A figure's rows carry its picture alone

CHANGELOG.md

@@ -52,6 +52,10 @@ follows [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Fixed
 
+- **A figure whose art is the picture's own placeholder is one picture.** Art marked as the picture
+  inline (a Markdown image laid out as a figure) carried both marks, so MXP, Pueblo and BBCode wrote the
+  picture twice or dropped its cells, and the text beside it moved. A figure's rows now carry its mark
+  alone.
 - **A figure's picture reaches MXP, Pueblo and BBCode.** A `Figure` laid out as text marked its picture
   only for a terminal that draws pictures in its cells, so every other format wrote the art alone and an
   MXP client was never sent `<IMAGE>`. Its rows (or its `[description]`) now always carry the picture

MarkupString.Tests/Layout/FigurePictureTests.cs

@@ -64,6 +64,34 @@ public async Task ArtOfLineBreaksAloneIsNoArt()
 		await Assert.That(laid.ToPlainText().TrimEnd()).IsEqualTo("[A cat]");
 	}
 
+	/// <summary>
+	/// Art that is the picture's own placeholder, marked as the picture inline, as a Markdown image laid out as
+	/// a figure is: still one picture, and the words beside it start where they do in the plain text.
+	/// </summary>
+	[Test]
+	[Arguments("mxp")]
+	[Arguments("pueblo")]
+	[Arguments("bbcode")]
+	public async Task ArtMarkedAsThePictureIsStillOnePicture(string format)
+	{
+		var placeholder = MarkupText.Wrap(Cat, "[image: A cat]");
+		var figure = new Figure(Cat, placeholder) { Float = FigureFloat.Left, Beside = new TextBlock(MarkupText.Plain("The cat sits by the fire.")) };
+		var laid = BlockLayout.Build(figure, 40);
+		var markupFormat = format switch { "mxp" => MarkupFormat.Mxp, "pueblo" => MarkupFormat.Pueblo, _ => MarkupFormat.BBCode };
+		var tag = format switch
+		{
+			"mxp" => "<IMAGE cat.png URL=https://example.test/img/>",
+			"pueblo" => "<img src=\"https://example.test/img/cat.png\" alt=\"A cat\">",
+			_ => "[img]https://example.test/img/cat.png[/img]",
+		};
+
+		var first = Lines(laid, markupFormat)[0];
+
+		await Assert.That(Count(first, tag)).IsEqualTo(1);
+		await Assert.That(first.Replace(tag, string.Empty).IndexOf("The cat", StringComparison.Ordinal))
+			.IsEqualTo(laid.ToPlainText().IndexOf("The cat", StringComparison.Ordinal));
+	}
+
 	/// <summary>The words beside a floated picture stay in the column they are in for a reader of the art.</summary>
 	[Test]
 	public async Task TextBesideAFloatedPictureStaysWhereItWas()

MarkupString/Layout/Blocks/Figure.cs

@@ -1,3 +1,4 @@
+using System.Collections.Immutable;
 namespace MarkupString.Layout;
 
 /// <summary>
@@ -118,10 +119,28 @@ private MarkupText[] Marked(MarkupText[] rows, int columns)
 	{
 		var marked = new MarkupText[rows.Length];
 		for (var row = 0; row < rows.Length; row++)
-			marked[row] = MarkupText.Wrap(Image with { Row = new PictureRow(row, rows.Length, columns) }, rows[row]);
+			marked[row] = MarkupText.Wrap(Image with { Row = new PictureRow(row, rows.Length, columns) }, Unpictured(rows[row]));
 		return marked;
 	}
 
+	/// <summary>
+	/// <paramref name="text"/> without the pictures it carries. Art is often the picture's own placeholder,
+	/// already marked as the picture inline; under the figure's mark that would be a second picture in the
+	/// same cells, written twice by a format with an element for it and pushing aside what is beside it.
+	/// </summary>
+	private static MarkupText Unpictured(MarkupText text)
+	{
+		if (!text.Runs.Any(run => run.Markups.Any(markup => markup is ImageMarkup))) return text;
+
+		var runs = ImmutableArray.CreateBuilder<Run>(text.Runs.Length);
+		foreach (var run in text.Runs)
+		{
+			var kept = run.Markups.Where(markup => markup is not ImageMarkup).ToArray();
+			if (kept.Length > 0) runs.Add(run with { Markups = MarkupSet.Of(kept) });
+		}
+		return new MarkupText(text.Text, runs.ToImmutable());
+	}
+
 	/// <inheritdoc/>
 	public override void DrawLinear(LayoutContext context, int width, IList<MarkupText> lines)
 	{