[Bf-committers] Automatic DPI detection issues

[Julian Eisel]

Hi all,

I'm definitely in favor of the change from having an absolute DPI user
setting in Blender to having an OS relative one.

> - This is totally unpredictable, changes Blender interface based on some rather random factors.
Where are those factors random? It keeps backwards compatibility if
needed, otherwise it just uses the OS setting.

> - Blender does not tell user what DPI it detected (yes, the commit removed setting from User Preferences)
Why should a user care? All the user cares about is is if things look
too small, too big or just fine. The UI is not printed to paper or
something.

> - If system reports buggy DPI, there is no easy way to know what's causing it and how to correct.
That was a concern I had too, but apparently it works quite reliable.
You can still tweak the UI scale if something doesn't look correctly.

> Any feature that attempts to automatically guess user needs is due to failure.
This is not attempting to guess anything automatically. This is an OS
wide option, with reasonable defaults and users have full control over
it. Why should you have to set this again in Blender? Why should
Blender ignore this OS wide setting while most other apps (that care
about UX) use it? It's just a redundant setting and redundant info.

So I agree with Brecht here: if there are issues with font drawing
then it's probably the font drawing itself that scales badly, the OS
DPI should be fine.

Also, Jonathan Williamson gave feedback on this as well:
https://developer.blender.org/D2539#59872

