無法在多行nsstring上得到陰影

Question

我想要使用陰影繪製多行文本而不使用不贊成使用的API。它適用於單行。相關的代碼看起來是這樣的：

-(void)drawRect:(CGRect)rect 
{ 
    NSMutableParagraphStyle *paragraph = [[NSMutableParagraphStyle defaultParagraphStyle] mutableCopy]; 
    paragraph.lineBreakMode = NSLineBreakByWordWrapping; 
    paragraph.alignment = NSTextAlignmentCenter; 

    UIFont *f = [UIFont systemFontOfSize:20.0]; 
    NSMutableDictionary *attributes = [NSMutableDictionary new]; 
    [attributes setValuesForKeysWithDictionary:@{ NSFontAttributeName : f, 
                NSParagraphStyleAttributeName : paragraph, 
                NSForegroundColorAttributeName : [UIColor blueColor] }]; 
    NSShadow * shadow = [NSShadow new]; 
    shadow.shadowOffset = CGSizeMake(4,4); 
    shadow.shadowColor = [UIColor redColor]; 

    [attributes setValue:shadow forKey:NSShadowAttributeName]; 

    rect.origin.y = 100; 
    [@"test string on one line" drawInRect:rect withAttributes:attributes]; 

    rect.origin.y = 150; 
    [@"test string spanning more than one line" drawInRect:rect withAttributes:attributes]; 
} 

和輸出看起來像這樣：

我已經在iPhone 5（7.1.2），iPhone 6（8.0），建築測試這與xCode 6.我也測試了它在iPhone 5上使用xCode 5構建時。

Answer 1

一些更多的實驗，我發現答案是使用NSAttributedString。

雖然這並不表明影子：

NSString *s = @"test string spanning more than one line" 
    [s drawInRect:rect withAttributes:attributes] 

這並不：

NSAttributedString *as = [[NSAttributedString alloc] initWithString:s attributes:attributes]; 
    [as drawInRect:rect]; 

我不認爲這是記錄任何地方，很想否則聽到。