' Inicializar variables
Dim Shared As Integer ancho, alto
ancho = 208: alto = 228
Dim As Integer hist(255), idx(255)
Dim As Integer i, j, x, y, l, total, half, median

' Inicializar pantalla(doble de ancho para mostrar ambas imágenes)
Screenres ancho * 2, alto, 32

' Cargar imagen
Bload "Lena-Grey.bmp", 0


' Copiar imagen original a la mitad izquierda de la pantalla
For y = 0 To alto - 1
    For x = 0 To ancho - 1
        Pset (x, y), Point(x, y)
    Next
Next

' Inicializar índices
For i = 0 To 255
    idx(i) = i
Next

' Construir histograma
For y = 0 To alto - 1
    For x = 0 To ancho - 1
        l = Point(x, y) And &HFF
        hist(l) += 1
    Next
Next

' Ordenar histograma (simple bubble sort)
For i = 0 To 254
    For j = i + 1 To 255
        If hist(i) > hist(j) Then
            Swap hist(i), hist(j)
            Swap idx(i), idx(j)
        End If
    Next
Next

' Encontrar la mediana
total = 0
For i = 0 To 255
    total += hist(i)
Next

half = 0
For i = 0 To 255
    half += hist(i)
    If half >= total \ 2 Then
        median = idx(i)
        Exit For
    End If
Next

'Windowtitle("Histogram")
Windowtitle "Original vs Black and White"

' Mostrar versión en blanco y negro en la mitad derecha
For y = 0 To alto - 1
    For x = 0 To ancho - 1
        l = Point(x, y) And &HFF
        If l > median Then
            Pset (x + ancho, y), Rgb(255, 255, 255)
        Else
            Pset (x + ancho, y), Rgb(0, 0, 0)
        End If
    Next
Next

' Guardar la imagen resultante (ambas imágenes juntas)
Bsave "Lena_Original_and_BW.bmp", 0

Sleep