org.eclipse.jface.layout.LayoutConstants.java Source code

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Here is the source code for org.eclipse.jface.layout.LayoutConstants.java

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/*******************************************************************************
 * Copyright (c) 2005, 2015 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.jface.layout;

import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Display;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.resource.JFaceResources;

/**
 * Contains various layout constants to be used in dialogs.
 *
 * @since 3.2
 */
public final class LayoutConstants {
    private static Point dialogMargins = null;
    private static Point dialogSpacing = null;
    private static Point minButtonSize = null;

    private static void initializeConstants() {
        if (dialogMargins != null) {
            return;
        }

        GC gc = new GC(Display.getCurrent());
        gc.setFont(JFaceResources.getDialogFont());
        FontMetrics fontMetrics = gc.getFontMetrics();

        dialogMargins = new Point(
                Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.HORIZONTAL_MARGIN),
                Dialog.convertVerticalDLUsToPixels(fontMetrics, IDialogConstants.VERTICAL_MARGIN));

        dialogSpacing = new Point(
                Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.HORIZONTAL_SPACING),
                Dialog.convertVerticalDLUsToPixels(fontMetrics, IDialogConstants.VERTICAL_SPACING));

        minButtonSize = new Point(Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.BUTTON_WIDTH),
                0);

        gc.dispose();
    }

    /**
     * Returns the default dialog margins, in pixels
     *
     * @return the default dialog margins, in pixels
     */
    public static final Point getMargins() {
        initializeConstants();
        return dialogMargins;
    }

    /**
     * Returns the default dialog spacing, in pixels
     *
     * @return the default dialog spacing, in pixels
     */
    public static final Point getSpacing() {
        initializeConstants();
        return dialogSpacing;
    }

    /**
     * Returns the default minimum button size, in pixels
     *
     * @return the default minimum button size, in pixels
     */
    public static final Point getMinButtonSize() {
        initializeConstants();
        return minButtonSize;
    }

    /**
     * Returns the indent of dependent controls, in pixels.
     *
     * @return the indent of dependent controls, in pixels.
     * @since 3.9
     */
    public static final int getIndent() {
        /*
         * Currently we return 20, which is the most widely used indent. Once
         * https://bugs.eclipse.org/400320 is fixed, we can compute the correct indent.
         */
        return 20;
    }
}