Feature: Color (#54)

* add color-command * add color-feature to the readme; add example * bugfix redraw * restructure for the color-command * bugfix failed travis build: UIColor->MTColor
kostub · Apr 13, 2017 · 563551f · 563551f
1 parent fd76ff2
commit 563551f
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diff --git a/Podfile.lock b/Podfile.lock
@@ -1,5 +1,5 @@
 PODS:
-  - iosMath (0.9.2)
+  - iosMath (0.9.3)
 
 DEPENDENCIES:
   - iosMath (from `./`)
@@ -9,8 +9,8 @@ EXTERNAL SOURCES:
     :path: ./
 
 SPEC CHECKSUMS:
-  iosMath: 0f978bf5528620d3fc585c33ff969839cfe611c1
+  iosMath: 619e53c34dfa19ac3062869f9974747b44507083
 
 PODFILE CHECKSUM: bade56080a0531a08830155fc215a0a5b44dd183
 
-COCOAPODS: 1.1.1
+COCOAPODS: 1.2.0
diff --git a/README.md b/README.md
@@ -109,6 +109,7 @@ This is a list of formula types that the library currently supports:
 * Equation alignment
 * Change bold, roman, caligraphic and other font styles (\\bf, \\text, etc.)
 * Most commonly used math symbols
+* Colors
 
 ### Example
 

diff --git a/iosMath/lib/MTMathList.h b/iosMath/lib/MTMathList.h
@@ -72,6 +72,7 @@ typedef NS_ENUM(NSUInteger, MTMathAtomType)
     kMTMathAtomSpace = 201,
     /// Denotes style changes during rendering.
     kMTMathAtomStyle,
+    kMTMathAtomColor,
 
     // Atoms after this point are not part of TeX and do not have the usual structure.
 
@@ -322,6 +323,23 @@ typedef NS_ENUM(unsigned int, MTLineStyle)  {
 
 @end
 
+/** An atom representing an color element.
+ @note None of the usual fields of the `MTMathAtom` apply even though this
+ class inherits from `MTMathAtom`. i.e. it is meaningless to have a value
+ in the nucleus, subscript or superscript fields. */
+@interface MTMathColor : MTMathAtom
+
+/// Creates an empty color with a nil environment
+- (instancetype) init NS_DESIGNATED_INITIALIZER;
+
+/** The style represented by this object. */
+@property (nonatomic, nullable) NSString* colorString;
+
+/// The inner math list
+@property (nonatomic, nullable) MTMathList* innerList;
+
+@end
+
 /** An atom representing an table element. This atom is not like other
  atoms and is not present in TeX. We use it to represent the `\halign` command
  in TeX with some simplifications. This is used for matrices, equation

diff --git a/iosMath/lib/MTMathList.m b/iosMath/lib/MTMathList.m
@@ -66,6 +66,8 @@ static BOOL isNotBinaryOperator(MTMathAtom* prevNode)
             return @"Space";
         case kMTMathAtomStyle:
             return @"Style";
+        case kMTMathAtomColor:
+            return @"Color";
         case kMTMathAtomTable:
             return @"Table";
     }
@@ -116,6 +118,9 @@ + (instancetype)atomWithType:(MTMathAtomType)type value:(NSString *)value
 
         case kMTMathAtomSpace:
             return [[MTMathSpace alloc] initWithSpace:0];
+
+        case kMTMathAtomColor:
+            return [[MTMathColor alloc] init];
 
         default:
             return [[MTMathAtom alloc] initWithType:type value:value];
@@ -652,6 +657,51 @@ - (id)copyWithZone:(NSZone *)zone
 
 @end
 
+#pragma mark - MTMathColor
+
+@implementation MTMathColor
+
+
+- (instancetype)init
+{
+    self = [super initWithType:kMTMathAtomColor value:@""];
+    return self;
+}
+
+- (instancetype)initWithType:(MTMathAtomType)type value:(NSString *)value
+{
+    if (type == kMTMathAtomColor) {
+        return [self init];
+    }
+    @throw [NSException exceptionWithName:@"InvalidMethod"
+                                   reason:@"[MTMathColor initWithType:value:] cannot be called. Use [MTMathColor init] instead."
+                                 userInfo:nil];
+}
+
+- (NSString *)stringValue
+{
+    NSMutableString* str = [NSMutableString stringWithString:@"\\color"];
+    [str appendFormat:@"{%@}{%@}", self.colorString, self.innerList.stringValue];
+    return str;
+}
+
+- (id)copyWithZone:(NSZone *)zone
+{
+    MTMathColor* op = [super copyWithZone:zone];
+    op.innerList = [self.innerList copyWithZone:zone];
+    op->_colorString = self.colorString;
+    return op;
+}
+
+- (instancetype)finalized
+{
+    MTMathColor *newInner = [super finalized];
+    newInner.innerList = newInner.innerList.finalized;
+    return newInner;
+}
+
+@end
+
 #pragma mark - MTMathTable
 
