iOS: Support allowFontScaling on TextInput

Summary:
Currently, only `Text` supports the `allowFontScaling` prop. This commit adds support for it on `TextInput`.

As part of this change, the TextInput setters for font attributes (e.g. size, weight) had to be refactored. The problem with them is that they use RCTFont's helpers which create a new font based on an existing font. These helpers lose information. In particular, they lose the scaleMultiplier.

For example, suppose the font size is 12 and the device's font multiplier is set to 1.5. So we'd create a font with size 12 and scaleMultiplier 1.5 which is an effective size of 18 (which is the only thing stored in the font). Next, suppose the device's font multiplier changes to 1. So we'd use an RCTFont helper to create a new font based on the existing font but with a scaleMultiplier of 1. However, the font didn't store the font size (12) and scaleMultiplier (1.5) separately. It just knows the (effective) font size of 18. So RCTFont thinks the new font has a font size of 18 and a scaleMultiplier of 1 so its effective font size is 18. This is incorrect and it should have been 12.

To fix this, the font attributes are now all stored individually. Anytime one of them changes, updateFont is called which recreates the font from scratch. This happens to fix some bugs around fontStyle and fontWeight which were reported several times before: #13730, #12738, #2140, #8533.

Created a test app where I verified that `allowFontScaling` works properly for `TextInputs` for all values (`undefined`, `true`, `false`) for a variety of `TextInputs`:
  - Singleline TextInput
  - Singleline TextInput's placeholder
  - Multiline TextInput
  - Multiline TextInput's placeholder
  - Multiline TextInput using children instead of `value`

Also, verified switching `fontSize`, `fontWeight`, `fontStyle` and `fontFamily` through a bunch of combinations works properly.

Lastly, my team has been using this change in our app.

Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/14030

Reviewed By: TheSavior

Differential Revision: D5899959

Pulled By: shergin

fbshipit-source-id: c8c8c4d4d670cd2a142286e79bfffef3b58cecd3

Libraries/Components/TextInput/TextInput.js

@@ -227,6 +227,11 @@ const TextInput = createReactClass({
      * @platform android
      */
     autoGrow: PropTypes.bool,
+    /**
+     * Specifies whether fonts should scale to respect Text Size accessibility settings. The
+     * default is `true`.
+     */
+    allowFontScaling: PropTypes.bool,
     /**
      * If `false`, text is not editable. The default value is `true`.
      */
@@ -566,7 +571,11 @@ const TextInput = createReactClass({
      */
     caretHidden: PropTypes.bool,
   },
-
+  getDefaultProps(): Object {
+    return {
+      allowFontScaling: true,
+    };
+  },
   /**
    * `NativeMethodsMixin` will look for this when invoking `setNativeProps`. We
    * make `this` look like an actual native component class.
@@ -704,7 +713,7 @@ const TextInput = createReactClass({
         'Cannot specify both value and children.'
       );
       if (childCount >= 1) {
-        children = <Text style={props.style}>{children}</Text>;
+        children = <Text style={props.style} allowFontScaling={props.allowFontScaling}>{children}</Text>;
       }
       if (props.inputView) {
         children = [children, props.inputView];

Libraries/Text/RCTFontAttributes.h

@@ -0,0 +1,31 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import "RCTFontAttributesDelegate.h"
+
+@class RCTAccessibilityManager;
+
+@interface RCTFontAttributes : NSObject
+
+@property (nonatomic, weak) id<RCTFontAttributesDelegate> delegate;
+
+@property (readonly, nonatomic, strong) UIFont *font;
+
+@property (nonatomic, assign) BOOL allowFontScaling;
+@property (nonatomic, copy) NSString *fontFamily;
+@property (nonatomic, strong) NSNumber *fontSize;
+@property (nonatomic, assign) CGFloat fontSizeMultiplier;
+@property (nonatomic, copy) NSString *fontStyle;
+@property (nonatomic, copy) NSString *fontWeight;
+
+- (instancetype)initWithAccessibilityManager:(RCTAccessibilityManager *)accessibilityManager;
+
+@end

