Visual Basic圖像縮放

Question

是否可以按比例縮放圖像而不使用3或4個內置屬性之一（因爲它們不能很好地工作）？

什麼我指的是東西，你可以在Java中這樣做：

Image newimg = img.getScaledInstance(230, 310, java.awt.Image.SCALE_SMOOTH); 

在Java上線似乎很好地縮放尺寸以符合指定大小的工作。

Answer 1

我有一個UserControl，我用來完成更好的質量調整。這裏有一個摘錄，希望你能找到它有用。

Private Const STRETCH_ANDSCANS = 1 
Private Const STRETCH_DELETESCANS = 3 
Private Const STRETCH_HALFTONE = 4 
Private Const STRETCH_ORSCANS = 2 
Private Const SRCCOPY = &HCC0020 

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 SetStretchBltMode Lib "gdi32" (ByVal hdc As Long, _ 
                 ByVal nStretchMode As Long) _ 
                 As Long 

，它被稱爲是這樣的：

Private Sub UserControl_Paint() 

    Dim lSave As Long 

    'set the stretchblit mode (saving the previous value) 
    lSave = SetStretchBltMode(UserControl.hdc, STRETCH_HALFTONE) 

    'perform blit 
    Call StretchBlt(UserControl.hdc, 0, 0, UserControl.ScaleWidth, _ 
        UserControl.ScaleHeight, picBuffer.hdc, 0, 0, _ 
        picBuffer.ScaleWidth, picBuffer.ScaleHeight, SRCCOPY) 

    'restore previous mode 
    Call SetStretchBltMode(UserControl.hdc, lSave) 

End Sub