private static Rgba32 Bilinear(this ImageBuffer image, double targetX, double targetY)
{
var xInt = (int)targetX;
var yInt = (int)targetY;
// Lazy approach for image edge
if (xInt + 1 == image.Size.Width || yInt + 1 == image.Size.Height)
{
return(NearestNeighbour(image, xInt, yInt));
}
var width = image.Size.Width;
var baseIndex = yInt * width + xInt;
var c00 = image.Buffer[baseIndex];
var c01 = image.Buffer[baseIndex + width];
var c10 = image.Buffer[baseIndex + 1];
var c11 = image.Buffer[baseIndex + 1 + width];
var amountX = targetX - xInt;
var amountY = targetY - yInt;
// Even though the IR images are greyscale, calculate RGB separately in case a colour image is passed
var red = Interpolation.Blerp(c00.R, c10.R, c01.R, c11.R, amountX, amountY);
var green = Interpolation.Blerp(c00.G, c10.G, c01.G, c11.G, amountX, amountY);
var blue = Interpolation.Blerp(c00.B, c10.B, c01.B, c11.B, amountX, amountY);
var alpha = Interpolation.Blerp(c00.A, c10.A, c01.A, c11.A, amountX, amountY);
return(new Rgba32((byte)red, (byte)green, (byte)blue, (byte)alpha));
}
