Bilinear interpolation: Difference between revisions

=={{header|Yabasic}}==

{{trans|Nim}}

<lang Yabasic>// Rosetta Code problem: http://rosettacode.org/wiki/Bilinear_interpolation

// Adapted from Nim to Yabasic by Galileo, 01/2022

import ReadFromPPM2

sub lerp(s, e, t)

return s + (e - s) * t

end sub

sub blerp(c00, c10, c01, c11, tx, ty)

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

end sub

sub scale(scaleX, scaleY)

local width, height, x, y, gx, gy, gxi, gyi, gxf, gyf, c00$, c10$, c01$, c11$

width = peek("winwidth")

height = peek("winheight")

let newWidth = int(width * scaleX)

let newHeight = int(height * scaleY)

dim result(newWidth, newHeight, 3)

for x = 1 to newWidth

for y = 1 to newHeight:

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

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

let gxi = int(gx)

let gyi = int(gy)

let gxf = gx - gxi

let gyf = gy - gyi

let c00$ = right$(getbit$(gxi, gyi, gxi, gyi), 6)

let c10$ = right$(getbit$(gxi + 1, gyi, gxi + 1, gyi), 6)

let c01$ = right$(getbit$(gxi, gyi + 1, gxi, gyi + 1), 6)

let c11$ = right$(getbit$(gxi + 1, gyi + 1, gxi + 1, gyi + 1), 6)

result(x, y, 1) = int(blerp(dec(left$(c00$, 2)), dec(left$(c10$, 2)), dec(left$(c01$, 2)), dec(left$(c11$, 2)), gxf, gyf))

result(x, y, 2) = int(blerp(dec(mid$(c00$, 3, 2)), dec(mid$(c10$, 3, 2)), dec(mid$(c01$, 3, 2)), dec(mid$(c11$, 3, 2)), gxf, gyf))

result(x, y, 3) = int(blerp(dec(right$(c00$, 2)), dec(right$(c10$, 2)), dec(right$(c01$, 2)), dec(right$(c11$, 2)), gxf, gyf))

next

next

end sub

readPPM("lena.ppm")

print "Be patient, please ..."

scale(1.6, 1.6)

close window

open window newWidth, newHeight

for x = 1 to newWidth

for y = 1 to newHeight

color result(x, y, 1), result(x, y, 2), result(x, y, 3)

dot x, y

next

next</lang>