Question

我正在使用Graphics.ScaleTransform拉伸文本行以使其符合页面宽度，然后打印该页面。但是，这会将打印作业转换为位图 - 对于具有许多页面的打印，这会导致打印作业的大小上升到不合适的比例，并且会大大减慢打印速度。

如果我不像这样缩放，打印作业仍然很小，因为它只是向打印机发送文本打印命令。

我的问题是，除了使用Graphics.ScaleTransform来拉伸文字的宽度之外，还有其他方法吗？

示例代码如下所示（将使用Print.Test(True)和Print.Test(False)调用以显示缩放对打印作业的影响）：

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

更新：我使用了与GDI调用的互操作。这是相关的代码; GDI类充满了我在http://pinvoke.net/从wiki复制的相关函数和常量的定义。

    ' 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)

Answer 1

是的，Graphics类支持缩放文本。但它需要首先将文本渲染为位图，重新缩放位图并将调整后的位图传递给打印机驱动程序。所有这些位图都是一个大型假脱机程序文件。

您需要自己证明文本的合理性。框架中没有对此的支持。一种方法是劫持一个丰富的编辑控件，让它来处理理由和打印。版本5，msftedit.dll，支持完全对齐。找到所需代码的最佳方法是找到许多使用RTB实现文本编辑器的项目之一，类似于Windows上的Wordpad。

Answer 2

我在这里猜测，但你应该按照你想要缩放的比例的百分比来增加字体的大小。

.NET Graphics.ScaleTransform将打印作业转换为位图。还有其他缩放文字的方法吗？

2 个答案: