IOS CoreText --- 图文混排

利用CORETEXT进行图文混排。

实现代码：

[cpp] view
plaincopy

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。

[cpp] view
plaincopy

-(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];



[cpp] view
plaincopy

//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：