NSAttributedString上的模糊图像（NSTextAttachment）

Question

我正在使用NSAttributedString将图像包含在字符串中。但是，图像有时会模糊，就像在非整数帧上绘制一样。

我试图确保每个NSTextAttachment的边界是整数大小，但这似乎没有帮助。关于如何确保它不模糊的任何提示？

参见附页截图，第一辆公交车并不模糊，但第二辆公交车是模糊的。

Answer 1

我通过在NSAttributedString上添加一个类别来解决这个问题。

基本上，您需要获取NSTextAttachment的框架，并添加其X坐标的缺失小数部分，以使其很好地对齐。

- (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

您可以使用以下代码进行图像轮次

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;
}