浅析CoreText自由绘制(2)

http://blog.youkuaiyun.com/xcysuccess3 版权所有 ，转载请说明

1.竖排绘制

- (void)drawRect:(CGRect)rect //竖排绘制
{
    // Drawing code here.
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetTextMatrix(context, CGAffineTransformIdentity);
    CGContextTranslateCTM(context, 0, self.bounds.size.height+20);
    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextSetTextMatrix(context, CGAffineTransformIdentity);
        NSAttributedString *str = [[NSAttributedString alloc ]
                               initWithString:@"学习 Core Text. Learning Core Text. 中华人民共和国。"
                               attributes:[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], (NSString *)kCTVerticalFormsAttributeName, nil]];
    CFAttributedStringRef attrString = (CFAttributedStringRef)str;
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrString);
    CGMutablePathRef path = CGPathCreateMutable();
    CGRect bounds = CGRectMake(10.0, 10.0, 200.0, 200.0);
    CGPathAddRect(path, NULL, bounds);
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, (CFDictionaryRef)[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithUnsignedInt:kCTFrameProgressionRightToLeft], (NSString *)kCTFrameProgressionAttributeName, nil]);
    CTFrameDraw(frame, context);
    CFRelease(attrString);
    CFRelease(framesetter);
    CFRelease(frame);
    CFRelease(path);
}

这里一定要是给NSAttrubuted字设置好属性，否则中文将是旋转角度。


2.旋转角度绘制

- (void)drawRect:(CGRect)rect //旋转
{
    [super drawRect:rect];
    CGContextRef context = UIGraphicsGetCurrentContext();
    
 //   CGContextSetTextMatrix(context, CGAffineTransformIdentity);
    CGContextTranslateCTM(context, 0, self.bounds.size.height+20);
//
    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextRotateCTM(context, radians(90));
    
   
    CGContextTranslateCTM(context, 20, -460);
    
    
    CGMutablePathRef path = CGPathCreateMutable(); //1
    CGPathAddRect(path, NULL, self.bounds );
    
    NSAttributedString* attString1 = [[[NSAttributedString alloc]
                                      initWithString:@"Hello core text world!"] autorelease]; //2
    
    CTFramesetterRef framesetter =
    CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attString1); //3
    CTFrameRef frame =
    CTFramesetterCreateFrame(framesetter,
                             CFRangeMake(0, [attString1 length]), path, NULL);
    
    CTFrameDraw(frame, context); //4
    
    CFRelease(frame); //5
    CFRelease(path);
    CFRelease(framesetter);  
}

这里的坐标系大家可以好好摸索一下。这个代码是我自己试出来的。坐标系翻转之前为什么是self.bounds.size+100,而不是-100我也不懂。望有高手解答。这里的原始坐标是x向右，y向下。在屏幕底部。这个我看网上说是Coretext的专有属性。

    起点随笔
    2012-10-23
    ios交流QQ群：237305299