///<summary>
/// Resize image.
///</summary>
/// <param name="env">The host environment.</param>
/// <param name="outputColumnName">Name of the column resulting from the transformation of <paramref name="inputColumnName"/>.</param>
/// <param name="imageWidth">Width of resized image.</param>
/// <param name="imageHeight">Height of resized image.</param>
/// <param name="inputColumnName">Name of the input column.</param>
/// <param name="resizing">What <see cref="ImageResizingEstimator.ResizingKind"/> to use.</param>
/// <param name="cropAnchor">If <paramref name="resizing"/> set to <see cref="ImageResizingEstimator.ResizingKind.IsoCrop"/> what anchor to use for cropping.</param>
internal ImageResizingTransformer(IHostEnvironment env, string outputColumnName,
int imageWidth, int imageHeight, string inputColumnName = null,
ImageResizingEstimator.ResizingKind resizing = ImageResizingEstimator.ResizingKind.IsoCrop,
ImageResizingEstimator.Anchor cropAnchor = ImageResizingEstimator.Anchor.Center)
: this(env, new ImageResizingEstimator.ColumnOptions(outputColumnName, imageWidth, imageHeight, inputColumnName, resizing, cropAnchor))
{
}
/// <summary>
/// Resizes the images to a new width and height.
/// </summary>
/// <remarks>
/// In image processing pipelines, often machine learning practitioner make use of<a href= "https://blogs.msdn.microsoft.com/mlserver/2017/04/12/image-featurization-with-a-pre-trained-deep-neural-network-model/">
/// pre-trained DNN featurizers</a> to extract features for usage in the machine learning algorithms.
/// Those pre-trained models have a defined width and height for their input images, so often, after getting loaded, the images will need to get resized before
/// further processing.
/// The new width and height can be specified in the <paramref name="imageWidth"/> and <paramref name="imageHeight"/>
/// <seealso cref = "ImageEstimatorsCatalog" />
/// <seealso cref= "ImageLoadingEstimator" />
/// </remarks >
/// <param name="catalog">The transform's catalog.</param>
/// <param name="outputColumnName">Name of the column resulting from the transformation of <paramref name="inputColumnName"/>.</param>
/// <param name="inputColumnName">Name of column to transform. If set to <see langword="null"/>, the value of the <paramref name="outputColumnName"/> will be used as source.</param>
/// <param name="imageWidth">The transformed image width.</param>
/// <param name="imageHeight">The transformed image height.</param>
/// <param name="resizing"> The type of image resizing as specified in <see cref="ImageResizingEstimator.ResizingKind"/>.</param>
/// <param name="cropAnchor">Where to place the anchor, to start cropping. Options defined in <see cref="ImageResizingEstimator.Anchor"/></param>
/// <example>
/// <format type="text/markdown">
/// <]
/// ]]></format>
/// </example>
public static ImageResizingEstimator ResizeImages(this TransformsCatalog catalog,
string outputColumnName,
int imageWidth,
int imageHeight,
string inputColumnName = null,
ImageResizingEstimator.ResizingKind resizing = ImageResizingEstimator.ResizingKind.IsoCrop,
ImageResizingEstimator.Anchor cropAnchor = ImageResizingEstimator.Anchor.Center)
=> new ImageResizingEstimator(CatalogUtils.GetEnvironment(catalog), outputColumnName, imageWidth, imageHeight, inputColumnName, resizing, cropAnchor);
/// <summary>
/// Given a column of images, resize them to a new fixed size.
/// </summary>
/// <param name="input">The input images</param>
/// <param name="width">The width to resize to</param>
/// <param name="height">The height to resize to</param>
/// <param name="resizing">The type of resizing to do</param>
/// <param name="cropAnchor">If cropping is necessary, at what </param>
/// <returns>The resized images</returns>
/// <seealso cref="ImageResizingEstimator"/>
public static Custom <Bitmap> Resize(this Custom <Bitmap> input, int width, int height,
ImageResizingEstimator.ResizingKind resizing = ImageResizingEstimator.ResizingKind.IsoCrop,
ImageResizingEstimator.Anchor cropAnchor = ImageResizingEstimator.Anchor.Center)
{
Contracts.CheckValue(input, nameof(input));
Contracts.CheckParam(width > 0, nameof(width), "Must be positive");
Contracts.CheckParam(height > 0, nameof(height), "Must be positive");
Contracts.CheckParam(Enum.IsDefined(typeof(ImageResizingEstimator.ResizingKind), resizing), nameof(resizing), "Undefined value detected");
Contracts.CheckParam(Enum.IsDefined(typeof(ImageResizingEstimator.Anchor), cropAnchor), nameof(cropAnchor), "Undefined value detected");
return(new ImageResizingStaticExtensions.OutPipelineColumn(input, width, height, resizing, cropAnchor));
}
