MaximYanchenko Reporter
	Description • 9 years ago

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:36.0) Gecko/20100101 Firefox/36.0
Build ID: 20150320202338
Firefox for Android

Steps to reproduce:

(FF for Android, 37.0.1, Galaxy Tab 3 Lite) 
1. Set your device in portrait orientation
2. Open http://learnyouahaskell.com/chapters
3. Scroll down until "3. Types and Typeclasses" is at the top of the screen. 
3. Rotate your device to a landscape orientation.



Actual results:

Now at the top of the screen I see "4. Syntax in Functions" (your results may differ, but it won't be "3. Types and Typeclasses").
It's even worse at long pages with a lot of text - it can jump the the end of the page on orientation change, and then jumps to some random place when you return to the original orientation.


Expected results:

"3. Types and Typeclasses" should remain at the top.

	Kartikaya Gupta (email:kats@mozilla.staktrace.com)
	Comment 1 • 9 years ago

This is a result of font inflation. When in landscape vs portrait we inflate text differently so the text is at different y-coordinates on the page. If you disable font inflation (go into Firefox settings -> Display -> Text Size -> set it to "Tiny") and reload the page this problem shouldn't happen any more.

Note that font inflation will be disabled by default in Firefox 39 and up (see bug 1127441).

	MaximYanchenko Reporter
	Comment 2 • 9 years ago

OK, setting "Tiny" appears to work, but now the page is just unreadable (or, if I pinch-zoom, the text line doesn't fit the screen width - which also makes the page essentially unreadable)...
You can see that on the same website, if you jump into any page from the Contents (e.g. "Typeclasses 101")
Is there any other setting that would help?
(The reading mode is not always available, and where it's available it kills color formatting - you can see that on the same page)

	Kartikaya Gupta (email:kats@mozilla.staktrace.com)
	Comment 3 • 9 years ago

Yeah the options here are not great. I guess to fix this properly we want to preserve the visible content area (rather than the scroll position) during relayout when font inflation is in effect. So this is basically a dupe of bug 755770.

	MaximYanchenko Reporter
	Comment 4 • 9 years ago

Yes, it appears to be a dup.

So what shall I do when the font inflation disappears?
My eyes are not as great as they used to be, my font inflation setting used to be "Large" for comfort reading.
What is the replacement for font inflation?
If there is none, maybe it wasn't a right decision to remove it?

	Kartikaya Gupta (email:kats@mozilla.staktrace.com)
	Comment 5 • 9 years ago

We are not planning a replacement for font inflation as far as i am aware. Note that the feature will remain in Firefox, it will just be disabled by default and you will have to go into the settings to bump up the text size manually. Feel free to argue your case in bug 1127441.

	Kevin Brosnan [Ex-Mozilla]
	Comment 6 • 9 years ago

FWIW I need to submit a patch for v39 to backout 1127441. I am concerned about bug 1139092. The plan was to set font inflation to off and allow users to re-enable. That does not seem to be working completely.