如何使用CGImageRef来循环调整大小而不增加像素的图像部分？

Question

我想创建一个看起来好像2个图像互相交织的效果。所以我缩放了第一张图片作为背景，并且我在背景上使用了几个UIIMageView来循环播放第二张图片，以提供我想要的外观。这适用于我使用不需要缩放以适合显示尺寸的图像，但是当我使用UIGraphics调整图像大小时，出现图像质量下降的问题。任何建议将不胜感激。

图片1.JPG为2112×2816

图片2.JPG是2000×3008

UIImage *bgImage = [UIImage imageNamed:@"1.jpg"]; 
UIImageView *bgView = [[UIImageView alloc] initWithImage:bgImage]; 
bgView.contentMode = UIViewContentModeScaleToFill; 
bgView.frame = CGRectMake(0,0,CGRectGetWidth(self.view.frame), (CGRectGetWidth(self.view.frame)/bgImage.size.width) * bgImage.size.height); 

bgView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth; 
[self.view addSubview:bgView]; 

UIImage *frontImage = [UIImage imageNamed:@"2.jpg"]; 
CGSize newSize = CGSizeMake(CGRectGetWidth(self.view.frame), (CGRectGetWidth(self.view.frame)/frontImage.size.width) * frontImage.size.height); 
UIGraphicsBeginImageContextWithOptions(newSize, YES, 0.0); 
[frontImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; 
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); 

int count = 0; 
int varX = 10; 
int varY = 10; 

CGFloat width = self.view.frame.size.width; 
CGFloat height = self.view.frame.size.height; 
CGFloat tileWidth = width/varX; 
CGFloat tileHeight = height/varY; 

for (int x = 0; x < varX; x++) { 
    for (int y = 0; y < varY; y++) { 

     NSLog(@"%f, %f, %f, %f",x*tileWidth, y*tileHeight, tileWidth, tileHeight); 

     CGImageRef scaledRef = CGImageCreateWithImageInRect(scaledImage.CGImage, CGRectMake(x*tileWidth, y*tileHeight, tileWidth, tileHeight)); 
     UIImage *image = [UIImage imageWithCGImage:scaledRef scale:scaledImage.scale orientation:scaledImage.imageOrientation]; 
     UIImageView *bgx = [[UIImageView alloc] initWithImage:image]; 
     CGImageRelease(scaledRef); 

     bgx.frame = CGRectMake((x*tileWidth), (y*tileHeight), tileWidth, tileHeight); 
     bgx.backgroundColor = [UIColor yellowColor]; 
     bgx.contentMode = UIViewContentModeTopLeft; 

     if(count%2==0){ 
      [self.view addSubview:bgx]; 
     } 
     count++; 
    } 
    count++; 
} 

Answer 1

我能够通过改变第二线在我的循环来解决我的问题：

CGImageRef scaledRef = CGImageCreateWithImageInRect(scaledImage.CGImage, CGRectMake(x*(tileWidth*2), y*(tileHeight*2), tileWidth*2, tileHeight*2)); 

我之前的输出结果是2倍，但我不知道为什么会这样。

任何洞察力是赞赏。