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hubob

Import vector graphics: dimensions not preserved (dpi settings)

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Dear Affinity team, 

 

it is part of my workflow to import vector graphics from the statistics program Graphpad Prism into Affinity designer. When I copy a given plot in Prism and paste it in Affinity the vector nature is preserved. However, I found that the size of the graph's components changed, e.g. a 0.5 pt line would end up being a 0.7 pt line and so forth. I found that when I set the document's dpi to 104 the dimensions seem to be preserved, but since I also work with raster images from other sources within the same document I don't want to switch back and forth changing the dpi for the document all the time. Am I missing an obvious solution so AD would paste vector graphics at a given size regardless of the document's dpi settings?

 

Thanks for your help,

-hubob

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I am not familiar with that app so I might be missing something, but since vector graphics have no inherent size (they are geometric descriptions of shapes) & can be resized to any arbitrary dimensions without any change in their resolution, why can't you just resize the imported vector objects to whatever size you want, if necessary grouping them all together to make the process quick & easy to do?


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Hi R C-R,

thanks for your response! The problem with that (at least as far as I can see) is that it is hard to drag the graphs to exactly match the line widths and font sizes as required (Prism does not show the dimensions of the graph to start with, so I could not enter x/y values to scale but would have to drag the graphic). 

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Try exporting the Graph to a PDF from Prism 7 and open it in AD. Now go to Document Setup and change the DPI to 300 making sure Pixels are not selected and select Rescale.

 

This should keep the correct Stroke Width for the lines. You can now copy this into your other document containing the images. 

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Hi Leigh,

 

thanks a lot for your answer. Unfortunately, when I do just as you suggested the line width is 0.7 pt while it's set to 0.5pt in Prism 7 (the font size matches, however). As far as I remember this wasn't the case in Illustrator, but unfortunately (for this case...) I don't have it any longer and cannot compare. On a more general note I don't quite understand why the dpi settings matters for pure vector graphics, shouldn't it be sufficient for the import of vectors to provide the dimensions and positions rather than any specific resolution? 

 

Thanks for your help,

-hubob

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Does anybody have a clue on why the import of purely vector graphics require tweaking the dpi and whether this behavior holds true in AI as well? Thanks in advance!

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Thanks for your answer JimmyJack and sorry for taking this long to post the graphic. 

These are the issues:

- after placing the pdf into an AD file I have to manually adjust the dpi of the placed vector graphic to match the intended size; I don't understand why AD does not just recognize the dimensions of the vectors but requires dpi for it? My understanding was that vector graphics don't really have an associated dpi but rather just position cues and dimensions... (i.e., the vector should always be for example 3x4cm regardless of whether pasted into a 72dpi or 1200dpi document)?

- after manually aligning the dpi of the placed pdf and the target file the font in the placed pdf is correct (7pt, Helvetica) but the weight of the lines (set at 1/2pt in Graphpad Prism v7) shows as 0.72 pt.  

 

thanks for your help!

 

affinity_test.pdf

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Thanks for posting.... but this is the re-sized graphic right?

I was hoping to get the original from Prism..... but now I see (upon re-reading) that it was a copy paste.

Is there any chance of saving a pdf or eps or svg from prism to post here?

 

Also, I just wanted to restate the issue.... as I'm understanding it. For (my own) clarity's sake.

 

The original paste in, without any manipulation, has a different relationship between text items and line items Prism to Affinity? In other words the text is coming in at 100% as done in Prism and the lines are coming in over 100%?

 

Or is the discrepency only occurring when you try to resize after pasting?

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Hi JimmyJack,

 

this actually is the pdf export from Prism prior to pasting into AD. You're absolutely right - when adjusting the dpi's of the pdf and the AD file the font comes in at 100% but the weight of the strokes is 0.72pt rather than 1/2 pt in Prism (this could potentially also be a problem on Prism's side). 

On a more general note, I don't understand why AD requires the adjustment of dpi's - a pure vector pdf should just carry dimensions, right? 

Thanks for your help!

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okay, weird.

 

I've opened in AI, Inkscape, and Scribus. All are text 7 line weight .72. (inkscape requires a conversion because it's a piece of ......)

BTW you've got one text element in Arial and at a different point size than the rest.... But whatever.

 

So not sure what the deal is. Occam's razor points to Prism. Are we 100% sure it was .5pt AND an export (not a copy/paste).... sorry, had to ask. Peace ;) .

 

As to your secondary question. You can work it both ways right?

It's the different between clicking Anchor to Page or Rescale when changing the dpi in doc settings. Try both to see the difference.

 

So, if you just go to Open File and select the pdf, a screen will come up asking what dpi you want to open it in.... (with a default of "estimate").

This will open the pdf at the "size" (dimensions) of the original document, but at any dpi you choose. It's kinda a version of "resample" used with raster imagery, but with vectors so there's no loss of quality issue.

 

But, if you have, just for the sake of argument, the pdf already open at A x B dimensions at 72dpi. Create another document at exactly A x B but at 720 dpi and try to copy an element from the first to the second.... well, then the element will be one tenth the size. 10pt will become 1pt. In this case, copying and pasting is the same as "Anchor to page".

 

Hope that wasn't even more confusing. Sorry, not my fault  :D, it IS confusing.

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Thanks so much for trying this out, JimmyJack, it certainly seems like Prism is to blame with regards to the first point (yes, it was 1/2pt and I exported the pdf); I'll get in touch with the developers there. 

 

As far as the second point is concerned: you're absolutely right, this way works to adjust the sizes and it's what I use to do. Since I import a lot of individual pdf's all the time (creating figures with multiple pdf-subpanels) it would be very useful, if AD recognized upon import that the placed file is a pure vector file and thus just recognizes the dimensions, regardless of whether pasting it into a 72dpi or a 300dpi document. With the current way I need to create an intermediary document in which I assign the required dpi value to the pdf before placing it into final document. I wonder which way it works in Illustrator?

 

Thanks again for your great help!

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Hi, I run into the same problem and it is quite annoying. 

Sure there are ways to get it right but in my opinion (and Adobe) the size of a vector object should never be influenced by the resolution of the document.

Is there a Staff member around who can comment on this?

 

Right now we are using Illustrator in our sign maker comp. but with the cloud version it became so slow that I was glad to welcome Affinity.

 

Thanks

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