با سلام
تمرین نه فصل سوم برنامه سازی 3
حل این تمرین بسیار ساده است .
برای حل این تمرین نیاز به استفاده از سه API(GetWindowDC وStretchBlt وPaintDesktop) می باشد.
ابتدا یک جعبه تصویر به نام p1 و سه دکمه فرمان به نامهای Command1,command2,command3 درفرم قراردهید وسپس کد زیررا در پنجره ی کدنویسی وارد کنید:
Private Declare Function GetWindowDC Lib "user32" (ByVal hwnd As Long) As Long
Private Declare Function StretchBlt Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal nSrcWidth As Long, ByVal nSrcHeight As Long, ByVal dwRop As Long) As Long
Private Declare Function PaintDesktop Lib "user32.dll" (ByVal hdc As Long) As Long
Private Sub Command1_Click()
DesktopHdc = GetWindowDC(0)
p1.Cls
StretchBlt p1.hdc,0, 0, p1.ScaleWidth, p1.ScaleHeight, DesktopHdc, 0, 0,_ Screen.Width, Screen.Height, vbSrcCopy
End Sub
Private Sub Command2_Click()
PaintDesktop p1.hdc
End Sub
Private Sub Command3_Click()
p1.Cls
End Sub
