Pseudorandom Color Transition

#include <GDIP.au3>

; - Author: name22 (www.autoit.de)

$hWnd = GUICreate("Example by name22", 400, 200)

$hWnd_Seed = GUICreate("Random Seed", 200, 60)
$cInput_Seed = GUICtrlCreateInput("Seed", 5, 5, 190, 20)
$cButton_Generate = GUICtrlCreateButton("Generate", 5, 30, 60, 25)
$cButton_Go = GUICtrlCreateButton("Go", 70, 30, 60, 25)
GUISetState(@SW_SHOW, $hWnd_Seed)

While True
    Switch GUIGetMsg()
        Case -3
            Exit
        Case $cButton_Generate
            $iSeed = Random(0, 2 ^ 31 - 1, 1) * -1 ^ Random(1, 2, 1)
            GUICtrlSetData($cInput_Seed, $iSeed)
        Case $cButton_Go
            $iSeed = GUICtrlRead($cInput_Seed)
            If Int($iSeed) Or $iSeed = 0 And $iSeed >= -2 ^ 31 And $iSeed < 2 ^ 31 Then ExitLoop
    EndSwitch
WEnd

GUIDelete($hWnd_Seed)

SRandom($iSeed)
$iARGB_Start = "0xFF" & Hex(Round(Random() * 0xFFFFFF), 6)
$iARGB_End = "0xFF" & Hex(Round(Random() * 0xFFFFFF), 6)

GUISetState(@SW_SHOW, $hWnd)

_GDIPlus_Startup()

$hGraphics = _GDIPlus_GraphicsCreateFromHWND($hWnd)
_GDIPlus_GraphicsSetSmoothingMode($hGraphics, 2)
_GDIPlus_GraphicsClear($hGraphics, 0xFFFFFFFF)

$hBrush = _GDIPlus_LineBrushCreate(0, 0, 400, 0, $iARGB_Start, $iARGB_End)

_GDIPlus_GraphicsFillRect($hGraphics, 0, 0, 400, 200, $hBrush)

_GDIPlus_GraphicsDispose($hGraphics)
_GDIPlus_BrushDispose($hBrush)
_GDIPlus_Shutdown()

While GUIGetMsg() <> -3
WEnd