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Firefox does not handle high DPI screens. It renders fonts at a fixed 96dpi and your only option is to crank up the devPixelsPerPx pref, which is akin to page z

Firefox does not handle high DPI screens. It renders fonts at a fixed 96dpi and your only option is to crank up the devPixelsPerPx pref, which is akin to page zoom. The bug has been reported multiple times. It always ends up being closed as wontfix, which is just burying the head in the sand. My laptop is 210dpi, and I guess we'll just go up from here. One instance of the bug:https://bugzilla.mozilla.org/show_bug.cgi?id=512522 https://bugzilla.mozilla.org/show_bug.cgi?id=512522

__david__ 12y ago
Firefox handles the high DPI (227) display on my Macbook just fine…
- orbifold 12y ago
  Presumably because it uses native libraries that have support for high DPI displays.
zokier 12y ago
> your only option is to crank up the devPixelsPerPx pref, which is akin to page zoom Since Firefox 22 you shouldn't need to adjust it manually. See eg this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=844604 https://bugzilla.mozilla.org/show_bug.cgi?id=844604 (Status: RESOLVED FIXED). I'm not sure why you seem to think that "akin page zoom" is not the proper result, what else you expected? Quoting Anandtech: > Chrome is scaled 150% as Windows asked, but it is hazy and blurry. Disabling DPI scaling for the application and then scaling to 150% inside Chrome produces crisp, clear text. Firefox also didn’t scale automatically, but it has a setting to adjust to make it follow the Windows DPI scaling rules. Once set, Firefox looks very nice and crisp. For most people, that setting should already be set to follow DPI scaling. http://www.anandtech.com/show/7157/asus-pq321q-ultrahd-4k-monitor-review/2 http://www.anandtech.com/show/7157/asus-pq321q-ultrahd-4k-mo... Note that the review predates the release of Firefox 22. edit: This is the tracking bug for Firefox HiDPI support on Windows: https://bugzilla.mozilla.org/showdependencytree.cgi?id=820679&hide_resolved=0 https://bugzilla.mozilla.org/showdependencytree.cgi?id=82067... . Hardly burying their heads in sand.
- sergiosgc 12y ago
  > I'm not sure why you seem to think that > "akin page zoom" is not the proper result, > what else you expected? It is not what I expect because it does not affect the browser chrome. See a screenshot of my current Firefox: https://dl.dropboxusercontent.com/u/461223/screenshot.png https://dl.dropboxusercontent.com/u/461223/screenshot.png Notice that the i3 bar at the top has the font at the correct scale. The page itself too (via devPixelsPerPx). Chrome elements such as tab names or the URL bar are at less than half the correct size and barely usable without a hack plugin (I use Theme Font and Size Changer). Everything other than FF or Thunderbird scales correctly. The X server is set to 210dpi and GTK reports the correct density too. It is firefox that is misbehaving. This is FF nightly (34, I believe), so way way after FF 22. It is not fixed, and it is not a loved bug. Time will make the bug bite the developers and by then it will be fixed, I'm sure. Edit: Here's a second screenshot, this time witout devPixelsPerPx, showing FF completely ignoring the system set DPI: https://dl.dropboxusercontent.com/u/461223/screenshot2.png https://dl.dropboxusercontent.com/u/461223/screenshot2.png
  - zokier 12y ago
    Oh, Linux. Yeah, the story there might be significantly worse, possibly even more if you are not running GNOME. I'll have to test that myself, but I can imagine that it is not as smooth as Win/OSX. I'll just say that it is not representative of Firefox as a whole. edit: Here is Firefox on Windows 7, Windows being configured at "150%", no tweaks on Firefox: http://zokier.net/stuff/firefox_150.png http://zokier.net/stuff/firefox_150.png here is 100% for comparison: http://zokier.net/stuff/firefox_100.png http://zokier.net/stuff/firefox_100.png Some of the icons etc are bit blurry, but at least they are scaled.
    - sergiosgc 12y ago
      From what I gather about in several submissions of the bug in the past, the problem is that properly setting display density in Linux has changed over time. So, it is inconsistent and is thus in many instances false. Firefox then concludes that X lies about display density and ignores it. It is a wrong assumption, and one that pegs FF to 96dpi on Linux. It is not a sustainable decision, but I guess it will only be reverted when the noise about it is enough, which will only happen when high dpi displays become more common. Anyhow, it is not correct to assume X lies about the display density. Modern distros set the density correctly, ever since the infrastructure for xrandr was put into place. Its only fault, today, is that display density can't be set per display. It is a setting of the root window, I believe, so it is shared by all displays. Side note: This is i3 running on top of a gnome3 session. For the sake of this problem, it can be seen as a gnome session.
hapless 12y ago
devPixelsPerPx is much, much better than "page zoom." For example, it displays 2x content correctly. In fact, Firefox is the only browser that supports high-DPI displays on Linux. Chrome doesn't bother.
- sergiosgc 12y ago
  It is good. Not perfect, but usable. Anyhow, web development has a problem with high screen displays. On the one hand, the px unit in CSS is not a real pixel, so it can be scaled with respect to screen pixel density without breaking the spec. On the other hand, images are really measured in screen pixels. The end result is that layouts break at densities other than 96dpi, where one CSS px is one screen pixel. The solution would be for image files to embed the display density, but from what I gather, browsers discard that information. As I posted in the other comment, the major problem now is that the browser UI is not drawn at the correct density and ends thus tiny on high dpi displays. Anyhow, as these displays become pervasive, it must get fixed.

