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| @interface ViewController () <UITextViewDelegate>
@property (nonatomic, strong) NSTextStorage *storage;
@property (nonatomic, strong) NSLayoutManager *layoutManager;
@property (nonatomic, strong) NSTextContainer *textContainer;
@property (nonatomic, strong) UITextView *textView;
@property (nonatomic, strong) dispatch_queue_t queue;
@property (nonatomic, strong) NSLock *lock;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
m = i = 0;
_storage = [NSTextStorage new];
_layoutManager = ({
NSLayoutManager *layoutManager = [NSLayoutManager new];
[self.storage addLayoutManager:layoutManager];
layoutManager;
});
self.lock = [NSLock new];
_textContainer = ({
NSTextContainer *container = [NSTextContainer new];
[_layoutManager addTextContainer:container];
container;
});
_textView = ({
UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(20, 100, 200, 200)
textContainer:_textContainer];
textView.textContainerInset = UIEdgeInsetsZero;
textView.textContainer.lineFragmentPadding = 0;
textView.backgroundColor = [UIColor clearColor];
textView.scrollEnabled = NO;
textView.showsVerticalScrollIndicator = NO;
textView.showsHorizontalScrollIndicator = NO;
textView.spellCheckingType = UITextSpellCheckingTypeNo;
textView;
});
[self.view addSubview:_textView];
_textView.text = @"啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊啊";
NSTimer *timer = [NSTimer timerWithTimeInterval:0 repeats:YES block:^(NSTimer * _Nonnull timer) {
[self updateAttributesInMainThread];
}];
[[NSRunLoop mainRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
_queue = dispatch_queue_create("com.jft0m.draw", 0);
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), self.queue, ^{
while (1) {
[self drawInBackgroundThread];
}
});
}
- (void)updateAttributesInMainThread {
// [self.lock lock];
if (i == 0) {
self.textView.frame = CGRectMake(20, 100, 200, 200);
i = 1;
} else {
self.textView.frame = CGRectMake(20, 100, 300, 200);
i = 0;
}
[self.textView sizeToFit];
// [self.lock unlock];
}
- (void)drawInBackgroundThread {
// [self.lock lock];
[self.storage beginEditing];
if (m == 0) {
NSDictionary *dic = @{NSFontAttributeName : [UIFont systemFontOfSize:14.f]};
NSRange range = NSMakeRange(0, self.layoutManager.numberOfGlyphs);
[self.storage removeAttribute:NSFontAttributeName
range:range];
[self.storage setAttributes:dic
range:range];
m = 1;
} else {
NSDictionary *dic = @{NSFontAttributeName : [UIFont systemFontOfSize:29.f]};
NSRange range = NSMakeRange(0, self.layoutManager.numberOfGlyphs);
[self.storage setAttributes:dic range:range];
m = 0;
}
[self.storage endEditing];
UIGraphicsBeginImageContext(CGSizeMake(10, 10));
CGContextRef ctx = UIGraphicsGetCurrentContext();
UIGraphicsPushContext(ctx);
NSRange range = NSMakeRange(0, self.layoutManager.numberOfGlyphs);
[self.layoutManager drawGlyphsForGlyphRange:range
atPoint:CGPointZero];
UIGraphicsPopContext();
UIGraphicsEndImageContext();
// [self.lock unlock];
}
@end
|