Libraries/Text/RCTFontAttributes.m

@@ -0,0 +1,112 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "RCTFontAttributes.h"
+
+#import <React/RCTAccessibilityManager.h>
+#import <React/RCTAssert.h>
+#import <React/RCTFont.h>
+#import <React/RCTLog.h>
+
+@interface RCTFontAttributes ()
+{
+  RCTAccessibilityManager *_accessibilityManager;
+}
+
+@property (nonatomic, strong) UIFont *font;
+
+@end
+
+@implementation RCTFontAttributes
+
+- (instancetype)initWithAccessibilityManager:(RCTAccessibilityManager *)accessibilityManager
+{
+  RCTAssertParam(accessibilityManager);
+
+  if (self = [super init]) {
+    _accessibilityManager = accessibilityManager;
+    _fontSizeMultiplier = _accessibilityManager.multiplier;
+
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(contentSizeMultiplierDidChange)
+                                                 name:RCTAccessibilityManagerDidUpdateMultiplierNotification
+                                               object:_accessibilityManager];
+
+    [self updateFont];
+  }
+  return self;
+}
+
+- (void)dealloc
+{
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+}
+
+- (void)contentSizeMultiplierDidChange
+{
+  self.fontSizeMultiplier = _accessibilityManager.multiplier;
+}
+
+- (void)setAllowFontScaling:(BOOL)allowFontScaling
+{
+  _allowFontScaling = allowFontScaling;
+  [self updateFont];
+}
+
+- (void)setFontFamily:(NSString *)fontFamily
+{
+  _fontFamily = fontFamily;
+  [self updateFont];
+}
+
+- (void)setFontSize:(NSNumber *)fontSize
+{
+  _fontSize = fontSize;
+  [self updateFont];
+}
+
+- (void)setFontSizeMultiplier:(CGFloat)fontSizeMultiplier
+{
+   _fontSizeMultiplier = fontSizeMultiplier;
+
+  if (_fontSizeMultiplier == 0) {
+    RCTLogError(@"fontSizeMultiplier value must be > zero.");
+    _fontSizeMultiplier = 1.0;
+  }
+
+  [self updateFont];
+}
+
+- (void)setFontStyle:(NSString *)fontStyle
+{
+  _fontStyle = fontStyle;
+  [self updateFont];
+}
+
+- (void)setFontWeight:(NSString *)fontWeight
+{
+  _fontWeight = fontWeight;
+  [self updateFont];
+}
+
+- (void)updateFont
+{
+  CGFloat scaleMultiplier = self.allowFontScaling ? self.fontSizeMultiplier : 1.0;
+  self.font = [RCTFont updateFont:nil
+                       withFamily:self.fontFamily
+                             size:self.fontSize
+                           weight:self.fontWeight
+                           style:self.fontStyle
+                         variant:nil
+                 scaleMultiplier:scaleMultiplier];
+
+  [self.delegate fontAttributesDidChangeWithFont:self.font];
+}
+
+@end

Libraries/Text/RCTFontAttributesDelegate.h

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+@protocol RCTFontAttributesDelegate <NSObject>
+
+- (void)fontAttributesDidChangeWithFont:(UIFont *)font;
+
+@end

