CustomGlyphBuilder.cs

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

using System.Numerics;
using SixLabors.Fonts;
using SixLabors.Fonts.Rendering;
using SixLabors.ImageSharp.Drawing;
using SixLabors.ImageSharp.Drawing.Text;

namespace DrawWithImageSharp;

/// <summary>
/// A custom glyph builder used to render character and text bounds.
/// </summary>
internal class CustomGlyphBuilder : GlyphBuilder
{
    private readonly List<FontRectangle> glyphBounds = [];

    public CustomGlyphBuilder()
    {
    }

    public CustomGlyphBuilder(Vector2 origin)
        : base(origin)
    {
    }

    /// <summary>
    /// Gets the paths that have been rendered by this.
    /// </summary>
    public IPathCollection Boxes => new PathCollection(this.glyphBounds.Select(x => new RectangularPolygon(x.X, x.Y, x.Width, x.Height)));

    /// <summary>
    /// Gets the paths that have been rendered by this builder.
    /// </summary>
    public IPath TextBox { get; private set; }

    protected override void BeginText(in FontRectangle bounds)
    {
        this.TextBox = new RectangularPolygon(bounds.X, bounds.Y, bounds.Width, bounds.Height);
        base.BeginText(bounds);
    }

    protected override void BeginGlyph(in FontRectangle bounds, in GlyphRendererParameters parameters)
    {
        this.glyphBounds.Add(bounds);

        base.BeginText(bounds);
    }
}