Printer Object - A Primer

All programmers creating software solutions for their client, invariably have to process data and generate output on paper, using the printer, in the form  of reports. There are many third party tools available in the market which are
instrucmental in generating beautifully crafted reports.

I, too, have used such report writers, until recently, for my even my most
simple printing requirements. That is until I discovered the power of the printer
object.

Most literature on Visual Basic, including books and articles, generally explore
this printer object superficially and this, I believe is, why most
of us tend to overlook this simple yet powerful printing tool.

The focus of my article is to demystify the printer object and
present it as a magnificient object, which can be used to churn out dashing
printouts without the support of any third party reporting tool. For detailed
syntaxes of the objects, statements, commands, properties and methods used here
you are requested to refer to the excellent documentation provided by Microsoft.

The sub-topics covered in the article include...

• Select Printer


• Set the Page dimensions


• Change to a new page


• End of a Print Job


• Cancel the Print Job


• Position the head


• Print the text


• Justification - Left, Right, Center


• Font - Name, Size and Style


• Print in Color


• Points for Consideration

Select the printer

Windows operating system allows you to install more than one printer. One of
these is marked as the default printer and is offered as choice for printing
by the applications.

VB provides us with the Printers collection and the Printer
object to take care of our printing requirements.

The printers collection contains a list of the printers installed
on your system. Printers.Count specifies the number of printers
installed and any printer can be selected as Printers(i), where
i is a number between 0 and Printer.Count-1.

To get a list of all the printers installed we could use a code snipet, like
this...

For i = 1 to Printers.Count - 1

    Printer.Print Printers(i).Name

Next i

Printer.EndDoc

or

For Each P in Printers

    Printer.Print P.Name

Next P

Printer.EndDoc

The Printer object represents the printer which has been marked
as the default printer in the Windows environment.

The entire discussion here uses the printer object and can
easily be modified to use the Printers(i) object.

Setup Page Dimensions

The next thing that you must do is setup the dimensions of the paper on which
you will be printing. Windows has 41 predefined paper sizes based on the standard
paper sizes available around the world. Other than these if the size of the
paper does not match any of these pre-defined sizes you may set it the custom
size and specify your own height and width for the paper. The properties used
here are Printer.PaperSize, Printer.Height and Printer.Width.

The more commonly used paper sizes are...

  Printer.PaperSize = vbPRPSLetter

or

  Printer.PaperSize = vbPRPSA4

Please refer to the Microsoft documentation for a complete list of paper size
constants.

To use a custom size paper your code will look something like...

  Printer.Height = 10 * 1440         '
10 inch height x 1440 twips per inch

  Printer.Width = 5 * 1440           '  5
inch height x 1440 twips per inch

Any attempt to alter the height or the width of the printer object,
automatically changes the Printer.PaperSize to vbPRPSUser.

While you are at it, you may also want to setup the orientation of the paper.

  Printer.Orientation = vbPRORPortrait

or

  Printer.Orientation = vbPRORLandscape

Any time during the print session you want to check the dimensions of the paper
size you can refer to the height and width properties
for the printer object.

While printing a page a typical use for the height is to compare the paper
length with current position of the printer head and determine whether the next
line can be printed on the same page or you should request for a new page.

Note: Depending upon the printer driver installed for the printer
it may or may not report an error is any of the printer properties is set beyond
the acceptable range.

Change to a new page

Printing to the printer is done in page mode, i.e. the printer
object sends data for printing to the operating system only after it is informed
that the current page formatting is complete and is ready for printing.

In VB, this is accomplished by invoking the NewPage method like
this...

Printer.NewPage

This method instructs the printer object to end the current page
and advance to the next page.

End of Print Job

When you have completed printing all the text and graphics that required to
be printed in this print job the printer object must be so informed.
You can do so using the EndDoc method.

Printer.EndDoc

This terminates a print operation and releases the document to the printer.
If something has been printed on the current page it automatically issues a
Printer.NewPage to complete printing of the page. If a Printer.NewPage
has been issued just before the Printer.EndDoc method, no blank
page is printed.

Cancel the Print Job

There will be occasions when you may want to abort the print session. This
may be in response to a cancel request from the user or any such situation requiring
you to do so.

For such times we have been provided with the KillDoc method.

Printer.KillDoc

The difference of the KillDoc and the EndDoc methods
is more apparent when the operating system's Print Manager is handling the print
jobs. If the operating system's Print Manager is handling the print job KillDoc
deletes the current print job and the printer receives nothing.

