title: iOS leak instrument CGContextDrawPDFPage
body: <p>I know this question has been asked several times, but I couldn't solve it for my particular case. CGContextDrawPDFPage is indicated as a leak in the leak instrument. Also when this segment of code is run the app crashes which I'm really sure is due to memory issues.</p>
  
  <pre><code>    pdfURLDocument = [[NSURL alloc] initFileURLWithPath: [docsDir stringByAppendingPathComponent:documentName]];
      pdfDocument = CGPDFDocumentCreateWithURL((CFURLRef)pdfURLDocument);
      [pdfURLDocument release];
  
      page = CGPDFDocumentGetPage(pdfDocument, 1);
      CGPDFPageRetain(page);
  
      // determine the size of the PDF page
      CGRect pageRect = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
      pdfScaleWidth = (1/((CGFloat) gridSizeDocument)) * self.frame.size.width/pageRect.size.width;
      pdfScaleHeight = (1/((CGFloat) gridSizeDocument)) * self.frame.size.height/pageRect.size.height;
      pageRect.size = CGSizeMake(pageRect.size.width*pdfScaleWidth, pageRect.size.height*pdfScaleHeight);
  
  
      // Create a low res image representation of the PDF page        
      UIGraphicsBeginImageContext(pageRect.size);
      CGContextRef context = UIGraphicsGetCurrentContext();
  
      // First fill the background with white.
      CGContextSetRGBFillColor(context, 1.0,1.0,1.0,1.0);
      CGContextFillRect(context,pageRect);
  
      CGContextSaveGState(context);
      // Flip the context so that the PDF page is rendered
      // right side up.
      CGContextTranslateCTM(context, 0.0, pageRect.size.height);
      CGContextScaleCTM(context, 1.0, -1.0);
  
      // Scale the context so that the PDF page is rendered 
      // at the correct size for the zoom level.
      CGContextScaleCTM(context, pdfScaleWidth, pdfScaleHeight);
      CGContextSetInterpolationQuality(context, kCGInterpolationHigh); 
      CGContextSetRenderingIntent(context, kCGRenderingIntentDefault); 
      CGContextDrawPDFPage(context, page);
      CGContextRestoreGState(context);
  
      backgroundImage = UIGraphicsGetImageFromCurrentImageContext();
  
      UIGraphicsEndImageContext();
      CGPDFPageRelease(page);
  </code></pre>
  
  <p>Also, I included CGPDFPageRelease(page); in the dealloc method. Also, it might be helpful to add that it works fine for small documents, but only crashes on large ones. Memory leaks still persist in the smaller ones, however.</p>