Texturing problem in Grasshopper

I am trying to preview textured geometry in Grasshopper, and I am having trouble displaying objects with pixel perfect texture previews for some reason.

I used the custom preview components from several plugins (ShapeDiver and Human), and they both produce the same issue. Below you can see what I mean with the image I am using (top) and the textured result (bottom) after I display it on a planar surface with dimensions matching exactly the image:

I wrote a version of this preview to try and see if I could solve the issue myself. Here is what the C# component looks like:

private void RunScript(string path, Plane plane, ref object A, ref object outBrep)
  material = new Material();
  material.DiffuseColor = Color.White;
  System.Drawing.Bitmap img = new Bitmap(path);
  brep = Brep.CreateFromSurface(new PlaneSurface(plane, new Interval(0, img.Width), new Interval(0, img.Height)));
  tm = Rhino.Render.TextureMapping.CreatePlaneMapping(plane, new Interval(0, img.Width), new Interval(0, img.Height), new Interval(0, 1));

// <Custom additional code> 
Material material;
Brep brep;
Rhino.Render.TextureMapping tm;

//Draw all meshes in this method.
public override void DrawViewportMeshes(IGH_PreviewArgs args)
  Mesh[] mesh = Mesh.CreateFromBrep(brep, MeshingParameters.Default);
  mesh[0].SetTextureCoordinates(tm, Transform.Identity, true);
  args.Display.DrawMeshShaded(mesh[0], new Rhino.Display.DisplayMaterial(material));

It seems to work fine, except that it has the exact same discrepancy than the two plugins mentioned above. This led me to two possible guesses:

  1. Obviously, resizing an image will tamper with the pixels since the resizing algorithm will interpolate the original colors to the new dimensions. I thought that maybe my surfaces were not exactly the right dimensions. However, if I bake the surface from Grasshopper and use the image as a texture directly in Rhino, I get exactly the result I want (see top image above).
  2. Somehow, the display pipeline in Grasshopper automatically does some sort of resizing and/or compression which I have no control over. In my script above, I tried playing with all the texture parameters without success.

I appreciate any help regarding this issue.

Is it possible the inaccuracy happens during the conversion from BRep to Mesh?

I’d also like to mention GH doesn’t have its own display pipeline.

Thanks for your feeback. The same problem happens if I work with input meshes and directly apply the textures on them unfortunately.

Yes, I’m aware that Grasshopper accesses the Rhino display pipeline, I meant that somewhere along this process, the texture seems to be degraded.