 @interface MTMathTable ()

diff --git a/iosMath/lib/MTMathListBuilder.m b/iosMath/lib/MTMathListBuilder.m
@@ -271,6 +271,38 @@ - (NSString*) readString
     return mutable;
 }
 
+- (NSString*) readColor
+{
+    if (![self expectCharacter:'{']) {
+        // We didn't find an opening brace, so no env found.
+        [self setError:MTParseErrorCharacterNotFound message:@"Missing {"];
+        return nil;
+    }
+
+    // Ignore spaces and nonascii.
+    [self skipSpaces];
+
+    // a string of all upper and lower case characters.
+    NSMutableString* mutable = [NSMutableString string];
+    while([self hasCharacters]) {
+        unichar ch = [self getNextCharacter];
+        if (ch == '#' || (ch >= 'A' && ch <= 'F') || (ch >= 'a' && ch <= 'f') || (ch >= '0' && ch <= '9')) {
+            [mutable appendString:[NSString stringWithCharacters:&ch length:1]];
+        } else {
+            // we went too far
+            [self unlookCharacter];
+            break;
+        }
+    }
+
+    if (![self expectCharacter:'}']) {
+        // We didn't find an closing brace, so invalid format.
+        [self setError:MTParseErrorCharacterNotFound message:@"Missing }"];
+        return nil;
+    }
+    return mutable;
+}
+
 - (void) skipSpaces
 {
     while ([self hasCharacters]) {
@@ -462,6 +494,12 @@ - (MTMathAtom*) atomForCommand:(NSString*) command
         }
         MTMathAtom* table = [self buildTable:env firstList:nil row:NO];
         return table;
+    } else if ([command isEqualToString:@"color"]) {
+        // A color command has 2 arguments
+        MTMathColor* mathColor = [[MTMathColor alloc] init];
+        mathColor.colorString = [self readColor];
+        mathColor.innerList = [self buildInternal:true];
+        return mathColor;
     } else {
         NSString* errorMessage = [NSString stringWithFormat:@"Invalid command \\%@", command];
         [self setError:MTParseErrorInvalidCommand message:errorMessage];

diff --git a/iosMath/render/MTConfig.h b/iosMath/render/MTConfig.h
@@ -16,6 +16,7 @@
 // TARGET_OS_MAC is defined as 1 for both Mac OS and iOS,
 // so TARGET_OS_IPHONE is reliable.
 @import UIKit;
+#import "UIColor+HexString.h"
 
 typedef UIView          MTView;
 typedef UIColor         MTColor;
@@ -31,6 +32,7 @@ typedef CGRect          MTRect;
 @import AppKit;
 #import "NSBezierPath+addLineToPoint.h"
 #import "NSView+backgroundColor.h"
+#import "NSColor+HexString.h"
 #import "MTLabel.h"
 
 typedef NSView          MTView;

diff --git a/iosMath/render/MTMathListDisplay.h b/iosMath/render/MTMathListDisplay.h
@@ -49,6 +49,9 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, readonly) BOOL hasScript;
 /// The text color for this display
 @property (nonatomic, nullable) MTColor *textColor;
+// The local color, if the color was mutated local with the color
+// command
+@property (nonatomic, nullable) MTColor *localTextColor;
 
 @end
 

diff --git a/iosMath/render/MTMathListDisplay.m b/iosMath/render/MTMathListDisplay.m
@@ -200,7 +200,13 @@ - (void)setTextColor:(MTColor *)textColor
     // Set the color on all subdisplays
     [super setTextColor:textColor];
     for (MTDisplay* displayAtom in self.subDisplays) {
-        displayAtom.textColor = textColor;
+        // set the global color, if there is no local color
+        if(displayAtom.localTextColor == nil) {
+            displayAtom.textColor = textColor;
+        } else {
+            displayAtom.textColor = displayAtom.localTextColor;
+        }
+
     }
 }
 