If Print Manager isn't handling the print job, some or all of the data may
be sent to the printer before KillDoc can take effect. In this
case, the printer driver resets the printer when possible and terminates the
print job.

Position the Head

We can get or set the position using the two properties, Printer.CurrentX
and Printer.CurrentY. As obvious by their names the return the
position on the X and Y axes respectively.

Label1.Caption = "(" & Printer.CurrentX & ", " & Printer.CurrentY & ")"

Alternately, you may use these very functions to position the printer head
as per your requirement.

Printer.CurrentX = 1440

Printer.CurrentY = 1440

Remember 1 inch = 1440 twips. so this previous code snipet should position
the printer head 1 inch from each the top and left margins. Similarly this next
code snipet here will position the printer head at the center of the page (half
of width and height).

Printer.CurrentX = Printer.Width / 2

Printer.CurrentY = Printer.Height / 2

Every print instruction issued to place text or graphic on the page moves the
CurrentX and CurrentY and should be considered and,
if necessary, taken care of before issuing the next print instruction.

Print out the text

To print use...



Printer.Print "Text to Print"



Printing starts at the location marked by the CurrentX and CurrentY.



After the text as been printed the values of the CurrentX and CurrentY
are changed to the new location. The new location is different when a , (comma)
or a ; (semi-colon) is added at the end of the Print statement.
Run the following code and compare the results...

Printer.CurrentX = 0

Printer.CurrentY = 0

For i = 1 to 5

   Printer.Print Printer.CurrentX & ", " &
Printer.CurrentY

Next i

Printer.CurrentX = 0

Printer.CurrentY = 0

For i = 1 to 5

   Printer.Print Printer.CurrentX & ", " &
Printer.CurrentY;

Next i

notice the ; (semi-colon) at the end of the print statement.

Printer.CurrentX = 0

Printer.CurrentY = 0

For i = 1 to 5

   Printer.Print Printer.CurrentX & ", " &
Printer.CurrentY,

Next i

in this case note the , (comma) at the end of the print statement.

Justification - Left, Right or Center

Justification is accomplished with the help of two methods of the printer
object, viz Printer.TextHeight(Text) and Printer.TextWidth(Text),
with which we can determine the about of vertical and horizontal space that
will be occupied when you print the Text.

So in this example...

mTxt = "Gajendra S. Dhir"

TxtWidth = Printer.TextWidth(mTxt)

TxtWidth is the amount of horizontal space required by the text
in mTxt to print.

Let us see print this as Left, Right and Center Justified.

'to leave 1" Margins on the Left, Right and Top of the Printer

Printer.CurrentX = 1440

MaxWidth = Printer.Width - 1440*2

Printer.CurrentY = 1440



Left Justified is the simplest form of justification and the head position
is already set.

Printer.Print mTxt

The printer head automatically moves to the starting point on the next line
as there is no comma or semi-colon at the end of the Print.

Lets try right justification. We have CurrentY set for
the next print statement. We need to set the CurrentX. Now we will
require the MaxWidth and TxtWidth values, which we
have ready with us (above).

' add 1440 is to maintain the 1" Left Margin.

Printer.CurrentX = 1440 + (MaxWidth - TxtWidth)

Printer.Print mTxt

Similarly, you can achieve center justification

Printer.CurrentX = 1440 + (MaxWidth - TxtWidth)/2    'again
1440 is to maintain Left Margin.

Printer.Print mTxt

This is all there is to printing text.

Ah yes ... just one more thing before we proceed. The above logic assume that
TxtWidth < MaxWidth. If the width of the text is greater than
the maximum print width then you must separately process the text to either
truncate it so that it fits the MaxWidth or split the lines suitably
to simulate word-wrap.

For those interested, here's the entire code,

mTxt = "Gajendra S. Dhir"

TxtWidth = Printer.TextWidth(mTxt)



'to leave 1" Margins on the Top, Left and Right of the page

Printer.CurrentY = 1440

Printer.CurrentX = 1440

MaxWidth = Printer.Width - 1440*2



'Left Justified - no extra work

Printer.Print mTxt



'Right Justified

Printer.CurrentX = 1440 + (MaxWidth - TxtWidth)  ' add 1440 is to
maintain the 1" Left Margin

Printer.Print mTxt



'Center Justified

Printer.CurrentX = 1440 + (MaxWidth - TxtWidth)/2    'again
1440 is to maintain Left Margin.

Printer.Print mTxt



'Terminate Printing

Printer.EndDoc

Font Name, Size and Style

A wide variety of fonts, also known as typefaces, are available under the Windows
operating system. Some are optimized for better screen appearance while others
are designed with the printed output in mind. The printer that you use also
has certain built-in fonts which you can access from your VB program.

