[plasmashell] [Bug 390639] New: bad picture on hidpi monitor in dual monitor setup where one monitor is hidpi and the other one not

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

Bug ID: 390639
Summary: bad picture on hidpi monitor in dual monitor setup
where one monitor is hidpi and the other one not
Product: plasmashell
Version: 5.12.1
Platform: Neon Packages
OS: Linux
Status: UNCONFIRMED
Severity: normal
Priority: NOR
Component: generic-wayland
Assignee: plasma-***@kde.org
Reporter: ***@gmail.com
Target Milestone: 1.0

Created attachment 110760
--> https://bugs.kde.org/attachment.cgi?id=110760&action=edit
phone taken picture shows font rendering with Kate on both monitors (left
monitor is normaldpi, right is hidpi)

having two monitors, where one is hidpi and the other one is not, the picture
on the hidpi monitor is quite worse when compared to the normal-dpi monitor.

scaling on hidpi monitor: 2
scaling on normaldpi monitor: 1

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #1 from Miroslav <***@gmail.com> ---
here are two pictures that show also how application icon is rendered (so not
only fonts are affected)

https://imgur.com/a/xrkYS

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

Miroslav <***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@gmail.com

[Kai Uwe Broulik]

https://bugs.kde.org/show_bug.cgi?id=390639

Kai Uwe Broulik <***@privat.broulik.de> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@privat.broulik.de

--- Comment #2 from Kai Uwe Broulik <***@privat.broulik.de> ---
It can't split the window in half, it renders at whatever largest scale and
then downscales for the other monitor.

What it will eventually do (Qt does not yet support that) is rerender at proper
scale once it moves to the other screen.

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #3 from Miroslav <***@gmail.com> ---
The point was not on the splitting the window.

The split i provided just to show how the same window is rendered on different
hidpi. If i move the complete window to the hidpi monitor, it is rendered in
the same 'bad' manner as in the picture.

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #4 from Miroslav <***@gmail.com> ---
Plus, this happens when whole window is on hidpi monitor:
- window titlebar fonts are rendered ok
- window titlebar icon is not rendered ok
- application menu bar is not rendered ok

[David Edmundson]

https://bugs.kde.org/show_bug.cgi?id=390639

David Edmundson <***@davidedmundson.co.uk> changed:

What |Removed |Added
----------------------------------------------------------------------------
Summary|bad picture on hidpi |Application Icon in
|monitor in dual monitor |decoration shown at
|setup where one monitor is |standard resolution on high
|hidpi and the other one not |DPI screen
Component|generic-wayland |decorations
Status|UNCONFIRMED |CONFIRMED
CC| |***@davidedmundson.co.uk
Assignee|plasma-***@kde.org |kwin-bugs-***@kde.org
Severity|normal |minor
Ever confirmed|0 |1
Target Milestone|1.0 |---
Product|plasmashell |kwin

--- Comment #5 from David Edmundson <***@davidedmundson.co.uk> ---
Decorations are all done properly with the right DPR on the paint device.
QIcon::pixmap() is scaled by the qApp->devicePixelRatio rather than the current
paint device.
This works in system settings, and everything looks spot-on.

In kwin qApp->devicePixelRatio doesn't work, so we get a standard res icon.

[David Edmundson]

https://bugs.kde.org/show_bug.cgi?id=390639

David Edmundson <***@davidedmundson.co.uk> changed:

What |Removed |Added
----------------------------------------------------------------------------
Assignee|kwin-bugs-***@kde.org |***@davidedmundson.co.uk

[Martin Flöser]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #6 from Martin Flöser <***@kde.org> ---
Is this on X11 or Wayland?

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #7 from Miroslav <***@gmail.com> ---
Wayland

[David Edmundson]

https://bugs.kde.org/show_bug.cgi?id=390639

David Edmundson <***@davidedmundson.co.uk> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|CONFIRMED |RESOLVED
Resolution|--- |FIXED

--- Comment #8 from David Edmundson <***@davidedmundson.co.uk> ---
Fixed with c32eb41292752fd9a82fa258fb93f538f712cb91

Don't know why this didn't auto-close

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #9 from Miroslav <***@gmail.com> ---
This only fixes the icon (since bug got categorized as decorations)? Or also
the menu bar and the content...?

[David Edmundson]

https://bugs.kde.org/show_bug.cgi?id=390639

David Edmundson <***@davidedmundson.co.uk> changed:

What |Removed |Added
----------------------------------------------------------------------------
Latest Commit| |https://commits.kde.org/bre
| |eze/c32eb41292752fd9a82fa25
| |8fb93f538f712cb91

--- Comment #10 from David Edmundson <***@davidedmundson.co.uk> ---
Git commit c32eb41292752fd9a82fa258fb93f538f712cb91 by David Edmundson.
Committed on 21/02/2018 at 13:35.
Pushed by davidedmundson into branch 'Plasma/5.12'.

Render application icon at paintdevice DPR

Summary:
QIcon::pixmap doesn't know anything about the paint device currently
being used so uses qApp->devicePixelRatio.
This works in systemsettings, but not in kwin and we get a standard
resolution pixmap returned.

We can't manually multiply by painter->device->dpr because then system
settings would get scaled twice.

QIcon::paint solves that in a way that won't break should kwin's
qApp->dpr change. Also it's IMHO cleaner as it does the alignment
internally.

Test Plan:
System settings look the same
Icon in kwin deco is crisper than before

Reviewers: #plasma, mart

Reviewed By: #plasma, mart

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D10713

M +2 -2 kdecoration/breezebutton.cpp

https://commits.kde.org/breeze/c32eb41292752fd9a82fa258fb93f538f712cb91

[David Edmundson]

https://bugs.kde.org/show_bug.cgi?id=390639

Post by Miroslav
This only fixes the icon (since bug got categorized as decorations)?

Yes.

Post by Miroslav
Or also the menu bar and the content...?

Is it just icons? If so, they should get fixed with Qt5.11.

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #12 from Miroslav <***@gmail.com> ---
It is also menu bar and content that have rendering issue. The pictures show
how it looks like (disregard that the window is split between standard and
hidpi monitor).

Do i need to open another bug to cover menu bar and content or this can be all
done through this one?

[Andrew Crouthamel]

https://bugs.kde.org/show_bug.cgi?id=390639

Andrew Crouthamel <***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@gmail.com

--- Comment #13 from Andrew Crouthamel <***@gmail.com> ---
(In reply to David Edmundson from comment #11)

Post by David Edmundson
Is it just icons? If so, they should get fixed with Qt5.11.

Could you elaborate on that?

[David Edmundson]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #14 from David Edmundson <***@davidedmundson.co.uk> ---
What's wrong with the menubar?

[Andrew Crouthamel]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #15 from Andrew Crouthamel <***@gmail.com> ---
(In reply to David Edmundson from comment #14)

Post by David Edmundson
What's wrong with the menubar?

The AppMenu in Kwin is pixelated when scaling on HiDPI. I was curious if Qt
5.11 as you mentioned might resolve that.

[Miroslav]

https://bugs.kde.org/show_bug.cgi?id=390639

--- Comment #16 from Miroslav <***@gmail.com> ---
Exactly, menu bar and window content are pixelated. If you check the
attachment, you'll see the extent of it.

Most severe effect is seen on '/'. It looks lika a saw.