Luis Sequeira1

Q: PDFKit problem with full screen redraw

I do a lot of presentations in PDF (they are usually created with LaTeX, but I as will explain below, this detail is irrelevant to the problem).

 

Very often a slide is shown in increments -  think of several bullet points that are revealed one by one.

What really happens is that each stage is a separate page, but the user should not notice it.

So if you have a bulleted list

•A

•B

•C

 

there are really three separate pages (one containing just A, one A and B, and one with A,B,C).

 

When you advance to the next overlay, it appears that a B was added to the screen, then a C (even though each time a full page is replaced by the next).

 

In Sierra this screen redrawing is not smooth and the audience can clearly see the screen "shaking".

I tested this on two machines. I did a test Keynote presentation, which looks great; and then did the same with the PDF version and it is shaky. This was regardless of which program I used to display it (Preview, Skim, TeXShop), which indicates that the problem is in the common framework they all use - PDFKit.

 

I have already submitted feedback to Apple, but I would to hear if people are also seeing this; just to make sure it is not something weird on my machines.

MacBook Pro with Retina display, macOS Sierra (10.12)

Posted on Sep 26, 2016 6:28 AM

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Q: PDFKit problem with full screen redraw

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  • by hmzppz,Helpful

    hmzppz hmzppz Sep 27, 2016 9:43 AM in response to Luis Sequeira1
    Level 1 (17 points)
    Mac OS X
    Sep 27, 2016 9:43 AM in response to Luis Sequeira1

    Yes, I confirm this. It appears that PDFKit "re-focuces" the fonts every time one turns the page. While this might be great for static pages (better font antialiasing) it is certainly a problem for presentations: you can clearly see the fonts going from fuzzy to sharp in slides with incremental changes. This is just terrible. In contrast, PDFKit doesn't smooth images embedded in pdf files in Sierra at all: the ones with straight lines will look jugged on the screen. Again, just terrible. Bad, Apple, bad!