Iphone 如何释放CGContextDrawPDFPage创建的内存
这是ipad杂志应用程序。我们需要阅读PDF并转换为图姆奈尔PNG图像。在转换前读取PDF(调用CGContextDrawPDFPage)后,内存会快速增长,直到崩溃时才会释放。我试过很多方法,但都不管用。如果有人能帮忙,我真的很感激 CGContextDrawPDFPage(上下文,aPage)//这是内存杀手 以下是完整的代码: -(UIImage*)image:(CGPDFPageRef)aPage rect:(CGRect)aRect { CGRect pdfcropBox=CGRectIntegral(CGPDFPageGetBoxRect(aPage,kCgpdFropbox))Iphone 如何释放CGContextDrawPDFPage创建的内存,iphone,Iphone,这是ipad杂志应用程序。我们需要阅读PDF并转换为图姆奈尔PNG图像。在转换前读取PDF(调用CGContextDrawPDFPage)后,内存会快速增长,直到崩溃时才会释放。我试过很多方法,但都不管用。如果有人能帮忙,我真的很感激 CGContextDrawPDFPage(上下文,aPage)//这是内存杀手 以下是完整的代码: -(UIImage*)image:(CGPDFPageRef)aPage rect:(CGRect)aRect { CGRect pdfcropBox=CGRect
}您需要释放并重新打开CGPDFDocument,如下所述
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;