Flow-Launcher/Flow.Launcher · warning · InvalidOperationException

Invalid SVG dimensions: Height must be greater than zero in

Error message

Invalid SVG dimensions: Height must be greater than zero in {path}

What it means

Thrown as InvalidOperationException from LoadSvgImage when, after parsing the SVG with FileSvgReader, drawing.Bounds.Height is <= 0. The renderer cannot compute a scale factor (desiredHeight / 0 would be infinity/NaN) so rendering is aborted. This guards the subsequent RenderTargetBitmap creation which would otherwise throw or produce a degenerate image.

Source

Thrown at Flow.Launcher.Infrastructure/Image/ImageLoader.cs:518

        {
            // Set up drawing settings
            var desiredHeight = loadFullImage ? FullImageSize : SmallIconSize;
            var drawingSettings = new WpfDrawingSettings
            {
                IncludeRuntime = true,
                // Set IgnoreRootViewbox to false to respect the SVG's viewBox
                IgnoreRootViewbox = false
            };

            // Load and render the SVG
            var converter = new FileSvgReader(drawingSettings);
            var drawing = converter.Read(new Uri(path));

            // Calculate scale to achieve desired height
            var drawingBounds = drawing.Bounds;
            if (drawingBounds.Height <= 0)
            {
                throw new InvalidOperationException($"Invalid SVG dimensions: Height must be greater than zero in {path}");
            }
            var scale = desiredHeight / drawingBounds.Height;
            var scaledWidth = drawingBounds.Width * scale;
            var scaledHeight = drawingBounds.Height * scale;

            // Convert the Drawing to a Bitmap
            var drawingVisual = new DrawingVisual();
            using (DrawingContext drawingContext = drawingVisual.RenderOpen())
            {
                drawingContext.PushTransform(new ScaleTransform(scale, scale));
                drawingContext.DrawDrawing(drawing);
            }

            // Create a RenderTargetBitmap to hold the rendered image
            var bitmap = new RenderTargetBitmap(
                (int)Math.Ceiling(scaledWidth),
                (int)Math.Ceiling(scaledHeight),
                96, // DpiX

View on GitHub (pinned to 7fc63b07bb)

Solutions

  1. Open the SVG in a browser/editor and confirm it renders with a real size.
  2. Add explicit width and height (or a viewBox) attributes to the <svg> root element.
  3. If the SVG is third-party, replace it with a version that declares dimensions or convert it to PNG.
  4. Handle the failure upstream by catching InvalidOperationException in the image loader and falling back to a default icon.

Example fix

// before
<svg xmlns="http://www.w3.org/2000/svg">...</svg>

// after — declare a viewBox so the renderer computes bounds
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="24" height="24">...</svg>
Defensive patterns

Strategy: try-catch

Validate before calling

using var reader = XmlReader.Create(path);
var doc = XDocument.Load(reader);
var root = doc.Root;
if (root?.Attribute("viewBox") == null && root?.Attribute("width") == null)
    return LoadDefaultIcon();

Type guard

// Ensure the SVG root declares a viewBox or width/height
static bool IsSvgRenderable(string path)
{
    var doc = XDocument.Load(path);
    var svg = doc.Root;
    return svg?.Attribute("viewBox") != null
        || (svg?.Attribute("width") != null && svg?.Attribute("height") != null);
}

Try / catch

try { return LoadSvgImage(path); }
catch (InvalidOperationException ex) when (ex.Message.Contains("SVG dimensions"))
{ Log.Warn(ClassName, $"Unrenderable SVG: {path}"); return LoadDefaultIcon(); }

Prevention

When it happens

Trigger: An SVG with no explicit width/height and no viewBox (Bounds stays at 0,0,0,0); an SVG whose root element has width/height of 0 or negative; a malformed SVG that FileSvgReader partially parses leaving an empty Drawing; an SVG that uses only CSS-based sizing that the SVG renderer doesn't resolve.

Common situations: Plugin author ships an icon SVG exported with no dimensions; web-optimized SVG stripped of width/height attributes; an SVG referencing external resources that fail to load, collapsing the bounds; an SVG designed with percentage-based sizing only.

Related errors

AI-assisted analysis of Flow-Launcher/Flow.Launcher@7fc63b07bb (2026-08-13). Data as JSON: /api/errors/8929bd106febdf88. Report an issue: GitHub.