表情符号打乱了object-c的大小和字体的数学关系-Emojismessingwithobj-c'ssizeWithFontmath

13  

- (CGFloat)heightStringWithEmojis:(NSString*)str fontType:(UIFont *)uiFont ForWidth:(CGFloat)width {

// Get text
CFMutableAttributedStringRef attrString = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
CFAttributedStringReplaceString (attrString, CFRangeMake(0, 0), (CFStringRef) str );
CFIndex stringLength = CFStringGetLength((CFStringRef) attrString);

// Change font
CTFontRef ctFOnt= CTFontCreateWithName((__bridge CFStringRef) uiFont.fontName, uiFont.pointSize, NULL);
CFAttributedStringSetAttribute(attrString, CFRangeMake(0, stringLength), kCTFontAttributeName, ctFont);

// Calc the size
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrString);
CFRange fitRange;
CGSize frameSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, CFRangeMake(0, 0), NULL, CGSizeMake(width, CGFLOAT_MAX), &fitRange);

CFRelease(ctFont);
CFRelease(framesetter);
CFRelease(attrString);

return frameSize.height + 10;

}

6  

Thank you @SergiSolanellas! Here's a version that takes an attributedString, shortening the method because the text and font are already set.

谢谢你@SergiSolanellas !这是一个使用attributedString的版本，它缩短了方法，因为文本和字体已经设置好了。

//
// Given an attributed string that may have emoji characters and the width of 
// the display area, return the required display height.
//
- (CGFloat)heightForAttributedStringWithEmojis:(NSAttributedString *)attributedString forWidth:(CGFloat)width {
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);
    CFRange fitRange;
    CGSize frameSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, CFRangeMake(0, 0), NULL, CGSizeMake(width, CGFLOAT_MAX), &fitRange);

    CFRelease(framesetter);

    return frameSize.height;
}