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/MPSumFunctionLayout.m

@@ -9,6 +9,13 @@
 #import "MPSumFunctionLayout.h"
 #import "MPSumFunction.h"
 
+#import "NSIndexPath+MPAdditions.h"
+
+#define kSumFunctionStartExpressionOffset 3
+#define kSumFunctionTargetExpressionOffset 0
+#define kSumFunctionSumExpressionOffset 3
+#define kSumFunctionTrailingOffset 5
+
 @implementation MPSumFunctionLayout
 
 - (MPSumFunction *)sumFunction
@@ -21,7 +28,7 @@
     CTLineRef line = [self lineForPrivateCacheIndex:0 generator:^CTLineRef{
         NSAttributedString *text =
             [[NSAttributedString alloc] initWithString:@"∑"
-                                            attributes:@{NSFontAttributeName: [NSFont fontWithName:@"Lucida Grande" size:18.0]}];
+                                            attributes:@{NSFontAttributeName: self.font}];
         CFAttributedStringRef attributedString = CFBridgingRetain(text);
         CTLineRef line = CTLineCreateWithAttributedString(attributedString);
         CFRelease(attributedString); // TODO: Is this release appropriate
@@ -30,31 +37,119 @@
     return line;
 }
 
-- (NSSize)generateSize
+- (NSRect)localLineBounds
 {
-    CTLineRef line = [self line];
-    CFRetain(line);
-    CGSize size = CTLineGetBoundsWithOptions(line, /*kCTLineBoundsUseOpticalBounds*/0).size;
-    CFRelease(line);
-    return size;
+    NSRect lineBounds = CTLineGetBoundsWithOptions(self.line, 0);
+    CGFloat width = MAX(MAX([self childLayoutAtIndex:0].bounds.size.width, [self childLayoutAtIndex:1].bounds.size.width), lineBounds.size.width);
+    CGFloat xPosition = (width - lineBounds.size.width) / 2;
+    return NSMakeRect(xPosition, lineBounds.origin.y, lineBounds.size.width, lineBounds.size.height);
 }
 
