Microsoft KB Archive/193943

= How To Use GetDeviceCaps to Determine Margins on a Page =

Article ID: 193943

Article Last Modified on 3/7/2005

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APPLIES TO


 * Microsoft Visual Basic 4.0 Standard Edition
 * Microsoft Visual Basic 4.0 Professional Edition
 * Microsoft Visual Basic 4.0 32-Bit Enterprise Edition
 * Microsoft Visual Basic 5.0 Learning Edition
 * Microsoft Visual Basic 6.0 Learning Edition
 * Microsoft Visual Basic 5.0 Professional Edition
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 5.0 Enterprise Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition

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This article was previously published under Q193943



SUMMARY
The Visual Basic Printer object only exposes the physical size and printable area of the paper you are printing on and does not give you access to the actual margins or unprintable areas. You can retrieve this information, however, by using the Win32 API function, GetDeviceCaps. This article demonstrates how to retrieve and use this information.



MORE INFORMATION
GetDeviceCaps only takes two arguments. The first is a handle to the Device Context, "DC", of the device you want to query. In the example below, this is always the current printer. The second argument is a Long value that specifies the item to return. The following example includes only the definitions for the constants actually used in the demonstration code. In general, the units of the return value vary, but for the items used here, the unit of measurement is always pixels.

In the sample below, Command1 contains code that calls the GetDeviceCaps API multiple times to retrieve various bits of printer information, which are then displayed all at once at the end of the routine. The information retrieved includes all of the default margins and describes the printable area of the page.

The code for Command2 retrieves and uses the printer information to determine the lowest printing position on the page, and uses this to print a centered page footer that includes a page number. A page header, including the current date, right-justified, is printer at the top of each page. In addition, a report header prints at the top of the first page only. The sample further demonstrates setting custom margins within the printable area using the technique of checking the current X or Y position against a limit imposed in the code. You can easily modify this to allow the user to choose these margins and even the text for the footers or headers.

The printable area of the page always starts at position 0,0 (Printer.CurrentX = 0 and Printer.CurrentY = 0). By setting these values you can get to any point on the page. The PrintHeader procedure prints some text in italics, and other text normally, on the same line. It does this by changing the CurrentX and CurrentY values to return to a new position on line that was previously printed.

NOTE: You can also mix font attributes by ending a print statement with a ";" semicolon. This retains the last print position without starting a new line at CurrentX = 0, which is the default behavior. In this way, you can print some text, change font attributes (bold, italic, and so on), then print more text starting right where you left off.

Step-by-Step Example
 Start a new project in Visual Basic. Form1 is created by default.  Add two CommandButtons to the Form and paste the following code into the Form's module: Option Explicit

Private Declare Function GetDeviceCaps Lib "gdi32" _ (ByVal hdc As Long, ByVal nIndex As Long) As Long

' Constants for nIndex argument of GetDeviceCaps Private Const HORZRES = 8 Private Const VERTRES = 10 Private Const LOGPIXELSX = 88 Private Const LOGPIXELSY = 90 Private Const PHYSICALWIDTH = 110 Private Const PHYSICALHEIGHT = 111 Private Const PHYSICALOFFSETX = 112 Private Const PHYSICALOFFSETY = 113

Private Sub PrintHeader(PrintTitle As Boolean, Margins As Long, _      LMargin As Long) Dim BodyFontBold As Boolean, BodyFontSize As Integer Dim BodyFontItalic As Boolean, HeaderLine As String Dim PrtPositionX As Integer, PrtPositionY As Integer

If PrintTitle Then ' Only Print Title on first Page PrtPositionX = Printer.Width / 2 ' center of page ' Save any attributes you change for the header... BodyFontBold = Printer.Font.Bold BodyFontSize = Printer.Font.Size ' Change the font for the header... Printer.Font.Size = 16 Printer.Font.Bold = True ' Print header lines... HeaderLine = "Title of This Test Report" ' Center Report title Printer.CurrentX = PrtPositionX - (LMargin + _           Printer.TextWidth(HeaderLine) / 2) Printer.Print HeaderLine ' Reset the font... Printer.Font.Size = BodyFontSize Printer.Font.Bold = BodyFontBold Else Printer.NewPage  ' Otherwise we are at the bottom of a page End If      PrtPositionY = Printer.CurrentY  ' remember this line BodyFontItalic = Printer.Font.Italic Printer.Font.Italic = True Printer.Print "My very nice, Visual Basic report" Printer.Font.Italic = BodyFontItalic HeaderLine = Format(Date, "Long Date") ' Right justify today's date Printer.CurrentX = Printer.Width - (Margins + _         Printer.TextWidth(HeaderLine)) Printer.CurrentY = PrtPositionY ' return to previous line Printer.Print HeaderLine End Sub

Private Sub PrintFooter(LastLine As Integer, _        LineHeight As Integer, LMargin As Long) Dim PrtPositionX As Integer, PrintText As String Static PageNum As Integer

