DOCUMENT:Q257777 11-SEP-2001 [vbwin]
TITLE :FIX: Printer.Height May Eject the Wrong Amount of Paper
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER::5.0,6.0
OPER/SYS:
KEYWORDS:kbprint kbPrinting kbVBp kbVBp500bug kbVBp600bug kbGrpDSVB kbDSupport kbVS600sp4fix kbV
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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
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SYMPTOMS
========
When you are using continuous feed paper (such as pin feed paper), and you
assign a value to the Printer.Height property, the amount of paper ejected by
the printer may be up to one tenth of one millimeter off the specified height.
This small discrepancy may not be visible when printing a single page, but it is
cumulative with each page.
CAUSE
=====
Visual Basic incorrectly converts the number assigned to Printer.Height from
TWIPS (1440 TWIPS to the inch) to tenths of millimeters, which it uses
internally to represent the height.
Prior to Visual Basic 6.0 Service Pack 4, Visual Basic performed the following
calculation:
' TMM stands for tenths of millimeters
Const TWIPS_PER_CM = 567
Const TMM_PER_CM = 100
Temp = ValueInTwips * TMM_PER_CM / TWIPS_PER_CM
ValueInTMM = Temp - (Temp - Int(Temp))
' First the wrong conversion factor is used
' and then the result is truncated.
Visual Basic 6.0 Service Pack 4 performs the following calculation:
Const TWIPS_PER_INCH = 1440
Const TMM_PER_INCH = 254
ValueInTMM = Int(ValueInTwips * TMM_PER_INCH / TWIPS_PER_INCH)
RESOLUTION
==========
You can use one of the following techniques to work around the problem:
- Compile the application using Visual Basic 6.0 Service Pack 4 or greater.
- Do not modify the Printer.Height property. Instead, make it a requirement
that the end user set the default height manually from the Printers folder.
On Microsoft Windows NT, this requires the addition of new "forms" as
described in the "More Information" section.
- Set the Printer.Height property to a value that produces the desired result.
First, determine the desired value in TWIPS, and then use the following
equation to assign that value to Printer.Height:
Printer.Height = ((((DesiredHeightInTwips * 254) / 1440) + 0.5) * 567) / 100 + 0.5
NOTE: Use this equation to obtain the correct height with versions of Visual
Basic prior to Visual Basic 6.0 Service Pack 4. Remove it if the code is
later compiled using Visual Basic 6.0 Service Pack 4 or greater.
STATUS
======
Microsoft has confirmed that this is a bug in the Microsoft products that are
listed at the beginning of this article. This bug was corrected in the latest
service pack for Visual Studio 6.0.
For additional information about Visual Studio service packs, click the following
article numbers to view the articles in the Microsoft Knowledge Base:
Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why
Q194295 HOWTO: Tell That a Visual Studio Service Pack Is Installed
To download the latest Visual Studio service pack, visit the following Microsoft
Web site:
http://msdn.microsoft.com/vstudio/downloads/updates.asp
MORE INFORMATION
================
The printer driver must support custom paper sizes in order to use the Printer
object's Height and Width properties.
- To determine if a printer driver supports custom paper sizes, open the
Printers folder and look at the list of paper sizes for that printer
Under Windows 95, Windows 98, and Windows Me, select Printer Properties. Under
Microsoft Windows NT 4.0, select Document Defaults. Under Microsoft Windows
2000, select Printing Preferences. Look for an entry named "custom" or
something similar. When this option is selected you should be able to enter a
custom paper height and width. If the printer driver that is used by the end
user of your application has this option, then Printer.Height and
Printer.Width can be set. If it does not have this option, then the behavior
depends on the printer driver. Most drivers select the nearest available
size.
- Very few printer drivers on Windows NT or Windows 2000 support custom paper
sizes
The recommended procedure is to have the end user add a new form of the
required size and set it as the default form for that printer. Visual Basic
then uses that form.
On Windows NT, highlight the printer icon in the Printers folder and then
select Server Properties from the File menu.
- Height and Width are stored in tenths of millimeters (TMM)
Windows 95, Windows 98, and Windows Me store paper size information in TMM.
Windows NT and Windows 2000 store "Forms" in thousandths of millimeters.
However, the Printer.Height and Printer.Width properties do not use forms and
store the data in TMM. If you need a height that does not divide evenly into
TMM, then either restrict your users to using "forms" on NT, or add one TMM
to the paper size as needed so that it averages out, just as the calendar
does on leap year. For example, if you need to eject an extra .25 TMM, then
every fourth page, change the height to one TMM more than it was, print one
page, and then set it back for three more pages.
NOTE: The paper size cannot be changed in the middle of a document, so the
Printer.EndDoc method must be called before the paper size can be changed.
- Troubleshooting suggestion
Try to obtain the results you want manually by changing the settings in the
Printers folder and then printing from Notepad. If you cannot get the results
you desire when printing from Notepad, then the issue is with the printer
driver rather than with Visual Basic.