-- (void)drawAtPoint:(NSPoint)point
+- (NSPoint)offsetOfChildLayoutAtIndex:(NSUInteger)index
+{
+    NSRect childBounds = [self childLayoutAtIndex:index].bounds;
+    NSRect localLineBounds = [self localLineBounds];
+    NSPoint offset;
+    if (index == 0) {
+        // Start Expression
+        offset.x = localLineBounds.origin.x + localLineBounds.size.width / 2 - childBounds.size.width / 2;
+        offset.y = -kSumFunctionStartExpressionOffset - childBounds.size.height;
+    } else if (index == 1) {
+        // Target Expression
+        offset.x = localLineBounds.origin.x + localLineBounds.size.width / 2 - childBounds.size.width / 2;
+        offset.y = localLineBounds.size.height + kSumFunctionTargetExpressionOffset;
+    } else {
+        // Sum Expression
+        MPLayout *startExpressionLayout = [self childLayoutAtIndex:0];
+        MPLayout *targetExpressionLayout = [self childLayoutAtIndex:1];
+        CGFloat sumWidth = MAX(MAX(localLineBounds.origin.x + localLineBounds.size.width, startExpressionLayout.bounds.size.width), targetExpressionLayout.bounds.size.width);
+        offset.x = sumWidth + kSumFunctionSumExpressionOffset;
+        offset.y = 0;
+    }
+    return offset;
+}
+
+- (NSIndexPath *)indexPathForMousePoint:(NSPoint)point
+{
+    // A single index is used to communicate back wether the
+    // selection should be before or after the function.
+    // A 0 means before, a 1 means after.
+    for (NSUInteger index = 0; index < self.function.numberOfChildren; index++) {
+        MPLayout *childLayout = [self childLayoutAtIndex:index];
+        NSRect childBounds = childLayout.bounds;
+        NSPoint childOffset = [self offsetOfChildLayoutAtIndex:index];
+        childBounds.origin.x += childOffset.x;
+        childBounds.origin.y += childOffset.y;
+        if (NSMouseInRect(point, childBounds, self.flipped)) {
+            NSPoint pointInChild = NSMakePoint(point.x + childOffset.x, point.y + childOffset.y);
+            NSIndexPath *subPath = [childLayout indexPathForMousePoint:pointInChild];
+            return [subPath indexPathByPreceedingIndex:index];
+        }
+    }
+    if (point.x < CTLineGetBoundsWithOptions(self.line, 0).size.width / 2) {
+        return [NSIndexPath indexPathWithIndex:0];
+    } else {
+        return [NSIndexPath indexPathWithIndex:1];
+    }
+}
+
+- (NSRect)generateBounds
+{
+    NSRect lineBounds = CTLineGetBoundsWithOptions(self.line, 0);
+    NSRect startExpressionBounds = [self childLayoutAtIndex:0].bounds;
+    NSRect targetExpressionBounds = [self childLayoutAtIndex:1].bounds;
+    NSRect sumExpressionBounds = [self childLayoutAtIndex:2].bounds;
+    NSRect bounds = lineBounds;
+    
+    bounds.size.width = MAX(lineBounds.size.width, startExpressionBounds.size.width);
+    bounds.size.height += startExpressionBounds.size.height + kSumFunctionStartExpressionOffset;
+    
+    bounds.size.width = MAX(bounds.size.width, targetExpressionBounds.size.width);
+    bounds.size.height += targetExpressionBounds.size.height + kSumFunctionTargetExpressionOffset;
+    
+    bounds.size.width += kSumFunctionSumExpressionOffset + sumExpressionBounds.size.width;
+    bounds.size.height = MAX(bounds.size.height, sumExpressionBounds.size.height);
+    
+    bounds.origin.y -= targetExpressionBounds.size.height + kSumFunctionStartExpressionOffset;
+    bounds.size.width += kSumFunctionTrailingOffset;
+    return bounds;
+}
+
+- (void)draw
 {
     // Get the current context
     CGContextRef context = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
-    
+        
     // Set the text matrix
     CGContextSetTextMatrix(context, CGAffineTransformIdentity);
     
-    // Get the line of text
+    // Draw the sum symbol
     CTLineRef line = [self line];
     CFRetain(line);
-    
-    // Draw the line
-    CGContextSetTextPosition(context, point.x, point.y);
+    NSRect localLineBounds = [self localLineBounds];
+    CGContextSetTextPosition(context, localLineBounds.origin.x, 0);
     CTLineDraw(line, context);
     
+    // Draw the start function
+    MPLayout *startExpressionLayout = [self childLayoutAtIndex:0];
+    NSPoint startExpressionLocation = NSMakePoint(localLineBounds.origin.x + localLineBounds.size.width / 2, 0);
+    startExpressionLocation.x -= startExpressionLayout.bounds.size.width / 2;
+    startExpressionLocation.y -= startExpressionLayout.bounds.size.height + kSumFunctionStartExpressionOffset;
+    [startExpressionLayout drawAtPoint:startExpressionLocation];
+    
+    // Draw the target function
+    MPLayout *targetExpressionLayout = [self childLayoutAtIndex:1];
+    NSPoint targetExpressionLocation = NSMakePoint(localLineBounds.origin.x + localLineBounds.size.width / 2, localLineBounds.size.height);
+    targetExpressionLocation.x -= targetExpressionLayout.bounds.size.width / 2;
+    targetExpressionLocation.y += kSumFunctionTargetExpressionOffset;
+    [targetExpressionLayout drawAtPoint:targetExpressionLocation];
+    
+    // Draw the sum function
+    MPLayout *sumExpressionLayout = [self childLayoutAtIndex:2];
+    CGFloat sumWidth = MAX(MAX(localLineBounds.origin.x + localLineBounds.size.width, startExpressionLayout.bounds.size.width), targetExpressionLayout.bounds.size.width);
+    sumWidth += kSumFunctionSumExpressionOffset;
+    [sumExpressionLayout drawAtPoint:NSMakePoint(sumWidth, 0)];
+    
     CFRelease(line);
 }