Added material to the BeyondFacts Lab (#1180)

app/MindWork AI Studio/Assistants/BeyondFactsLab/BflMaterialImage.cs

@@ -0,0 +1,39 @@
+namespace AIStudio.Assistants.BeyondFactsLab;
+
+/// <summary>
+/// The copy of an image which the lab keeps as material.
+/// </summary>
+/// <remarks>
+/// The copy is prepared for models when the person adds the image: turned upright, at most 2,560 pixels along each
+/// edge, as JPEG or PNG, and without metadata such as the place where a photo was taken. It lies beside the record
+/// of the material as materials/ID.EXTENSION.
+/// </remarks>
+public sealed class BflMaterialImage
+{
+    /// <summary>
+    /// The file extensions a copy may have; the runtime tells the format of an image by its extension.
+    /// </summary>
+    public static readonly IReadOnlySet<string> EXTENSIONS = new HashSet<string>(StringComparer.Ordinal) { "jpg", "png" };
+
+    /// <summary>
+    /// Gets or sets the file extension of the copy, without the dot, e.g., "jpg".
+    /// </summary>
+    public string Extension { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the width of the copy in pixels.
+    /// </summary>
+    public int Width { get; set; }
+
+    /// <summary>
+    /// Gets or sets the height of the copy in pixels.
+    /// </summary>
+    public int Height { get; set; }
+
+    /// <summary>
+    /// Checks whether the description of a copy is complete: a known extension and a size.
+    /// </summary>
+    /// <param name="image">The description, or null.</param>
+    /// <returns>True when the description is complete; false for null.</returns>
+    public static bool IsValid(BflMaterialImage? image) => image is { Width: > 0, Height: > 0 } && EXTENSIONS.Contains(image.Extension);
+}