Internal Redesign:

- Combined MPExpression and MPMutableExpression
- Abstracted children of MPExpression into MPExpressionElement protocol
- Abstracted most of MPExpressionLayout and MPFunctionLayout into common superclass MPLayout

MathPad/MPSumFunctionLayout.m

@@ -16,20 +16,21 @@
     return (MPSumFunction *)self.function;
 }
 
-- (NSSize)calculateSize
+- (NSBezierPath *)generateBezierPath
 {
-    NSAttributedString *text = [[NSAttributedString alloc] initWithString:@"∑" attributes:@{NSFontAttributeName: [NSFont fontWithName:@"HelveticaNeue" size:50.0]}];
-    [self.textStorage setAttributedString:text];
+    NSAttributedString *text = [[NSAttributedString alloc] initWithString:@"∑"
+                                                               attributes:@{NSFontAttributeName: [NSFont fontWithName:@"Lucida Grande" size:18.0]}];
+    self.textStorage.attributedString = text;
     NSRange glyphRange = [self.layoutManager glyphRangeForTextContainer:self.textContainer];
-    return [self.layoutManager boundingRectForGlyphRange:glyphRange inTextContainer:self.textContainer].size;
-}
-
-- (void)drawFunctionAtPoint:(NSPoint)point
-{
-    NSAttributedString *text = [[NSAttributedString alloc] initWithString:@"∑" attributes:@{NSFontAttributeName: [NSFont fontWithName:@"HelveticaNeue" size:50.0]}];
-    [self.textStorage setAttributedString:text];
-    NSRange glyphRange = [self.layoutManager glyphRangeForTextContainer:self.textContainer];
-    [self.layoutManager drawGlyphsForGlyphRange:glyphRange atPoint:point];
+    NSGlyph glyphs[glyphRange.length+1];
+    NSUInteger actualGylphCount = [self.layoutManager getGlyphs:glyphs
+                                                          range:glyphRange];
+    NSBezierPath *path = [NSBezierPath bezierPath];
+    [path moveToPoint:NSZeroPoint];
+    [path appendBezierPathWithGlyphs:glyphs
+                               count:actualGylphCount
+                              inFont:[NSFont fontWithName:@"Lucida Grande" size:18.0]];
+    return path;
 }
 
 @end