Ios 为什么不是'；我的文字在视网膜上画得不对吗

我试图画一些文本，在非视网膜显示器上可以，但在视网膜显示器上分辨率不高

以下是我的iPad Air的屏幕截图：

请参见下面的代码，该代码实际上将文本绘制为半透明，周围有一个几乎不透明的遮罩，因此您可以通过文本看到图像

-(void) maskImage:(UIImageView *)imageView withText:(NSString *)text font:(UIFont *)font attributes:(NSDictionary *)attributes yOffset:(CGFloat)yOffset 
{ 
  NSStringDrawingContext *paraContext = [[NSStringDrawingContext alloc] init];
  NSStringDrawingOptions stringDrawingOptions = NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingTruncatesLastVisibleLine;

  // find out how much space we need for the text
  CGSize textSize = CGSizeIntegral([text boundingRectWithSize:CGSizeMake(kNowPlayingTrackDetailsMaxWidth, kNowPlayingTrackDetailsMaxHeight) options:stringDrawingOptions attributes:attributes context:paraContext].size);

  // set up the frame for drawing the text, including some padding

  CGSize drawingSize = {textSize.width + 80, textSize.height + 60};
  CGRect drawingFrame = { 0, 0, drawingSize.width, drawingSize.height};
  CGRect textFrame = { 40, 30, textSize.width, textSize.height };

  UIGraphicsBeginImageContextWithOptions(drawingSize, YES, 0);

  UIColor *bgColor = [UIColor colorWithWhite:1 alpha:.98];
  [bgColor setFill];
  [bgColor setStroke];

  UIBezierPath *path = [UIBezierPath bezierPathWithRect:drawingFrame];
  [path fill];

  // draw the text

  [text drawWithRect:textFrame options:stringDrawingOptions attributes:attributes context:paraContext];
  UIImage *textImage = UIGraphicsGetImageFromCurrentImageContext();

  UIGraphicsEndImageContext();

  // now create an image mask from the text image

  CIImage *inputImage = [CIImage imageWithCGImage:textImage.CGImage];
  CIFilter *filter = [CIFilter filterWithName:@"CIMaskToAlpha" keysAndValues:kCIInputImageKey, inputImage, nil];
  CIImage *outputImage = [filter outputImage];

  imageView.image = [UIImage imageWithCIImage:outputImage];

  // final set the UIImageView size to match the drawing size
  CGRect imageViewFrame = imageView.frame;
  imageViewFrame.size = drawingSize;
  imageView.frame = imageViewFrame;
}

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奥利弗·琼斯帮我解决了这个问题。谢谢@orj

答案是使用创建UIImage

    [UIImage imageWithCIImage:outputImage scale:textImage.scale orientation:UIImageOrientationUp];

而不是

    imageView.image = [UIImage imageWithCIImage:outputImage];

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这将正确设置输出图像的比例。

遮罩的大小（以像素和点为单位）是多少？我的意思是，您是否放大了遮罩图像以获得视网膜分辨率？在开始图像上下文时是否尝试过缩放因子，如下所示：

UIGraphicsBeginImageContextWithOptions（drawingSize，YES，[[UIScreen mainScreen]scale]）@holex，我很确定我在任何地方都使用点，如我的代码所示。@AdilSoomro我已经试过了。将0传递给scale参数会告诉UIGraphics使用主屏幕的比例。
输出图像的比例是多少？