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| - (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
// 1.获取上下文
CGContextRef contextRef = UIGraphicsGetCurrentContext();
// [a,b,c,d,tx,ty]
NSLog(@"转换前的坐标：%@",NSStringFromCGAffineTransform(CGContextGetCTM(contextRef)));
// 2.转换坐标系,CoreText的原点在左下角，UIKit原点在左上角
CGContextSetTextMatrix(contextRef, CGAffineTransformIdentity);
// 这两种转换坐标的方式效果一样
// 2.1
// CGContextTranslateCTM(contextRef, 0, self.bounds.size.height);
// CGContextScaleCTM(contextRef, 1.0, -1.0);
// 2.2
CGContextConcatCTM(contextRef, CGAffineTransformMake(1, 0, 0, -1, 0, self.bounds.size.height));
NSLog(@"转换后的坐标：%@",NSStringFromCGAffineTransform(CGContextGetCTM(contextRef)));
// 3.创建绘制区域，可以对path进行个性化裁剪以改变显示区域
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, self.bounds);
// CGPathAddEllipseInRect(path, NULL, self.bounds);
// 4.创建需要绘制的文字
NSMutableAttributedString *attributed = [[NSMutableAttributedString alloc] initWithString:@"这是我的第一个coreText demo，我是要给兵来自老白干I型那个饿哦个呢给个I类回滚igkhpwfh 评估后共和国开不开vbdkaphphohghg 的分工额好几个辽宁省更怕hi维护你不看hi好人佛【井柏然把饿哦个"];
[attributed addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:20] range:NSMakeRange(0, 5)];
// 两种方式皆可
[attributed addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(3, 10)];
[attributed addAttribute:(id)kCTForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(0, 2)];
// 设置行距等样式
CGFloat lineSpace = 10; // 行距一般取决于这个值
CGFloat lineSpaceMax = 20;
CGFloat lineSpaceMin = 2;
const CFIndex kNumberOfSettings = 3;
// 结构体数组
CTParagraphStyleSetting theSettings[kNumberOfSettings] = {
{kCTParagraphStyleSpecifierLineSpacingAdjustment,sizeof(CGFloat),&lineSpace},
{kCTParagraphStyleSpecifierMaximumLineSpacing,sizeof(CGFloat),&lineSpaceMax},
{kCTParagraphStyleSpecifierMinimumLineSpacing,sizeof(CGFloat),&lineSpaceMin}
};
CTParagraphStyleRef theParagraphRef = CTParagraphStyleCreate(theSettings, kNumberOfSettings);
// 单个元素的形式
// CTParagraphStyleSetting theSettings = {kCTParagraphStyleSpecifierLineSpacingAdjustment,sizeof(CGFloat),&lineSpace};
// CTParagraphStyleRef theParagraphRef = CTParagraphStyleCreate(&theSettings, kNumberOfSettings);
// 两种方式皆可
// [attributed addAttribute:(id)kCTParagraphStyleAttributeName value:(__bridge id)theParagraphRef range:NSMakeRange(0, attributed.length)];
// 将设置的行距应用于整段文字
[attributed addAttribute:NSParagraphStyleAttributeName value:(__bridge id)(theParagraphRef) range:NSMakeRange(0, attributed.length)];
CFRelease(theParagraphRef);
// 5.根据NSAttributedString生成CTFramesetterRef
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributed);
CTFrameRef ctFrame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, attributed.length), path, NULL);
// 6.绘制除图片以外的部分
CTFrameDraw(ctFrame, contextRef);
// 7.内存管理，ARC不能管理CF开头的对象，需要我们自己手动释放内存
CFRelease(path);
CFRelease(framesetter);
CFRelease(ctFrame);
}
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