add ASTextKitFontSizeAdjuster

AsyncDisplayKit/TextKit/ASTextKitAttributes.h

@@ -81,6 +81,10 @@ struct ASTextKitAttributes {
    The radius that should be applied to the shadow blur.  Larger values mean a larger, more blurred shadow.
    */
   CGFloat shadowRadius;
+  /**
+   The minimum scale that the textnode can apply to fit long words in constrained size.
+   */
+  CGFloat minimumScaleFactor;
   /**
    A pointer to a function that that returns a custom layout manager subclass. If nil, defaults to NSLayoutManager.
    */
@@ -103,6 +107,7 @@ struct ASTextKitAttributes {
       [shadowColor copy],
       shadowOpacity,
       shadowRadius,
+      minimumScaleFactor,
       layoutManagerFactory
     };
   };
@@ -114,6 +119,7 @@ struct ASTextKitAttributes {
     && maximumNumberOfLines == other.maximumNumberOfLines
     && shadowOpacity == other.shadowOpacity
     && shadowRadius == other.shadowRadius
+    && minimumScaleFactor == other.minimumScaleFactor
     && layoutManagerFactory == other.layoutManagerFactory
     && CGSizeEqualToSize(shadowOffset, other.shadowOffset)
     && _objectsEqual(exclusionPaths, other.exclusionPaths)

AsyncDisplayKit/TextKit/ASTextKitFontSizeAdjuster.h

@@ -0,0 +1,19 @@
+//
+//  ASTextKitFontSizeAdjuster.h
+//  AsyncDisplayKit
+//
+//  Created by Luke on 1/20/16.
+//  Copyright © 2016 Facebook. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface ASTextKitFontSizeAdjuster : NSObject
+
+
+- (instancetype)initWithContext:(ASTextKitContext *)context
+             minimumScaleFactor:(CGFloat)minimumScaleFactor
+                constrainedSize:(CGSize)constrainedSize;
+
+- (void) adjustFontSize;
+@end

AsyncDisplayKit/TextKit/ASTextKitFontSizeAdjuster.m

@@ -0,0 +1,100 @@
+//
+//  ASTextKitFontSizeAdjuster.m
+//  AsyncDisplayKit
+//
+//  Created by Luke on 1/20/16.
+//  Copyright © 2016 Facebook. All rights reserved.
+//
+
+#import "ASTextKitContext.h"
+#import "ASTextKitFontSizeAdjuster.h"
+
+@implementation ASTextKitFontSizeAdjuster
+{
+  __weak ASTextKitContext *_context;
+  CGFloat _minimumScaleFactor;
+  CGSize _constrainedSize;
+}
+
+- (instancetype)initWithContext:(ASTextKitContext *)context
+             minimumScaleFactor:(CGFloat)minimumScaleFactor
+                constrainedSize:(CGSize)constrainedSize
+{
+  if (self = [super init]) {
+    _context = context;
+    _minimumScaleFactor = minimumScaleFactor;
+    _constrainedSize = constrainedSize;
+  }
+  return self;
+}
+
+
+- (CGSize)sizeForAttributedString:(NSAttributedString *)attrString
+{
+  return [attrString boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX)
+                                  options:NSStringDrawingUsesLineFragmentOrigin
+                                  context:nil].size;
+}
+
+
+- (void) adjustFontSizeForAttributeString:(NSMutableAttributedString *)attrString withScaleFactor:(CGFloat)scaleFactor
+{
+  {
+    [attrString beginEditing];
+
+    [attrString enumerateAttribute:NSFontAttributeName inRange:NSMakeRange(0, attrString.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
+
+      UIFont* font = value;
+      font = [font fontWithSize:font.pointSize * scaleFactor];
+
+      [attrString removeAttribute:NSFontAttributeName range:range];
+      [attrString addAttribute:NSFontAttributeName value:font range:range];
+    }];
+
+    [attrString endEditing];
+  }
+}
+
+
+- (void)adjustFontSize
+{
+  if (_minimumScaleFactor <= 0 || _minimumScaleFactor >= 1) {
+    return;
+  }
+  [_context performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
+    NSString *str = textStorage.string;
+    NSArray *words = [str componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+    NSString *longestWordNeedingResize = @"";
+    for (NSString *word in words) {
+      if ([word length] > [longestWordNeedingResize length]) {
+        longestWordNeedingResize = word;
+      }
+    }
+
+    if ([longestWordNeedingResize length] == 0) {
+      return;
+    }
+
+    NSRange range = [str rangeOfString:longestWordNeedingResize];
+    NSMutableAttributedString *attrString = [textStorage attributedSubstringFromRange:range].mutableCopy;
+    CGSize defaultSize = [self sizeForAttributedString:attrString];
+
+    if (defaultSize.width > _constrainedSize.width) {
+      [attrString removeAttribute:NSParagraphStyleAttributeName range:NSMakeRange(0, [attrString length])];
+      NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
+      context.minimumScaleFactor = _minimumScaleFactor;
+      [attrString boundingRectWithSize:CGSizeMake(_constrainedSize.width, defaultSize.height)
+                               options:NSStringDrawingUsesLineFragmentOrigin
+                               context:context];
+
+      [self adjustFontSizeForAttributeString:attrString withScaleFactor:context.actualScaleFactor];
+
+      if ([self sizeForAttributedString:attrString].width <= _constrainedSize.width) {
+        [self adjustFontSizeForAttributeString:textStorage withScaleFactor:context.actualScaleFactor];
+        NSLog(@"ASTextKitFontSizeAdjuster : adjusted \"%@\"to fontsize actualScaleFactor:%f", longestWordNeedingResize, context.actualScaleFactor);
+      }
+    }
+  }];
+}
+
+@end

