How to Use SizeMode Property of OLE Control to Size Display

- Standard and Professional Editions of Microsoft Visual Basic for

  Windows, version 3.0

SUMMARY

This article shows by example how to use the SizeMode property of the OLE Control for Visual Basic version 3.0 to obtain a proportional display in a limited screen space.

MORE INFORMATION

The SizeMode property of the OLE Control determines how the OLE control is sized or how its image is displayed when it contains an object.

Here are the valid settings for the SizeMode property:

 0 (Default) Clip -- The object is displayed in actual size. If the
   object is larger than the OLE control, its image is clipped by
   the control's borders, showing the upper-left portion of the image.

 1 Stretch -- The object's image is sized to fill the OLE control. The
   height of the image is stretched (or shrunk) to fit the OLE control.
   The same thing happens to the width. As a result, you may get a
   distorted image. Height and width are independent, not proportional.

 2 Autosize -- The OLE control is resized to display the entire object.
   The object is displayed in actual size. By using the resize event of
   the OLE control, you can adjust the HeightNew and WidthNew parameters
   to maintain size limits of the OLE control. However, the display
   behaves as if you had used the clip setting.

Step-by-Step Example

The goal of this example is to obtain a proportional display that is restricted to a limited screen space, that of the size of the form the OLE control is on.

The example uses AutoSize and Stretch settings to find a proportional best fit. The height and width of the container form supply the maximum height and width of the image. The Autosize property supplies best-fit information.

Then the Autosize property is set to Stretch mode for display.

1. Start Visual Basic or from the File menu, choose New Project (ALT, F, N) if Visual Basic is already running. Form1 is created by default.

2. Add an MSOLE2 control to the form. When the Insert Object dialog box asks what type of object to insert, select the Create From File option and a Microsoft Word .DOC file.

3. Set the SizeMode property of the OLE control to 1 (Stretch).

4. Add the following code to the Form_Load event:

      Sub Form_Load()
         OLE1.Top = 0
         OLE1.Left = 0
      End Sub
   
   

5. Add the following code to the Resize event of the OLE control:

      Sub OLE1_Resize (heightNew As Single, WidthNew As Single)
         Dim wRatio As Single, hRatio As Single, cRatio As Single
         Dim MaxHeight As Single, MaxWidth As Single
   
         If OLE1.SizeMode = 2 Then
            MaxHeight = Me.Height
            MaxWidth = Me.Width
            'Calculate hRatio
            If heightNew > MaxHeight Then
               hRatio = 1 - (heightNew - MaxHeight) / heightNew
            Else
               hRatio = 1 + (MaxHeight - heightNew) / heightNew
            End If
            'Calculate wRatio
            If WidthNew > MaxWidth Then
               wRatio = 1 - (WidthNew - MaxWidth) / WidthNew
            Else
               wRatio = 1 + (MaxWidth - WidthNew) / WidthNew
            End If
            'Pick best ratio for cRatio
            If hRatio < wRatio Then
               cRatio = hRatio
            Else
               cRatio = wRatio
            End If
            'Apply changes
            OLE1.Height = CInt(cRatio * heightNew)
            OLE1.Width = CInt(cRatio * WidthNew)
            OLE1.SizeMode = 1
         ElseIf OLE1.SizeMode = 1 Then
            'Use AutoSize to recalculate ratio.
            OLE1.SizeMode = 2
         End If
      End Sub
   
   

6. Run the program.