react-native/Libraries/Text/BaseText/RCTBaseTextShadowView.m
Valentin Shergin 2716f53220 The New <Text> on iOS
Summary:
This is a complete rewrite of RCTText, the part of React Native which manages Text and TextInput components.

Key points:

* It's understandable now. It follows a simple architectural pattern, and it's easy to debug and iterate. Text flow layout is a first-class citizen in React Native layout system now, not just a wired special case. It also brings entirely new possibilities such as nested interleaving <Text> and <View> components.
* All <Text>-specific APIs were removed from UIManager and co (it's about ~16 public methods which were used exclusively only by <Text>).
* It relies on new Yoga measurement/cloning API and on-dirty handler. So, it removes built-in dirty propagation subsystem from RN completely.
* It caches string fragments properly and granularly on a per-node basis which makes updating text-containing components more performant.
* It does not instantiate UIView for virtual components which reduces memory utilization.
* It drastically improves <TextInput> capabilities (e.g. rich text inside single line <TextInput> is now supported).

Screenshots:
https://cl.ly/2j3r1V0L0324
https://cl.ly/3N2V3C3d3q3R

Reviewed By: mmmulani

Differential Revision: D6617326

fbshipit-source-id: 35d4d81b35c9870e9557d0211c0e934e6072a41e
2018-01-24 00:03:01 -08:00

126 lines
3.9 KiB
Objective-C

/**
* 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 "RCTBaseTextShadowView.h"
#import <React/RCTShadowView+Layout.h>
#import "RCTRawTextShadowView.h"
#import "RCTVirtualTextShadowView.h"
NSString *const RCTBaseTextShadowViewEmbeddedShadowViewAttributeName = @"RCTBaseTextShadowViewEmbeddedShadowViewAttributeName";
@implementation RCTBaseTextShadowView
{
NSAttributedString *_Nullable _cachedAttributedText;
RCTTextAttributes *_Nullable _cachedTextAttributes;
}
- (instancetype)init
{
if (self = [super init]) {
_textAttributes = [RCTTextAttributes new];
}
return self;
}
- (void)setReactTag:(NSNumber *)reactTag
{
[super setReactTag:reactTag];
_textAttributes.tag = reactTag;
}
#pragma mark - attributedString
- (NSAttributedString *)attributedTextWithBaseTextAttributes:(nullable RCTTextAttributes *)baseTextAttributes
{
RCTTextAttributes *textAttributes;
if (baseTextAttributes) {
textAttributes = [baseTextAttributes copy];
[textAttributes applyTextAttributes:self.textAttributes];
} else {
textAttributes = [self.textAttributes copy];
}
if (_cachedAttributedText && [_cachedTextAttributes isEqual:textAttributes]) {
return _cachedAttributedText;
}
NSMutableAttributedString *attributedText = [NSMutableAttributedString new];
[attributedText beginEditing];
for (RCTShadowView *shadowView in self.reactSubviews) {
// Special Case: RCTRawTextShadowView
if ([shadowView isKindOfClass:[RCTRawTextShadowView class]]) {
RCTRawTextShadowView *rawTextShadowView = (RCTRawTextShadowView *)shadowView;
NSString *text = rawTextShadowView.text;
if (text) {
NSAttributedString *rawTextAttributedString =
[[NSAttributedString alloc] initWithString:rawTextShadowView.text
attributes:textAttributes.effectiveTextAttributes];
[attributedText appendAttributedString:rawTextAttributedString];
}
continue;
}
// Special Case: RCTBaseTextShadowView
if ([shadowView isKindOfClass:[RCTBaseTextShadowView class]]) {
RCTBaseTextShadowView *baseTextShadowView = (RCTBaseTextShadowView *)shadowView;
NSAttributedString *baseTextAttributedString =
[baseTextShadowView attributedTextWithBaseTextAttributes:textAttributes];
[attributedText appendAttributedString:baseTextAttributedString];
continue;
}
// Generic Case: Any RCTShadowView
NSTextAttachment *attachment = [NSTextAttachment new];
NSMutableAttributedString *embeddedShadowViewAttributedString = [NSMutableAttributedString new];
[embeddedShadowViewAttributedString beginEditing];
[embeddedShadowViewAttributedString appendAttributedString:[NSAttributedString attributedStringWithAttachment:attachment]];
[embeddedShadowViewAttributedString addAttribute:RCTBaseTextShadowViewEmbeddedShadowViewAttributeName
value:shadowView
range:(NSRange){0, embeddedShadowViewAttributedString.length}];
[embeddedShadowViewAttributedString endEditing];
[attributedText appendAttributedString:embeddedShadowViewAttributedString];
}
[attributedText endEditing];
[self clearLayout];
_cachedAttributedText = [attributedText copy];
_cachedTextAttributes = textAttributes;
return _cachedAttributedText;
}
- (void)dirtyLayout
{
[super dirtyLayout];
_cachedAttributedText = nil;
_cachedTextAttributes = nil;
}
- (void)didUpdateReactSubviews
{
[super didUpdateReactSubviews];
[self dirtyLayout];
}
- (void)didSetProps:(NSArray<NSString *> *)changedProps
{
[super didSetProps:changedProps];
[self dirtyLayout];
}
@end