Ghost-borders (‘ringing’) when resizing in GDI+

by

I finally found an article which talks about this.

Libor Tinka casually mentions this before going on to show his extensive set of filters which way outperform GDI+ scaling:

From his advice, it sounds like it is doing exactly what we suspected: it is pulling averaging detail from surrounding pixels beyond the edge of the image. This seems like a flaw in the algorithm to me, but that is open to debate. To solve this, there is an ImageAttributes class where you can specify that the pixels beyond are simply mirror images of the pixels within. Setting this seems to completely remove the ringing:

using (ImageAttributes wrapMode = new ImageAttributes())
{
    wrapMode.SetWrapMode(WrapMode.TileFlipXY);
    g.DrawImage(input, rect, 0, 0, input.Width, input.Height, GraphicsUnit.Pixel, wrapMode);
}

Huge thanks to both Libor Tinka for the solution, and to Mark Ransom for helping me think through this and for giving me the term “ringing” which was what made Libor Tinka’s solution even show up in my searches.

More Related Contents:

  1. Resize image proportionally with MaxHeight and MaxWidth constraints
  2. Properly draw text using GraphicsPath
  3. How to make two transparent layer with c#?
  4. Double Buffering when not drawing in OnPaint(): why doesn’t it work?
  5. How can I treat the circle as a control after drawing it? – Moving and selecting shapes
  6. Graphics.DrawString vs TextRenderer.DrawText?Which can Deliver Better Quality
  7. How to find reason for Generic GDI+ error when saving an image?
  8. Creating Custom Picturebox with Draggable and Resizable Selection Window
  9. Hiding unwanted properties in custom controls
  10. Image is not drawn at the correct spot
  11. Show Transparent Loading Spinner above other Controls
  12. Flip the GraphicsPath that draws the text/string
  13. How to highlight wrapped text in a control using the graphics?
  14. JPEG 2000 support in C#.NET
  15. How to save shapes which I draw on a Panel as binary
  16. Drawing a Long String on to a Bitmap results in Drawing Issues
  17. How can I tell if a point belongs to a certain line?
  18. How to create a User Control with rounded corners?
  19. How to eliminate flicker in Windows.Forms custom control when scrolling?
  20. Can you make an alpha transparent PNG with C#?
  21. Remove top and bottom padding from Text drawn on an Image
  22. How to Convert JSON object to Custom C# object?
  23. Good or bad practice for Dialogs in wpf with MVVM?
  24. Puzzling Enumerable.Cast InvalidCastException
  25. ShouldSerialize*() vs *Specified Conditional Serialization Pattern
  26. C# Thread Termination and Thread.Abort()
  27. What are the benefits of resource(.resx) files?
  28. How do I launch files in C#
  29. DataTable to JSON [duplicate]
  30. How to debug “Could not load file or assembly” runtime errors?

Leave a Comment