避免在UIImageView中拉伸UIImage

CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, colorSpace, bitmapInfo);
UIImage *compressedImage = [UIImage imageWithCGImage:imageRef];

UIImage *compressedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);

CIImage *ciImage = [[CIImage alloc] initWithImage:compressedImage];
CIContext *context = [CIContext contextWithOptions:@{ kCIContextWorkingColorSpace: (__bridge id)CGColorSpaceCreateWithName(kCGColorSpaceDisplayP3) }];
CGImageRef compressedImageRef = [context createCGImage:ciImage fromRect:[ciImage extent]];
UIImage *compressedImage2 = [UIImage imageWithCGImage:compressedImageRef];
CGImageRelease(compressedImageRef);

- (UIImage *)compressImage:(UIImage *)image {
    // 获取图片的CGImageRef
    CGImageRef imageRef = image.CGImage;
    // 获取CGImageRef的尺寸
    NSUInteger width = CGImageGetWidth(imageRef);
    NSUInteger height = CGImageGetHeight(imageRef);
    // 释放CGImageRef占用的内存
    CGImageRelease(imageRef);
    
    // 创建压缩后的图片
    UIImage *compressedImage = [UIImage imageWithCGImage:imageRef];
    CGImageRelease(imageRef);
    
    // 使用ZIP压缩图片
    CGImageRef zipImageRef = CGImageCreateWithImageInRect(compressedImage.CGImage, CGRectMake(0, 0, width, height));
    if (zipImageRef) {
        // 释放占用的内存
        CGImageRelease(zipImageRef);
        // 把压缩后的图片赋值给原UIImage对象
        UIImage *compressedImage2 = [UIImage imageWithCGImage:zipImageRef];
        CGImageRelease(zipImageRef);
        return compressedImage2;
    }
    
    return compressedImage;
}