C# Resized images have black borders

Question

I have a problem with image scaling in .NET. I use the standard Graphics type to resize images like in this example:

public static Image Scale(Image sourceIm         


        

Answer 1

This can be caused by pixels around the edges being wrongly interpolated. I'd call this a bug.

Here's the solution, though:

graphics.CompositingMode = CompositingMode.SourceCopy;
graphics.PixelOffsetMode = PixelOffsetMode.Half;
graphics.InterpolationMode = InterpolationMode.NearestNeighbor;

// Draw your image here.

graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

// Draw it again.

What this does is first drawing a "background" with the edges correctly-filled, and then draw it again with interpolation. If you don't need interpolation, then this is not necessary.