/*
* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
package org.antlr.v4.gui;
/** Font metrics. The only way to generate accurate images
* in any format that contain text is to know the font metrics.
* Specifically, we need to know the width of every character and the
* maximum height (since we want all characters to fit within same line height).
* I used ttf2tfm to dump the font metrics from Mac TrueType fonts and
* then converted that to a Java class for use in a PostScript generator
* for trees. Commands:
*
* <pre>
* $ ttf2tfm /Library/Fonts/Arial\ Black.ttf > metrics
* </pre>
*
* Then run metrics into python code after stripping header/footer:
*
* <pre>
* #
* # Process lines from ttf2tfm that look like this:
* # Glyph Code Glyph Name Width llx lly urx ury
* # ------------------------------------------------------------------------
* # 3 00020 space 333 0, 0 -- 0, 0
* #
* lines = open("metrics").read().split('\n')
* print "public class FontName {"
* print " {"
* maxh = 0;
* for line in lines[4:]: # skip header 0..3
* all = line.split(' ')
* words = [x for x in all if len(x)>0]
* ascii = int(words[1], 16)
* height = int(words[8])
* if height>maxh: maxh = height
* if ascii>=128: break
* print " widths[%d] = %s; // %s" % (ascii, words[3], words[2])
*
* print " maxCharHeight = "+str(maxh)+";"
* print " }"
* print "}"
* </pre>
*
* Units are 1000th of an 'em'.
*/
public abstract class BasicFontMetrics {
public static final int MAX_CHAR = '\u00FF';
protected int maxCharHeight;
protected int[] widths = new int[MAX_CHAR+1];
public double getWidth(String s, int fontSize) {
double w = 0;
for (char c : s.toCharArray()) {
w += getWidth(c, fontSize);
}
return w;
}
public double getWidth(char c, int fontSize) {
if ( c > MAX_CHAR || widths[c]==0 ) return widths['m']/1000.0; // return width('m')
return widths[c]/1000.0 * fontSize;
}
public double getLineHeight(int fontSize) {
return maxCharHeight / 1000.0 * fontSize;
}
}