Libraries/Text/RCTText.xcodeproj/project.pbxproj

@@ -43,6 +43,7 @@
 		59F60E921E661BDD0081153B /* RCTShadowTextField.m in Sources */ = {isa = PBXBuildFile; fileRef = 59F60E8E1E661BDD0081153B /* RCTShadowTextField.m */; };
 		59F60E931E661BDD0081153B /* RCTShadowTextView.m in Sources */ = {isa = PBXBuildFile; fileRef = 59F60E901E661BDD0081153B /* RCTShadowTextView.m */; };
 		59F60E941E661BDD0081153B /* RCTShadowTextView.m in Sources */ = {isa = PBXBuildFile; fileRef = 59F60E901E661BDD0081153B /* RCTShadowTextView.m */; };
+		A85C829A1F742AA20036C019 /* RCTFontAttributes.m in Sources */ = {isa = PBXBuildFile; fileRef = A85C82991F742AA20036C019 /* RCTFontAttributes.m */; };
 		AF3225F91DE5574F00D3E7E7 /* RCTConvert+Text.m in Sources */ = {isa = PBXBuildFile; fileRef = AF3225F81DE5574F00D3E7E7 /* RCTConvert+Text.m */; };
 		AF3225FA1DE5574F00D3E7E7 /* RCTConvert+Text.m in Sources */ = {isa = PBXBuildFile; fileRef = AF3225F81DE5574F00D3E7E7 /* RCTConvert+Text.m */; };
 /* End PBXBuildFile section */
@@ -111,6 +112,9 @@
 		59F60E8E1E661BDD0081153B /* RCTShadowTextField.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTShadowTextField.m; sourceTree = "<group>"; };
 		59F60E8F1E661BDD0081153B /* RCTShadowTextView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTShadowTextView.h; sourceTree = "<group>"; };
 		59F60E901E661BDD0081153B /* RCTShadowTextView.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTShadowTextView.m; sourceTree = "<group>"; };
+		A85C82981F742AA20036C019 /* RCTFontAttributes.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTFontAttributes.h; sourceTree = "<group>"; };
+		A85C82991F742AA20036C019 /* RCTFontAttributes.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTFontAttributes.m; sourceTree = "<group>"; };
+		A85C82BA1F742D8F0036C019 /* RCTFontAttributesDelegate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTFontAttributesDelegate.h; sourceTree = "<group>"; };
 		AF3225F71DE5574F00D3E7E7 /* RCTConvert+Text.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "RCTConvert+Text.h"; sourceTree = "<group>"; };
 		AF3225F81DE5574F00D3E7E7 /* RCTConvert+Text.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "RCTConvert+Text.m"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -126,6 +130,9 @@
 				599DF25D1F0304B30079B53E /* RCTBackedTextInputViewProtocol.h */,
 				AF3225F71DE5574F00D3E7E7 /* RCTConvert+Text.h */,
 				AF3225F81DE5574F00D3E7E7 /* RCTConvert+Text.m */,
+				A85C82981F742AA20036C019 /* RCTFontAttributes.h */,
+				A85C82991F742AA20036C019 /* RCTFontAttributes.m */,
+				A85C82BA1F742D8F0036C019 /* RCTFontAttributesDelegate.h */,
 				58B511C61A9E6C5C00147676 /* RCTRawTextManager.h */,
 				58B511C71A9E6C5C00147676 /* RCTRawTextManager.m */,
 				58B511C81A9E6C5C00147676 /* RCTShadowRawText.h */,
@@ -278,6 +285,7 @@
 				1362F1001B4D51F400E06D8C /* RCTTextField.m in Sources */,
 				59AF89AA1EDCBCC700F004B1 /* RCTUITextField.m in Sources */,
 				598F41261F145D4900B8495B /* RCTBackedTextInputDelegateAdapter.m in Sources */,
+				A85C829A1F742AA20036C019 /* RCTFontAttributes.m in Sources */,
 				58B512161A9E6EFF00147676 /* RCTText.m in Sources */,
 				599DF2641F03076D0079B53E /* RCTTextInput.m in Sources */,
 				1362F1011B4D51F400E06D8C /* RCTTextFieldManager.m in Sources */,

Libraries/Text/RCTTextField.m

@@ -12,6 +12,7 @@
 #import <React/RCTBridge.h>
 #import <React/RCTConvert.h>
 #import <React/RCTEventDispatcher.h>
+#import <React/RCTFont.h>
 #import <React/RCTUIManager.h>
 #import <React/RCTUtils.h>
 #import <React/UIView+React.h>
@@ -40,6 +41,7 @@
     _backedTextInput = [[RCTUITextField alloc] initWithFrame:self.bounds];
     _backedTextInput.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
     _backedTextInput.textInputDelegate = self;
+    _backedTextInput.font = self.fontAttributes.font;
 
     [self addSubview:_backedTextInput];
   }

Libraries/Text/RCTTextFieldManager.m

@@ -35,11 +35,16 @@ RCT_EXPORT_MODULE()
 
