Class BasicFontMetrics

java.lang.Object
org.antlr.v4.gui.BasicFontMetrics
Direct Known Subclasses:
SystemFontMetrics

public abstract class BasicFontMetrics extends Object
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:
         $ ttf2tfm /Library/Fonts/Arial\ Black.ttf > metrics
 
Then run metrics into python code after stripping header/footer:
         #
         # 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 "}"
 
Units are 1000th of an 'em'.
  • Field Details

    • MAX_CHAR

      public static final int MAX_CHAR
      See Also:
    • maxCharHeight

      protected int maxCharHeight
    • widths

      protected int[] widths
  • Constructor Details

    • BasicFontMetrics

      public BasicFontMetrics()
  • Method Details

    • getWidth

      public double getWidth(String s, int fontSize)
    • getWidth

      public double getWidth(char c, int fontSize)
    • getLineHeight

      public double getLineHeight(int fontSize)