cocoa - 核心文本具有不同高度的多列

Question

我需要创建一个 View ，该 View 在列中呈现文本，其第一列高度比其余列短，并且所有列都位于底部。当我尝试更改第一个列的高度时，所有列都会缩小到相同的大小并在顶部对齐。如果我尝试为 y 值添加负数，它会降低列，但会切断矩形底部的一些文本。任何帮助将不胜感激。

这是代码:

#import "StoryCoreTextView.h"
#import <CoreText/CoreText.h>


@implementation StoryCoreTextView

@synthesize story;


- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code.
    }
    return self;
}


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code.
    NSString *myLongText = [self getLongText]; /* ... */

    NSMutableAttributedString *string = [[NSMutableAttributedString alloc]initWithString:myLongText];

    // make a few words bold
    CTFontRef georgia = CTFontCreateWithName(CFSTR("Georgia"), 14.0, NULL);
    CTFontRef georgiaBold = CTFontCreateWithName(CFSTR("Georgia-Bold"), 14.0, NULL);

    [string addAttribute:(id)kCTFontAttributeName
                   value:(id)georgia
                   range:NSMakeRange(0, [string length])];

                   range:NSMakeRange(223, 6)];

    //    create paragraph style and assign text alignment to it
    CTTextAlignment alignment = kCTJustifiedTextAlignment;
    CTParagraphStyleSetting _settings[] = { {kCTParagraphStyleSpecifierAlignment, sizeof(alignment), &alignment} };
    CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(_settings, sizeof(_settings) / sizeof(_settings[0]));

    //    set paragraph style attribute
    CFAttributedStringSetAttribute(string, CFRangeMake(0, CFAttributedStringGetLength(string)), kCTParagraphStyleAttributeName, paragraphStyle);


    // layout master
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)string);

    // column 1 form
    CGMutablePathRef column1Path = CGPathCreateMutable();
    CGPathAddRect(column1Path, NULL, 
                  CGRectMake(10, -200, self.bounds.size.width / 6.0 - 20, self.bounds.size.height - 200));

    // column 1 frame
    CTFrameRef column1Frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), column1Path, NULL);

    // column 2 form
    CGMutablePathRef column2Path = CGPathCreateMutable();
    CGPathAddRect(column2Path, NULL, 
                  CGRectMake(self.bounds.size.width/6.0 + 10, 10, 
                             self.bounds.size.width/6.0 - 20,
                             self.bounds.size.height - 20));

    NSInteger colum2Start = CTFrameGetVisibleStringRange(column1Frame).length;

    // column 2 frame
    CTFrameRef column2Frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(colum2Start - 250, 0), column2Path, NULL);

    // column 3 form
    CGMutablePathRef column3Path = CGPathCreateMutable();
    CGPathAddRect(column3Path, NULL, 
                  CGRectMake(2 * self.bounds.size.width/6.0+10, 10, 
                             self.bounds.size.width/6.0 -20,
                             self.bounds.size.height-20));

    NSInteger colum3Start = CTFrameGetVisibleStringRange(column2Frame).length;

    // column 3 frame
    CTFrameRef column3Frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(colum3Start, 0), column3Path, NULL);

    // column 4 form
    CGMutablePathRef column4Path = CGPathCreateMutable();
    CGPathAddRect(column4Path, NULL, 
                  CGRectMake(3 *self.bounds.size.width/6.0+10, 10, 
                             self.bounds.size.width/6.0-20,
                             self.bounds.size.height-20));

    NSInteger colum4Start = CTFrameGetVisibleStringRange(column3Frame).length;

    // column 4 frame
    CTFrameRef column4Frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(colum4Start, 0), column4Path, NULL);

    // flip the coordinate system
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetTextMatrix(context, CGAffineTransformIdentity);
    CGContextTranslateCTM(context, 0, self.bounds.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

    // draw
    CTFrameDraw(column1Frame, context);
    CTFrameDraw(column2Frame, context);
    CTFrameDraw(column3Frame, context);
    CTFrameDraw(column4Frame, context);
    CTFrameDraw(column5Frame, context);
    CTFrameDraw(column6Frame, context);

    // cleanup
    CFRelease(column1Frame);
    CGPathRelease(column1Path);
    CFRelease(column2Frame);
    CGPathRelease(column2Path);
    CFRelease(column3Frame);
    CGPathRelease(column3Path);
    CFRelease(column4Frame);
    CGPathRelease(column4Path);
    CFRelease(framesetter);
    CFRelease(georgia);
    CFRelease(georgiaBold);
    [string release];
}


- (void)dealloc {
    [super dealloc];
}

- (NSString *)getLongText {

    NSString *longText = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum facilisis imperdiet sem, eu fermentum metus rhoncus ac. Nunc luctus ligula at erat varius at laoreet dolor iaculis. Nulla facilisi. Vivamus vestibulum massa tristique magna convallis ut suscipit dolor aliquet. Aliquam mollis porttitor tortor a venenatis. In tincidunt ornare posuere. In varius augue ut orci interdum in hendrerit tortor volutpat. Integer nec libero vel eros dignissim porta in nec nibh. Aenean sollicitudin justo vel augue pulvinar tincidunt. Phasellus dictum convallis dui in semper. Nam eros leo, dapibus eu porta non, aliquet id velit. Integer felis nisl, fermentum facilisis rutrum eget, consequat non nisl.";
    return longText;
}


@end

Answer 1

我宁愿建议您从多个矩形创建路径:

  // column 1 and 2 form
    CGMutablePathRef columnPath = CGPathCreateMutable();
    CGPathAddRect(column1Path, NULL, 
                  CGRectMake(10, -200, self.bounds.size.width / 6.0 - 20, self.bounds.size.height - 200));
    CGPathAddRect(column2Path, NULL, 
                  CGRectMake(self.bounds.size.width/6.0 + 10, 10, 
                             self.bounds.size.width/6.0 - 20,
                             self.bounds.size.height - 20));
...
    // use this CGPathRef for CTFramesetterRef
...