Bilinear interpolation: Difference between revisions

=={{header|Visual Basic .NET}}==

{{trans|C#}}

<lang vbnet>Imports System.Drawing

Module Module1

Function Lerp(s As Single, e As Single, t As Single) As Single

Return s + (e - s) * t

End Function

Function Blerp(c00 As Single, c10 As Single, c01 As Single, c11 As Single, tx As Single, ty As Single) As Single

Return Lerp(Lerp(c00, c10, tx), Lerp(c01, c11, tx), ty)

End Function

Function Scale(self As Bitmap, scaleX As Single, scaleY As Single) As Image

Dim newWidth = CInt(Math.Floor(self.Width * scaleX))

Dim newHeight = CInt(Math.Floor(self.Height * scaleY))

Dim newImage As New Bitmap(newWidth, newHeight, self.PixelFormat)

For x = 0 To newWidth - 1

For y = 0 To newHeight - 1

Dim gx = CSng(x) / newWidth * (self.Width - 1)

Dim gy = CSng(y) / newHeight * (self.Height - 1)

Dim gxi = CInt(Math.Floor(gx))

Dim gyi = CInt(Math.Floor(gy))

Dim c00 = self.GetPixel(gxi, gyi)

Dim c10 = self.GetPixel(gxi + 1, gyi)

Dim c01 = self.GetPixel(gxi, gyi + 1)

Dim c11 = self.GetPixel(gxi + 1, gyi + 1)

Dim red = CInt(Blerp(c00.R, c10.R, c01.R, c11.R, gx - gxi, gy - gyi))

Dim green = CInt(Blerp(c00.G, c10.G, c01.G, c11.G, gx - gxi, gy - gyi))

Dim blue = CInt(Blerp(c00.B, c10.B, c01.B, c11.B, gx - gxi, gy - gyi))

Dim rgb = Color.FromArgb(red, green, blue)

newImage.SetPixel(x, y, rgb)

Next

Next

Return newImage

End Function

Sub Main()

Dim newImage = Image.FromFile("Lenna100.jpg")

If TypeOf newImage Is Bitmap Then

Dim oi As Bitmap = newImage

Dim result = Scale(oi, 1.6, 1.6)

result.Save("Lenna100_larger.jpg")

Else

Console.WriteLine("Could not open the source file.")

End If

End Sub

End Module</lang>