UIImageView transform锯齿

在UIImage上加个1像素宽的透明边框

UIImage *image = [UIImage imageNamed:@"cardBackDown.png"];

CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height);

UIGraphicsBeginImageContext(imageRect.size); 

[image drawInRect:CGRectMake(1,1,image.size.width-2,image.size.height-2)];

image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

UIImageView *backCard = [[UIImageView alloc] initWithImage:image];

backCard.frame = CGRectMake(120, 100, 79, 50);

[self insertSubview:backCard atIndex:0];

[backCard release];