvider;
import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;

import edu.harvard.i2b2.eclipse.plugins.querytool.ui.utils.Colors;

/*
 * 
 * Adapted from http://tom-eclipse-dev.blogspot.com/2007/01/tableviewers-and-nativelooking.html
 *       Takes screenshot (makes images) of native checkboxes in different states: {checked, unchecked} x {enabled, disabled}
 *     and use these images to draw checkboxes in TableViewers/TreeViewers
 */

public abstract class EmulatedNativeCheckboxLabelProvider extends ColumnLabelProvider {

    protected static final String CHECKED_KEY = "CHECKED";
    protected static final String UNCHECK_KEY = "UNCHECKED";

    protected static final String DISABLED_CHECKED_KEY = "DCHECKED";
    protected static final String DISABLED_UNCHECK_KEY = "DUNCHECKED";

    public EmulatedNativeCheckboxLabelProvider(ColumnViewer viewer) {
        if (JFaceResources.getImageRegistry().getDescriptor(CHECKED_KEY) == null) {
            JFaceResources.getImageRegistry().put(UNCHECK_KEY, makeShot(viewer.getControl(), false, false));
            JFaceResources.getImageRegistry().put(CHECKED_KEY, makeShot(viewer.getControl(), false, true));
            JFaceResources.getImageRegistry().put(DISABLED_UNCHECK_KEY, makeShot(viewer.getControl(), true, false));
            JFaceResources.getImageRegistry().put(DISABLED_CHECKED_KEY, makeShot(viewer.getControl(), true, true));
        }
    }

    private Image makeShot(Control control, boolean disabled, boolean type) {
        Shell shell = new Shell(control.getShell(), SWT.NO_TRIM | SWT.NO_BACKGROUND);
        shell.setBackground(Colors.OFF_WHITE); // use off-white as the transparent background color

        Button button = new Button(shell, SWT.CHECK | SWT.NO_BACKGROUND);
        button.setBackground(Colors.OFF_WHITE);
        button.setSelection(type);
        button.setEnabled(!disabled);

        button.setLocation(0, 0);
        Point bsize = button.computeSize(SWT.DEFAULT, SWT.DEFAULT);

        bsize.x = Math.max(bsize.x, bsize.y);
        bsize.y = Math.max(bsize.x, bsize.y);
        button.setSize(bsize);
        shell.setSize(bsize);

        shell.open();
        GC gc = new GC(shell);
        Image image = new Image(control.getDisplay(), bsize.x - 3, bsize.y - 2);
        gc.copyArea(image, 0, 0);
        gc.dispose();
        shell.close();

        ImageData imageData = image.getImageData();
        imageData.transparentPixel = imageData.palette.getPixel(Colors.OFF_WHITE.getRGB());
        return new Image(control.getDisplay(), imageData);
    }

    public Image getImage(Object element) {
        if (isEnabled(element)) {
            if (isChecked(element))
                return JFaceResources.getImageRegistry().get(CHECKED_KEY);
            else
                return JFaceResources.getImageRegistry().get(UNCHECK_KEY);
        } else {
            if (isChecked(element))
                return JFaceResources.getImageRegistry().get(DISABLED_CHECKED_KEY);
            else
                return JFaceResources.getImageRegistry().get(DISABLED_UNCHECK_KEY);
        }
    }

    protected abstract boolean isEnabled(Object element);

    protected abstract boolean isChecked(Object element);

}