GPU Drawing - lines not 1px wide?

[toe_head2001]

When I draw a 1px Black horizontal line, it comes out as a 2px Grey line.

I thought maybe StrokeTransformType.Hairline would solve the problem, but it did not.

 

Is there a workaround (other than disabling anti-aliasing)?

 

using IDeviceBrush blackBrush = deviceContext.CreateSolidColorBrush(Color.Black);
using IStrokeStyle strokeStyle = deviceContext.Factory.CreateStrokeStyle(
    StrokeStyleProperties.Default with { TransformType = StrokeTransformType.Hairline },
    Array.Empty<float>());

deviceContext.DrawLine(new Point2Float(0, 10), new Point2Float(100, 10), blackBrush, 1f, strokeStyle);

 

[BoltBait]

you have to offset your drawing points by 0.5

 

search around... there's a code sample around here somewhere.

 

EDIT: found it...

 

ICommandList commandList = deviceContext.CreateCommandList();
using (commandList.UseBeginDraw(deviceContext))
{
	deviceContext.AntialiasMode = AntialiasMode.PerPrimitive;

	// GDI+ uses a default PixelOffsetMode of Half, which shifts all drawing calls by 0.5 pixels.
	// This produces good results for drawing antialiased primitives when supplying integer pixel
	// coordinates, but is technically the wrong way to do it. Direct2D does it the right way; if you
	// need a sharp antialiased line on pixel boundaries, you need to specify coordinates that are
	// at the center of pixels. The stroke is then drawn centered around those coordinates.
	// See here for more info: https://stackoverflow.com/a/10773729/1191082
	// So for converting to Direct2D, we either have to apply a transform, or adjust our drawing
	// calls by half-pixels when translating code that relied on PixelOffsetMode.Half.
	using (deviceContext.UseTranslateTransform(0.5f, 0.5f))
	{
		deviceContext.DrawLine(X1, Y1, X2, Y2, whiteBrush, whiteStrokeWidth, whiteStrokeStyle);
		// more drawing commands snipped...

		// The default GraphicsUnit for a System.Drawing.Font is Points, which are 1/72inch and scaled with
		// the user's global DPI/scaling setting.
		// When drawing with Direct2D/DirectWrite, the font size is specified as DIPs (device independent
		// pixels), and the DPI of the device context is always set to 96 when we're in Paint.NET (so,
		// 1 DIP = 1 pixel, even if your DPI settings are higher).
		// If we don't convert, font sizes are much smaller than the classic code that uses System.Drawing.
		float fontSize = (float)UIScaleFactor.Current.ConvertFontPointsToPixels(16);

		IDirectWriteFactory textFactory = this.Services.GetService<IDirectWriteFactory>();
		ITextFormat textFormat = textFactory.CreateTextFormat("Arial", null, FontWeight.Normal, FontStyle.Normal, FontStretch.Normal, fontSize);
		string text = direction + " " + angle.ToString() + "°";

		deviceContext.DrawText(text, textFormat, sourceBounds, blackBrush);
	}
}

 

Above is a snippet from my Level Horizon plugin.