GDI+ Printing Lines - Xtreme Visual Basic Talk

08-08-2012, 10:29 AM

mms

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Join Date: Jul 2002

Location: Hamilton, Ontario

Posts: 1,665

GDI+ Printing Lines

I'm trying to print a fixed number of lines per printed page.

The first page however, I want to have a lesser number of lines, starting
further down the page than the subsequent pages
(space at top to be equal to number of lines not printed X spacing between the lines).

I would think this should be an easy thing to do, but I am coming up totally blank.

I guess this is more a coding algorithm problem than a GDI+ problem.

This is my code to print the same number of lines on each page
(3 printed pages with 8 lines each and the last page with 1 line).

Code:

Private Sub Command1_Click()

    Dim hdcPrint As Long
    hdcPrint = CreateDC(Printer.DriverName, Printer.DeviceName, 0, 0)

    Dim myDocInfo As DOCINFO
    myDocInfo.cbSize = Len(myDocInfo)
    myDocInfo.lpszDocName = "GdiplusPrint"
    
    Call StartDoc(hdcPrint, myDocInfo)
    Call StartPage(hdcPrint)

    Dim stat As Long
    
    Dim graphics As Long
    stat = GdipCreateFromHDC(hdcPrint, graphics)
    
    Dim pen As Long
    stat = GdipCreatePen1(&HFF000000, 1, UnitPixel, pen)

    Dim i As Long
    Dim offsetY As Single
    Dim lineSpacing As Single
    Dim linesToPrint As Long
    Dim linesPerPage As Long
    Dim linesFirstPage As Long
    
    offsetY = 10
    lineSpacing = 10
    linesPerPage = 8
    linesToPrint = 25
    
    linesFirstPage = 7

    For i = 0 To (linesToPrint - 1)
        
        If (i Mod linesPerPage = 0) And i <> 0 Then
    
            Call EndPage(hdcPrint)
            
            offsetY = offsetY - (linesPerPage * lineSpacing)
    
        End If

        stat = GdipDrawLine(graphics, pen, _
                            0, offsetY + (i * lineSpacing), _
                            500, offsetY + (i * lineSpacing))

    Next i

    Call EndPage(hdcPrint)
    Call EndDoc(hdcPrint)
    
    Call DeleteDC(hdcPrint)
    
    stat = GdipDeletePen(pen)
    stat = GdipDeleteGraphics(graphics)
    
End Sub

08-08-2012, 11:39 AM

passel

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Location: Upstate New York, usa

Posts: 7,714

I'm not really clear on the question, but I'll assume the code you posted works, and what you want is to modify it in some way to meet your new requirement.

It sounds like you want to "print" empty lines on the first page, and I believe you're calculating offset based on the line number, so I think you could just add an offset of how many blank lines you want and it would take care of itself.

If ((i-linesFirstPage) Mod linesPerPage = 0) Then

I'll have to test that to see if that works. It may have an "off by 1" problem and you have to carry the adjustment through to your other calculations.

My initial thought was to use the number of blank lines you wanted on the first page and you would add that to your loop index to create a virtual YLinePosition.
You would use the YLinePosition for all your placement calculations.

Again, untested:

Code:

    For i = 0 To (linesToPrint - 1)
        YLinePosition = i + NumberOfBlankLinesFirstPage
        If (YLinePosition Mod linesPerPage = 0) Then
            Call EndPage(hdcPrint)
            offsetY = offsetY - (linesPerPage * lineSpacing)
        End If
        stat = GdipDrawLine(graphics, pen, _
                            0, offsetY + (YLinePosition * lineSpacing), _
                            500, offsetY + (YLinePosition * lineSpacing))
    Next i

I think that will work, but to be honest, I don't think I would have done it that way,
Rather than have to calculate an ever decreasing offsetY to compensate for the page you're on, I would used the mod position of the line so it's coordinates are local to the page

Code:

        ModYLinePosition = YLinePosition Mod linesPerPage 
        stat = GdipDrawLine(graphics, pen, _
                            0, ModYLinePosition * lineSpacing, _
                            500, ModYLinePosition * lineSpacing)

but, perhaps offseting the "coordinate system" by page suits the way you are drawing other objects.

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08-08-2012, 02:27 PM

mms

Ultimate Contributor

Join Date: Jul 2002

Location: Hamilton, Ontario

Posts: 1,665

You understood the question correctly, and the code you posted (both methods) produces printed output exactly as I wanted.

Thank you!!

I want to use your second method (the one you said was best) with the PrintClip function you wrote for me a while back, and don't see why this won't work.

I had come up with some code (finally) that worked, trouble is, it is so cumbersome that in a few weeks time I would never remember what I was doing.
I have this (unwanted) ability to produce code that is overly complicated.

This is what I came up with:

Code:

    Dim modCheck As Long
    modCheck = linesFirstPage
   
    Dim firstPageAdjustment As Long
    'firstPageAdjustment = linesPerPage - linesFirstPage
    
    Dim pageNum As Long

    For i = 0 To (linesToPrint - 1)

        If (i Mod modCheck = 0) And i <> 0 Then
    
            Call EndPage(hdcPrint)
            offsetY = offsetY - (linesPerPage * lineSpacing) + (firstPageAdjustment * lineSpacing)
            pageNum = pageNum + 1
            
            Debug.Print i & "," & modCheck & "," & pageNum & "," & offsetY
    
        End If

        If i >= 0 And i < linesFirstPage Then
            modCheck = linesFirstPage
            firstPageAdjustment = linesPerPage - linesFirstPage
        Else
            modCheck = pageNum * linesPerPage + linesFirstPage
            firstPageAdjustment = 0
        End If

        stat = GdipDrawLine(graphics, pen, _
                            0, offsetY + ((firstPageAdjustment + i) * lineSpacing), _
                            500, offsetY + ((firstPageAdjustment + i) * lineSpacing))
        
        Debug.Print offsetY + ((firstPageAdjustment + i) * lineSpacing)
        
    Next i

08-09-2012, 07:49 AM

mms

Ultimate Contributor

Join Date: Jul 2002

Location: Hamilton, Ontario

Posts: 1,665

Your code works perfectly in the context of my main program where I use the PrintClip function.

A problem with Windows7 Print Dialog;
It reports 1 page printed when in fact 4 pages were sent to the printer.
The correct document name is displayed (GdiplusPrint).

myDocInfo.lpszDocName = "GdiplusPrint" from in Post #1 sets this.

How then to display the correct number of pages if this is not tracked automatically?

Attached Images

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