iOS 11下Objective-C旧应用刮刮卡视图图像处理函数报错求助

Hey there, let's dig into this iOS 11-specific scratch card bug you're hitting. That CGImageMaskCreate: invalid image provider: NULL error is a classic sign that the CGDataProviderRef you're passing in is empty or invalid—and iOS 11 tightened up Core Graphics rules that let this slip by on older versions. Here's how to fix it step by step:

• First, audit your CGDataProvider creation logic
  Chances are your old code is creating the provider from a data source that's getting released early or isn't properly initialized. For example, if you're using CGDataProviderCreateWithData with a custom release callback, iOS 11 might be stricter about how that memory is managed. Switch to a safer approach using NSData and ARC:

  NSData *maskImageData = [self getValidMaskImageData]; // Replace with your data fetch logic
  if (!maskImageData || maskImageData.length == 0) {
      NSLog(@"Uh-oh, mask data is empty!");
      return;
  }
  CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData((__bridge CFDataRef)maskImageData);
  

  This lets ARC handle memory cleanup, reducing the chance of the provider becoming NULL unexpectedly.

• Verify your mask image is iOS 11-compliant
  iOS 11 enforces stricter rules for mask images. Make sure your mask is a grayscale image (mask images rely on luminance values to determine scratchable areas) and that its dimensions match the main scratch view exactly. If you're loading the mask from an asset, double-check that the image isn't corrupted or missing from your iOS 11 test device's bundle.

• Pull the provider directly from a valid CGImage (if possible)
  If your mask comes from a UIImage, skip manual data conversion entirely and grab the provider straight from the underlying CGImage—this avoids data mishandling:

  UIImage *maskImage = [UIImage imageNamed:@"scratch_mask"];
  if (!maskImage || !maskImage.CGImage) {
      NSLog(@"Mask image failed to load!");
      return;
  }
  CGDataProviderRef dataProvider = CGImageGetDataProvider(maskImage.CGImage);
  

  This is far more reliable than converting the image to data yourself, especially on iOS 11+.

• Add debug checks to catch NULL providers early
  Stick a quick log right after creating the provider to confirm it's valid before passing it to CGImageMaskCreate:

  if (!dataProvider) {
      NSLog(@"CGDataProvider is NULL—check your mask source!");
      return;
  }
  // Proceed with creating the mask
  CGImageRef maskImage = CGImageMaskCreate(
      CGImageGetWidth(mainImage.CGImage),
      CGImageGetHeight(mainImage.CGImage),
      CGImageGetBitsPerComponent(mainImage.CGImage),
      CGImageGetBitsPerPixel(mainImage.CGImage),
      CGImageGetBytesPerRow(mainImage.CGImage),
      dataProvider,
      NULL,
      false
  );
  

  This will help you pinpoint whether the issue is in data sourcing or provider creation.

The root cause here is almost always a combination of iOS 11's stricter Core Graphics memory management and invalid/missing mask data. By validating your sources and using safer provider creation methods, you'll get that scratch card working again on iOS 11.

内容的提问来源于stack exchange，提问作者user2850059