diff --git a/iosMath/render/NSColor+HexString.h b/iosMath/render/NSColor+HexString.h
@@ -0,0 +1,19 @@
+//
+//  NSColor+HexString.h
+//  iosMath
+//
+//  Created by Markus Sähn on 21/03/2017.
+//
+//
+
+#include <TargetConditionals.h>
+
+#if !TARGET_OS_IPHONE
+#import <Cocoa/Cocoa.h>
+
+@interface NSColor (HexString)
+
++ (NSColor *)colorFromHexString:(NSString *)hexString;
+
+@end
+#endif
diff --git a/iosMath/render/NSColor+HexString.m b/iosMath/render/NSColor+HexString.m
@@ -0,0 +1,35 @@
+//
+//  NSColor+HexString.m
+//  iosMath
+//
+//  Created by Markus Sähn on 21/03/2017.
+//
+//
+
+#import "NSColor+HexString.h"
+
+#if !TARGET_OS_IPHONE
+@implementation NSColor (HexString)
+
++ (NSColor *)colorFromHexString:(NSString *)hexString {
+    if ([hexString isEqualToString:@""]) {
+        return nil;
+    }
+
+    if ([hexString characterAtIndex:0] != '#') {
+        return nil;
+    }
+
+    unsigned rgbValue = 0;
+
+    NSScanner *scanner = [NSScanner scannerWithString:hexString];
+    if ([hexString characterAtIndex:0] == '#') {
+        [scanner setScanLocation:1];
+    }
+
+    [scanner scanHexInt:&rgbValue];
+    return [NSColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
+}
+
+@end
+#endif
diff --git a/iosMath/render/UIColor+HexString.h b/iosMath/render/UIColor+HexString.h
@@ -0,0 +1,16 @@
+//
+//  UIColor+HexString.h
+//  iosMath
+//
+//  Created by Markus Sähn on 21/03/2017.
+//
+//
+
+#if TARGET_OS_IPHONE
+
+@interface UIColor (HexString)
+
++ (UIColor *)colorFromHexString:(NSString *)hexString;
+
+@end
+#endif
diff --git a/iosMath/render/UIColor+HexString.m b/iosMath/render/UIColor+HexString.m
@@ -0,0 +1,36 @@
+//
+//  UIColor+HexString.m
+//  iosMath
+//
+//  Created by Markus Sähn on 21/03/2017.
+//
+//
+
+#import "UIColor+HexString.h"
+
+#if TARGET_OS_IPHONE
+
+@implementation UIColor (HexString)
+
++ (UIColor *)colorFromHexString:(NSString *)hexString {
+    if ([hexString isEqualToString:@""]) {
+        return nil;
+    }
+
+    if ([hexString characterAtIndex:0] != '#') {
+        return nil;
+    }
+
+    unsigned rgbValue = 0;
+
+    NSScanner *scanner = [NSScanner scannerWithString:hexString];
+    if ([hexString characterAtIndex:0] == '#') {
+        [scanner setScanLocation:1];
+    }
+
+    [scanner scanHexInt:&rgbValue];
+    return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
+}
+
+@end
+#endif
diff --git a/iosMath/render/internal/MTTypesetter.m b/iosMath/render/internal/MTTypesetter.m
@@ -47,6 +47,7 @@ typedef NS_ENUM(int, MTInterElementSpaceType) {
 // Get's the index for the given type. If row is true, the index is for the row (i.e. left element) otherwise it is for the column (right element)
 NSUInteger getInterElementSpaceArrayIndexForType(MTMathAtomType type, BOOL row) {
     switch (type) {
+        case kMTMathAtomColor:
         case kMTMathAtomOrdinary:
         case kMTMathAtomPlaceholder:   // A placeholder is treated as ordinary
             return 0;
@@ -614,6 +615,20 @@ - (void) createDisplayAtoms:(NSArray*) preprocessed
                 continue;
             }
 
+            case kMTMathAtomColor: {
+                // stash the existing layout
+                if (_currentLine.length > 0) {
+                    [self addDisplayLine];
+                }
+                MTMathColor* colorAtom = (MTMathColor*) atom;
+                MTDisplay* display = [MTTypesetter createLineForMathList:colorAtom.innerList font:_font style:_style];
+                display.localTextColor = [MTColor colorFromHexString:colorAtom.colorString];
+                display.position = _currentPosition;
+                _currentPosition.x += display.width;
+                [_displayAtoms addObject:display];
+                break;
+            }
+
             case kMTMathAtomRadical: {
                 // stash the existing layout
                 if (_currentLine.length > 0) {

diff --git a/iosMathExample/example/ViewController.m b/iosMathExample/example/ViewController.m
@@ -99,7 +99,7 @@ - (void)viewDidLoad
                                                                                       views:views]];
 
 
-    self.demoLabels[1] = [self createMathLabel:@"(a_1+a_2)^2=a_1^2+2a_1a_2+a_2^2" withHeight:40];
+    self.demoLabels[1] = [self createMathLabel:@"\\color{#ff3399}{(a_1+a_2)^2}=a_1^2+2a_1a_2+a_2^2" withHeight:40];
 
     self.demoLabels[2] = [self createMathLabel:@"\\cos(\\theta + \\varphi) = \
                                  \\cos(\\theta)\\cos(\\varphi) - \\sin(\\theta)\\sin(\\varphi)"
@@ -175,6 +175,8 @@ - (void)viewDidLoad
                            "\\frac{e^x}{2} & x \\geq 0 \\\\"
                            "1 & x < 0"
                            "\\end{cases}" withHeight:60];
+
+    self.demoLabels[21] = [self createMathLabel:@"\\color{#ff3333}{c}\\color{#9933ff}{o}\\color{#ff0080}{l}+\\color{#99ff33}{\\frac{\\color{#ff99ff}{o}}{\\color{#990099}{r}}}-\\color{#33ffff}{\\sqrt[\\color{#3399ff}{e}]{\\color{#3333ff}{d}}}" withHeight:60];
 
 
     for (NSUInteger i = 1; i < self.demoLabels.count; i++) {