Added MPExpressionLayout, MPFunctionLayout and MPExpressionStorage as Rendering System for Expressions

MathPad/MPExpressionLayout.m

@@ -0,0 +1,209 @@
+//
+//  MPExpressionLayout.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 22.04.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPExpressionLayout.h"
+#import "MPExpressionStorage.h"
+#import "MPFunctionLayout.h"
+#import "MPModel.h"
+
+@implementation MPExpressionLayout
+
+#pragma mark Creation Methods
+
+- (instancetype)initRootLayoutWithExpressionStorage:(MPExpressionStorage *)expressionStorage
+{
+    self = [super init];
+    if (self) {
+        _symbolCache = [[NSMutableArray alloc] init];
+        _expressionStorage = expressionStorage;
+        _expressionPath = [[NSIndexPath alloc] init];
+    }
+    return self;
+}
+
+- (instancetype)initWithExpressionPath:(NSIndexPath *)expressionPath
+                                parent:(MPFunctionLayout *)parent
+{
+    self = [super init];
+    if (self) {
+        _symbolCache = [[NSMutableArray alloc] init];
+        _expressionPath = expressionPath;
+        _parent = parent;
+    }
+    return self;
+}
+
+#pragma mark Properties
+
+@synthesize expressionStorage = _expressionStorage;
+- (MPExpressionStorage *)expressionStorage
+{
+    if (_expressionStorage) {
+        return _expressionStorage;
+    }
+    return self.parent.expressionStorage;
+}
+
+- (MPExpression *)expression
+{
+    return [self.expressionStorage symbolAtIndexPath:self.expressionPath];
+}
+
+- (NSLayoutManager *)layoutManager
+{
+    return self.expressionStorage.layoutManager;
+}
+
+- (NSTextContainer *)textContainer
+{
+    return self.expressionStorage.textContainer;
+}
+
+- (NSTextStorage *)textStorage
+{
+    return self.expressionStorage.textStorage;
+}
+
+#pragma mark Cache Methods
+
+- (void)invalidate
+{
+    _valid = NO;
+}
+
+- (void)expressionEditedInRange:(NSRange)range replacementLength:(NSUInteger)length
+{
+    while (_symbolCache.count < self.expression.numberOfSymbols) {
+        [_symbolCache addObject:[NSNull null]];
+    }
+    NSMutableArray *newPlaceholders = [[NSMutableArray alloc] initWithCapacity:length];
+    while (newPlaceholders.count < length) {
+        [newPlaceholders addObject:[NSNull null]];
+    }
+    [_symbolCache replaceObjectsInRange:range withObjectsFromArray:newPlaceholders];
+    _valid = NO;
+}
+
+- (BOOL)hasCacheForSymbolAtIndex:(NSUInteger)index
+{
+    if (index >= _symbolCache.count) {
+        return NO;
+    }
+    return _symbolCache[index] != [NSNull null];
+}
+
+- (MPFunctionLayout *)functionLayoutForFunctionAtIndex:(NSUInteger)index;
+{
+    if ([self hasCacheForSymbolAtIndex:index]) {
+        return _symbolCache[index];
+    }
+     MPFunctionLayout *layout = [MPFunctionLayout functionLayoutForFunctionAtIndexPath:[self.expressionPath indexPathByAddingIndex:index] parent:self];
+    while (index >= _symbolCache.count) {
+        [_symbolCache addObject:[NSNull null]];
+    }
+    _symbolCache[index] = layout;
+    return layout;
+}
+
+- (NSSize)cachedSizeForSymbolAtIndex:(NSUInteger)index
+{
+    id cachedSymbol = _symbolCache[index];
+    if ([cachedSymbol isKindOfClass:[NSValue class]]) {
+        return [cachedSymbol sizeValue];
+    }
+    return [(MPFunctionLayout *)cachedSymbol sizeOfFunction];
+}
+
+- (void)cacheSize:(NSSize)size forSymbolAtIndex:(NSUInteger)index
+{
+    while (index >= _symbolCache.count) {
+        [_symbolCache addObject:[NSNull null]];
+    }
+    _symbolCache[index] = [NSValue valueWithSize:size];
+}
+
+#pragma mark Size Calculation Methods
+
+- (NSSize)sizeForAllSymbols
+{
+    if (!_valid) {
+        _cachedSize = [self sizeForSymbolsInRange:NSMakeRange(0, self.expression.numberOfSymbols)];
+        _valid = YES;
+    }
+    return _cachedSize;
+}
+
+- (NSSize)sizeForSymbolsInRange:(NSRange)range
+{
+    NSSize size = NSMakeSize(0, 0);
+    for (NSUInteger index = range.location; index < NSMaxRange(range); index++) {
+        NSSize symbolSize = [self sizeForSymbolAtIndex:index];
+        size.width += symbolSize.width;
+        size.height = MAX(size.height, symbolSize.height);
+    }
+    return size;
+}
+
+- (NSSize)sizeForSymbolAtIndex:(NSUInteger)index
+{
+    if ([self hasCacheForSymbolAtIndex:index]) {
+        return [self cachedSizeForSymbolAtIndex:index];
+    }
+    id symbol = [self.expression symbolAtIndex:index];
+    if ([symbol isString]) {
+        [self.textStorage setString:symbol];
+        NSRange glyphRange = [self.layoutManager glyphRangeForTextContainer:self.textContainer];
+        NSSize symbolSize = [self.layoutManager boundingRectForGlyphRange:glyphRange
+                                                          inTextContainer:self.textContainer].size;
+        [self cacheSize:symbolSize
+       forSymbolAtIndex:index];
+
+        return symbolSize;
+    } else {
+        MPFunctionLayout *layout = [self functionLayoutForFunctionAtIndex:index];
+        return [layout sizeOfFunction];
+    }
+}
+
+#pragma mark Drawing Methods
+
+- (void)drawSymbolAtIndex:(NSUInteger)index
+                  atPoint:(NSPoint)point
+{
+    id symbol = [self.expression symbolAtIndex:index];
+    if ([symbol isString]) {
+        [self.textStorage setString:symbol];
+        NSRange glyphRange = [self.layoutManager glyphRangeForTextContainer:self.textContainer];
+        [self.layoutManager drawGlyphsForGlyphRange:glyphRange
+                                            atPoint:point];
+    } else {
+        MPFunctionLayout *layout = [self functionLayoutForFunctionAtIndex:index];
+        [layout drawFunctionAtPoint:point];
+    }
+}
+
+- (void)drawSymbolsInRange:(NSRange)range
+                   atPoint:(NSPoint)point
+{
+    NSSize overallSize = [self sizeForSymbolsInRange:range];
+    CGFloat x = point.x;
+    for (NSUInteger index = range.location; index < NSMaxRange(range); index++) {
+        NSSize symbolSize = [self sizeForSymbolAtIndex:index];
+        CGFloat dy = (overallSize.height - symbolSize.height) / 2;
+        [self drawSymbolAtIndex:index
+                        atPoint:NSMakePoint(x, point.y + dy)];
+        x += symbolSize.width;
+    }
+}
+
+- (void)drawAllSymbolsAtPoint:(NSPoint)point
+{
+    [self drawSymbolsInRange:NSMakeRange(0, [self.expression numberOfSymbols]) atPoint:point];
+}
+
+@end