941331 - Double-tap zoom should include a margin around the tapped element

Status: RESOLVED FIXED

(Firefox for Metro Graveyard :: Pan and Zoom, defect)

Description

[Matt Brubeck (:mbrubeck)]

When zooming into a block of text, it's easier to read the text if it doesn't extend all the way to the edge of the screen, but instead has a small margin around it -- maybe 16px added to each side of the rectangle.

Comment 1

[Matt Brubeck (:mbrubeck)]

Attachment: patch

Comment 2

[Jim Mathies [:jimm]]

Just 16 pixels? I think we should be much more subtle - maybe 10% of the view width or height, whichever is smaller? It feels like we are too aggressive in our zoom in.

Comment 3

[Matt Brubeck (:mbrubeck)]

(In reply to Jim Mathies [:jimm] from comment #2)
> Just 16 pixels? I think we should be much more subtle - maybe 10% of the
> view width or height, whichever is smaller? It feels like we are too
> aggressive in our zoom in.

The downside of making the margin much larger is that, instead of seeing just the element you tapped, you get other elements peeeking in at the edges of the screen -- ads and navigation bars in particular.

Note that this is 16px in page coordinates, not screen coordinates.  If you are zoomed in to 2x scale, then those "16px" will be 32px (1/3") on screen.  On a high-dpi screen (1.8dppx), that's a margin of 58 device pixels on each side.

Comment 4

[Allison Naaktgeboren :ally]

Comment on attachment 8335721 [details] [diff] [review]
patch

Review of attachment 8335721 [details] [diff] [review]:
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nit: Please stick the '16' in a const, maybe at the top of the file. Jimm, we can tune that margin as needed.

Comment 5

[Matt Brubeck (:mbrubeck)]

(In reply to :Ally Naaktgeboren from comment #4)
> nit: Please stick the '16' in a const, maybe at the top of the file.

Fixed:
https://hg.mozilla.org/integration/fx-team/rev/5c11b81a0c91

Comment 6

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/5c11b81a0c91