fixed some minor sizing issues

src/main/java/de/neemann/digital/draw/graphics/text/formatter/GraphicsFormatter.java

@@ -58,7 +58,6 @@ public final class GraphicsFormatter {
             // if there was an exception, return the complete raw text as a fragment
             fragment = new TextFragment(sizer, font, text);
         }
-        fragment.dx += font.getSize() / 10;
         return fragment;
     }
 
@@ -132,7 +131,7 @@ public final class GraphicsFormatter {
      * @param expression the expression
      * @return the fragment
      */
-    private static Fragment createFragment(FontSizer sizer, Font font, Expression expression) throws FormatterException {
+    public static Fragment createFragment(FontSizer sizer, Font font, Expression expression) throws FormatterException {
         if (expression instanceof Variable) {
             String ident = ((Variable) expression).getIdentifier();
             return createFragment(sizer, font, ident);

src/main/java/de/neemann/digital/gui/components/table/ExpressionComponent.java

@@ -7,9 +7,13 @@ package de.neemann.digital.gui.components.table;
 
 import de.neemann.digital.analyse.expression.Expression;
 import de.neemann.digital.draw.graphics.text.formatter.GraphicsFormatter;
+import sun.font.FontDesignMetrics;
 
 import javax.swing.*;
 import java.awt.*;
+import java.awt.font.FontRenderContext;
+import java.awt.geom.AffineTransform;
+import java.awt.geom.Rectangle2D;
 import java.util.ArrayList;
 
 import static de.neemann.digital.draw.graphics.text.formatter.GraphicsFormatter.createFragment;
@@ -20,8 +24,6 @@ import static de.neemann.digital.draw.graphics.text.formatter.GraphicsFormatter.
 public class ExpressionComponent extends JComponent {
     private static final int XPAD = 5;
     private ArrayList<Expression> expressions;
-    private Dimension lastRectSet;
-
 
     /**
      * Sets a single expression to visualize
@@ -29,7 +31,7 @@ public class ExpressionComponent extends JComponent {
      * @param expression the expression
      */
     public void setExpression(Expression expression) {
-        ArrayList<Expression> l = new ArrayList<Expression>();
+        ArrayList<Expression> l = new ArrayList<>();
         l.add(expression);
         setExpressions(l);
     }
@@ -41,6 +43,7 @@ public class ExpressionComponent extends JComponent {
      */
     public void setExpressions(ArrayList<Expression> expressions) {
         this.expressions = expressions;
+        setPreferredSize(calcSize());
         revalidate();
         repaint();
     }
@@ -59,13 +62,33 @@ public class ExpressionComponent extends JComponent {
         gr.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
         int lineSpacing = getFont().getSize() / 2;
         int y = 0;
-        int dx = 0;
         for (Expression e : expressions) {
             try {
                 GraphicsFormatter.Fragment fr = createFragment(gr, e);
                 y += fr.getHeight();
                 fr.draw(gr, XPAD, y);
                 y += lineSpacing;
+            } catch (GraphicsFormatter.FormatterException ex) {
+            }
+        }
+    }
+
+    private Dimension calcSize() {
+        FontRenderContext frc = new FontRenderContext(new AffineTransform(), true, false);
+
+        int lineSpacing = getFont().getSize() / 2;
+        int dx = 0;
+        int y = 0;
+        for (Expression e : expressions) {
+            try {
+                GraphicsFormatter.Fragment fr = createFragment((fragment, font, str) -> {
+                    Rectangle2D rec = font.getStringBounds(str, frc);
+                    final FontDesignMetrics metrics = FontDesignMetrics.getMetrics(font, frc);
+                    fragment.set((int) rec.getWidth(), (int) rec.getHeight(), metrics.getDescent());
+                }, getFont(), e);
+
+                y += fr.getHeight();
+                y += lineSpacing;
 
                 if (dx < fr.getWidth())
                     dx = fr.getWidth();
@@ -73,14 +96,7 @@ public class ExpressionComponent extends JComponent {
             } catch (GraphicsFormatter.FormatterException ex) {
             }
         }
-
+        return new Dimension(dx + XPAD * 2, y);
-        Dimension p = new Dimension(dx+XPAD*2, y);
-        if (!p.equals(lastRectSet)) {
-            lastRectSet = p;
-            SwingUtilities.invokeLater(() -> {
-                setPreferredSize(p);
-                revalidate();
-            });
-        }
     }
+
 }

src/test/java/de/neemann/digital/draw/graphics/text/formatter/GraphicsFormatterTest.java

@@ -25,4 +25,15 @@ public class GraphicsFormatterTest extends TestCase {
         assertTrue(f instanceof GraphicsFormatter.TextFragment);
     }
 
+    public void testInvert() {
+        GraphicsFormatter.Fragment f = GraphicsFormatter.createFragment(
+                (fragment, font, str) -> {
+                    assertEquals("Q", str);
+                    fragment.set(10, 10, 5);
+                },
+                Font.decode(null), "~{~Q}");
+
+        assertEquals(10, f.dx);
+    }
+
 }