// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

namespace SixLabors.Fonts {
  /// <summary>
  /// Defines the registered design-variation axis tags for variable fonts.
  /// These tags are used with <see cref="FontVariation"/> to control font design axes.
  /// <see href="https://learn.microsoft.com/en-us/typography/opentype/spec/dvaraxisreg"/>
  /// </summary>
  public static class KnownVariationAxes
  {
      /// <summary>
      /// Italic axis ('ital'). Controls the italic angle of the font.
      /// Value range: 0 (upright) to 1 (italic).
      /// <see href="https://learn.microsoft.com/en-us/typography/opentype/spec/dvaraxistag_ital"/>
      /// </summary>
      public const string Italic = "ital";

      /// <summary>
      /// Optical size axis ('opsz'). Adjusts the design for a specific text size in points.
      /// Typical range: 6 to 144. Larger values optimize for display use; smaller for body text.
      /// <see href="https://learn.microsoft.com/en-us/typography/opentype/spec/dvaraxistag_opsz"/>
      /// </summary>
      public const string OpticalSize = "opsz";

      /// <summary>
      /// Slant axis ('slnt'). Controls the slant angle of upright glyphs in degrees.
      /// Typical range: -90 to 90. Negative values slant to the right (the common direction).
      /// <see href="https://learn.microsoft.com/en-us/typography/opentype/spec/dvaraxistag_slnt"/>
      /// </summary>
      public const string Slant = "slnt";

      /// <summary>
      /// Width axis ('wdth'). Controls the relative width of the font as a percentage of normal.
      /// Typical range: 75 (condensed) to 125 (expanded). 100 represents the normal width.
      /// <see href="https://learn.microsoft.com/en-us/typography/opentype/spec/dvaraxistag_wdth"/>
      /// </summary>
      public const string Width = "wdth";

      /// <summary>
      /// Weight axis ('wght'). Controls the weight (boldness) of the font.
      /// Range: 1 to 1000. Common values: 100 (Thin), 300 (Light), 400 (Regular),
      /// 700 (Bold), 900 (Black).
      /// <see href="https://learn.microsoft.com/en-us/typography/opentype/spec/dvaraxistag_wght"/>
      /// </summary>
      public const string Weight = "wght";
  }
}