放大圖片箱中的圖片

Question

什麼是調整圖片箱中圖片縮放距離的方法？

我加載從文件的圖像到一個PictureBox，這裏是我的代碼...

Dim fs As FileStream 

OpenFileDialog1.Filter = "JPG files (*.jpg)|*.jpg|" & "BMP Files (*.bmp)|*.bmp|" _ 
    & "TIF Files (*.tif)|*.tif|" & "PNG Files (*.png)|*.png|" & "ALL Files (*.*)|*.*" 
OpenFileDialog1.Title = "Select an Image File" 
If OpenFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then 
    currentfilename = OpenFileDialog1.FileName 
    If currentfilename.ToUpper.EndsWith(".JPG") Or _ 
    currentfilename.ToUpper.EndsWith(".BMP") Or _ 
    currentfilename.ToUpper.EndsWith(".TIF") Or _ 
    currentfilename.ToUpper.EndsWith(".PNG") Then 
     If Not (Pic.Image Is Nothing) Then 
      Pic.Image.Dispose() 
      Pic.Image = Nothing 
     End If 
     fs = New FileStream(currentfilename, IO.FileMode.Open, IO.FileAccess.Read) 
     Pic.Image = Image.FromStream(fs) 
     original = Pic.Image 
    End If 
End If 

然後我調整使用此代碼變焦距離...

If original Is Nothing Then 
    Exit Sub 
End If 
If Not converted Is Nothing Then 
    converted.Dispose() 
End If 
If Not zoomImage Is Nothing Then 
    zoomImage.Dispose() 
End If 

zoomImage = New Bitmap(original, _ 
      (Convert.ToInt64(original.Width * (ZoomValue)/100)), _ 
      (Convert.ToInt64(original.Height * (ZoomValue/100)))) 

converted = Graphics.FromImage(zoomImage) 

converted.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic 

Pic.Image = Nothing 
Pic.Image = zoomImage 

我沒有這個問題，如果我只是使用小圖像，但它使用大量的內存，如果我有一個大的圖像，例如，我顯示的一個圖像是一個1.5MB的TIFF文件，有一個尺寸爲33000 x 4000.我只想調整圖像的縮放級別，我不需要像在圖像上繪製任何東西，改變顏色像素或任何其他操作。

Answer 1

退房this answer這表明你可能要處理您的面板的Paint事件/ PictureBox的

你可以做到這一點，像這樣：

Private Sub Pic_Paint(sender As Object, e As PaintEventArgs) Handles Pic.Paint 
    Dim newRect = New Rectangle(0, 0, _ 
     (Convert.ToInt64(original.Width * (ZoomValue/100))), _ 
     (Convert.ToInt64(original.Height * (ZoomValue/100)))) 
    e.Graphics.DrawImage(u, New Rectangle(0, 0, Pic.Width, Pic.Height), _ 
          newRect, GraphicsUnit.Pixel) 
End Sub