[URGENT BUG!!] Exported PDF format has different dimensions!

[JeffreyWalther]

Hello Affinity,

my colleague and I are working on a couple of documents in A4 format. In the process, we have encountered an extremely serious bug.

When exporting the PDF, the format is changed.
From 210 x 297mm document format in the designer, becomes a PDF
with 210,1 x 297mm. This must not be!!! This is a serious bug in the software and must be fixed immediately.

Error appears in version 1.8.5.703, Windows 10. Tested on two different computers.

Error is reproducible:

1. Open Affinity Designer.
2. Create a new A4 document.
   
    
3. Check the document setup again. 210 x 297mm. All okay here:
   
    
4. Export the blank sheet as PDF:
   
    
5. Open the generated PDF in a viewer and check the dimensions: now they are wrong!
   
    
6. Double-check: Import the PDF in Affinity Designer and even there check the dimensions: wrong!
   Instead of 210 x 297mm, we've got 210,1 x 297mm. 
   
   
    

Please Affinity, fix this as soon as possible. Thank you.

 

Jeff

[MikeW]

Part of the issue is a rounding issue due to the number of digits. This is what I get in both Acrobat and my copy of AD/Windows, both using more digits to display the values.

[MikeW]

btw, I think that as a pdf's native units are points (72 pts/inch), I'm not aware of any application that can do an a4 document to precise mm units in both dimensions--at least if the digits are increased enough to display where rounding does occur..

Adobe Illustrator:

CorelDraw:

Xara:

[JeffreyWalther]

Mike.... 210.0000xxxx by other applications is far away from 210.1. 
Even Word can export a PDF with the proper dimensions.

Affinity Designer, Photo and even Publisher suffer from this issue and
this is not good if you work with printing companies.
 

 

[MikeW]

1 minute ago, JeffreyWalther said:

Mike.... 210.0000xxxx by other applications is far away from 210.1. 
Even Word can export a PDF with the proper dimensions.
Affinity Designer, Photo and even Publisher suffer from this issue and
this is not good if you work with printing companies.

Look again at my screen shot of AD. It's not 210.1

[MikeW]

MS Word:

[MikeW]

The layout applications I use are consistent...but still off if one desires absolute precision.

InDesign:

VivaDesigner:

QuarkXpress:

[lepr]

12 hours ago, JeffreyWalther said:

From 210 x 297mm document format in the designer, becomes a PDF
with 210,1 x 297mm.

 

Affinity exports documents to a rounded-up size that would contain whole pixels at the Affinity document PPI. (All Affinity documents have a PPI regardless of whether they contain raster objects.)

210 x 297 mm

300 ppi => 2480.315 x 3507.874 pixels 
rounded up to integers => 2481 x 3508 pixels 
expressed in mm again => 210.058 x 297.011 mm

72 ppi => 595.276 x 841.89 pixels 
rounded up to integers => 596 x 842 pixels 
expressed in mm again => 210.256 x 297.039 mm

In my opinion, that resizing for whole pixels is ridiculous when exporting to a vector document such as a PDF, but there was no response from Serif when I posted about it before.

 

[MikeW]

8 hours ago, anon2 said:

Affinity exports documents to a rounded-up size that would contain whole pixels at the Affinity document PPI. (All Affinity documents have a PPI regardless of whether they contain raster objects.)...

Sort of / Mostly true. But not universally.

A pdf is using points per inch internally--always--other math units will always be fractional. Try a US Letter, 72 dpi document. Export it as a 72 dpi document. Now try a 300 dpi export with the same document. Or vice versa (US Letter, 300 dpi document, 300 dpi export and a 72 dpi export). You'll find the export is a proper/even export of points (612 pts x 792 pts) both times.

Now try the same as I did above, using a wider range of software that is dpi agnostic, and an A4 document. There will always be a fractional mm measurement using their pdf export.

While I have always "railed" against a document-based dpi in APub/AD (for other reasons), this non-exact mm measurement in a pdf is mostly a non-issue.

[lepr]

1 hour ago, MikeW said:

Sort of / Mostly true. But not universally.

I have to disagree. Your experiment with a Letter size document was flawed for the reason I give below.

 

1 hour ago, MikeW said:

A pdf is using points per inch internally--always--other math units will always be fractional. Try a US Letter, 72 dpi document. Export it as a 72 dpi document. Now try a 300 dpi export with the same document. Or vice versa (US Letter, 300 dpi document, 300 dpi export and a 72 dpi export). You'll find the export is a proper/even export of points (612 pts x 792 pts) both times.

My explanation of Affinity's expansion of export size is not invalidated by a Letter size document. Letter size (8.5 x 11 inch) is an integer quantity of DTP points (612 x 792) and it is an integer quantity of pixels when ppi is an even integer, so the export from Affinity will not require rounding up to accomodate whole pixels when ppi is either 72 or 300. That is why Affinity's export of Letter size is a proper 612 x 792 points.

Try Letter with an odd numbered ppi to see that Affinity will round up the export size to accomodate whole pixels at the Affinity document's ppi.

8.5 x 11 inches / 612 x 792 points
73 ppi => 620.5 x 803 pixels 
rounded up to integers => 621 x 803 pixels 
expressed in inches and points again => 8.507 x 11 inches / 612.493 x 792 points

 

1 hour ago, MikeW said:

Now try the same as I did above, using a wider range of software that is dpi agnostic, and an A4 document. There will always be a fractional mm measurement using their pdf export.

I have used other software. These fractional mm measurements do not invalidate my explanation of Affinity's behaviour.

[MikeW]

Yes. No.

The letter-size document experiment all depends on the document dpi, not the export dpi (at least as far as I have tried). However, nothing is gonna export an even, proper, a4 mm dimension. Not even printing to Adobe's pdf driver set to a4.

I'm not really disagreeing with you. Having a dependent document dpi is a boneheaded decision for vector applications. That it can affect a resulting pdf's size in varying amounts is proof of a faulty decision to have a document dpi.

[lepr]

1 hour ago, MikeW said:

The letter-size document experiment all depends on the document dpi, not the export dpi (at least as far as I have tried).

I did explicitly write "the Affinity document's ppi" with the (apparently futile) hope that it would be clear that I was not talking about export ppi.

1 hour ago, MikeW said:

However, nothing is gonna export an even, proper, a4 mm dimension. Not even printing to Adobe's pdf driver set to a4.

The error will usually be orders of magnitude smaller than Affinity's ppi-dependent expansion nonsense, though.

Affinity, when its document ppi is 300, exports an A4 document to a PDF measuring 210.057992 mm x 297.010655 mm.

Inkscape, for example, exports an A4 document to a PDF measuring 209.999986 x 296.999991 mm.

 

1 hour ago, MikeW said:

I'm not really disagreeing with you. Having a dependent document dpi is a boneheaded decision for vector applications. That it can affect a resulting pdf's size in varying amounts is proof of a faulty decision to have a document dpi.

The fact that there is a document ppi in Affinity does not necessitate Affinity's vector file export size being affected by that ppi. That just happens to be the misguided way the export code is currently written.

[Gabe]

Hi all,

Sorry for the delayed reply. We were closed over Christmas/NY. 

We are aware of this and it has already been logged with our developers.