Rendering a gradient using SvgDocument.Draw() runs out of memory in Svg 3.4.2

[aewjones]

Description

Rendering an SvgDocument containing a gradient to a bitmap runs out of memory if the document is repeatedly rendered.

Example data

Example project that repeatedly renders an SvgDocument to a Bitmap and displays the bitmap in a PictureBox.
SvgGradientTest.zip

Used Versions

Svg 3.4.2 (problem does not occur in earlier versions)
Windows 11
.NET 6

Additional information

This problem may be related to issue #978, which also uses a gradient.

The problem appears to be caused by SvgGradientServer.LoadStops(), which was introduced in version 3.4.2:

        private void LoadStops(SvgVisualElement parent)
        {
            var gradient = this;
            while (gradient?.Stops.Count == 0)
                gradient = SvgDeferredPaintServer.TryGet<SvgGradientServer>(gradient.InheritGradient, parent);

            if (gradient != null)
                Stops.AddRange(gradient.Stops);
        }

If this.Stops.Count is nonzero on entry, Stops.AddRange(gradient.Stops) will append this.Stops to itself. If this is done repeatedly, the length of this.Stops increases geometrically, leading to an out-of-memory condition. One solution is to check for this condition:

        private void LoadStops(SvgVisualElement parent)
        {
            var gradient = this;
            while (gradient?.Stops.Count == 0)
                gradient = SvgDeferredPaintServer.TryGet<SvgGradientServer>(gradient.InheritGradient, parent);

            if (gradient != null && gradient != this)
                Stops.AddRange(gradient.Stops);
        }