用于打印的缩放图像 [英] Scaling image for printing

问题描述

我正在使用以下代码从 PictureBox 打印图像.如果图像比打印页面大，则除了缩小图像外，其他一切都很好.有没有我缺少的方法来做到这一点?

I'm using the following code to print an image from a PictureBox. All works great except for scaling images down if they are bigger than the print page. Is there a method I'm missing to do this?

屏幕截图，纸张边界外的大图:

Screenshot, large image outside of the paper bounds:

http://a.yfrog.com/img46/63/problemsh.pnghttp://a.yfrog.com/img46/63/problemsh.png

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    AddHandler PrintDocument1.PrintPage, AddressOf OnPrintPage

    With PageSetupDialog1
        .Document = PrintDocument1
        .PageSettings = PrintDocument1.DefaultPageSettings

        If PictureEdit1.Image.Height >= PictureEdit1.Image.Width Then
            PageSetupDialog1.PageSettings.Landscape = False
        Else
            PageSetupDialog1.PageSettings.Landscape = True
        End If

    End With

    PrintDialog1.UseEXDialog = True
    PrintDialog1.Document = PrintDocument1

    If PrintDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
        PrintPreviewDialog1.Document = PrintDocument1
        If PrintPreviewDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then

            PrintDocument1.DefaultPageSettings = PageSetupDialog1.PageSettings
            PrintDocument1.Print()

        End If
    End If
End Sub

Private Sub OnPrintPage(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs)
    Dim img As Image = PictureEdit1.Image

    Dim sz As New SizeF(100 * img.Width / img.HorizontalResolution, 100 * img.Height / img.VerticalResolution)
    Dim p As New PointF((e.PageBounds.Width - sz.Width) / 2, (e.PageBounds.Height - sz.Height) / 2)
    e.Graphics.DrawImage(img, p)
End Sub

推荐答案

替换:

Dim sz As New SizeF(100 * img.Width / img.HorizontalResolution, 100 * img.Height / img.VerticalResolution) 

用这样的东西来适应页面中的图像:

With something like this to fit the image in the page:

dim ScaleFac as integer = 100
While (ScaleFac * img.Width / img.HorizontalResolution > e.PageBounds.Width or ScaleFac * img.Height / img.VerticalResolution > e.PageBounds.Height) and ScaleFac > 2
    ScaleFac -= 1
Wend
Dim sz As New SizeF(ScaleFac * img.Width / img.HorizontalResolution, ScaleFac* img.Height / img.VerticalResolution) 

您可以使用代数来求解正确的 scalefac，但我没有时间对其进行测试，如果您不了解我所做的工作，那么调试起来会困难得多.很确定你会从代码中看到我在这里尝试做的事情！问候.

You could use algebra to solve for the proper scalefac, but I don't have time to test it and if you didn't understand what I'd done that would be a lot harder for you to debug. Pretty sure you'll see what I'm trying to do here from the just the code alone! Regards.

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