-(void)drawRect:(CGRect)rect
{
[super drawRect:rect];
// 开启上下文
CGContextRef context = UIGraphicsGetCurrentContext();
// 翻转坐标轴
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CGContextTranslateCTM(context, 0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// 创建 富文本字符串
NSMutableAttributedString * attributeStr = [[NSMutableAttributedString alloc] initWithString:@"\n这里在测试图文混排,\n我是一个富文本"];
// CTRun 的回调//创建一个回调结构体,设置相关参数
CTRunDelegateCallbacks callBacks;
//memset将已开辟内存空间 callbacks 的首 n 个字节的值设为值 0, 相当于对CTRunDelegateCallbacks内存空间初始化
memset(&callBacks,0,sizeof(CTRunDelegateCallbacks));
callBacks.version = kCTRunDelegateVersion1;//设置回调版本,默认这个
/**
*创建三个代理方法 拿到图片的 长和 宽
*/
callBacks.getAscent = ascentCallBacks;//设置图片顶部距离基线的距离
callBacks.getDescent = descentCallBacks;//设置图片底部距离基线的距离
callBacks.getWidth = widthCallBacks;//设置图片宽度
/*
创建一个代理
*/
NSDictionary * dicPic = @{@"height":@129,@"width":@400};//创建一个图片尺寸的字典,初始化代理对象需要
CTRunDelegateRef delegate = CTRunDelegateCreate(& callBacks, (__bridge void *)dicPic);//创建代理
/**
*图片的插入
*/
unichar placeHolder = 0xFFFC; //创建空白字符
NSString * placeHolderStr = [NSString stringWithCharacters:&placeHolder length:1];//已空白字符生成字符串
NSMutableAttributedString * placeHolderAttrStr = [[NSMutableAttributedString alloc] initWithString:placeHolderStr]; //用字符串初始化占位符的富文本
///设置代理
CFAttributedStringSetAttribute((CFMutableAttributedStringRef)placeHolderAttrStr, CFRangeMake(0, 1), kCTRunDelegateAttributeName, delegate);//给字符串中的范围中字符串 设置代理
CFRelease(delegate);//释放(__bridge进行C与OC数据类型的转换,C为非ARC,需要手动管理)
[attributeStr insertAttributedString:placeHolderAttrStr atIndex:12];//将占位符插入原富文本
/**
*绘制文本
*/
CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributeStr);//一个frame的工厂,负责生成frame
CGMutablePathRef path = CGPathCreateMutable();//创建绘制区域
CGPathAddRect(path, NULL, self.bounds);//添加绘制尺寸
NSInteger length = attributeStr.length;
CTFrameRef frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, length), path, NULL);
CTFrameDraw(frame, context);
UIImage * image = [UIImage imageNamed:@"bd_logo1"];
CGRect imgFrm = [self calculateImageRectWithFrame:frame];
CGContextDrawImage(context,imgFrm, image.CGImage);//绘制图片
CFRelease(frame);
CFRelease(path);
CFRelease(frameSetter);
}
#pragma mark ---- 代理方法
static CGFloat ascentCallBacks(void * ref)
{
return [(NSNumber *)[(__bridge NSDictionary *)ref valueForKey:@"height"] floatValue];
}
static CGFloat descentCallBacks(void * ref)
{
return 0;
}
static CGFloat widthCallBacks(void * ref)
{
return [(NSNumber *)[(__bridge NSDictionary *)ref valueForKey:@"width"] floatValue];
}
-(CGRect)calculateImageRectWithFrame:(CTFrameRef)frame
{
NSArray * arrLines = (NSArray *)CTFrameGetLines(frame);
NSInteger count = [arrLines count];
CGPoint points[count];
CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), points);
for (int i = 0; i < count; i ++) {
CTLineRef line = (__bridge CTLineRef)arrLines[i];
NSArray * arrGlyphRun = (NSArray *)CTLineGetGlyphRuns(line);
for (int j = 0; j < arrGlyphRun.count; j ++) {
CTRunRef run = (__bridge CTRunRef)arrGlyphRun[j];
NSDictionary * attributes = (NSDictionary *)CTRunGetAttributes(run); CTRunDelegateRef delegate = (__bridge CTRunDelegateRef)[attributes valueForKey:(id)kCTRunDelegateAttributeName];
if (delegate == nil) {
continue;
}
NSDictionary * dic = CTRunDelegateGetRefCon(delegate);
if (![dic isKindOfClass:[NSDictionary class]]) {
continue;
}
CGPoint point = points[i];
CGFloat ascent;
CGFloat descent;
CGRect boundsRun;
boundsRun.size.width = CTRunGetTypographicBounds(run, CFRangeMake(0, 0), &ascent, &descent, NULL);
boundsRun.size.height = ascent + descent;
CGFloat xOffset = CTLineGetOffsetForStringIndex(line, CTRunGetStringRange(run).location, NULL);
boundsRun.origin.x = point.x + xOffset;
boundsRun.origin.y = point.y - descent;
CGPathRef path = CTFrameGetPath(frame);
CGRect colRect = CGPathGetBoundingBox(path);
CGRect imageBounds = CGRectOffset(boundsRun, colRect.origin.x, colRect.origin.y);
return imageBounds;
}
}
return CGRectZero;
}
```
coretext 使用
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