 #pragma mark - Unified <TextInput> properties
 
+RCT_REMAP_VIEW_PROPERTY(allowFontScaling, fontAttributes.allowFontScaling, BOOL)
 RCT_REMAP_VIEW_PROPERTY(autoCapitalize, backedTextInputView.autocapitalizationType, UITextAutocapitalizationType)
 RCT_REMAP_VIEW_PROPERTY(autoCorrect, backedTextInputView.autocorrectionType, UITextAutocorrectionType)
 RCT_REMAP_VIEW_PROPERTY(color, backedTextInputView.textColor, UIColor)
 RCT_REMAP_VIEW_PROPERTY(editable, backedTextInputView.editable, BOOL)
 RCT_REMAP_VIEW_PROPERTY(enablesReturnKeyAutomatically, backedTextInputView.enablesReturnKeyAutomatically, BOOL)
+RCT_REMAP_VIEW_PROPERTY(fontSize, fontAttributes.fontSize, NSNumber)
+RCT_REMAP_VIEW_PROPERTY(fontWeight, fontAttributes.fontWeight, NSString)
+RCT_REMAP_VIEW_PROPERTY(fontStyle, fontAttributes.fontStyle, NSString)
+RCT_REMAP_VIEW_PROPERTY(fontFamily, fontAttributes.fontFamily, NSString)
 RCT_REMAP_VIEW_PROPERTY(keyboardAppearance, backedTextInputView.keyboardAppearance, UIKeyboardAppearance)
 RCT_REMAP_VIEW_PROPERTY(keyboardType, backedTextInputView.keyboardType, UIKeyboardType)
 RCT_REMAP_VIEW_PROPERTY(placeholder, backedTextInputView.placeholder, NSString)
@@ -61,22 +66,7 @@ RCT_EXPORT_VIEW_PROPERTY(text, NSString)
 RCT_REMAP_VIEW_PROPERTY(caretHidden, backedTextInputView.caretHidden, BOOL)
 RCT_REMAP_VIEW_PROPERTY(clearButtonMode, backedTextInputView.clearButtonMode, UITextFieldViewMode)
 RCT_EXPORT_VIEW_PROPERTY(onSelectionChange, RCTDirectEventBlock)
-RCT_CUSTOM_VIEW_PROPERTY(fontSize, NSNumber, RCTTextField)
-{
-  view.backedTextInputView.font = [RCTFont updateFont:view.backedTextInputView.font withSize:json ?: @(defaultView.backedTextInputView.font.pointSize)];
-}
-RCT_CUSTOM_VIEW_PROPERTY(fontWeight, NSString, __unused RCTTextField)
-{
-  view.backedTextInputView.font = [RCTFont updateFont:view.backedTextInputView.font withWeight:json]; // defaults to normal
-}
-RCT_CUSTOM_VIEW_PROPERTY(fontStyle, NSString, __unused RCTTextField)
-{
-  view.backedTextInputView.font = [RCTFont updateFont:view.backedTextInputView.font withStyle:json]; // defaults to normal
-}
-RCT_CUSTOM_VIEW_PROPERTY(fontFamily, NSString, RCTTextField)
-{
-  view.backedTextInputView.font = [RCTFont updateFont:view.backedTextInputView.font withFamily:json ?: defaultView.backedTextInputView.font.familyName];
-}
+
 RCT_EXPORT_VIEW_PROPERTY(mostRecentEventCount, NSInteger)
 
 - (RCTViewManagerUIBlock)uiBlockToAmendWithShadowView:(RCTShadowView *)shadowView

Libraries/Text/RCTTextInput.h

@@ -12,12 +12,14 @@
 #import <React/RCTView.h>
 
 #import "RCTBackedTextInputViewProtocol.h"
+#import "RCTFontAttributes.h"
+#import "RCTFontAttributesDelegate.h"
 
 @class RCTBridge;
 @class RCTEventDispatcher;
 @class RCTTextSelection;
 
-@interface RCTTextInput : RCTView {
+@interface RCTTextInput : RCTView <RCTFontAttributesDelegate> {
 @protected
   RCTBridge *_bridge;
   RCTEventDispatcher *_eventDispatcher;
@@ -41,12 +43,16 @@
 @property (nonatomic, copy) RCTDirectEventBlock onContentSizeChange;
 @property (nonatomic, copy) RCTDirectEventBlock onSelectionChange;
 
+@property (nonatomic, readonly, strong) RCTFontAttributes *fontAttributes;
+
 @property (nonatomic, assign) NSInteger mostRecentEventCount;
 @property (nonatomic, assign) BOOL blurOnSubmit;
 @property (nonatomic, assign) BOOL selectTextOnFocus;
 @property (nonatomic, assign) BOOL clearTextOnFocus;
 @property (nonatomic, copy) RCTTextSelection *selection;
 
+- (void)setFont:(UIFont *)font;
+
 - (void)invalidateContentSize;
 
 // Temporary exposure of particial `RCTBackedTextInputDelegate` support.

