FestiveEditor - 11

FestiveImageAdornmentTagger.cs

internal sealed class FestiveImageAdornmentTagger
    : IntraTextAdornmentTagger<FestiveImageTag, FestiveImageAdornment>
{
    private readonly ITagAggregator<FestiveImageTag> tagger;

    private FestiveImageAdornmentTagger(IWpfTextView view, ITagAggregator<FestiveImageTag> tagger)
        : base(view)
    {
        this.tagger = tagger;
    }

    public void Dispose()
    {
        this.tagger.Dispose();

        this.view.Properties.RemoveProperty(typeof(FestiveImageAdornmentTagger));
    }

    internal static ITagger<IntraTextAdornmentTag> GetTagger(IWpfTextView view, Lazy<ITagAggregator<FestiveImageTag>> tagger)
    {
        return view.Properties.GetOrCreateSingletonProperty(
            () => new FestiveImageAdornmentTagger(view, tagger.Value));
    }

    protected override IEnumerable<Tuple<SnapshotSpan, PositionAffinity?, FestiveImageTag>> GetAdornmentData(NormalizedSnapshotSpanCollection spans)
    {
        if (spans.Count == 0)
        {
            yield break;
        }

        ITextSnapshot snapshot = spans[0].Snapshot;

        var fiTags = this.tagger.GetTags(spans);

        foreach (IMappingTagSpan<FestiveImageTag> tagSpan in fiTags)
        {
            NormalizedSnapshotSpanCollection linkTagSpans = tagSpan.Span.GetSpans(snapshot);

            // Ignore tags that are split by projection.
            // This is theoretically possible but highly unlikely.
            if (linkTagSpans.Count != 1)
            {
                continue;
            }

            // If the length of the term is an odd number put the image at the start
            //  other wise put it at the end of the span
            // Move 1 from the start or end as the RegEx matches an extra (non-"word")
            //  character either side of the matching characters
            SnapshotSpan adornmentSpan = tagSpan.Tag.Term.Length % 2 == 1
                ? new SnapshotSpan(linkTagSpans[0].Start + 1, 0)
                : new SnapshotSpan(linkTagSpans[0].End - 1, 0);

            yield return Tuple.Create(adornmentSpan, (PositionAffinity?)PositionAffinity.Successor, tagSpan.Tag);
        }
    }

    protected override FestiveImageAdornment CreateAdornment(FestiveImageTag dataTag, SnapshotSpan span)
    {
        return new FestiveImageAdornment(dataTag);
    }

    protected override bool UpdateAdornment(FestiveImageAdornment adornment, FestiveImageTag dataTag)
    {
        adornment.Update(dataTag);
        return true;
    }
}