CTFrameGetLineOrigins返回长Y坐标
所有x坐标都是正确的，但所有y坐标都不正确 - 总是3.40282e + 38 。 如何为每个CTLine获得正确的y ？
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)self.attString);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0, 0, self.frameSize.width, CGFLOAT_MAX));
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, self.attString.length), path, NULL);
CFArrayRef lines = CTFrameGetLines(frame);
size_t numOfLines = CFArrayGetCount(lines);
CGPoint lineOrigins[numOfLines];
CTFrameGetLineOrigins(frame, CFRangeMake(0, numOfLines), lineOrigins);
NSLog(@"Lines count %ld", numOfLines);
for (CFIndex i = 0; i < numOfLines; i++)
{
CTLineRef line = CFArrayGetValueAtIndex(lines, i);
[self draw:frame line:line];
NSLog(@"%@", NSStringFromCGPoint(lineOrigins[i]));
}
输出：
2014-04-11 10:45:27.095 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.099 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.105 Backgammon HD Narde[2221:707] {84.997, 3.40282e+38}
2014-04-11 10:45:27.111 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.117 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.121 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.124 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.126 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
2014-04-11 10:45:27.128 Backgammon HD Narde[2221:707] {136.804, 3.40282e+38}
2014-04-11 10:45:27.132 Backgammon HD Narde[2221:707] {0, 3.40282e+38}
你得到了正确的坐标，但是CoreText起源是“左下角”，当你使用CGFLOAT_MAX来使用巨大的CGFLOAT_MAX你看不到它们。 示例代码（基于您的代码）使用较小的高度（1e7），并显示底座和翻转的线条坐标。
NSAttributedString *attString = [[NSAttributedString alloc] initWithString:@"Lorem ipsum dolor sit amet, ..."];
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attString);
CGMutablePathRef path = CGPathCreateMutable();
// used a smaller height
CGPathAddRect(path, NULL, CGRectMake(0, 0, self.view.frame.size.width, 1e7));
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
CFArrayRef lines = CTFrameGetLines(frame);
size_t numOfLines = CFArrayGetCount(lines);
CGPoint lineOrigins[numOfLines];
CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), lineOrigins);
// transform to flip coordinate
CGAffineTransform transform = CGAffineTransformMakeTranslation(0, 1e7);
transform = CGAffineTransformScale(transform, 1, -1);
NSLog(@"Lines count %ld", numOfLines);
for (CFIndex i = 0; i < numOfLines; i++)
{
CGPoint flipped; // flipped line location
flipped = CGPointApplyAffineTransform(lineOrigins[i], transform);
NSLog(@"origin=%@ flipped=%@", NSStringFromCGPoint(lineOrigins[i]), NSStringFromCGPoint(flipped));
}
日志输出：
Lines count 8
origin={0, 9.99999e+06} flipped={0, 12}
origin={0, 9.99997e+06} flipped={0, 27}
origin={0, 9.99996e+06} flipped={0, 42}
origin={0, 9.99994e+06} flipped={0, 57}
origin={0, 9.99993e+06} flipped={0, 72}
origin={0, 9.99991e+06} flipped={0, 87}
origin={0, 9.9999e+06} flipped={0, 102}
origin={0, 9.99988e+06} flipped={0, 117}
正确的方法：
使用CTFramesetterCreateWithAttributedString获取文本框架。 使用返回值的高度。
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)self.attString);
CGSize suggestedSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter,
CFRangeMake(0, self.attString.length),
NULL,
CGSizeMake(self.width, CGFLOAT_MAX),
NULL);
suggestedSize.width = self.width;
suggestedSize.height = ceilf(suggestedSize.height);
[self setContentSize:suggestedSize];
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0, 0, suggestedSize.width, suggestedSize.height));
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, self.attString.length), path, NULL);
CFArrayRef lines = CTFrameGetLines(frame);
size_t numOfLines = CFArrayGetCount(lines);
CGPoint lineOrigins[numOfLines];
CTFrameGetLineOrigins(frame, CFRangeMake(0, numOfLines), lineOrigins);
for (CFIndex i = 0; i < numOfLines; i++)
{
CTLineRef line = CFArrayGetValueAtIndex(lines, i);
CCSprite *sprite = [self draw:frame line:line];
NSLog(@"%@", NSStringFromCGPoint(lineOrigins[i]));
sprite.position = lineOrigins[i];
}