Improved Model

Added Keyboard Selection Support
Added Mouse Selection Support
Added Keyboard Editing Support
Corrected Some Bugs
Abstracted the Layout System further
Added Functions Button (test)

MathPad/MPLayout.m

@@ -7,6 +7,9 @@
 //
 
 #import "MPLayout.h"
+#import "MPRangePath.h"
+
+#import "NSIndexPath+MPAdditions.h"
 
 @interface MPLayout ()
 
@@ -18,7 +21,7 @@
 
 @implementation MPLayout {
     NSMutableArray *_cache;
-    NSSize _cachedSize;
+    NSRect _cachedBounds;
 }
 
 #pragma mark Creation Methods
@@ -27,13 +30,14 @@
     self = [super init];
     if (self) {
         _cache = [[NSMutableArray alloc] init];
-        _cachedSize = NSZeroSize;
+        _cachedBounds = NSZeroRect;
     }
     return self;
 }
 
-- (id)initWithPath:(NSIndexPath *)path
-            parent:(MPLayout *)parent
+- (instancetype)initWithElementAtPath:(NSIndexPath *)path
+                     inRootExpression:(MPExpression *)rootExpression
+                               parent:(MPLayout *)parent
 {
     self = [self init];
     if (self) {
@@ -42,10 +46,37 @@
     return self;
 }
 
-#pragma Text System Objects
-- (MPExpressionStorage *)expressionStorage
+#pragma mark Properties
+- (NSFont *)font
 {
-    return self.parent.expressionStorage;
+    return self.usesSmallSize ? self.smallFont : self.normalFont;
+}
+
+- (CGFloat)fontSize
+{
+    return self.usesSmallSize ? self.smallFontSize : self.normalFontSize;
+}
+
+- (NSFont *)normalFont
+{
+    return [NSFont fontWithName:@"CMU Serif"
+                           size:self.fontSize];
+}
+
+- (CGFloat)normalFontSize
+{
+    return 18.0;
+}
+
+- (NSFont *)smallFont
+{
+    return [NSFont fontWithName:@"CMU Serif"
+                           size:self.smallFontSize];
+}
+
+- (CGFloat)smallFontSize
+{
+    return 12.0;
 }
 
 #pragma mark Cache Tree
@@ -92,22 +123,42 @@
 
 - (void)invalidate
 {
-    _cachedSize = NSZeroSize;
+    _cachedBounds = NSZeroRect;
     [self.parent invalidate];
 }
 
 #pragma mark Calculation and Drawing Methods
-- (NSSize)size
+- (NSRect)bounds
 {
-    if (NSEqualSizes(_cachedSize, NSZeroSize)) {
-        _cachedSize = [self generateSize];
+    if (NSEqualRects(_cachedBounds, NSZeroRect)) {
+        _cachedBounds = [self generateBounds];
     }
-    return _cachedSize;
+    return _cachedBounds;
+}
+
+- (NSRect)boundingRectForRangePath:(MPRangePath *)rangePath
+{
+    if (rangePath.location.length == 1) {
+        return [self boundingRectForRange:rangePath.rangeAtLastIndex];
+    }
+    NSUInteger nextIndex = [rangePath.location indexAtPosition:0];
+    NSIndexPath *newLocation = [rangePath.location indexPathByRemovingFirstIndex];
+    MPRangePath *newRangePath = [[MPRangePath alloc] initWithLocation:newLocation length:rangePath.length];
+    NSRect bounds = [[self childLayoutAtIndex:nextIndex] boundingRectForRangePath:newRangePath];
+    NSPoint offset = [self offsetOfChildLayoutAtIndex:nextIndex];
+    bounds.origin = NSMakePoint(bounds.origin.x + offset.x, bounds.origin.y + offset.y);
+    return bounds;
 }
 
 - (void)drawAtPoint:(NSPoint)point
 {
-    
+    NSAffineTransform *transform = [NSAffineTransform transform];
+    [transform translateXBy:point.x
+                        yBy:point.y];
+    [transform concat];
+    [self draw];
+    [transform invert];
+    [transform concat];
 }
 
 @end
@@ -119,14 +170,24 @@
     return nil;
 }
 
-- (NSSize)sizeForChildAtIndex:(NSUInteger)index
+- (NSRect)generateBounds
 {
-    return NSZeroSize;
+    return NSZeroRect;
 }
 
-- (NSSize)generateSize
+- (NSRect)boundingRectForRange:(NSRange)range
 {
-    return NSZeroSize;
+    return NSZeroRect;
+}
+
+- (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
+{
+    return NSZeroPoint;
+}
+
+- (void)draw
+{
+    
 }
 
 @end