PageNum = PageNum + 1 PrtPositionX = Printer.Width / 2  ' center of page ' Move to the end of the page to print the Page Footer: ' LastLine is where there is only room for one more line. ' Set CurrentY to LastLine minus LineHeight times the number of      ' additional lines in the Footer. Printer.CurrentY = LastLine - LineHeight ' for 2 footer lines PrintText = "Sample Page Footer" ' Print the Footer text centered Printer.CurrentX = PrtPositionX - (LMargin + _         Printer.TextWidth(PrintText) / 2) Printer.Print PrintText PrintText = "This is Page " & CStr(PageNum) & " of Test Report" Printer.CurrentX = PrtPositionX - (LMargin + _         Printer.TextWidth(PrintText) / 2) Printer.Print PrintText End Sub

Private Function GetLargeString As String Dim BaseString As String, I As Integer

BaseString = "This is just a fairly long string to demonstrate how " BaseString = BaseString & "to wrap text to impose your own right " BaseString = BaseString & "margin. " For I = 1 To 2  ' See Q298825 to use a larger String BaseString = BaseString & BaseString Next I      GetLargeString = BaseString End Function

Private Sub Command1_Click Dim dpiX As Long, dpiY As Long Dim MarginLeft As Long, MarginRight As Long Dim MarginTop As Long, MarginBottom As Long Dim PrintAreaHorz As Long, PrintAreaVert As Long Dim PhysHeight As Long, PhysWidth As Long Dim Info As String

dpiX = GetDeviceCaps(Printer.hdc, LOGPIXELSX) Info = "Pixels X: " & dpiX & " dpi"

dpiY = GetDeviceCaps(Printer.hdc, LOGPIXELSY) Info = Info & vbCrLf & "Pixels Y: " & dpiY & " dpi"

MarginLeft = GetDeviceCaps(Printer.hdc, PHYSICALOFFSETX) Info = Info & vbCrLf & "Unprintable space on left: " & _ MarginLeft & " pixels = " & MarginLeft / dpiX & " inches"

MarginTop = GetDeviceCaps(Printer.hdc, PHYSICALOFFSETY) Info = Info & vbCrLf & "Unprintable space on top: " & _ MarginTop & " pixels = " & MarginTop / dpiY & " inches"

PrintAreaHorz = GetDeviceCaps(Printer.hdc, HORZRES) Info = Info & vbCrLf & "Printable space (Horizontal): " & _ PrintAreaHorz & " pixels = " & PrintAreaHorz / dpiX & " inches"

PrintAreaVert = GetDeviceCaps(Printer.hdc, VERTRES) Info = Info & vbCrLf & "Printable space (Vertical): " & _ PrintAreaVert & " pixels = " & PrintAreaVert / dpiY & " inches"

PhysWidth = GetDeviceCaps(Printer.hdc, PHYSICALWIDTH) Info = Info & vbCrLf & "Total space (Horizontal): " & _ PhysWidth & " pixels = " & PhysWidth / dpiX & " inches"

MarginRight = PhysWidth - PrintAreaHorz - MarginLeft Info = Info & vbCrLf & "Unprintable space on right: " & _ MarginRight & " pixels = " & MarginRight / dpiX & " inches"

PhysHeight = GetDeviceCaps(Printer.hdc, PHYSICALHEIGHT) Info = Info & vbCrLf & "Total space (Vertical): " & _ PhysHeight & " pixels = " & PhysHeight / dpiY & " inches"

MarginBottom = PhysHeight - PrintAreaVert - MarginTop Info = Info & vbCrLf & "Unprintable space on bottom: " & _ MarginBottom & " pixels = " & MarginBottom / dpiY & " inches"

MsgBox Info,, "GetDeviceCaps Returned the Following:" End Sub

Private Sub Command2_Click Dim FooterLines As Integer, TextLine As String Dim LineHeight As Integer, LastLine As Integer Dim TotWidth As Long, TotHeight As Long Dim MarginTop As Long, MarginBottom As Long Dim TotalPrtAreaVert As Long, TotalPrtAreaHorz As Long Dim MarginLeft As Long, MarginRight As Long Dim LeftMargin As Long, HorzMargins As Long Dim Line As Integer, RptHeaderPrint As Boolean Dim BreakPoint As Integer, PrintLength As Integer Dim TempString As String, CharLength As Integer Dim WrapPoint As Integer, EstWrapPoint As Integer

