Replace SpDPIResizeBitmap with a higher quality one.

[pyscripter]

The following code does a much better job at scaling bitmaps than SpDPIResizeBitmap.

procedure ResizeBitmap(Bitmap: TBitmap; const NewWidth, NewHeight: Integer);
var
  Factory: IWICImagingFactory;
  Scaler: IWICBitmapScaler;
  Source : TWICImage;
  IBitmap: IWICBitmap;
begin
  Source := TWICImage.Create;
  try
    Factory := TWICImage.ImagingFactory;
    Factory.CreateBitmapFromHBITMAP(Bitmap.Handle, Bitmap.Palette,
      WICBitmapUsePremultipliedAlpha, IBitmap);
    Factory.CreateBitmapScaler(Scaler);
    try
      Scaler.Initialize(IBitmap, NewWidth, NewHeight,
        WICBitmapInterpolationModeHighQualityCubic);
      Source.Handle := IWICBitmap(Scaler);
    finally
      Scaler := nil;
      Factory := nil;
    end;
    Bitmap.Assign(Source);
  finally
    Source.Free;
  end;