ios - coretext 从文本字段的底部到顶部显示文本

Question

我正在绘制一个文本字段，并且已将一个文本字段添加到 UIView 中。文本位于路径内。它绘制正确，但内容从底部开始到顶部结束。有办法解决这个问题吗？

这是我的代码:

// Draw text into a circle using Core Text and Quartz
 - (void) drawRect:(CGRect)rect
 {
[super drawRect: rect];

CGContextRef context = UIGraphicsGetCurrentContext();
self.layer.rasterizationScale = [[UIScreen mainScreen] scale];

// Flip the context
CGContextTranslateCTM(context, 0, 3);
CGContextSetTextMatrix(context, CGAffineTransformIdentity);

CGContextSetTextMatrix(context, CGAffineTransformMakeScale(1.0f, -1.0f));


// Stroke that path
CGContextAddPath(context, backPath);
CGContextSetLineWidth(context, 1.0f);
//[[UIColor blackColor] setStroke];
CGContextStrokePath(context);

// Fill that path
CGContextAddPath(context, backPath);
[[UIColor whiteColor] setFill];
CGContextFillPath(context);

CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)string);
CTFrameRef theFrame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, string.length),backPath, NULL);
CTFrameDraw(theFrame, context);

CFRelease(framesetter);
CFRelease(theFrame);
CFRelease(backPath);

 }

我的路径是这样的:

 - (id) initWithAttributedString: (NSAttributedString *) aString path:   (vector<ofPoint>)paths
 {
 backPath = CGPathCreateMutable();

CGPathMoveToPoint(backPath, NULL, paths[0].x, paths[0].y);  // Bottom left

for(int x=1; x< paths.size(); x++){
CGPathAddLineToPoint(backPath, NULL, paths[x].x,paths[x].y);    // Bottom right
}
CGPathCloseSubpath(backPath);

 if (!(self = [super initWithFrame:CGRectZero])) return self;

 self.backgroundColor = [UIColor clearColor];
 string = aString;
 return self;
 }

并制作文本字段:

  path.push_back(ofPoint(ofGetWidth()/4,ofGetHeight()/4));
    // point to user
 //   path.push_back(ofPoint((position.x-(ofGetWidth()/4))/2,ofGetHeight()/4));
    // point to right top
    path.push_back(ofPoint(ofGetWidth()/4,ofGetHeight()/4));
    // point to  end x, pos y user
    path.push_back(ofPoint((ofGetWidth()/4),(position.y-(ofGetHeight()/4))/2));

    path.push_back(ofPoint((position.x-(ofGetWidth()/4))/2-100,(position.y-(ofGetHeight()/4))/2-100));

    path.push_back(ofPoint((position.x-(ofGetWidth()/4))/2,(position.y-(ofGetHeight()/4))/2));

Answer 1

你正在翻转文本矩阵。相反，翻转整个 CTM:

CGContextScaleCTM(context, 1, -1);
CGContextTranslateCTM(context, 0, self.bounds.size.height);