Adds a special type for inner displays.

iosMath/lib/MTMathListIndex.h

@@ -49,7 +49,9 @@ typedef NS_ENUM(unsigned int, MTMathListSubIndexType) {
     /// The subindex indexes into the radicand (only valid for radicals)
     kMTSubIndexTypeRadicand,
     /// The subindex indexes into the degree (only valid for radicals)
-    kMTSubIndexTypeDegree
+    kMTSubIndexTypeDegree,
+    /// The subindex indexes into the inner list (only valid for inner)
+    kMTSubIndexTypeInner
 };
 
 

iosMath/render/MTMathListDisplay.h

@@ -88,7 +88,9 @@ typedef NS_ENUM(unsigned int, MTLinePosition)  {
     /// Positioned at a subscript
     kMTLinePositionSubscript,
     /// Positioned at a superscript
-    kMTLinePositionSuperscript
+    kMTLinePositionSuperscript,
+    /// Positioned at an inner
+    kMTLinePositionInner
 };
 
 /// Where the line is positioned
@@ -185,4 +187,25 @@ typedef NS_ENUM(unsigned int, MTLinePosition)  {
 
 @end
 
+/// Rendering of an list with delimiters
+@interface MTInnerDisplay : MTDisplay
+
+- (instancetype)init NS_UNAVAILABLE;
+
+/** A display representing the inner list that can be wrapped in delimiters.
+ It's position is relative to the parent is not treated as a sub-display.
+ */
+@property (nonatomic, readonly) MTMathListDisplay* inner;
+
+/** A display representing the delimiters. Their position is relative
+ to the parent are not treated as a sub-display.
+ */
+@property (nonatomic, readonly, nullable) MTDisplay* leftDelimiter;
+@property (nonatomic, readonly, nullable) MTDisplay* rightDelimiter;
+
+/// Denotes the location in the parent MTList.
+@property (nonatomic, readonly) NSUInteger index;
+
+@end
+
 NS_ASSUME_NONNULL_END

iosMath/render/MTMathListDisplay.m

@@ -798,3 +798,108 @@ - (void)draw:(CGContextRef)context
     CGContextRestoreGState(context);
 }
 @end
+
+#pragma mark - MTInnerDisplay
+
+@implementation MTInnerDisplay {
+  MTMathListDisplay *_inner;
+}
+
+- (instancetype) initWithInner:(MTMathListDisplay*) inner leftDelimiter:(MTDisplay*) leftDelimiter rightDelimiter:(MTDisplay*) rightDelimiter atIndex:(NSUInteger) index
+{
+  self = [super init];
+  if (self) {
+    _leftDelimiter = leftDelimiter;
+    _rightDelimiter = rightDelimiter;
+    _inner = inner;
+    _index = index;
+    self.range = NSMakeRange(_index, 1);
+
+    self.width = leftDelimiter.width + inner.width + rightDelimiter.width;
+  }
+  return self;
+}
+
+- (void)setPosition:(CGPoint)position
+{
+  super.position = position;
+  [self updateLeftDelimiterPosition];
+  [self updateInnerPosition];
+  [self updateRightDelimiterPosition];
+}
+
+- (void) updateLeftDelimiterPosition
+{
+  if (_leftDelimiter) {
+    _leftDelimiter.position = self.position;
+  }
+}
+
+- (void) updateRightDelimiterPosition
+{
+  if (_rightDelimiter) {
+    _rightDelimiter.position = CGPointMake(_inner.position.x + _inner.width, self.position.y);    
+  }
+}
+
+- (void) updateInnerPosition
+{
+  if (_leftDelimiter) {
+    _inner.position = CGPointMake(_leftDelimiter.position.x + _leftDelimiter.width, self.position.y);
+  } else {
+    _inner.position = self.position;
+  }
+}
+
+- (CGFloat)ascent
+{
+  if (_leftDelimiter) {
+    return _leftDelimiter.ascent;
+  }
+  if (_rightDelimiter) {
+    return _rightDelimiter.ascent;
+  }
+  return _inner.ascent;
+}
+
+- (CGFloat)descent
+{
+  if (_leftDelimiter) {
+    return _leftDelimiter.descent;
+  }
+  if (_rightDelimiter) {
+    return _rightDelimiter.descent;
+  }
+  return _inner.descent;
+}
+
+- (CGFloat)width
+{
+  CGFloat w = _inner.width;
+  if (_leftDelimiter) {
+    w += _leftDelimiter.width;
+  }
+  if (_rightDelimiter) {
+    w += _rightDelimiter.width;
+  }
+  return w;
+}
+
+- (void)setTextColor:(MTColor *)textColor
+{
+  [super setTextColor:textColor];
+  self.leftDelimiter.textColor = textColor;
+  self.rightDelimiter.textColor = textColor;
+  _inner.textColor = textColor;
+}
+
+- (void)draw:(CGContextRef)context
+{
+  [super draw:context];
+  // Draw the elements.
+  [self.leftDelimiter draw:context];
+  [self.rightDelimiter draw:context];
+  [_inner draw:context];
+}
+
+@end

