Consider support for different cursor shapes

[marmarek]

https://groups.google.com/d/msgid/qubes-devel/20151226141511.GA95308%40cowbell.employees.org

Something I've noticed when using a web browser is that the cursor shape never changes,
always staying as a simple arrow pointer.

Having control over cursor shape it may mislead the user actions. While it shouldn't be a problem inside the same VM, it may be complex to do it right - to not interfere with windows of other VMs.
In short: without prior proper design, which would be simple and simple to implement, we don't want to have such feature, at least not by default.

But generally it is something to consider, because:

Cursor shape is a functional part of the UI, to the point of being critical
for certain apps like spreadsheets and drawing. If Qubes deems this a possible
source of confusion then it should explain the threat model for cursors
(having already done so for windows).

[mfc]

at congress it was suggested that cursor changing be allowed when a vm is in full-screen mode as a UX/security compromise.

[bnvk]

While it shouldn't be a problem inside the same VM, it may be complex to do it right - to not interfere with windows of other VMs.

Getting the cursor to change within the same VM will be a significant UX improvement. A whole range of GUI apps like graphic design programs, IDE's etc... all suffer from this fixed pointer cursor which make simple things like re-sizing a window pane hard to do!

at congress it was suggested that cursor changing be allowed when a vm is in full-screen mode as a UX/security compromise.

Disallowing in full-screen, but allowing in non-full-screen mode, is still a significant UX improvement. However, if we are able to (and proceed) in doing that, we should try to trigger an overlay that communicates this to user when toggling between full-screen and non mode!

[v6ak]

In-window cursors

What about just providing a way to hide the cursor when it is on app's window? Custom cursors would be then implemented on top of this feature in the VM agent.

• + Simple design for dom0.
• + Cursors do not open a way to show arbitrary content outside of the window, as they are shown within the window only.
• - Having mouse at edge of some window would cause clipped cursor.

Cursor classes

Another option is having some predefined cursor types (e.g. hand, standard pointer, cross, …).

• + Simple design for dom0.
• + Cursors do not open a way to show arbitrary content outside of the window, as they come form dom0 and are trusted.
• + Unifies cursor set.
• + No issues with cursor at edge.
• - No support for custom cursors.
• - Might require some more effort for various systems in AppVMs.

[marmarek]

On Fri, Jan 08, 2016 at 12:43:44PM -0800, Vít Šesták wrote:

In-window cursors

What about just providing a way to hide the cursor when it is on app's window? Custom cursors would be then implemented on top of this feature in the VM agent.

• + Simple design for dom0.
• + Cursors do not open a way to show arbitrary content outside of the window, as they are shown within the window only.
• - Having mouse at edge of some window would cause clipped cursor.

From the security point of view, I like this idea. But from the
usability POV I'm afraid it would be horrible. Even small lag of cursor
position would be really frustrating. In early Windows Tools we had both
cursors visible (dom0 and windows) and it was bad - VM cursor was
lagging, even when click events were delivered correctly.

Also some technical problem would be that cursor is not part of the
window composition buffer (this is what is directly mapped as window
content in dom0). So it would be quite complex at VM side - not
affecting security, but most likely performance.

Cursor classes

Another option is having some predefined cursor types (e.g. hand, standard pointer, cross, …).

• + Simple design for dom0.
• + Cursors do not open a way to show arbitrary content outside of the window, as they come form dom0 and are trusted.
• + Unifies cursor set.
• + No issues with cursor at edge.
• - No support for custom cursors.
• - Might require some more effort for various systems in AppVMs.

I know exactly nothing about cursor shapes in X11 protocol. If it is
possible to extract such information, it would be good. If not, that
would require some guessing (OCSR - "optical cursor shape recognition"
;) ), not reliable. Even if that would be possible only at some higher
level (like for GTK based applications), that would be still an
improvement.

Since it is possible to set cursor theme globally, I guess it is
possible to extract abstract information about desired cursor shape.

Quick duckduckgo returns this:
http://stackoverflow.com/questions/6751928/set-x11-cursor-to-arrow

Looks promising. Especially the part about setting it as window property

• it would mean that X server would handle switching its shape, so no
  need to do that manually on enter/leave events (which would be really
  fragile, probably a showstopper).

Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

[andrewdavidwong]

Comment/suggestion: https://groups.google.com/d/msgid/qubes-devel/29fb6fa1-1a64-310d-e52d-f21db7c1a4b7%40openmailbox.org

[Joeviocoe]

Does this issue being labeled "Help Wanted" mean that it has the lowest priority and nobody from the dev team is working on it?

[v6ak]

I don't think so. It has major priority and assigned milestone. It however seems undecided which way to go.

[andrewdavidwong]

Does this issue being labeled "Help Wanted" mean that it has the lowest priority and nobody from the dev team is working on it?

