I'm using Graphics.ScaleTransform
to stretch lines of text so they fit the width of the page, and then printing that page. However, this converts the print job to a bitmap - for a print with many pages this causes the size of the print job to rise to obscene proportions, and slows down printing immensely.
If I don't scale like this, the print job remains very small as it is just sending text print commands to the printer.
My question is, is there any way other than using Graphics.ScaleTransform
to stretch the width of the text?
Sample code to demonstrate this is below (would be called with Print.Test(True)
and Print.Test(False)
to show the effects of scaling on print job):
Imports System.Drawing
Imports System.Drawing.Printing
Imports System.Drawing.Imaging
Public Class Print
Dim FixedFont As Font
Dim Area As RectangleF
Dim CharHeight As Double
Dim CharWidth As Double
Dim Scale As Boolean
Const CharsAcross = 80
Const CharsDown = 66
Const TestString = "!""#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~"
Private Sub PagePrinter(ByVal sender As Object, ByVal e As PrintPageEventArgs)
Dim G As Graphics = e.Graphics
If Scale Then
Dim ws = Area.Width / G.MeasureString(Space(CharsAcross).Replace(" ", "X"), FixedFont).Width
G.ScaleTransform(ws, 1)
End If
For CurrentLine = 1 To CharsDown
G.DrawString(Mid(TestString & TestString & TestString, CurrentLine, CharsAcross), FixedFont, Brushes.Black, 0, Convert.ToSingle(CharHeight * (CurrentLine - 1)))
Next
e.HasMorePages = False
End Sub
Public Shared Sub Test(ByVal Scale As Boolean)
Dim OutputDocument As New PrintDocument
With OutputDocument
Dim DP As New Print
.PrintController = New StandardPrintController
.DefaultPageSettings.Landscape = False
DP.Area = .DefaultPageSettings.PrintableArea
DP.CharHeight = DP.Area.Height / CharsDown
DP.CharWidth = DP.Area.Width / CharsAcross
DP.Scale = Scale
DP.FixedFont = New Font("Courier New", DP.CharHeight / 100, FontStyle.Regular, GraphicsUnit.Inch)
.DocumentName = "Test print (with" & IIf(Scale, "", "out") & " scaling)"
AddHandler .PrintPage, AddressOf DP.PagePrinter
.Print()
End With
End Sub
End Class
UPDATE: I used interop with GDI calls instead. Here's the relevant code; the GDI class is just 开发者_如何学JAVAfull of definitions I copied from the wiki at http://pinvoke.net/ for the relevant functions and constants.
' convert from Graphics units (100 dpi) to device units
Dim GDIMappedCharHeight As Double = CharHeight * G.DpiY / 100
Dim GDIMappedCharWidth As Double = CharWidth * G.DpiX / 100
Dim FixedFontGDI As IntPtr = GDI.CreateFont(GDIMappedCharHeight, GDIMappedCharWidth, 0, 0, 0, 0, 0, 0, GDI.DEFAULT_CHARSET, GDI.OUT_DEFAULT_PRECIS, GDI.CLIP_DEFAULT_PRECIS, GDI.DEFAULT_QUALITY, GDI.FIXED_PITCH, "Courier New")
Dim CharRect As New GDI.STRUCT_RECT
Dim hdc As IntPtr = G.GetHdc()
GDI.SelectObject(hdc, FixedFontGDI)
' I used SetBkMode transparent as my text needed to overlay a background
GDI.SetBkMode(hdc, GDI.TRANSPARENT)
' draw it character by character to get precise grid
For CurrentLine = 1 To CharsDown
For CurrentColumn = 1 To CharsAcross
With CharRect
.left = GDIMappedCharWidth * (CurrentColumn - 1)
.right = GDIMappedCharWidth * CurrentColumn
.top = GDIMappedCharHeight * (CurrentLine - 1)
.bottom = GDIMappedCharHeight * CurrentLine
End With
' 2341 == DT_NOPREFIX|DT_NOCLIP|DT_VCENTER|DT_CENTER|DT_SINGLELINE
GDI.DrawText(hdc, Mid(TestString & TestString & TestString, CurrentLine+CurrentColumn, 1), 1, CharRect, 2341)
Next
Next
GDI.DeleteObject(FixedFontGDI)
G.ReleaseHdc(hdc)
Yes, the Graphics class supports scaling text. But it needs to do so by rendering the text to a bitmap first, rescale the bitmap and pass that resized bitmap to the printer driver. All those bitmaps make for a large spooler file.
You will need to justify the text yourself. There's no support for this in the framework. One way to do it is to hijack a rich edit control and let it take care of the justification and printing. Version 5, msftedit.dll, supports full justification. The best way to find the code you need is to find one of the many projects that implement a text editor with RTB, similar to Wordpad on Windows.
Im guessing here but you should increase the size of the Font by a percentage of the proportion you want to scale by.
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