iosMath/render/internal/MTMathListDisplayInternal.h

@@ -111,3 +111,17 @@
 - (instancetype)initWithAccent:(MTGlyphDisplay*) glyph accentee:(MTMathListDisplay*) accentee range:(NSRange) range NS_DESIGNATED_INITIALIZER;
 
 @end
+
+
+@interface MTInnerDisplay ()
+
+- (instancetype) initWithInner:(MTMathListDisplay*) inner leftDelimiter:(MTDisplay*) leftDelimiter rightDelimiter:(MTDisplay*) rightDelimiter atIndex:(NSUInteger) index NS_DESIGNATED_INITIALIZER;
+
+@property (nonatomic) MTMathListDisplay* inner;
+
+@property (nonatomic, nullable) MTDisplay* leftDelimiter;
+@property (nonatomic, nullable) MTDisplay* rightDelimiter;
+
+@property (nonatomic) NSUInteger index;
+
+@end

iosMath/render/internal/MTTypesetter.m

@@ -707,12 +707,7 @@ - (void) createDisplayAtoms:(NSArray*) preprocessed
                 }
                 [self addInterElementSpace:prevNode currentType:atom.type];
                 MTInner* inner = (MTInner*) atom;
-                MTDisplay* display = nil;
-                if (inner.leftBoundary || inner.rightBoundary) {
-                    display = [self makeLeftRight:inner];
-                } else {
-                    display = [MTTypesetter createLineForMathList:inner.innerList font:_font style:_style cramped:_cramped];
-                }
+              MTInnerDisplay* display = [self makeInner:inner atIndex:atom.indexRange.location];
                 display.position = _currentPosition;
                 _currentPosition.x += display.width;
                 [_displayAtoms addObject:display];
@@ -1507,47 +1502,6 @@ - (MTDisplay*) addLimitsToDisplay:(MTDisplay*) display forOperator:(MTLargeOpera
 
