iOS 调整大小并保存为调整后的图像

Question

代码工作正常，但当我保存此图像时，它保存为原始大小。我怎样才能将其保存为缩放后的尺寸？

- (UIImage*) scaleImage:(UIImage*)image toSize:(CGSize)newSize {

CGSize scaledSize = newSize;
float scaleFactor = 1.0;
if( image.size.width > image.size.height ) {
    scaleFactor = image.size.width / image.size.height;
    scaledSize.width = newSize.width;
    scaledSize.height = newSize.height / scaleFactor;
}
else {
    scaleFactor = image.size.height / image.size.width;
    scaledSize.height = newSize.height;
    scaledSize.width = newSize.width / scaleFactor;
}

UIGraphicsBeginImageContextWithOptions( scaledSize, NO, 0.0 );
CGRect scaledImageRect = CGRectMake( 0.0, 0.0, scaledSize.width, scaledSize.height );
[image drawInRect:scaledImageRect];
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

   return scaledImage;
}

Answer 1

将 UIGraphicsBeginImageContextWithOptions 中的比例因子设置为 1.0。将其设置为 0.0 会将比例设置为设备的屏幕比例因子。