1130992 - height calculation in box model in dev tools shows one pixel too much

Status: RESOLVED WORKSFORME

(DevTools :: Inspector, defect)

Description

[lamotte.cyril]

Attachment: template_a_valider_v4.zip

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.111 Safari/537.36

Steps to reproduce:

I am calculating div's height and apply by JS a min-height


Actual results:

In the dev tools, the box model show 255 (height) + 3 (border-bottom).
Whereas the overlay indicate 259. 


Expected results:

Overlay should indicate 258 (255 + 3) OR box model should indicate
It is not coherent

I join the mockup

Comment 1

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

What version of Firefox did you test with here?

Comment 2

[lamotte.cyril]

Hi,

The current stable : 37.01

Comment 3

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

(In reply to lamotte.cyril from comment #2)
> Hi,
> 
> The current stable : 37.01

Can check in the latest Developer Edition[1] (Fx 39)?  A fix for this was recently made in bug 1113761 for Firefox 39, currently in Dev. Edition.

[1]: https://www.mozilla.org/en-US/firefox/channel/#developer

Comment 4

[lamotte.cyril]

Hi,

Same result with : Dev Edition : 39.0a2 (2015-04-07)

Comment 5

[lamotte.cyril]

Actually, there is a 0.317px difference. Div is 258.317px, height calculation return 255 (258 - 3 of border). 

Maybe the height calculation does not care about subpixels ? (I use the jquery "height()" method)

Comment 6

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

(In reply to lamotte.cyril from comment #5)
> Actually, there is a 0.317px difference. Div is 258.317px, height
> calculation return 255 (258 - 3 of border). 
> 
> Maybe the height calculation does not care about subpixels ? (I use the
> jquery "height()" method)

Yes, it seems that way.  Many older methods round to integers.

You can use something like element.getClientRects() to receive the true size.

I believe this means the tools are now working correctly, but please reopen if you disagree!

Comment 7

[lamotte.cyril]

Ok for me
Thanks a lot