Option Explicit

Private Declare Function SelectObject Lib "gdi32" _
        (ByVal hdc As Long, ByVal hObject As Long) _
        As Long
        
Private Declare Function CreateSolidBrush Lib "gdi32" _
        (ByVal crColor As Long) As Long
        
Private Declare Function DeleteObject Lib "gdi32" _
        (ByVal hObject As Long) As Long
        
Private Declare Function GetPixel Lib "gdi32" (ByVal _
        hdc As Long, ByVal x As Long, ByVal y As Long) _
        As Long
        
Private Declare Function ExtFloodFill Lib "gdi32" _
        (ByVal hdc As Long, ByVal x As Long, ByVal y _
        As Long, ByVal crColor As Long, ByVal wFillType _
        As Long) As Long

Const FLOODFILLSURFACE = 1

Private Sub Picture1_MouseDown(Button As Integer, Shift As _
                               Integer, x As Single, y As Single)
  Dim hBrush&, Col&
    hBrush = CreateSolidBrush(CLng(RGB(128 * Rnd + 128, 0, 0)))
    With Picture1
      Call SelectObject(.hdc, hBrush)
      Col = GetPixel(.hdc, x, y)
      Call ExtFloodFill(.hdc, x, y, Col, FLOODFILLSURFACE)
      Call DeleteObject(hBrush)
    End With
End Sub