这是ipad杂志的应用。我们需要阅读PDF并转换为PNG图像用于thumnail。在转换之前读取PDF(调用CGContextDrawPDFPage)后,内存会快速上升并且永远不会释放直到崩溃。我试过很多方面,但它不起作用。如果有人能提供帮助我真的很感激。
CGContextDrawPDFPage(context,aPage); //这是记忆杀手
以下是完整的代码:
- (UIImage *)image:(CGPDFPageRef)aPage rect:(CGRect)aRect { CGRect pdfcropBox = CGRectIntegral(CGPDFPageGetBoxRect(aPage,kCGPDFCropBox));
if ((float)pdfcropBox.size.width/(float)pdfcropBox.size.height >
(float)aRect.size.width/(float)aRect.size.height) //pdf width too big
{
aRect.size.height = aRect.size.width * pdfcropBox.size.height / pdfcropBox.size.width;
}
//CGRect pdfcropBox = aRect;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL,aRect.size.width,
aRect.size.height,
8,
(int)aRect.size.width * 4,
colorSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
colorSpace = nil;
CGPDFPageRetain(aPage);
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(aPage,
kCGPDFCropBox,
CGRectMake(0, 0, aRect.size.width,aRect.size.height),
0, true);
CGContextSaveGState(context);
CGContextConcatCTM(context, pdfTransform);
CGContextDrawPDFPage(context, aPage);
CGPDFPageRelease (aPage);
aPage = nil;
CGContextRestoreGState(context);
CGImageRef image = CGBitmapContextCreateImage(context);
UIImage *resultingImage = [UIImage imageWithCGImage:image];
CGContextClearRect(context, aRect);
CGContextClearRect(context, pdfcropBox);
CGContextRelease(context);
CGImageRelease(image);
context = nil;
NSLog(@"colorSpace :%d,aPage :%d,context :%d",[colorSpace retainCount],[aPage retainCount],[context retainCount]);
return resultingImage;
}
答案 0 :(得分:5)
您需要释放并重新打开CGPDFDocument,如此处所述Fast and Lean PDF Viewer for iPhone / iPad / iOs - tips and hints?