melnorme.util.swt.MetricsUtil.java Source code

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Here is the source code for melnorme.util.swt.MetricsUtil.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 melnorme.util.swt;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Layout;

public class MetricsUtil {

    /** Gets FontMetrics for the given control */
    protected static FontMetrics getFontMetrics(Control testControl) {
        FontMetrics fontMetrics;
        // Compute and store a font metric
        GC gc = new GC(testControl);
        gc.setFont(JFaceResources.getDialogFont());
        fontMetrics = gc.getFontMetrics();
        gc.dispose();
        return fontMetrics;
    }

    /** Initializes a layout with dialog unit settings. 
     * @param testControl the control used to obtain FontMetrics. */
    public static void initGridLayoutWithDLUs(GridLayout layout, Control testControl) {

        FontMetrics fontMetrics = getFontMetrics(testControl);

        layout.horizontalSpacing = Dialog.convertHorizontalDLUsToPixels(fontMetrics,
                IDialogConstants.HORIZONTAL_SPACING);
        layout.verticalSpacing = Dialog.convertHorizontalDLUsToPixels(fontMetrics,
                IDialogConstants.VERTICAL_SPACING);
        layout.marginWidth = Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.HORIZONTAL_MARGIN);
        layout.marginHeight = Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.VERTICAL_MARGIN);
    }

    /** Initializes a GridLayout with some default settings.
     * @param margins if the layout should have margins
     * @param testControl the control used to obtain FontMetrics. If null then 
     * SWT defaults will be used
     */
    public static void initGridLayout(GridLayout gl, boolean margins, Control testControl) {
        if (testControl != null)
            initGridLayoutWithDLUs(gl, testControl);

        if (!margins) {
            gl.marginWidth = 0;
            gl.marginHeight = 0;
        }
    }

    /** Creates and initializes a new GridLayout with numColumns and margins. */
    public static Layout createGridLayout(int numColumns, Control testControl) {
        GridLayout gd = new GridLayout(numColumns, false);
        initGridLayout(gd, true, testControl);
        return gd;
    }

}