 #pragma mark Large delimiters
 
-// Delimiter shortfall from plain.tex
-static const NSInteger kDelimiterFactor = 901;
-static const NSInteger kDelimiterShortfallPoints = 5;
-
-- (MTDisplay*) makeLeftRight:(MTInner*) inner
-{
-    NSAssert(inner.leftBoundary || inner.rightBoundary, @"Inner should have a boundary to call this function");
-
-    MTMathListDisplay* innerListDisplay = [MTTypesetter createLineForMathList:inner.innerList font:_font style:_style cramped:_cramped spaced:YES];
-    CGFloat axisHeight = _styleFont.mathTable.axisHeight;
-    // delta is the max distance from the axis
-    CGFloat delta = MAX(innerListDisplay.ascent - axisHeight, innerListDisplay.descent + axisHeight);
-    CGFloat d1 = (delta / 500) * kDelimiterFactor;  // This represents atleast 90% of the formula
-    CGFloat d2 = 2 * delta - kDelimiterShortfallPoints;  // This represents a shortfall of 5pt
-    // The size of the delimiter glyph should cover at least 90% of the formula or
-    // be at most 5pt short.
-    CGFloat glyphHeight = MAX(d1, d2);
-
-    NSMutableArray* innerElements = [[NSMutableArray alloc] init];
-    CGPoint position = CGPointZero;
-    if (inner.leftBoundary && inner.leftBoundary.nucleus.length > 0) {
-        MTDisplay* leftGlyph = [self findGlyphForBoundary:inner.leftBoundary.nucleus withHeight:glyphHeight];
-        leftGlyph.position = position;
-        position.x += leftGlyph.width;
-        [innerElements addObject:leftGlyph];
-    }
-
-    innerListDisplay.position = position;
-    position.x += innerListDisplay.width;
-    [innerElements addObject:innerListDisplay];
-
-    if (inner.rightBoundary && inner.rightBoundary.nucleus.length > 0) {
-        MTDisplay* rightGlyph = [self findGlyphForBoundary:inner.rightBoundary.nucleus withHeight:glyphHeight];
-        rightGlyph.position = position;
-        position.x += rightGlyph.width;
-        [innerElements addObject:rightGlyph];
-    }
-    MTMathListDisplay* innerDisplay = [[MTMathListDisplay alloc] initWithDisplays:innerElements range:inner.indexRange];
-    return innerDisplay;
-}
-
 - (MTDisplay*) findGlyphForBoundary:(NSString*) delimiter withHeight:(CGFloat) glyphHeight
 {
     CGFloat glyphAscent, glyphDescent, glyphWidth;
@@ -1858,4 +1812,46 @@ - (void) positionRows:(NSArray<MTDisplay*>*) rows forTable:(MTMathTable*) table
         row.position = CGPointMake(row.position.x, row.position.y - shiftDown);
     }
 }
+
+#pragma mark inner
+
+// Delimiter shortfall from plain.tex
+static const NSInteger kDelimiterFactor = 901;
+static const NSInteger kDelimiterShortfallPoints = 5;
+
+- (MTInnerDisplay*) makeInner:(MTInner*) inner atIndex:(NSUInteger) index
+{
+  NSAssert(inner.leftBoundary || inner.rightBoundary, @"Inner should have a boundary to call this function");
+
+  MTMathListDisplay* innerListDisplay = [MTTypesetter createLineForMathList:inner.innerList font:_font style:_style cramped:_cramped];
+  CGFloat axisHeight = _styleFont.mathTable.axisHeight;
+  // delta is the max distance from the axis
+  CGFloat delta = MAX(innerListDisplay.ascent - axisHeight, innerListDisplay.descent + axisHeight);
+  CGFloat d1 = (delta / 500) * kDelimiterFactor;  // This represents atleast 90% of the formula
+  CGFloat d2 = 2 * delta - kDelimiterShortfallPoints;  // This represents a shortfall of 5pt
+  // The size of the delimiter glyph should cover at least 90% of the formula or
+  // be at most 5pt short.
+  CGFloat glyphHeight = MAX(d1, d2);
+
+  MTDisplay* leftDelimiter = nil;
+  if (inner.leftBoundary && inner.leftBoundary.nucleus.length > 0) {
+    MTDisplay* leftGlyph = [self findGlyphForBoundary:inner.leftBoundary.nucleus withHeight:glyphHeight];
+    if (leftGlyph) {
+      leftDelimiter = leftGlyph;
+    }
+  }
+
+  MTDisplay* rightDelimiter = nil;
+  if (inner.rightBoundary && inner.rightBoundary.nucleus.length > 0) {
+    MTDisplay* rightGlyph = [self findGlyphForBoundary:inner.rightBoundary.nucleus withHeight:glyphHeight];
+    if (rightGlyph) {
+      rightDelimiter = rightGlyph;
+    }
+  }
+
+  MTInnerDisplay* innerDisplay = [[MTInnerDisplay alloc] initWithInner:innerListDisplay leftDelimiter:leftDelimiter rightDelimiter:rightDelimiter atIndex: index];
+
+  return innerDisplay;
+}
+
 @end

iosMathTests/MTTypesetterTest.m

@@ -993,53 +993,46 @@ - (void)testInner {
     XCTAssertEqual(display.subDisplays.count, 1);
 
