Re: [xep-support] Order of region background-color in PDF output from regions is non-deterministic

From: Jason Zaugg <>
Date: Fri May 02 2008 - 10:29:27 PDT

On Thu, Feb 7, 2008 at 1:24 AM, Michael Sulyaev <> wrote:
> Indeed static regions come out in an unpredictable order, but the
> Recommendation does not specify which is the correct order. If regions have
> borders (which is a handy extension) visual effects may appear as well.
> > We are able to run a tool to visually compare the PDFs as a
> > workaround, but this is much slower than comparing the PDF bytes
> > (stripped of CreationDate / ModDate / ID fields)
> >
> I would not rely on bitwise comparison of PDF files, even after filtering
> out CreationDate, ModDate, ID fields. It may possibly fail if settings
> change, or if RenderX changes the PDF back-end code.
> Using GhostScript for batch-mode PDF->PNG[*] rasterization at 72dpi is both
> fast and accurate enough for bitwise comparison of PNG images. I use this
> approach regularly.
> > Is it possible to update XEP to make the PDF output predictable?
> >
> We will consider this as a request for enhancement, although no promises
> can be given at the moment.

I am using pixel comparison of the PDFs in my test suite at the
moment. However, even this is not working 100% now that I am creating
a document with a non-white backround.

I am using the Java PDFRenderer library. See the attachment for the
two PDFs generated by XEP, and the rasterizations and difference

This is probably just a bug in the PDFRenderer library, as Acrobat
displays both PDFs identically. But I could live with this bug if you
were able to produce stable PDF output within a given release of XEP.

In addition, being able to use bitwise comparisons as the first check
in my test suite will cut my functional test run time down by ~ 25%,
and help our productivity and generally make the developers happier :)

Have you considered this enhancement?


Jason Zaugg

EFG Financial Products
Zurich, Switzerland

 <xsl:variable name="background-color">rgb(213, 214, 215)</xsl:variable>
            <fo:simple-page-master master-name="A5"
page-height="210mm" page-width="148mm"
margin-left="0.0pt" margin-bottom="0.0pt"
                <fo:region-body margin-left="28.0pt"
margin-top="28.0pt" margin-bottom="28.0pt"
                <fo:region-before extent="28.0pt" precedence="true"
                <fo:region-after extent="28.0pt" precedence="true"
                <fo:region-start extent="28.0pt" precedence="false"
                <fo:region-end extent="28.0pt" precedence="false"

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Received on Fri May 2 12:13:42 2008

This archive was generated by hypermail 2.1.8 : Fri May 02 2008 - 12:13:43 PDT