IOS 图文混排（CoreText.framework）

本文主要介绍了IOS图文混排的资料，这里整理了在网上查找的内容，帮助理解，掌握这部分知识，以下就是整理的内容：

利用CORETEXT进行图文混排。

实现代码：

void RunDelegateDeallocCallback( void* refCon ){ } CGFloat RunDelegateGetAscentCallback( void *refCon ){ NSString *imageName = (NSString *)refCon; return 80;//[UIImage imageNamed:imageName].size.height; } CGFloat RunDelegateGetDescentCallback(void *refCon){ return 0; } CGFloat RunDelegateGetWidthCallback(void *refCon){ NSString *imageName = (NSString *)refCon; return 100;//[UIImage imageNamed:imageName].size.width; }

先设置一个CTRun的委托，主要是用于指定对象的上行高，宽，或上下文释放时使用。

-(void)drawCharAndPicture { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetTextMatrix(context, CGAffineTransformIdentity);//设置字形变换矩阵为CGAffineTransformIdentity，也就是说每一个字形都不做图形变换 CGAffineTransform flipVertical = CGAffineTransformMake(1,0,0,-1,0,self.bounds.size.height); CGContextConcatCTM(context, flipVertical);//将当前context的坐标系进行flip NSLog(@"bh=%f",self.bounds.size.height); NSMutableAttributedString *attributedString = [[[NSMutableAttributedString alloc] initWithString:@"请在这里插入一张图片位置"] autorelease]; //为图片设置CTRunDelegate,delegate决定留给图片的空间大小 NSString *imgName = @"img.png"; CTRunDelegateCallbacks imageCallbacks; imageCallbacks.version = kCTRunDelegateVersion1; imageCallbacks.dealloc = RunDelegateDeallocCallback; imageCallbacks.getAscent = RunDelegateGetAscentCallback; imageCallbacks.getDescent = RunDelegateGetDescentCallback; imageCallbacks.getWidth = RunDelegateGetWidthCallback; CTRunDelegateRef runDelegate = CTRunDelegateCreate(&imageCallbacks, imgName); NSMutableAttributedString *imageAttributedString = [[NSMutableAttributedString alloc] initWithString:@" "];//空格用于给图片留位置 [imageAttributedString addAttribute:(NSString *)kCTRunDelegateAttributeName value:(id)runDelegate range:NSMakeRange(0, 1)]; CFRelease(runDelegate); [imageAttributedString addAttribute:@"imageName" value:imgName range:NSMakeRange(0, 1)]; [attributedString insertAttributedString:imageAttributedString atIndex:4];

//换行模式 CTParagraphStyleSetting lineBreakMode; CTLineBreakMode lineBreak = kCTLineBreakByCharWrapping; lineBreakMode.spec = kCTParagraphStyleSpecifierLineBreakMode; lineBreakMode.value = &lineBreak; lineBreakMode.valueSize = sizeof(CTLineBreakMode); CTParagraphStyleSetting settings[] = { lineBreakMode }; CTParagraphStyleRef style = CTParagraphStyleCreate(settings, 1); // build attributes NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithObject:(id)style forKey:(id)kCTParagraphStyleAttributeName ]; // set attributes to attributed string [attributedString addAttributes:attributes range:NSMakeRange(0, [attributedString length])]; CTFramesetterRef ctFramesetter = CTFramesetterCreateWithAttributedString((CFMutableAttributedStringRef)attributedString); CGMutablePathRef path = CGPathCreateMutable(); CGRect bounds = CGRectMake(0.0, 0.0, self.bounds.size.width, self.bounds.size.height); CGPathAddRect(path, NULL, bounds); CTFrameRef ctFrame = CTFramesetterCreateFrame(ctFramesetter,CFRangeMake(0, 0), path, NULL); CTFrameDraw(ctFrame, context); CFArrayRef lines = CTFrameGetLines(ctFrame); CGPoint lineOrigins[CFArrayGetCount(lines)]; CTFrameGetLineOrigins(ctFrame, CFRangeMake(0, 0), lineOrigins); NSLog(@"line count = %ld",CFArrayGetCount(lines)); for (int i = 0; i < CFArrayGetCount(lines); i++) { CTLineRef line = CFArrayGetValueAtIndex(lines, i); CGFloat lineAscent; CGFloat lineDescent; CGFloat lineLeading; CTLineGetTypographicBounds(line, &lineAscent, &lineDescent, &lineLeading); NSLog(@"ascent = %f,descent = %f,leading = %f",lineAscent,lineDescent,lineLeading); CFArrayRef runs = CTLineGetGlyphRuns(line); NSLog(@"run count = %ld",CFArrayGetCount(runs)); for (int j = 0; j < CFArrayGetCount(runs); j++) { CGFloat runAscent; CGFloat runDescent; CGPoint lineOrigin = lineOrigins[i]; CTRunRef run = CFArrayGetValueAtIndex(runs, j); NSDictionary* attributes = (NSDictionary*)CTRunGetAttributes(run); CGRect runRect; runRect.size.width = CTRunGetTypographicBounds(run, CFRangeMake(0,0), &runAscent, &runDescent, NULL); NSLog(@"width = %f",runRect.size.width); runRect=CGRectMake(lineOrigin.x + CTLineGetOffsetForStringIndex(line, CTRunGetStringRange(run).location, NULL), lineOrigin.y - runDescent, runRect.size.width, runAscent + runDescent); NSString *imageName = [attributes objectForKey:@"imageName"]; //图片渲染逻辑 if (imageName) { UIImage *image = [UIImage imageNamed:imageName]; if (image) { CGRect imageDrawRect; imageDrawRect.size = image.size; imageDrawRect.origin.x = runRect.origin.x + lineOrigin.x; imageDrawRect.origin.y = lineOrigin.y; CGContextDrawImage(context, imageDrawRect, image.CGImage); } } } } CFRelease(ctFrame); CFRelease(path); CFRelease(ctFramesetter); }

效果：

从上面看大家可能没有发现什么问题，当把图片放在字的最左边会是什么样子的？

因此为了避免这种情况发生，我在代码中添加了换行模式。添加换行后的效果：

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