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技术开发2024-06-07 阅读()
本范例是以一个stdPicture物件来存图形,之後於PictureBox中以特殊效果来显示。 因为我们想显示的只有一个图,所以不想多用另一个PictureBox来存原始图,而后再画到另一个PictureBox上,那只有用StdPicture 物件来取代PictureBox(存来源图),但是BitBlt这个绘图函式需来源与目的的hDc,而StdPicture物件没有hDc,它只有一个Handle值,以本例来说,这Handle值便是图形的hBitmap值。所以我们只好使用 MemoryDC的方式来做,产生一个MemoryDc後将BitMap图放於其上,之後便可以使用BitBlt来绘图了。'需求一个PictureBox( Named picture2),一个Command按键)

Option Explicit

Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC 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 dwRop As Long) As Long

Private Declare Function CreateCompatibleDC Lib "gdi32" _

(ByVal hdc As Long) As Long

Private Declare Function SelectObject Lib "gdi32" _

(ByVal hdc As Long, ByVal hObject As Long) As Long

Private Declare Function DeleteDC Lib "gdi32" (ByVal hdc As Long) As Long

Const SRCCOPY = HCC0020

Private Picture1 As New StdPicture


Private Sub Command1_Click()

Dim i As Long

Dim j As Long

Dim height5 As Long, width5 As Long

Dim hMemDc As Long


'stdPicture物件的度量单位是Himetric所以要转换成Pixel

height5 = ScaleY(Picture1.Height, vbHimetric, vbPixels)

If height5 > Picture2.ScaleHeight Then

height5 = Picture2.ScaleHeight

End If

width5 = ScaleX(Picture1.Width, vbHimetric, vbPixels)

If width5 > Picture2.ScaleWidth Then

width5 = Picture2.ScaleWidth

End If

'Create Memory DC

hMemDc = CreateCompatibleDC(Picture2.hdc)

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