This code uses BitmapCreator class to create a Mandelbrot fractal:
B4X:
Sub CreateMandelbrotFractal As B4XBitmap
Dim w As Int = bc.mWidth
Dim h As Int = bc.mHeight
Dim tx = FractalRect.Width, ty = FractalRect.Height As Double
For row = 0 To w - 1
For col = 0 To h - 1
Dim real As Double = col / w * tx + FractalRect.Left
Dim img As Double = row / h * ty + FractalRect.Top
Dim x = 0, y = 0 As Double
Dim iterations As Int
Do While x * x + y * y < 4 And iterations < MAX_ITERATIONS
Dim x_new As Double = x * x - y * y + real
y = 2 * x * y + img
x = x_new
iterations = iterations + 1
Loop
If iterations < MAX_ITERATIONS Then
bc.SetHSV(col, row, iterations / MAX_ITERATIONS * 360, 1, iterations / (iterations + 8))
Else
bc.SetColor(col, row, xui.Color_Black)
End If
Next
Next
Return bc.Bitmap
End Sub
Example is attached.