Add new tool FontViewer for examining existing fonts.

The goal of the FontViewer is to allow inspection of a font file, being
close to the actual representation in the file.

Only a few tables are implemented yet.

java/src/com/google/typography/font/tools/fontviewer/FontNode.java

@@ -4,6 +4,7 @@
 import com.google.typography.font.sfntly.Tag;
 import com.google.typography.font.sfntly.table.Table;
 import com.google.typography.font.sfntly.table.core.NameTable;
+import com.google.typography.font.sfntly.table.opentype.GSubTable;
 import com.google.typography.font.sfntly.table.truetype.GlyphTable;
 import com.google.typography.font.sfntly.table.truetype.LocaTable;
 
@@ -30,13 +31,7 @@ private static List<AbstractNode> createTableNodes(Font font) {
     List<AbstractNode> tableNodes = new ArrayList<AbstractNode>();
     for (Iterator<? extends Table> it = font.iterator(); it.hasNext(); ) {
       Table table = it.next();
-      if (table instanceof LocaTable) {
-        tableNodes.add(new LocaTableNode((LocaTable) table, Tag.stringValue(table.headerTag())));
-      } else if (table instanceof GlyphTable) {
-        tableNodes.add(new GlyfTableNode((GlyphTable) table, (LocaTable) font.getTable(Tag.loca)));
-      } else {
-        tableNodes.add(new SubTableNode(table, Tag.stringValue(table.headerTag())));
-      }
+      tableNodes.add(nodeFor(font, table));
     }
     Collections.sort(tableNodes, new Comparator<AbstractNode>() {
       @Override
@@ -47,6 +42,19 @@ public int compare(AbstractNode o1, AbstractNode o2) {
     return tableNodes;
   }
 
+  private static AbstractNode nodeFor(Font font, Table table) {
+    int tag = table.headerTag();
+    if (tag == Tag.loca) {
+      return new LocaTableNode((LocaTable) table, Tag.stringValue(table.headerTag()));
+    } else if (tag == Tag.glyf) {
+      return new GlyfTableNode((GlyphTable) table, (LocaTable) font.getTable(Tag.loca));
+    } else if (tag == Tag.GSUB) {
+      return new GsubTableNode((GSubTable) table);
+    } else {
+      return new SubTableNode(table, Tag.stringValue(table.headerTag()));
+    }
+  }
+
   @Override
   public int getChildCount() {
     return this.tables.size();

java/src/com/google/typography/font/tools/fontviewer/GsubTableNode.java

@@ -0,0 +1,42 @@
+package com.google.typography.font.tools.fontviewer;
+
+import com.google.typography.font.sfntly.table.opentype.GSubTable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.swing.JComponent;
+import javax.swing.JTextArea;
+
+public class GsubTableNode extends AbstractNode {
+
+  private final GSubTable gsub;
+  private final List<AbstractNode> children = new ArrayList<AbstractNode>();
+
+  public GsubTableNode(GSubTable gsub) {
+    this.gsub = gsub;
+    this.children.add(new SubTableNode(gsub.scriptList(), "script"));
+    this.children.add(new SubTableNode(gsub.featureList(), "feature"));
+    this.children.add(new SubTableNode(gsub.lookupList(), "lookup"));
+  }
+
+  @Override
+  protected String getNodeName() {
+    return "GSUB";
+  }
+
+  @Override
+  public int getChildCount() {
+    return children.size();
+  }
+
+  @Override
+  public AbstractNode getChildAt(int index) {
+    return children.get(index);
+  }
+
+  @Override
+  JComponent render() {
+    return new JTextArea(this.gsub.toString());
+  }
+}