How to calculate FixedPage dimensions

Question

This snippet is part of some code used to generate an XPS document. XPS document generation is no joke. I wish to avoid pasting any of that XPS code here if at all possible. Instead, this code focuses on the WPF portion of the problem.

The problem I am asking for you to help with is here. I have hard coded the dimensions to work for a test image:

double magicNumber_X = 3.5;//trial and error...3 too small 4 too big
fixedPage.Arrange(new Rect(new Point(magicNumber_X, 0), size));

Instead, how can I fix this code to calculate the coordinates?

Full Method:

    private PageContent AddContentFromImage()
    {
        var pageContent = new PageContent();
        var fixedPage = new FixedPage();            

        var bitmapImage = new BitmapImage(new Uri(hardCodedImageSampleFilePath, UriKind.RelativeOrAbsolute));

        var image = new Image();
        image.Source = bitmapImage;            
        fixedPage.Children.Add(image);

        ((IAddChild)pageContent).AddChild(fixedPage);

        double pageWidth = 96 * 8.5;//XPS documents are 96 units per inch
        double pageHeight = 96 * 11;

        fixedPage.Width = pageWidth;
        fixedPage.Height = pageHeight;

        var size = new Size(8.5 * 96, 11 * 96);

        fixedPage.Measure(size);
        double magicNumber_X = 3.5;//trial and error...3 too small 4 too big
        double magicNumber_Y = 0;
        fixedPage.Arrange(new Rect(new Point(magicNumber_X, magicNumber_Y), size));
        fixedPage.UpdateLayout();

        return pageContent;
    }

I'm a little surprised FixedPage.Measure(size) does not correct the issue by itself. I tried passing no params, e.g. fixedPage.Arrange(new Rect(), size)) still no go.

FWIW, this calculation worked fine when I was using PrintDocument.

private void pd_PrintPage(object sender, PrintPageEventArgs e)
    {
        Graphics g = e.Graphics;
        RectangleF marginBounds = e.MarginBounds;
        RectangleF printableArea = e.PageSettings.PrintableArea;

        int availableWidth = (int)Math.Floor(printDocument.OriginAtMargins ? marginBounds.Width : (e.PageSettings.Landscape ? printableArea.Height : printableArea.Width));
        int availableHeight = (int)Math.Floor(printDocument.OriginAtMargins ? marginBounds.Height : (e.PageSettings.Landscape ? printableArea.Width : printableArea.Height));

        Rectangle rectangle = new Rectangle(0,0, availableWidth -1, availableHeight - 1);        
        g.DrawImage(_image, rectangle);

What happens if your magicNumber_X is 0? What if it is 4? Is your image being clipped by the edge of the page? — Jon, Oct 04 '13 at 13:13
@Jon Yes, exactly...clipping occurs on the physical print. Only the magic "3.5" has no clipping. To be clear the XPS document itself shows no clipping...only the physical print. — P.Brian.Mackey, Oct 04 '13 at 13:18
Most printers have a non-printable area around the edge of the page. If you look into PrintCapabilities.PageImageableArea property, you should find the appropriate offsets and extents to use for your image. This does mean that you will need to know your target printer before creating the XPS document. Alternatively, you could assume a half inch margin around the page, and that should cover you for most printers. — Jon, Oct 04 '13 at 13:33

score 1 · Accepted Answer · answered Oct 09 '13 at 13:36

I hooked into FixedPage.Loaded event because FixedPage.ActualHeight is required in order to perform the calculation and will not be set until the control has loaded. This also means that with this mechanism FixedPage has to be displayed to correctly perform an automated print.

    void fixedPage_Loaded(object sender, RoutedEventArgs e)
    {
        var fixedDocument = sender as FixedPage;
        CalculateSize(fixedDocument);
    }
    private void CalculateSize(FixedPage fixedPage)
    {
        PrintQueue printQueue = LocalPrintServer.GetDefaultPrintQueue();
        PrintCapabilities capabilities = printQueue.GetPrintCapabilities();

        //get scale of the print wrt to screen of WPF visual
        double scale = Math.Min(capabilities.PageImageableArea.ExtentWidth / fixedPage.ActualWidth, capabilities.PageImageableArea.ExtentHeight / fixedPage.ActualHeight);

        //Transform the Visual to scale
        fixedPage.LayoutTransform = new ScaleTransform(scale, scale);

        //get the size of the printer page
        var sz = new Size(capabilities.PageImageableArea.ExtentWidth, capabilities.PageImageableArea.ExtentHeight);

        //update the layout of the visual to the printer page size.
        fixedPage.Measure(sz);
        double x = capabilities.PageImageableArea.OriginWidth;
        double y = capabilities.PageImageableArea.OriginHeight;
        fixedPage.Arrange(new Rect(new Point(x, y), sz));
        fixedPage.UpdateLayout();
    }

How to calculate FixedPage dimensions

1 Answers1

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