AsyncDisplayKit/TextKit/ASTextKitRenderer.h

@@ -16,6 +16,7 @@
 
 @class ASTextKitContext;
 @class ASTextKitShadower;
+@class ASTextKitFontSizeAdjuster;
 @protocol ASTextKitTruncating;
 
 /**
@@ -47,6 +48,8 @@ dvlkferufedgjnhjjfhldjedlunvtdtv
 
 @property (nonatomic, strong, readonly) id<ASTextKitTruncating> truncater;
 
+@property (nonatomic, strong, readonly) ASTextKitFontSizeAdjuster *fontSizeAdjuster;
+
 @property (nonatomic, strong, readonly) ASTextKitShadower *shadower;
 
 @property (nonatomic, assign, readonly) ASTextKitAttributes attributes;

AsyncDisplayKit/TextKit/ASTextKitRenderer.mm

@@ -15,6 +15,7 @@
 #import "ASTextKitContext.h"
 #import "ASTextKitShadower.h"
 #import "ASTextKitTailTruncater.h"
+#import "ASTextKitFontSizeAdjuster.h"
 #import "ASTextKitTruncating.h"
 
 static NSCharacterSet *_defaultAvoidTruncationCharacterSet()
@@ -34,7 +35,7 @@ static NSCharacterSet *_defaultAvoidTruncationCharacterSet()
   CGSize _calculatedSize;
   BOOL _sizeIsCalculated;
 }
-@synthesize attributes = _attributes, context = _context, shadower = _shadower, truncater = _truncater;
+@synthesize attributes = _attributes, context = _context, shadower = _shadower, truncater = _truncater, fontSizeAdjuster = _fontSizeAdjuster;
 
 #pragma mark - Initialization
 
@@ -75,6 +76,19 @@ static NSCharacterSet *_defaultAvoidTruncationCharacterSet()
   return _truncater;
 }
 
+- (ASTextKitFontSizeAdjuster *)fontSizeAdjuster
+{
+  if (!_fontSizeAdjuster) {
+    ASTextKitAttributes attributes = _attributes;
+    // We must inset the constrained size by the size of the shadower.
+    CGSize shadowConstrainedSize = [[self shadower] insetSizeWithConstrainedSize:_constrainedSize];
+    _fontSizeAdjuster = [[ASTextKitFontSizeAdjuster alloc] initWithContext:[self context]
+                                                        minimumScaleFactor:attributes.minimumScaleFactor
+                                                           constrainedSize:shadowConstrainedSize];
+  }
+  return _fontSizeAdjuster;
+}
+
 - (ASTextKitContext *)context
 {
   if (!_context) {
@@ -94,13 +108,16 @@ static NSCharacterSet *_defaultAvoidTruncationCharacterSet()
 
 - (void)_calculateSize
 {
+  if (_attributes.minimumScaleFactor < 1 && _attributes.minimumScaleFactor > 0) {
+    [[self fontSizeAdjuster] adjustFontSize];
+  }
+
   // Force glyph generation and layout, which may not have happened yet (and isn't triggered by
   // -usedRectForTextContainer:).
   [[self context] performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
     [layoutManager ensureLayoutForTextContainer:textContainer];
   }];
 
-
   CGRect constrainedRect = {CGPointZero, _constrainedSize};
   __block CGRect boundingRect;
   [[self context] performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {