我正在使用Core Text绘制一些文字。我想获得各种运行边界,但是当我调用CTRunGetImageBounds
时,返回的rect是正确的大小,但位置错误。具体来说,行原点位于整个文本的末尾。
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
self.transform = CGAffineTransformMakeScale(1.0, -1.0);
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
[[UIColor whiteColor] set];
CGContextFillRect(context, self.bounds);
NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:@"Blue should be underlined."];
NSRange blueRange = NSMakeRange(0, 4);
[attrString beginEditing];
//make all text size 20.0
[attrString addAttribute:(NSString *)kCTFontAttributeName value:(id)CTFontCreateWithName((CFStringRef)@"Helvetica", 20.0, NULL) range:NSMakeRange(0, [attrString length])];
//make the text appear in blue
[attrString addAttribute:(NSString *)kCTForegroundColorAttributeName value:(id)[[UIColor blueColor] CGColor] range:blueRange];
//next make the text appear with an underline
[attrString addAttribute:(NSString *)kCTUnderlineStyleAttributeName value:[NSNumber numberWithInt:1] range:blueRange];
[attrString endEditing];
CGMutablePathRef path = CGPathCreateMutable();
CGRect bounds = CGRectMake(10.0, 10.0, 200.0, 200.0);
[[UIColor redColor] set];
CGContextFillRect(context, bounds);
CGPathAddRect(path, NULL, bounds);
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attrString);
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
CTFrameDraw(frame, context);
for (id lineObj in (NSArray *)CTFrameGetLines(frame)) {
CTLineRef line = (CTLineRef)lineObj;
for (id runObj in (NSArray *)CTLineGetGlyphRuns(line)) {
CTRunRef run = (CTRunRef)runObj;
CGRect runBounds = CTRunGetImageBounds(run, context, CFRangeMake(0, 0));
NSLog(@"bounds: %@", NSStringFromCGRect(runBounds));
[[UIColor greenColor] set];
CGContextFillRect(context, runBounds);
}
}
CFRelease(framesetter);
CFRelease(frame);
[attrString release];
}
产地:
答案 0 :(得分:10)
这是我想出的。这完全准确。
CTFrameRef frame = [self _frameWithRect:rect];
NSArray *lines = (NSArray *)CTFrameGetLines(frame);
CGPoint origins[[lines count]];//the origins of each line at the baseline
CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), origins);
NSUInteger lineIndex = 0;
for (id lineObj in lines) {
CTLineRef line = (CTLineRef)lineObj;
for (id runObj in (NSArray *)CTLineGetGlyphRuns(line)) {
CTRunRef run = (CTRunRef)runObj;
CFRange runRange = CTRunGetStringRange(run);
CGRect runBounds;
CGFloat ascent;//height above the baseline
CGFloat descent;//height below the baseline
runBounds.size.width = CTRunGetTypographicBounds(run, CFRangeMake(0, 0), &ascent, &descent, NULL);
runBounds.size.height = ascent + descent;
CGFloat xOffset = CTLineGetOffsetForStringIndex(line, CTRunGetStringRange(run).location, NULL);
runBounds.origin.x = origins[lineIndex].x + rect.origin.x + xOffset;
runBounds.origin.y = origins[lineIndex].y + rect.origin.y;
runBounds.origin.y -= descent;
//do something with runBounds
}
lineIndex++;
}
答案 1 :(得分:4)
在使用CTRunGetImageBounds()或CTLineDraw()之前,您需要在绘制或计算每一行之前通过调用CGContextSetTextPosition()来设置起始文本位置。原因是CTLine不知道从哪里开始绘图(或计算),它使用最后的文本位置,所以你需要给它一个XY起点。要获取帧的行数组的原点,请使用点数组调用CTFrameGetLineOrigins()。然后,在绘制或计算每一行之前 - 通过CGContextSetTextPosition()设置该行的原点。
NSArray *lines = (NSArray *)CTFrameGetLines(frame);
CGPoint origins[[lines count]]; // the origins of each line at the baseline
CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), origins);
int i, lineCount;
lineCount = [lines count];
for (i = 0; i < lineCount; i++) {
CTLineRef line = (CTLineRef)[lines objectAtIndex:i];
CGContextSetTextPosition(context, origins[i].x, origins[i].y);
CTLineDraw(line, context);
}