Sumatra PDF is a PDF, ePub, MOBI, CHM, XPS, DjVu, CBZ, CBR reader for Windows

Pinch to zoom and pan like Microsoft Edge

When you view a PDF:

In Microsoft Edge, when you pinch the touch screen, it zooms relative to your finger position, so you can also use it to pan.

In SumatraPDF, when you pinch the touch screen, it zooms into the top left corner of the screen. If you zoom out far enough, the zoom center becomes the center of the document instead of your finger position. So it doesn’t allow zooming on a particular part of the document or panning at the same time.

Can it be made to function like Edge?

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Dear Microsoft
When you view a PDF: with a Real Document application like Adobe Acrobat a “normal” page zoom is initially focused in the centre until the page boundaries are met then it re-focuses into the Top Left origin Your browser behaves differently to a PDF browser, can you please change your Web browser to work like Acrobat ?

@GitHubRulesOK: The OP’s not talking about zooming using the menu. When one is Ctrl+mousewheel zooming or pinch zooming, the zooming always has to happen with the cursor/static finger position being treated as the center. If Acrobat doesn’t follow this basic rule then that’s just one more way in which it is a crappy app!

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@SumatraPeter
I dont disagree about the logic
select a word or a marquee zone and Acrobat (or SumatraPDF) will zoom about that object
select a page and the 0,0 (notional centre) is nominally top left even if real centre is bottom left !!!

The zoom center should be the cursor/static finger position even if nothing has been selected previously.

Just to clarify, did you test pinch zoom on a touchscreen Windows tablet to confirm what the OP wrote? I’m asking because he wants Sumatra’s pinch zoom to behave like Edge’s, but it looks like you’re suggesting Edge is doing it wrong?

Also, just to be extra clear to prevent any confusion, which exact version of Edge are we all talking about here - legacy or ChrEdge? I’m using the latest stable release of ChrEdge (Chromium-based Edge) i.e. 80.0.361.69, but I don’t have a touchscreen Windows tablet right now to confirm the issue.

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To be clear I am saying MS Edge is not a dedicated PDF reader with the same traditional decades of pdf reader behaviours. That go back to the days of DinOSaurs
For good or bad SumatraPDF emulates Adobe Software on both touch screen and touchpad from more than a decade ago.
It is possible Acrobat have changed some behaviours to conform with MS apps but I only use Portable Acrobat 9 so can only vouch that SumatraPDF mimics its behaviour.

If the tablet is rotated the origin may then be relocated to top right (so it follows the hamburger)

Panning is a separate task and I see no issue over how that works
Naturally at most basic it is either orthogonal horizontal or vertical steps
however, depending on how your defaults are set, simply hold down on a tablet to “grab and go” free-form or right-click whilst moving on a touchpad

Yeah, Acrobat DC works the wrong way, too.

Its Edge that can’t get its act together. Seems to be building itself backwards
Highlight you see it, Highlight you don’t, so no more living on the Edge for me.

Proudly written in FireFox Which Correctly Pinch Zooms to Top Left

For reference the Issue is covered at

No, Sumatra and Acrobat behave incorrectly, and Edge behaves correctly. Here are recordings of each: https://imgur.com/a/eenW6Mf

Actually I tried Acrobat again and it zooms to wherever the mouse cursor is, rather than to where the fingers are. Sumatra always goes to the top left, though, regardless of mouse cursor.

When using touchscreen windows 10 pinch zoom, it zooms from top left corner. Is there option to use center of the pinch as zoom center? Thank You! I like sumatra because of its speed and lightweight design, but beacause of this I still have to use Adobe reader as my default pdf viewer. If this worked i could definitely get rid of it :slight_smile:

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