Text is blurred when transformed in WPF

Question

I'm using DrawingContext.DrawText and DrawingContext.PushTransfrom to create rotated text on Visual Layer in WPF but as you see in the image below, the rotated text is rather blurry in some areas of the image..

Is there any option I can use to improve this? The Arial font is used for the text.

public class BeamTextDrawing : FrameworkElement
{
    private readonly VisualCollection _visuals;
    public BeamTextDrawing(double scale)
    {
        if (scale <= 0)
        {
            scale = 1;
        }
        var typeface = Settings.BeamTextTypeface;
        var cultureinfo = Settings.CultureInfo;
        var flowdirection = Settings.FlowDirection;
        var textsize = Settings.BeamTextSize / scale;
        var beamtextcolor = Settings.InPlanBeamTextColor;

        _visuals = new VisualCollection(this);

        foreach (var beam in Building.BeamsInTheElevation)
        {
            var drawingVisual = new DrawingVisual();
            using (var dc = drawingVisual.RenderOpen())
            {
                var text = Convert.ToString(beam.Section.Id);
                //text = scale.ToString();
                var ft = new FormattedText(text, cultureinfo, flowdirection,
                                            typeface, textsize, beamtextcolor)
                {
                    TextAlignment = TextAlignment.Center
                };

                var x1 = beam.ConnectivityLine.I.X;
                var y1 = beam.ConnectivityLine.I.Y;
                var x2 = beam.ConnectivityLine.J.X;
                var y2 = beam.ConnectivityLine.J.Y;

                var v1 = new Point(x2, y2) - new Point(x1, y1);
                var v2 = new Vector(1, 0);

                var hwidth = textsize;
                var l = Geometrics.GetOffset(x1, y1, x2, y2, hwidth + 5/scale);

                var angle = Vector.AngleBetween(v1, v2);
                var x = 0.5 * (l.X1 + l.X2);
                var y = 0.5 * (l.Y1 + l.Y2);

                var r = new RotateTransform(angle, x, SelectableModel.FlipYAxis(y));
                dc.PushTransform(r);
                dc.DrawText(ft, SelectableModel.FlipYAxis(x, y));
            }
            _visuals.Add(drawingVisual);
        }
    }

    protected override Visual GetVisualChild(int index)
    {
        return _visuals[index];
    }

    protected override int VisualChildrenCount
    {
        get
        {
            return _visuals.Count;
        }
    }
}

Update:

Here is the image after using this code:

TextOptions.SetTextFormattingMode(this, TextFormattingMode.Display);

I'm still getting blurry results. Look at the middle beam text at the lower part of the image.

Answer 1

Check out this article - Pixel Snapping in WPF Applications

Since WPF uses device independent pixels it can create irregular edge rendering due to anti-aliasing when it undergoes transformation. Pixel snapping is a means to suppress these visual artifacts by applying small offsets to the geometry of the visual to align the geometry to device pixels.

Setting the SnapsToDevicePixels Property to "True" for your UI elements should be able to fix your issue.