Cheers,
- Julian -

On 13 July 2017 at 16:45, Ton Roosendaal <ton at blender.org> wrote:
> Hi,
>
> Any feature that attempts to automatically guess user needs is due to failure.
> The only automatic DPI setting I would accept is to detect High DPI screens (4k or more).
>
> -Ton-
>
> --------------------------------------------------------
> Ton Roosendaal  -  ton at blender.org   -   www.blender.org
> Chairman Blender Foundation, Director Blender Institute
> Entrepotdok 57A, 1018 AD, Amsterdam, the Netherlands
>
>
>
>> On 13 Jul 2017, at 16:25, Brecht Van Lommel <brechtvanlommel at pandora.be> wrote:
>>
>> Then I think the real issue is that Blender fonts draw blurry below a
>> certain size. It seems to happen when changing the DPI, but also when
>> changing the font size or zooming.
>>
>> So I think the solution is to either solve that problem (not sure if it's
>> something that can be tweaked in font drawing or would need a different
>> font), or work around it by biasing the auto DPI a bit towards 92.
>>
>> On Thu, Jul 13, 2017 at 2:37 PM, Sergey Sharybin <sergey.vfx at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> Answers are inlined.
>>>
>>> It the UI is too small you scale it up, if it's too big you scale it down?
>>>>
>>>
>>> Is this interface too small or too big:
>>> http://pasteall.org/pic/show.php?id=117179
>>>
>>> What should i put to a Scale factor to make it proper "kerning" ?
>>>
>>> It's not clear to me what you mean by improperly displayed fonts here, I
>>>> tried various DPI values in 2.78 and various UI scale values in master
>>> and
>>>> the fonts always look ok to me.
>>>>
>>>
>>> Just force getDPIHint() to return 88 and see font artifacts, similar to the
>>> screenshot above.
>>>
>>>
>>>>> - Not reporting detected DPI is also wrong.
>>>>>
>>>>
>>>> I don't know of any other application reporting this in the UI, why does
>>>> the absolute value matter to the user?
>>>>
>>>
>>> Maybe because other applications are not failing that badly on displaying
>>> good fonts by default?
>>>
>>>
>>>>> - Not being able to correct auto-detected DPI also sounds wrong. All
>>> the
>>>> DE
>>>>> will have option to override X11 DPI specifically for the case when X11
>>>>> reports wrong DPI.
>>>>>
>>>>
>>>> Again, it can be corrected by changing the UI scale. This is fully
>>>> equivalent to adjusting the DPI value.
>>>>
>>>
>>> With the difference that i do have a remote idea what my DPI should be, but
>>> i've got no idea what should be the scaling factor to compensate badly
>>> working fonts in Blender.
>>>
>>>
>>>>>
>>>>> P.S. I wouldn't know if other applications are detecting DPI correctly
>>>> (as
>>>>> in, not sure they are using crappy DPI of 88x89 or are rounding it to
>>>> some
>>>>> more commonly used DPI), but it's only Blender which has badly rendered
>>>>> fonts on my system.
>>>>> P.P.S. Surely i can force/correct X11/DE's DPI, but then i don't see
>>> any
>>>>> benefit on the auto-detection of DPI. It only causes issues rather than
>>>>> solving anything.
>>>>>
>>>>> On Thu, Jul 13, 2017 at 1:15 PM, Brecht Van Lommel <
>>>>> brechtvanlommel at pandora.be> wrote:
>>>>>
>>>>>> As mentioned in the commit log, the UI Scale setting in the Interface
>>>> tab
>>>>>> can be used, doesn't that work?
>>>>>>
>>>>>> If you look at the equivalent settings for
>>> Windows/macOS/Gnome/Unity/..
>>>>>> they also offer a scale or percentage. I see no reason to show the
>>>>> absolute
>>>>>> DPI.
>>>>>>
>>>>>> Linux doesn't have a single window manager standard for specifying
>>> DPI,
>>>>> but
>>>>>> we use the same convention as Chrome or Firefox which works in many
>>>>> window
>>>>>> managers, it certainly isn't random. Are you saying the DPI is not
>>>> being
>>>>>> detect correctly on your system, while it works in other
>>> applications?
>>>>>> Perhaps we can fix that?
>>>>>>
>>>>>> On Thu, Jul 13, 2017 at 12:32 PM, Sergey Sharybin <
>>>> sergey.vfx at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi everyone,
>>>>>>>
>>>>>>> Today i've run into annoying/hard to predict situation: running my
>>>>>> regular
>>>>>>> blender was working fine, but doing --factory-startup was messing
>>> up
>>>>>> fonts
>>>>>>> in Blender's interface.
>>>>>>>
>>>>>>> it turns out, this commit is responsible for such behavior [1].
>>>>>>>
>>>>>>> What happens is, when there is existing user-preferences.blend,
>>>> Blender
>>>>>>> will use DPI stored in there. Otherwise, Blender will use
>>>> auto-detected
>>>>>>> DPI. This has following issues:
>>>>>>>
>>>>>>> - This is totally unpredictable, changes Blender interface based on
>>>>> some
>>>>>>> rather random factors.
>>>>>>> - Blender does not tell user what DPI it detected (yes, the commit
>>>>>> removed
>>>>>>> setting from User Preferences)
>>>>>>> - If system reports buggy DPI, there is no easy way to know what's
>>>>>> causing
>>>>>>> it and how to correct.
>>>>>>>
>>>>>>> So i think we should bring DPI setting back to user preferences. It
>>>> is
>>>>>>> really bad practice to secretly use setting, without even telling
>>>> what
>>>>>> the
>>>>>>> value of the setting is. It is also bad practice to auto-detect
>>>>> something
>>>>>>> and not give any clues to user what the detected value is. And
>>>> finally,
>>>>>>> there should be a way to override auto-detected DPI, for the exact
>>>> case
>>>>>>> when the reported one is bad.
>>>>>>>
>>>>>>> [1] https://developer.blender.org/rBfe3fb23
>>>>>>>
>>>>>>> --
>>>>>>> With best regards, Sergey Sharybin
>>>>>>> _______________________________________________
>>>>>>> Bf-committers mailing list
>>>>>>> Bf-committers at blender.org
>>>>>>> https://lists.blender.org/mailman/listinfo/bf-committers
>>>>>>>
>>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> With best regards, Sergey Sharybin
>>>>> _______________________________________________
>>>>> Bf-committers mailing list
>>>>> Bf-committers at blender.org
>>>>> https://lists.blender.org/mailman/listinfo/bf-committers
>>>>>
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>>>
>>>
>>>
>>> --
>>> With best regards, Sergey Sharybin
>>> _______________________________________________
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