iOS：具有透明度的PDF图形会导致内存泄漏

Question

使用下面的代码我可以将pdf矢量图形图像添加到视图中。效果很好。问题是当PDF具有透明或半透明图形元素时，此代码会在添加图形时导致泄漏。

透明或半透明图形元素是指用透明或半透明颜色填充的矢量路径，而不是实心填充路径。或空白的帆布区域，不会造成泄漏问题。

- (id)initWithPDFResourceAtPath:(NSString *)path center:(CGPoint)center {
    if ((self = [super init])){
        CGPDFPageRelease(pageRef);
        CGPDFDocumentRef documentRef = CGPDFDocumentCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:path]);
        pageRef = CGPDFDocumentGetPage(documentRef, 1);
        CGPDFPageRetain(pageRef);
        CGPDFDocumentRelease(documentRef);
        [self setBounds];
    }
    return self;
}

-(void)setBounds {
    [self setBounds:CGRectApplyAffineTransform(CGPDFPageGetBoxRect(pageRef, kCGPDFMediaBox), CGAffineTransformMakeScale(scaleH, scaleV))];
    size = self.bounds.size;
    [self getPDFimage];
}

-(void)getPDFimage {
    UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextScaleCTM(context, scaleH, scaleV);
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
    CGContextSetRenderingIntent(context, kCGRenderingIntentDefault);
    CGContextDrawPDFPage(context, pageRef);
    [self setImage:UIGraphicsGetImageFromCurrentImageContext()];
     UIGraphicsEndImageContext();
}