Question

When converting PDF Pages into UIImages I receive memory warnings all the time.

It seems there is either some leak or something else that eats my memory.

Using instruments didn’t give me any helpful details.

I’m using the following function to generate images from a pdf file:

- (UIImage*)pdfImage:(NSString*)pdfFilename page:(int)page {

 CFURLRef pdfURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (CFStringRef)pdfFilename, kCFURLPOSIXPathStyle, false);
 CGPDFDocumentRef pdfRef = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL);
 CFRelease(pdfURL);

 CGPDFPageRef pdfPage = CGPDFDocumentGetPage(pdfRef, page);
 CGRect pdfPageSize = CGPDFPageGetBoxRect(pdfPage, kCGPDFBleedBox);

 float pdfScale;
 if ( pdfPageSize.size.width < pdfPageSize.size.height ) {
  pdfScale = PDF_MIN_SIZE / pdfPageSize.size.width;
 }
 else {
  pdfScale = PDF_MIN_SIZE / pdfPageSize.size.height;
 }


 CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
 CGContextRef context = CGBitmapContextCreate(NULL, 
             pdfPageSize.size.width*pdfScale,
             pdfPageSize.size.height*pdfScale,
             8,
             (int)pdfPageSize.size.width*pdfScale * 4,
             colorSpace, 
             kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
 CGColorSpaceRelease(colorSpace);
 // CGContextClipToRect(context, pdfPageView.frame);

// CGPDFPageRetain(pdfPage);
 CGAffineTransform transform = aspectFit(CGPDFPageGetBoxRect(pdfPage, kCGPDFBleedBox),
             CGContextGetClipBoundingBox(context));
 CGContextConcatCTM(context, transform);
 CGContextDrawPDFPage(context, pdfPage);
// CGPDFPageRelease (pdfPage);

 CGImageRef image = CGBitmapContextCreateImage(context);
 CGContextRelease(context);

 UIImage *finalImage = [UIImage imageWithCGImage:image];
 CGImageRelease(image);
 CGPDFDocumentRelease(pdfRef);


 return finalImage;
}

I am releasing the document and everything else, so where could be the problem?

Thanks for your help!

Answer 1

Leaks does sometimes give false positives or may even be reporting leaks that are not in your code. What does the analyzer (shift-option-A) say? I would trust it first. Another thing to check is whether your leak problem goes away with a move to a new version of the simulator.