NSAttributedString模糊圖像（NSTextAttachment）

Question

我使用NSAttributedString將圖像包含在字符串中。但是，如果在非整數幀上繪製圖像，圖像有時會模糊不清。

我試圖確保每個NSTextAttachment的邊界是整數大小，但這似乎沒有幫助。有關如何確保它不模糊的任何提示？

查看附件截圖，第一條公共汽車不是模糊的，但第二條是。

Answer 1

我通過在NSAttributedString上添加一個類別來解決這個問題。

基本上，您需要獲取NSTextAttachment的框架並添加其X座標的缺失小數部分以使其很好地舍入。

- (void)applyBlurrinessFixToAttachments { 
    [self enumerateAttribute:NSAttachmentAttributeName inRange:NSMakeRange(0, self.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) { 
     if (![value isKindOfClass:[NSTextAttachment class]]) { 
      return; 
     } 
     NSTextAttachment *attachment = (NSTextAttachment*)value; 
     CGRect bounds = attachment.bounds; 
     CGRect attributedStringRect = [self boundingRectForCharacterRange:range]; 

     double integral; 
     double fractional = modf(attributedStringRect.origin.x, &integral); 
     if (fractional > 0) { 
      double roundedXOrigin = 1.0 - fractional; 

      // If X coordinate starts at 0.7, add 0.3 to it 
      bounds.origin.x += roundedXOrigin; 
      attachment.bounds = bounds; 
     } 
    }]; 
} 

- (CGRect)boundingRectForCharacterRange:(NSRange)range { 
    NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:self]; 
    NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init]; 
    [textStorage addLayoutManager:layoutManager]; 
    NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX)]; 
textContainer.lineFragmentPadding = 0; 
    [layoutManager addTextContainer:textContainer]; 

    NSRange glyphRange; 
    [layoutManager characterRangeForGlyphRange:range actualGlyphRange:&glyphRange]; 

    return [layoutManager boundingRectForGlyphRange:glyphRange inTextContainer:textContainer]; 
} 

Answer 2

則可以使用下面的代碼圖像圓

UIGraphicsBeginImageContextWithOptions（CGSizeMake（14，14），NO，[UIScreen mainScreen] .scale）;

-(UIImage *)makeRoundedImage:(UIImage *) image radius: (float) radius { 
CALayer *imageLayer = [CALayer layer]; 
imageLayer.frame = CGRectMake(0, 0, 14, 14); 
imageLayer.contents = (id) image.CGImage; 

imageLayer.masksToBounds = YES; 
imageLayer.cornerRadius = radius; 

UIGraphicsBeginImageContextWithOptions(CGSizeMake(14, 14), NO, [UIScreen mainScreen].scale); 
[imageLayer renderInContext:UIGraphicsGetCurrentContext()]; 
UIImage *roundedImage = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); 

return roundedImage; 
}