Printer.Font.Name = "Arial" Printer.Font.Size = 12

' The next 8 values are in Pixels. ' TotalPrtAreaVert is eqivalent to Printer.ScaleHeight TotalPrtAreaVert = GetDeviceCaps(Printer.hdc, VERTRES) TotHeight = GetDeviceCaps(Printer.hdc, PHYSICALHEIGHT) MarginTop = GetDeviceCaps(Printer.hdc, PHYSICALOFFSETY) MarginBottom = TotHeight - TotalPrtAreaVert - MarginTop ' TotalPrtAreaHorz is eqivalent to Printer.ScaleWidth TotalPrtAreaHorz = GetDeviceCaps(Printer.hdc, HORZRES) TotWidth = GetDeviceCaps(Printer.hdc, PHYSICALWIDTH) MarginLeft = GetDeviceCaps(Printer.hdc, PHYSICALOFFSETX) MarginRight = TotWidth - TotalPrtAreaHorz - MarginLeft

HorzMargins = (MarginRight + MarginLeft) * Printer.TwipsPerPixelX LeftMargin = MarginLeft * Printer.TwipsPerPixelX ' Covert to twips for ease of use TotalPrtAreaHorz = TotalPrtAreaHorz * Printer.TwipsPerPixelX LineHeight = Printer.TextHeight("Test") FooterLines = 2  ' number of lines in footer LastLine = TotalPrtAreaVert * Printer.TwipsPerPixelY - LineHeight ' Set the break point a line high so we can check it after printing BreakPoint = LastLine - LineHeight * FooterLines ' reduce the right margin by 1 inch, which is 1440 twips PrintLength = TotalPrtAreaHorz - 1440

PrintHeader True, HorzMargins, LeftMargin ' Report Header RptHeaderPrint = False ' Print the Footer when the current Y position >= ' LastLine - LineHeight *  For Line = 1 To 120 If RptHeaderPrint Then PrintHeader False, HorzMargins, LeftMargin ' Page Header RptHeaderPrint = False End If        TextLine = "This is line " & Line ' To indent or set a new left margin, reset CurrentX before each ' new line. ' To use a new right margin, wrap lines at appropriate points. If Line >= 10 And Line <= 14 Then TextLine = TextLine & " indented." Printer.CurrentX = 2 * 1440 ' indent 2 additional inches ElseIf Line >= 48 And Line <= 52 Then TextLine = GetLargeString ' Need String long for demo End If        ' Use TotalPrtAreaHorz to use the default right margin ' or use your own value for PrintLength for a custom right margin ' in this example we bring in the right margin by 1 inch If Printer.TextWidth(TextLine) > PrintLength Then ' Wrap text ' This estimating technique is used for simplicity ' First, approximate character length CharLength = Printer.TextWidth("aeiou.") / 6 ' Where to start looking for a line break (wrap) EstWrapPoint = PrintLength / CharLength WrapPoint = EstWrapPoint Line = Line - 1 ' Since current line has already been counted

Do While Len(TextLine) > EstWrapPoint TextLine = Trim(TextLine)  ' remove spaces from either end ' break on a space near the estimated break point Do While InStr(WrapPoint, TextLine, " ") <> WrapPoint WrapPoint = WrapPoint - 1 Loop TempString = Mid(TextLine, 1, WrapPoint) ' what will fit Printer.Print Trim(TempString) ' print what will fit TextLine = Mid(TextLine, WrapPoint + 1) ' get remaining text WrapPoint = EstWrapPoint ' Reset the estimated wrap point Line = Line + 1 ' Increment line counter If Printer.CurrentY >= BreakPoint Then ' another line? PrintFooter LastLine, LineHeight, LeftMargin If Len(TextLine) > 0 Then ' Print header if text remains PrintHeader False, HorzMargins, LeftMargin End If              End If            Loop If Len(TextLine) > 0 Then ' leftover text? Printer.Print TextLine Line = Line + 1 ' Increment line counter If Printer.CurrentY >= BreakPoint Then ' another line? PrintFooter LastLine, LineHeight, LeftMargin RptHeaderPrint = True ' Print Header if more lines End If           End If         Else Printer.Print TextLine If Printer.CurrentY >= BreakPoint Then PrintFooter LastLine, LineHeight, LeftMargin RptHeaderPrint = True ' Print Header if more lines End If        End If      Next Line If Printer.CurrentY > 0 Then PrintFooter LastLine, LineHeight, LeftMargin ' For last page End If     Printer.EndDoc   ' Finish MsgBox "Check Printer for results.",, "Done!" End Sub

 Run the project. Click Command1. You will see a message box listing the margins and printable area of the page. Click Command2. Several pages are printed. The printing includes:

Report Header - Only printed at the top of page 1.

Page Header - Consists of some text printed in italics and the current date right-justified on the page. Printed on all pages.

Page Footer - Consists of some text and a page number printed on multiple lines. Printed on all pages.

Additionally, lines numbered 10 through 14 are indented an additional 2 inches and lines numbered 48 through 56 demonstrate enforcing a custom right margin.

For additional information about using the TextWidth method with large strings, click the article number below to view the article in the Microsoft Knowledge Base:

298825 PRB: Run-time Error '6' When You Use the TextWidth Method

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by Chris E. Jolley, Microsoft Corporation.

Keywords: kbhowto kbprint kbapi KB193943

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