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Visual Basic 6

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Printer Object - A Primer by, Gajendra S. Dhir Team Leader Data Spec Bilaspur-CG, INDIA PRELUDE 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... Code 1 Printer.CurrentX = 0 Printer.CurrentY = 0 For i = 1 to 5 ˙˙˙Printer.Print Printer.CurrentX & ", " & Printer.CurrentY Next i Code 2 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. and Code 3 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.