- Unit Of Measurement Conversion Function
Because units of measurement (UOM) are critical to using paper size correctly,
the following conversion function may prove useful.
Note that this function requires an hDC parameter as provided by the
Printer.hDC file. Many laser printers are either 300dpi or 600dpi (dots per
inch). On a 600dpi printer, each individual dot, or pixel, is 1/600 of an
inch. The hDC parameter is required in order to correctly convert to or from
the pixels UOM.
Public Function ConvertUnits(ByVal hDC As Long, _
ByVal OriginalLength As Single, _
ByVal OriginalWidth As Single, _
ResultLength As Single, _
ResultWidth As Single, _
FromUnits As ScaleModeConstants, _
ToUnits As ScaleModeConstants) As Boolean
Dim hiHeight As Double ' tenths of millimeters
Dim hiWidth As Double ' tenths of millimeters
Select Case FromUnits
Case vbInches
hiHeight = OriginalLength * TenthsOfMillimetersPerInch
hiWidth = OriginalWidth * TenthsOfMillimetersPerInch
Case vbMillimeters
hiHeight = OriginalLength * 10
hiWidth = OriginalWidth * 10
Case vbTwips
hiHeight = (CDbl(OriginalLength) / TwipsPerInch) * _
TenthsOfMillimetersPerInch
hiWidth = (CDbl(OriginalWidth) / TwipsPerInch) * _
TenthsOfMillimetersPerInch
Case vbPixels
On Error Resume Next
hiHeight = (CDbl(OriginalLength) / CDbl(GetDeviceCaps(hDC, _
LOGPIXELSY))) * TenthsOfMillimetersPerInch
hiWidth = (CDbl(OriginalWidth) / CDbl(GetDeviceCaps(hDC, _
LOGPIXELSX))) * TenthsOfMillimetersPerInch
If Err.Number <> 0 Then
ConvertUnits = False
Exit Function
End If
On Error GoTo 0
Case vbCentimeters
hiHeight = OriginalLength * 100
hiWidth = OriginalWidth * 100
Case vbCharacters
hiHeight = (CDbl(OriginalLength) / CharactersPerInch) * _
TenthsOfMillimetersPerInch
hiWidth = (CDbl(OriginalWidth) / CharactersPerInch) * _
TenthsOfMillimetersPerInch
Case vbHimetric
hiHeight = OriginalLength
hiWidth = OriginalWidth
Case vbPoints
hiHeight = (CDbl(OriginalLength) / PointsPerInch) * _
TenthsOfMillimetersPerInch
hiWidth = (CDbl(OriginalWidth) / PointsPerInch) * _
TenthsOfMillimetersPerInch
Case Else
ConvertUnits = False
Exit Function
End Select
Select Case ToUnits
Case vbInches
ResultLength = hiHeight / TenthsOfMillimetersPerInch
ResultWidth = hiWidth / TenthsOfMillimetersPerInch
Case vbMillimeters
ResultLength = hiHeight / 10
ResultWidth = hiWidth / 10
Case vbTwips
ResultLength = (hiHeight / TenthsOfMillimetersPerInch) * _
TwipsPerInch
ResultWidth = (hiWidth / TenthsOfMillimetersPerInch) * _
TwipsPerInch
Case vbPixels
ResultLength = (hiHeight / TenthsOfMillimetersPerInch) * _
GetDeviceCaps(hDC, LOGPIXELSY)
ResultWidth = (hiWidth / TenthsOfMillimetersPerInch) * _
GetDeviceCaps(hDC, LOGPIXELSX)
If Err.Number <> 0 Then
ConvertUnits = False
Exit Function
End If
Case vbCentimeters
ResultLength = hiHeight / 100
ResultWidth = hiWidth / 100
Case vbCharacters
ResultLength = hiHeight / (TenthsOfMillimetersPerInch) * _
CharactersPerInch
ResultWidth = hiWidth / (TenthsOfMillimetersPerInch) * _
CharactersPerInch
Case vbHimetric
ResultLength = hiHeight
ResultWidth = hiWidth
Case vbPoints
ResultLength = (hiHeight / TenthsOfMillimetersPerInch) * _
PointsPerInch
ResultWidth = (hiWidth / TenthsOfMillimetersPerInch) * _
PointsPerInch
Case Else
ConvertUnits = False
Exit Function
End Select
ConvertUnits = True
End Function ' ConvertUnits
REFERENCES
==========
For additional information, click the article number below to view the article
in the Microsoft Knowledge Base:
Q157172 How to Create Custom Forms in Windows NT 4.0
Additional query words: sp4
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Keywords : kbprint kbPrinting kbVBp kbVBp500bug kbVBp600bug kbGrpDSVB kbDSupport kbVS600sp4fix kbVS600sp5fix
Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVB500 kbVB600
Version : :5.0,6.0
Issue type : kbbug
Solution Type : kbfix
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