     MTDisplay* sub0 = display.subDisplays[0];
-    XCTAssertTrue([sub0 isKindOfClass:[MTMathListDisplay class]]);
-    MTMathListDisplay* display2 = (MTMathListDisplay*) sub0;
-    XCTAssertEqual(display2.type, kMTLinePositionRegular);
+    XCTAssertTrue([sub0 isKindOfClass:[MTInnerDisplay class]]);
+    MTInnerDisplay* display2 = (MTInnerDisplay*) sub0;
     XCTAssertTrue(CGPointEqualToPoint(display2.position, CGPointZero));
     XCTAssertTrue(NSEqualRanges(display2.range, NSMakeRange(0, 1)));
     XCTAssertFalse(display2.hasScript);
-    XCTAssertEqual(display2.index, NSNotFound);
-    XCTAssertEqual(display2.subDisplays.count, 3);
-
-    MTDisplay* subLeft = display2.subDisplays[0];
-    XCTAssertTrue([subLeft isKindOfClass:[MTGlyphDisplay class]]);
-    MTGlyphDisplay* glyph = (MTGlyphDisplay*) subLeft;
+    XCTAssertTrue([display2.leftDelimiter isKindOfClass:[MTGlyphDisplay class]]);
+
+    MTGlyphDisplay* glyph = (MTGlyphDisplay*) display2.leftDelimiter;
     XCTAssertTrue(CGPointEqualToPoint(glyph.position, CGPointZero));
     XCTAssertTrue(NSEqualRanges(glyph.range, NSMakeRange(NSNotFound, 0)));
     XCTAssertFalse(glyph.hasScript);
-
-    MTDisplay* sub3 = display2.subDisplays[1];
-    XCTAssertTrue([sub3 isKindOfClass:[MTMathListDisplay class]]);
-    MTMathListDisplay* display3 = (MTMathListDisplay*) sub3;
-    XCTAssertEqual(display3.type, kMTLinePositionRegular);
-    XCTAssertEqualsCGPoint(display3.position, CGPointMake(7.78, 0), 0.01);
-    XCTAssertTrue(NSEqualRanges(display3.range, NSMakeRange(0, 1)));
-    XCTAssertFalse(display3.hasScript);
-    XCTAssertEqual(display3.index, NSNotFound);
-    XCTAssertEqual(display3.subDisplays.count, 1);
-
-    MTDisplay* subsub3 = display3.subDisplays[0];
+
+    XCTAssertTrue([display2.inner isKindOfClass:[MTMathListDisplay class]]);
+    MTMathListDisplay* innerMathListDisplay = (MTMathListDisplay*) display2.inner;
+    XCTAssertEqualsCGPoint(innerMathListDisplay.position, CGPointMake(7.78, 0), 0.001);
+    XCTAssertTrue(NSEqualRanges(innerMathListDisplay.range, NSMakeRange(0, 1)));
+    XCTAssertFalse(innerMathListDisplay.hasScript);
+    XCTAssertEqual(innerMathListDisplay.index, NSNotFound);
+    XCTAssertEqual(innerMathListDisplay.subDisplays.count, 1);
+
+    MTDisplay* subsub3 = innerMathListDisplay.subDisplays[0];
     XCTAssertTrue([subsub3 isKindOfClass:[MTCTLineDisplay class]]);
     MTCTLineDisplay* line = (MTCTLineDisplay*) subsub3;
     XCTAssertEqual(line.atoms.count, 1);
     // The x is italicized
     XCTAssertEqualObjects(line.attributedString.string, @"𝑥");
     XCTAssertTrue(CGPointEqualToPoint(line.position, CGPointZero));
     XCTAssertFalse(line.hasScript);
-
-    MTDisplay* subRight = display2.subDisplays[2];
-    XCTAssertTrue([subRight isKindOfClass:[MTGlyphDisplay class]]);
-    MTGlyphDisplay* glyph2 = (MTGlyphDisplay*) subRight;
-    XCTAssertEqualsCGPoint(glyph2.position, CGPointMake(19.22, 0), 0.01);
+
+    XCTAssertTrue([display2.rightDelimiter isKindOfClass:[MTGlyphDisplay class]]);
+    MTGlyphDisplay* glyph2 = (MTGlyphDisplay*) display2.rightDelimiter;
+    XCTAssertEqualsCGPoint(glyph2.position, CGPointMake(19.22, 0), 0.001);
     XCTAssertTrue(NSEqualRanges(glyph2.range, NSMakeRange(NSNotFound, 0)), "Got %@ instead", NSStringFromRange(glyph2.range));
     XCTAssertFalse(glyph2.hasScript);
-    
+
     // dimensions
     XCTAssertEqual(display.ascent, display2.ascent);
     XCTAssertEqual(display.descent, display2.descent);
     XCTAssertEqual(display.width, display2.width);
-    
+
     XCTAssertEqualWithAccuracy(display.ascent, 14.97, 0.001);
     XCTAssertEqualWithAccuracy(display.descent, 4.97, 0.001);
     XCTAssertEqualWithAccuracy(display.width, 27, 0.01);