textkit自定义文本属性在跨越多行时绘制大矩形

我基本上创建一个自定义属性，在我的文本子类中使用drawGlyphsForGlyphRange方法在NSLayoutManager中绘制一个圆角矩形。 下面就像一个范围跨越一行的魅力。 但是，当文本范围跨越两行时，我得到一个大矩形，沿着这两行绘制属性。 我想我应该在这里使用不同的方法，我尝试使用nsbackgroundattribute来绘制突出显示但不幸的是我不能使用它来突出显示圆角矩形。

我会很感激任何指示。

-(void)drawGlyphsForGlyphRange:(NSRange)glyphsToShow atPoint:(CGPoint)origin { NSTextStorage *textStorage = self.textStorage; NSRange glyphRange = glyphsToShow; while (glyphRange.length > 0) { NSRange charRange = [self characterRangeForGlyphRange:glyphRange actualGlyphRange:NULL], attributeCharRange, attributeGlyphRange; id attribute = [textStorage attribute:IKSpecialHighlightAttributeName atIndex:charRange.location longestEffectiveRange:&attributeCharRange inRange:charRange]; attributeGlyphRange = [self glyphRangeForCharacterRange:attributeCharRange actualCharacterRange:NULL]; attributeGlyphRange = NSIntersectionRange(attributeGlyphRange, glyphRange); if( attribute != nil ) { NSTextContainer *textContainer = self.textContainers[0]; CGRect boundingRect = [self boundingRectForGlyphRange:attributeGlyphRange inTextContainer:textContainer]; [[UIColor colorWithRed:221.0/255.0 green:255.0/255.0 blue:0.0/255.0 alpha:1] setFill]; // set rounded rect's bg color boundingRect.origin.x += origin.x-3.0; boundingRect.origin.y += origin.y+3.0; boundingRect.size.width += 6.0; UIBezierPath *roundedRect = [UIBezierPath bezierPathWithRoundedRect:boundingRect cornerRadius: 3.0]; [roundedRect fillWithBlendMode: kCGBlendModeNormal alpha:1.0f]; [super drawGlyphsForGlyphRange:attributeGlyphRange atPoint:origin]; } else { [super drawGlyphsForGlyphRange:glyphsToShow atPoint:origin]; } glyphRange.length = NSMaxRange(glyphRange) - NSMaxRange(attributeGlyphRange); glyphRange.location = NSMaxRange(attributeGlyphRange); } 

}