Bilinear interpolation: Difference between revisions

=={{header|Nim}}==

{{trans|F#}}

{{libheader|imageman}}

<lang Nim>import imageman

func lerp(s, e, t: float): float =

s + (e - s) * t

func blerp(c00, c10, c01, c11, tx, ty: float): float =

lerp(lerp(c00, c10, tx), lerp(c01, c11, tx), ty)

func scale(img: Image; scaleX, scaleY: float): Image =

let newWidth = (img.width.toFloat * scaleX).toInt

let newHeight = (img.height.toFloat * scaleY).toInt

result = initImage[ColorRGBU](newWidth, newHeight)

for x in 0..<newWidth:

for y in 0..<newHeight:

let gx = x * (img.width - 1) / newWidth

let gy = y * (img.height - 1) / newHeight

let gxi = gx.int

let gyi = gy.int

let gxf = gx - float(gxi)

let gyf = gy - float(gyi)

let c00 = img[gxi, gyi]

let c10 = img[gxi + 1, gyi]

let c01 = img[gxi, gyi + 1]

let c11 = img[gxi + 1, gyi + 1]

let red = blerp(float(c00[0]), float(c10[0]), float(c01[0]), float(c11[0]), gxf, gyf).toInt

let green = blerp(float(c00[1]), float(c10[1]), float(c01[1]), float(c11[1]), gxf, gyf).toInt

let blue = blerp(float(c00[2]), float(c10[2]), float(c01[2]), float(c11[2]), gxf, gyf).toInt

result[x, y] = ColorRGBU([byte(red), byte(green), byte(blue)])

when isMainModule:

let image = loadImage[ColorRGBU]("Lenna100.jpg")

let newImage = image.scale(1.6, 1.6)

newImage.saveJPEG("Lenna100_bilinear.jpg")</lang>