__david__ 12y ago

Firefox handles the high DPI (227) display on my Macbook just fine…

orbifold 12y ago
Presumably because it uses native libraries that have support for high DPI displays.

zokier 12y ago

> your only option is to crank up the devPixelsPerPx pref, which is akin to page zoom Since Firefox 22 you shouldn't need to adjust it manually. See eg this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=844604 https://bugzilla.mozilla.org/show_bug.cgi?id=844604 (Status: RESOLVED FIXED). I'm not sure why you seem to think that "akin page zoom" is not the proper result, what else you expected? Quoting Anandtech: > Chrome is scaled 150% as Windows asked, but it is hazy and blurry. Disabling DPI scaling for the application and then scaling to 150% inside Chrome produces crisp, clear text. Firefox also didn’t scale automatically, but it has a setting to adjust to make it follow the Windows DPI scaling rules. Once set, Firefox looks very nice and crisp. For most people, that setting should already be set to follow DPI scaling. http://www.anandtech.com/show/7157/asus-pq321q-ultrahd-4k-monitor-review/2 http://www.anandtech.com/show/7157/asus-pq321q-ultrahd-4k-mo... Note that the review predates the release of Firefox 22. edit: This is the tracking bug for Firefox HiDPI support on Windows: https://bugzilla.mozilla.org/showdependencytree.cgi?id=820679&hide_resolved=0 https://bugzilla.mozilla.org/showdependencytree.cgi?id=82067... . Hardly burying their heads in sand.

sergiosgc 12y ago
> I'm not sure why you seem to think that > "akin page zoom" is not the proper result, > what else you expected? It is not what I expect because it does not affect the browser chrome. See a screenshot of my current Firefox: https://dl.dropboxusercontent.com/u/461223/screenshot.png https://dl.dropboxusercontent.com/u/461223/screenshot.png Notice that the i3 bar at the top has the font at the correct scale. The page itself too (via devPixelsPerPx). Chrome elements such as tab names or the URL bar are at less than half the correct size and barely usable without a hack plugin (I use Theme Font and Size Changer). Everything other than FF or Thunderbird scales correctly. The X server is set to 210dpi and GTK reports the correct density too. It is firefox that is misbehaving. This is FF nightly (34, I believe), so way way after FF 22. It is not fixed, and it is not a loved bug. Time will make the bug bite the developers and by then it will be fixed, I'm sure. Edit: Here's a second screenshot, this time witout devPixelsPerPx, showing FF completely ignoring the system set DPI: https://dl.dropboxusercontent.com/u/461223/screenshot2.png https://dl.dropboxusercontent.com/u/461223/screenshot2.png
- zokier 12y ago
  Oh, Linux. Yeah, the story there might be significantly worse, possibly even more if you are not running GNOME. I'll have to test that myself, but I can imagine that it is not as smooth as Win/OSX. I'll just say that it is not representative of Firefox as a whole. edit: Here is Firefox on Windows 7, Windows being configured at "150%", no tweaks on Firefox: http://zokier.net/stuff/firefox_150.png http://zokier.net/stuff/firefox_150.png here is 100% for comparison: http://zokier.net/stuff/firefox_100.png http://zokier.net/stuff/firefox_100.png Some of the icons etc are bit blurry, but at least they are scaled.
  - sergiosgc 12y ago
    From what I gather about in several submissions of the bug in the past, the problem is that properly setting display density in Linux has changed over time. So, it is inconsistent and is thus in many instances false. Firefox then concludes that X lies about display density and ignores it. It is a wrong assumption, and one that pegs FF to 96dpi on Linux. It is not a sustainable decision, but I guess it will only be reverted when the noise about it is enough, which will only happen when high dpi displays become more common. Anyhow, it is not correct to assume X lies about the display density. Modern distros set the density correctly, ever since the infrastructure for xrandr was put into place. Its only fault, today, is that display density can't be set per display. It is a setting of the root window, I believe, so it is shared by all displays. Side note: This is i3 running on top of a gnome3 session. For the sake of this problem, it can be seen as a gnome session.

hapless 12y ago

devPixelsPerPx is much, much better than "page zoom." For example, it displays 2x content correctly. In fact, Firefox is the only browser that supports high-DPI displays on Linux. Chrome doesn't bother.

sergiosgc 12y ago
It is good. Not perfect, but usable. Anyhow, web development has a problem with high screen displays. On the one hand, the px unit in CSS is not a real pixel, so it can be scaled with respect to screen pixel density without breaking the spec. On the other hand, images are really measured in screen pixels. The end result is that layouts break at densities other than 96dpi, where one CSS px is one screen pixel. The solution would be for image files to embed the display density, but from what I gather, browsers discard that information. As I posted in the other comment, the major problem now is that the browser UI is not drawn at the correct density and ends thus tiny on high dpi displays. Anyhow, as these displays become pervasive, it must get fixed.