The Printer.FontCount property tells you the number of fonts that
are available in your system and are supported by current the printer. You can
select the name of the font that you want to use for printing your text from
the Printer.Fonts collection

To get a list of the names of the fonts available you can use a loop like this...

For i = 0 to Printer.FontCount-1

    Printer.Print Printer.Fonts(i)

Next i

or better still you could use the Printer.Font.Name property like
this...

For i = 0 to Printer.FontCount-1

    Printer.Font.Name = Printer.Fonts(i)

    Printer.Print Printer.Font.Name

Next i

to get a complete list of the fonts available with each Font.Name
printed using that very typeface.

To determine or alter the size of the text that is being printed you must access
the Printer.Font.Size property. Mayby something like this...

mSize = Printer.Font.Size

Printer.Font.Size = mSize + 4

Printer.Print "THE TITLE TEXT"

Printer.Font.Size = mSize

Other than this, control for Bold, Italic, Underline and
Strikethru characteristics of a font that are available at your disposal
as a Visual Basic programmer. These are boolean properties and take the values
True or False. You may use these properties as...

 Printer.Font.Bold = True to enable and False
to disable

 Printer.Font.Italic = True to enable and False
to disable

 Printer.Font.Strikethrough = True to enable and False
to disable

and

 Printer.Font.Underline = True to enable and False
to disable

The following code will give you a printout of all the printer fonts installed
on your system along with the "bold" and "italic"
texts printed next to the font name.

With Printer

  For i = 0 to .FontCount-1

    .Font.Name = Printer.Fonts(i)

    .Print Printer.Font.Name;     'Note
the ; (semi-colon) at the end of print

    .Font.Bold = True

    .Print " Bold";               'Note
the ; (semi-colon) at the end of print

    .Font.Bold = False

    .Font.Italic = True

    .Print " Italic"              'Note
no ; (semi-colon) at the end of print

    .Font.Italic = False

    If Printer.CurrentY + Printer.TextHeight("NextLine")
> Printer.Height - 720 Then

      Printer.NewPage

    End If

  Next i

End Width



'Terminate Printing

Printer.EndDoc



When working with the fonts you can also use .FontName, .FontSize,
.FontBold, .FontItalic, .FontStrikeThru,
.FontUnderline for .Font.Name, .Font.Size,
.Font.Bold, .Font.Italic, .Font.Strikethrough,
.Font.Underline used above.

Print in Color

Printing in color adds to the presentation value of the final output. Let us
add some color to our printing.

Use the Printer.ColorMode to enable or disable color printing for your color printer.

Printer.ColorMode = vbPRCMColor

or

Printer.ColorMode = vbPRCMMonochrome



Depending on the printer installed, when you the set the printer to vbPRCMMonochrome
prints in shades of black and white.

Once you have activated color printing you can control the color of the output
through two properties two properties, backcolor and forecolor,
of the printer, to control the color of the background and the
foreground respectively. The color values can be assigned to these properties
using the RGB() function.

Printer.ForeColor = RGB(255, 0, 0)     ' For
Text in Red Color

Printer.Print "This text is in Red ";

Printer.ForeColor = RGB(0, 0, 255)     ' For Text in
Blue

Printer.Print "and this is in Blue"

Printer.BackColor = RGB(255, 255, 0)   ' For Background in Yellow

Printer.Print "The text here is Blue and the background is Yellow"

Visual Basic has provided color constants for the standard colors, namely vbBlue,
vbRed, vbGreen, vbMagenta, vbCyan,
vbYellow, vbBlack and vbWhite.

Points for Consideration

Here are some tips which I think you will find useful during your exploration
of the printer object...

• You will need simple sub-routines to print text - left, right and center
    justified within a maximum width that you may specify. This will allow you
    to create the columns in a tabular report and adequately justify the text
    within the column.


• You could write a function to split long strings based on the print width
    to enable word wrapping. See my previous code submitted titled
    Split Strings for Word Wrapping.


• The printer uses the same concept of device contexts that is used by Form
    and PictureBox Control. The difference is only in methods like EndDoc,
    KillDoc, Cls etc. Using code like...
  
    If Destination = "Printer" Then

      Set objDC = Printer

  Else

      Set objDC = Picture1

  Endif

  objDC.Print "Hello! This is Gajendra"
  
    you can easily create a print preview.

I welcome and will appreciate constructive feedback and creative suggestions.