第9月第9天 CTFramesetterCreateWithAttributedString

1.

        NSString  *text = @"This
is
some
multi-line
sample
text.";
        UIFont    *uiFont = [UIFont fontWithName:@"Helvetica" size:17.0];
        CTFontRef ctFont = CTFontCreateWithName((CFStringRef) uiFont.fontName, uiFont.pointSize, NULL);
//
//        //  When you create an attributed string the default paragraph style has a leading
//        //  of 0.0. Create a paragraph style that will set the line adjustment equal to
//        //  the leading value of the font.
//        CGFloat leading = uiFont.lineHeight - uiFont.ascender + uiFont.descender;
//        CTParagraphStyleSetting paragraphSettings[1] = { kCTParagraphStyleSpecifierLineSpacingAdjustment, sizeof (CGFloat), &leading };
//        
//        CTParagraphStyleRef  paragraphStyle = CTParagraphStyleCreate(paragraphSettings, 1);

        // direction
        CTWritingDirection direction = kCTWritingDirectionLeftToRight;
        // leading
        CGFloat firstLineIndent = 0.0;
        CGFloat headIndent = 0.0;
        CGFloat tailIndent = 0.0;
        CGFloat lineHeightMultiple = 1.0;
        CGFloat maxLineHeight = 0;
        CGFloat minLineHeight = 0;
        CGFloat paragraphSpacing = 0.0;
        CGFloat paragraphSpacingBefore = 0.0;
        CTTextAlignment textAlignment = kCTTextAlignmentLeft;//(CTTextAlignment)_textAlignment;
        CTLineBreakMode lineBreakMode = kCTLineBreakByWordWrapping;//(CTLineBreakMode)_lineBreakMode;
        CGFloat lineSpacing = 3;//_lineSpacing;
        
        CTParagraphStyleSetting theSettings[] =
        {
            { kCTParagraphStyleSpecifierAlignment, sizeof(CTTextAlignment), &textAlignment },
            { kCTParagraphStyleSpecifierLineBreakMode, sizeof(CTLineBreakMode), &lineBreakMode  },
            { kCTParagraphStyleSpecifierBaseWritingDirection, sizeof(CTWritingDirection), &direction },
            { kCTParagraphStyleSpecifierMinimumLineSpacing, sizeof(CGFloat), &lineSpacing }, // leading
            { kCTParagraphStyleSpecifierMaximumLineSpacing, sizeof(CGFloat), &lineSpacing }, // leading
            { kCTParagraphStyleSpecifierFirstLineHeadIndent, sizeof(CGFloat), &firstLineIndent },
            { kCTParagraphStyleSpecifierHeadIndent, sizeof(CGFloat), &headIndent },
            { kCTParagraphStyleSpecifierTailIndent, sizeof(CGFloat), &tailIndent },
            { kCTParagraphStyleSpecifierLineHeightMultiple, sizeof(CGFloat), &lineHeightMultiple },
            { kCTParagraphStyleSpecifierMaximumLineHeight, sizeof(CGFloat), &maxLineHeight },
            { kCTParagraphStyleSpecifierMinimumLineHeight, sizeof(CGFloat), &minLineHeight },
            { kCTParagraphStyleSpecifierParagraphSpacing, sizeof(CGFloat), &paragraphSpacing },
            { kCTParagraphStyleSpecifierParagraphSpacingBefore, sizeof(CGFloat), &paragraphSpacingBefore }
        };
        
        
        CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(theSettings, sizeof(theSettings) / sizeof(CTParagraphStyleSetting));
        
        CFRange textRange = CFRangeMake(0, text.length);
        
        //  Create an empty mutable string big enough to hold our test
        CFMutableAttributedStringRef string = CFAttributedStringCreateMutable(kCFAllocatorDefault, text.length);
        
        //  Inject our text into it
        CFAttributedStringReplaceString(string, CFRangeMake(0, 0), (CFStringRef) text);
        
        //  Apply our font and line spacing attributes over the span
        CFAttributedStringSetAttribute(string, textRange, kCTFontAttributeName, ctFont);
        CFAttributedStringSetAttribute(string, textRange, kCTParagraphStyleAttributeName, paragraphStyle);
        
        CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(string);
        CFRange fitRange;
        
        CGSize frameSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, textRange, NULL, self.view.bounds.size, &fitRange);
        

　　　　　　CFRelease(paragraphStyle);
　　　　　　CFRelease(ctFont);

        CFRelease(framesetter);
        CFRelease(string);

https://github.com/honcheng/RTLabel

https://stackoverflow.com/questions/3374591/ctframesettersuggestframesizewithconstraints-sometimes-returns-incorrect-size