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/*******************************************************************************
* Copyright (c) 2000, 2008 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.compare.examples.xml;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Caret;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Widget;
/**
* Utility class to simplify access to some SWT resources.
*/
public class SWTUtil {
/*
* Returns the standard display to be used. The method first checks, if
* the thread calling this method has an associated disaply. If so, this
* display is returned. Otherwise the method returns the default display.
*/
public static Display getStandardDisplay() {
Display display;
display= Display.getCurrent();
if (display == null)
display= Display.getDefault();
return display;
}
/*
* Returns the shell for the given widget. If the widget doesn't represent
* a SWT object that manage a shell, <code>null</code> is returned.
*
* @return the shell for the given widget
*/
public static Shell getShell(Widget widget) {
if (widget instanceof Control)
return ((Control)widget).getShell();
if (widget instanceof Caret)
return ((Caret)widget).getParent().getShell();
if (widget instanceof DragSource)
return ((DragSource)widget).getControl().getShell();
if (widget instanceof DropTarget)
return ((DropTarget)widget).getControl().getShell();
if (widget instanceof Menu)
return ((Menu)widget).getParent().getShell();
if (widget instanceof ScrollBar)
return ((ScrollBar)widget).getParent().getShell();
return null;
}
private static double getVerticalDialogUnitSize(Control control) {
GC gc= new GC(control);
try {
int height = gc.getFontMetrics().getHeight();
return height * 0.125;
} finally {
gc.dispose();
}
}
private static double getHorizontalDialogUnitSize(Control control) {
GC gc= new GC(control);
try {
int averageWidth= gc.getFontMetrics().getAverageCharWidth();
return averageWidth * 0.25;
} finally {
gc.dispose();
}
}
public static int convertHeightInCharsToPixels(int chars, Control control) {
return convertVerticalDLUsToPixels(chars * 8, control);
}
public static int convertHorizontalDLUsToPixels(int dlus, Control control) {
return (int)Math.round(dlus * getHorizontalDialogUnitSize(control));
}
public static int convertVerticalDLUsToPixels(int dlus, Control control) {
return (int)Math.round(dlus * getVerticalDialogUnitSize(control));
}
public static int convertWidthInCharsToPixels(int chars, Control control) {
return convertHorizontalDLUsToPixels(chars * 4, control);
}
/*
* Returns a width hint for a button control.
*/
public static int getButtonWidthHint(Button button) {
int widthHint= convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH, button);
return Math.max(widthHint, button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x);
}
/*
* Returns a height hint for a button control.
*/
// public static int getButtonHeigthHint(Button button) {
// return convertVerticalDLUsToPixels(IDialogConstants.BUTTON_HEIGHT, button);
// }
/*
* Sets width and height hint for the button control.
* <b>Note:</b> This is a NOP if the button's layout data is not
* an instance of <code>GridData</code>.
*
* @param the button for which to set the dimension hint
*/
public static void setButtonDimensionHint(Button button) {
Assert.isNotNull(button);
Object gd= button.getLayoutData();
if (gd instanceof GridData) {
//((GridData)gd).heightHint= getButtonHeigthHint(button);
((GridData)gd).widthHint= getButtonWidthHint(button);
}
}
}
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