Corrected MVC Implementation

MathKit/MPLayout.m

@@ -8,6 +8,8 @@
 
 #import "MPLayout.h"
 
+#import "MPExpressionView.h"
+
 #import "MPRangePath.h"
 #import "NSIndexPath+MPAdditions.h"
 
@@ -54,6 +56,14 @@
 #pragma mark Properties
 
 
+- (void)setExpressionView:(MPExpressionView *)expressionView
+{
+    self.flipped = expressionView.flipped;
+    [_cache removeAllObjects];
+    [self invalidate];
+}
+
+
 - (NSFont *)normalFontWithSize:(CGFloat)size
 {
     return [NSFont fontWithName:@"CMU Serif"
@@ -135,6 +145,8 @@
     [_cache replaceObjectsInRange:range
              withObjectsFromArray:placeholders];
     [self invalidate];
+    [self.expressionView invalidateIntrinsicContentSize];
+    self.expressionView.needsDisplay = YES;
 }