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/*******************************************************************************
* Copyright (c) 2008, 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.Font;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Control;
import org.eclipse.jface.dialogs.Dialog;
/**
* PixelConverter performs various conversions from device-independent units
* (such as DLUs or characters) to pixels. It can be associated with a control or
* a font. In the case of a control, the font used by the control at the time
* the PixelConverter is created is used for the pixel calculations. In the case
* of a specific font, the supplied font is used for the calculations.
*
* The control and/or font must not be disposed at the time the PixelConverter
* is created.
*
* @since 3.5
*/
public class PixelConverter {
private final FontMetrics fontMetrics;
/**
* Create a PixelConverter which will convert device-independent units to
* pixels using the font of the specified control.
*
* @param control
* the control whose font should be used for pixel conversions.
* Note that the font used by the control at the time this
* constructor is called is the font that will be used for all
* calculations. If the font of the specified control is changed
* after this PixelConverter is created, then the conversions
* from this instance will not produce the desired effect.
*/
public PixelConverter(Control control) {
this(control.getFont());
}
/**
* Create a PixelConverter which will convert device-independent units to
* pixels using the specified font.
*
* @param font
* the font that should be used for pixel conversions.
*/
public PixelConverter(Font font) {
GC gc = new GC(font.getDevice());
gc.setFont(font);
fontMetrics = gc.getFontMetrics();
gc.dispose();
}
/**
* Returns the number of pixels corresponding to the height of the given
* number of characters.
*
* @param chars
* the number of characters
* @return the number of pixels
*/
public int convertHeightInCharsToPixels(int chars) {
return Dialog.convertHeightInCharsToPixels(fontMetrics, chars);
}
/**
* Returns the number of pixels corresponding to the given number of
* horizontal dialog units.
*
* @param dlus
* the number of horizontal dialog units
* @return the number of pixels
*/
public int convertHorizontalDLUsToPixels(int dlus) {
return Dialog.convertHorizontalDLUsToPixels(fontMetrics, dlus);
}
/**
* Returns the number of pixels corresponding to the given number of
* vertical dialog units.
*
* @param dlus
* the number of vertical dialog units
* @return the number of pixels
*/
public int convertVerticalDLUsToPixels(int dlus) {
return Dialog.convertVerticalDLUsToPixels(fontMetrics, dlus);
}
/**
* Returns the number of pixels corresponding to the width of the given
* number of characters.
*
* @param chars
* the number of characters
* @return the number of pixels
*/
public int convertWidthInCharsToPixels(int chars) {
return Dialog.convertWidthInCharsToPixels(fontMetrics, chars);
}
}