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/*******************************************************************************
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* Copyright (c) 2007, 2010 IBM Corporation and others.
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* IBM Corporation - initial API and implementation
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*******************************************************************************/
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package org.eclipse.draw2d;
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import org.eclipse.swt.graphics.Font;
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import org.eclipse.swt.graphics.FontMetrics;
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import org.eclipse.draw2d.geometry.Dimension;
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/**
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* Provides miscellaneous text operations. Clients may subclass this class if
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* necessary.
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*
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* @author crevells
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* @since 3.4
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*/
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public class TextUtilities {
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/**
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* a singleton default instance
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*/
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public static TextUtilities INSTANCE = new TextUtilities();
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/**
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* Returns the Dimensions of <i>s</i> in Font <i>f</i>.
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*
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* @param s
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* the string
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* @param f
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* the font
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* @return the dimensions of the given string
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*/
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public Dimension getStringExtents(String s, Font f) {
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return FigureUtilities.getStringExtents(s, f);
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}
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/**
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* Returns the Dimensions of the given text, converting newlines and tabs
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* appropriately.
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*
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* @param s
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* the text
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* @param f
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* the font
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* @return the dimensions of the given text
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*/
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public Dimension getTextExtents(String s, Font f) {
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return FigureUtilities.getTextExtents(s, f);
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}
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/**
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* Gets the font's ascent.
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*
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* @param font
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* @return the font's ascent
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*/
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public int getAscent(Font font) {
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FontMetrics fm = FigureUtilities.getFontMetrics(font);
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// UNSUPPORTED - getDescent() not implemented in RAP
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// return fm.getHeight() - fm.getDescent();
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return fm.getHeight();
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}
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/**
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* Gets the font's descent.
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*
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* @param font
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* @return the font's descent
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*/
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public int getDescent(Font font) {
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// UNSUPPORTED - getDescent() not implemented in RAP
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// return FigureUtilities.getFontMetrics(font).getDescent();
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return 0;
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}
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/**
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* Returns the largest substring of <i>s</i> in Font <i>f</i> that can be
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* confined to the number of pixels in <i>availableWidth<i>.
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*
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* @param s
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* the original string
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* @param f
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* the font
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* @param availableWidth
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* the available width
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* @return the largest substring that fits in the given width
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*/
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public int getLargestSubstringConfinedTo(String s, Font f,
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int availableWidth) {
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FontMetrics metrics = FigureUtilities.getFontMetrics(f);
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int min, max;
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float avg = metrics.getAverageCharWidth();
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min = 0;
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max = s.length() + 1;
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// The size of the current guess
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int guess = 0, guessSize = 0;
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while ((max - min) > 1) {
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// Pick a new guess size
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// New guess is the last guess plus the missing width in pixels
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// divided by the average character size in pixels
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guess = guess + (int) ((availableWidth - guessSize) / avg);
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if (guess >= max)
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guess = max - 1;
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if (guess <= min)
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guess = min + 1;
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// Measure the current guess
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guessSize = getTextExtents(s.substring(0, guess), f).width;
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if (guessSize < availableWidth)
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// We did not use the available width
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min = guess;
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else
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// We exceeded the available width
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max = guess;
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}
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return min;
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}
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}
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