It does mean that the Qubes devs do not expect to have time to work on it in the foreseeable future. However, "priority" is somewhat orthogonal. An issue can have a high priority even if the Qubes devs can't work on it. In that case, we really want someone to help! 🙂

[t4777sd]

Is there any plans to have this for 4.1? Would increase usability for a lot of apps and web pages.

[marmarek]

It is something that indeed would align very well the goals of 4.1 (improving usability).

Right now, there is (at least) one technical difficulty: how to get current cursor shape. I can find a dozen of ways to set the cursor shape (libXcursor, XCreateWindow parameter, XSetWindowAttributes, ...), but it looks like none of them provide matching functionality to retrieve what was set.
I've also tried to look at X server sources, and it looks like very few places read this property and none of them are available for applications. While we have technical means to access X server internal structures, I'd really like to avoid going this way...

Any ideas?

[t4777sd]

I spent a couple hours searching to see if I could find any projects that retrieved that information using some type of generalize-able methods and I could not identify any easy out of the box way to do it either, unfortunately.

[a-barinov]

It is something that indeed would align very well the goals of 4.1 (improving usability).

Right now, there is (at least) one technical difficulty: how to get current cursor shape. I can find a dozen of ways to set the cursor shape (libXcursor, XCreateWindow parameter, XSetWindowAttributes, ...), but it looks like none of them provide matching functionality to retrieve what was set.
I've also tried to look at X server sources, and it looks like very few places read this property and none of them are available for applications. While we have technical means to access X server internal structures, I'd really like to avoid going this way...

Any ideas?

Since there is no obvious way to retrieve cursor shape the only option seems to be intercepting cursor-setting calls mentioned above using ld_preload. Pretty sure a few intercepts and qubes gui protocol extension can solve this.

[ninavizz]

Oyy, this is important. Flagging to possibly discuss in a forthcoming UX meeting #5523 .

[ninavizz]

Hey gang: So... I just had a lovely ice-bucket moment, realizing there is no multi-cursor state support within VMs, on Qubes. I'd created this issue for the SecureDrop workstation client, which I just learned we cannot implement. So: sad-panda for me, but I wanted to ask y'all... how feesable is it to do this, and might it be possible to prioritize in a forthcoming release?

As a global usability thing, it's a pretty big deal.

As with my other requests to date, purely making them as "nina," not as "person on SecureDrop team."

[pwmarcz]

[kajmagnus]

@pwmarcz — that looks nice :- ) does that (your screencast) mean that different cursor shapes are available today in Qubes 4.1?

Anyone knows if there're any plans to backported to 4.0 some day?

Or, would it be a crazy idea to upgrade to 4.1, just to get these custom cursors, although 4.1 it's not yet released? Maybe I could do that on 1 out of 2 laptops, hmm.

( Currently I try to resize different windows in an IDE, click and drag the border between the windows ... doesn't work, I try again and again, but fail to hit the tiny press-&-drag-mouse-resize area, ... I give up, and continue working although the inside-IDE window is too small. )

[pwmarcz]

Yes, they were merged to 4.1 a few months ago. No plans to backport to 4.0, I think - the GUI protocol changed a bit since, so it would complicate things too much. Regarding how ready / stable 4.1 is right now, I'd ask @marmarek :) But I've been using it for some time now.

[jamke]

Please help me better understand my related problems:

• I have R4.1.1 and I changed cursor theme and cursor size via usual xfce's Settings Manager. And currently I have a fixed cursor for everything the same it was in R4.0. I did not know it can change itself in R4.1 before reading this issue.
  Are automatic changes of the cursor not active by default in R4.1.1 or do I have a bug?

• I have a problem that cursor disappears completely quite often, very annoying. I can see the movement of mouse by control reactions on mouse-over events. I think it's somehow connected with youtube in Firefox that hides cursor spontaneously, even being on pause in inactive window. Or maybe the reason is different.
  I can make cursor visible again by dragging or resizing any actual window in dom0.
  Is it possible to get a stable always-visible cursor like it was in R4.0? At least until disappearance is fixed eventually, because fixed cursor is better for me than no cursor several times a day.

• Should I file a issue-ticket for both this problems or those are well-known?

[resulin]

@jamke I think it's better that you file a new issue for each problem that you encountered.

[jamke]

@resulin yes, but first I have to understand - do I have a problem at the first bullet-point or not? Is the cursor excepted to change itself if user set custom cursor in Xfce's Settings Manager?

[andrewdavidwong]

Please note that the issue tracker (qubes-issues) is not intended to be a place for fielding questions (especially on closed issues, unless there is a reason to reopen them). Instead, we have other venues meant for asking questions, asking for help, and having discussions. (By contrast, the issue tracker is more of a technical tool intended to support our developers in their work.) Thank you for your understanding!

[jamke]

Information for people who could find this topic and my messages above:
I've created a separate issue about disappearance of mouse cursor here: #7890.