Libraries/Text/RCTTextInput.m

@@ -9,11 +9,12 @@
 
 #import "RCTTextInput.h"
 
+#import <React/RCTAccessibilityManager.h>
 #import <React/RCTBridge.h>
 #import <React/RCTConvert.h>
 #import <React/RCTEventDispatcher.h>
-#import <React/RCTUtils.h>
 #import <React/RCTUIManager.h>
+#import <React/RCTUtils.h>
 #import <React/UIView+React.h>
 
 #import "RCTTextSelection.h"
@@ -29,6 +30,8 @@
   if (self = [super initWithFrame:CGRectZero]) {
     _bridge = bridge;
     _eventDispatcher = bridge.eventDispatcher;
+    _fontAttributes = [[RCTFontAttributes alloc] initWithAccessibilityManager:bridge.accessibilityManager];
+    _fontAttributes.delegate = self;
   }
 
   return self;
@@ -44,6 +47,17 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithFrame:(CGRect)frame)
   return nil;
 }
 
+- (void)setFont:(UIFont *)font
+{
+  self.backedTextInputView.font = font;
+  [self invalidateContentSize];
+}
+
+- (void)fontAttributesDidChangeWithFont:(UIFont *)font
+{
+  self.font = font;
+}
+
 #pragma mark - Properties
 
 - (void)setReactPaddingInsets:(UIEdgeInsets)reactPaddingInsets

Libraries/Text/RCTTextView.m

@@ -11,6 +11,7 @@
 
 #import <React/RCTConvert.h>
 #import <React/RCTEventDispatcher.h>
+#import <React/RCTFont.h>
 #import <React/RCTUIManager.h>
 #import <React/RCTUtils.h>
 #import <React/UIView+React.h>
@@ -54,8 +55,8 @@
     _backedTextInput.scrollsToTop = NO;
 #endif
     _backedTextInput.scrollEnabled = YES;
-
     _backedTextInput.textInputDelegate = self;
+    _backedTextInput.font = self.fontAttributes.font;
 
     [self addSubview:_backedTextInput];
   }

Libraries/Text/RCTTextViewManager.m

@@ -35,11 +35,16 @@ RCT_EXPORT_MODULE()
 
 #pragma mark - Unified <TextInput> properties
 
+RCT_REMAP_VIEW_PROPERTY(allowFontScaling, fontAttributes.allowFontScaling, BOOL)
 RCT_REMAP_VIEW_PROPERTY(autoCapitalize, backedTextInputView.autocapitalizationType, UITextAutocapitalizationType)
 RCT_REMAP_VIEW_PROPERTY(autoCorrect, backedTextInputView.autocorrectionType, UITextAutocorrectionType)
 RCT_REMAP_VIEW_PROPERTY(color, backedTextInputView.textColor, UIColor)
 RCT_REMAP_VIEW_PROPERTY(editable, backedTextInputView.editable, BOOL)
 RCT_REMAP_VIEW_PROPERTY(enablesReturnKeyAutomatically, backedTextInputView.enablesReturnKeyAutomatically, BOOL)
+RCT_REMAP_VIEW_PROPERTY(fontSize, fontAttributes.fontSize, NSNumber)
+RCT_REMAP_VIEW_PROPERTY(fontWeight, fontAttributes.fontWeight, NSString)
+RCT_REMAP_VIEW_PROPERTY(fontStyle, fontAttributes.fontStyle, NSString)
+RCT_REMAP_VIEW_PROPERTY(fontFamily, fontAttributes.fontFamily, NSString)
 RCT_REMAP_VIEW_PROPERTY(keyboardAppearance, backedTextInputView.keyboardAppearance, UIKeyboardAppearance)
 RCT_REMAP_VIEW_PROPERTY(keyboardType, backedTextInputView.keyboardType, UIKeyboardType)
 RCT_REMAP_VIEW_PROPERTY(placeholder, backedTextInputView.placeholder, NSString)
@@ -64,22 +69,6 @@ RCT_EXPORT_VIEW_PROPERTY(onSelectionChange, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onScroll, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onTextInput, RCTDirectEventBlock)
 
-RCT_CUSTOM_VIEW_PROPERTY(fontSize, NSNumber, RCTTextView)
-{
-  view.font = [RCTFont updateFont:view.font withSize:json ?: @(defaultView.font.pointSize)];
-}
-RCT_CUSTOM_VIEW_PROPERTY(fontWeight, NSString, __unused RCTTextView)
-{
-  view.font = [RCTFont updateFont:view.font withWeight:json]; // defaults to normal
-}
-RCT_CUSTOM_VIEW_PROPERTY(fontStyle, NSString, __unused RCTTextView)
-{
-  view.font = [RCTFont updateFont:view.font withStyle:json]; // defaults to normal
-}
-RCT_CUSTOM_VIEW_PROPERTY(fontFamily, NSString, RCTTextView)
-{
-  view.font = [RCTFont updateFont:view.font withFamily:json ?: defaultView.font.familyName];
-}
 RCT_EXPORT_VIEW_PROPERTY(mostRecentEventCount, NSInteger)
 
 #if !TARGET_OS_TV