Q190223: PRB: StdFont Rescales When Shared with Printer Object

Article: Q190223
Product(s): Microsoft Visual Basic for Windows
Version(s): 
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SYMPTOMS
========

Using a StdFont object and printing to a Form or PictureBox, the font appears to
be the wrong size, but the Size property is correct.

CAUSE
=====

The Form or PictureBox is sharing the StdFont object with the Printer object
which silently changes the Scale of fonts for proper printing.

RESOLUTION
==========

Do not share a StdFont object between the Printer object and any other object.

STATUS
======

This behavior is by design.

MORE INFORMATION
================

When the Printer object gets a new font, it adjusts the scaling factor on the
font for the current printer. So if another object is set to the same StdFont,
this scaling adjustment will affect it as well. The scaling factor is not
exposed to the user, so there is no way to determine that this has happened.

Steps to Reproduce Behavior
---------------------------

1. Create a new Standard EXE project. Form1 is created by default.

2. Paste the following code into the module of Form1:

        Private Sub Form_Click()
           Dim MyFont As New StdFont
           Dim outstring As String

           MyFont.Name = "Arial"
           MyFont.Size = 12
           MyFont.Bold = False
           MyFont.Italic = False
           Me.Cls

           Set Me.Font = MyFont
           outstring = Me.Font.Name & ", " & Me.Font.Size
           Me.Print outstring    ' This prints in normal size
           Set Printer.Font = MyFont

           ' Since VB caches the font information, we need to refresh it
           Me.Font.Italic = True ' Change Italic to True for demonstration

           Me.Print outstring    ' prints out much larger than the first line
       End Sub

3. Run the project and click on the form. The following line appears twice on
  the form:

     Arial, 12

  The first line is in a normal 12 point font, but the second line is obviously
  much larger, even though it reports still being 12 point. This is because the
  Printer object has changed the font's scaling.

When the code executes "Set Me.Font = MyFont" it is not copying the font into the
form's font property, instead it is setting the form's font to the actual
instance of the font object. Both the Printer object and the form are
referencing the same font object rather than having their own copies. So if one
owner changes the object, it changes for both owners.

Additional query words: kbDSupport kbDSD FontSize kbVBp kbVBp400 kbVBp500 kbVBp600 kbVBp kbdsd kbDSupport

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600 kbVB400Search kbVB400 kbVB16bitSearch
Issue type        : kbprb

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