<AWT Dev> [13] JDK-8218917: KeyEvent.getModifiers() returns inconsistent values for ALT keys

Fri Mar 15 12:54:47 UTC 2019

Hi guys,

We have a major issue about unexpected AltGr in the keyboard layout
that should not have AltGr at all:
http://youtrack.jetbrains.com/issue/IDEA-206348
Why you decided to support AltGr for every keyboard layout? It really
breaks backward compatibility!

> Unfortunately it is not possible to drop ALT_DOWN_MASK(to support 'Alt+AltGr+Right')
from the "right alt", it should work as alt for compatibility reasons,
it is known that some
applications depends on it."

I think the main client is Swing and pressed AltGr that looks like
'Alt+AltGr+' breaks all Alt-based shortcuts defined in
javax.swing.plaf.basic.BasicLookAndFeel#initComponentDefaults and
other places. Now, if you press "alt LEFT", the "moveColumnLeft"
action is performed only for the left Alt. And this also breaks a
backward compatibility.

It is not backward compatible to use AltGr instead of right Alt in
both cases. Instead of 'Alt+key' you will get 'AltGr+key' or
'Alt+AltGr+key', which are not bound to any action.

On Fri, Mar 15, 2019 at 9:27 AM Krishna Addepalli
<krishna.addepalli at oracle.com> wrote:
>
> Hi Sergey Malenkov,
>
> > 'Alt+AltGr+Right' does nothing, because we do not assign this shortcut yet
> In my personal experience, I did not find any instance, wherein a shortcut had left and right alt in it.
> Although it is not impossible, it seems weird to define such shortcuts.
> It would be helpful if you could point to some resources, wherein defining such shortcuts is acceptable.
>
> Thanks,
> Krishna
>
> > On 14-Mar-2019, at 4:03 PM, Sergey Malenkov <malenkov at gmail.com> wrote:
> >
> > I strongly don't like two masks for one key. If you press VK_ALT,
> > ALT_DOWN_MASK should be set. If you press VK_SHIFT then,
> > SHIFT_DOWN_MASK should be added to indicate that both keys are
> > pressed. And if you press VK_ALT_GRAPH, only ALT_GRAPH_DOWN_MASK
> > should be added. Otherwise, you can't distinguish the following key
> > strokes: 'AltGr+Right' and 'Alt+AltGr+Right'. But these keystrokes are
> > different and should invoke different actions. For example,
> > 'Alt+Right' moves cursor to the next word
> > 'Alt+Shift+Right' moves cursor to the next word AND adds all skipped
> > characters to selection
> > 'Alt+AltGr+Right' does nothing, because we do not assign this shortcut yet
> >
> > On Thu, Mar 14, 2019 at 12:09 AM Sergey Bylokhov
> > <Sergey.Bylokhov at oracle.com> wrote:
> >>
> >> On 13/03/2019 03:59, Sergey Malenkov wrote:
> >>> I missed the "for ALT keys" in the bug title and thought that
> >>> "KeyEvent.getModifiers() returns inconsistent values" was about
> >>> incompatible behaviour on different platforms. In fact, JDK-8218917
> >>> should be renamed to something like “The right Alt key on Mac should
> >>> behave as Alt and must not break the left Alt key processing”.
> >>
> >> But the "right Alt" should behave like a "left alt" already, it should use both flags:
> >> the common alt(ALT_DOWN_MASK) and the altGr(ALT_GRAPH_DOWN_MASK).
> >>
> >> So if the client will follow the spec below it should work as before, isn't it?:
> >> https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/event/InputEvent.html#getModifiersEx()
> >>
> >>> On Wed, Mar 13, 2019 at 6:57 AM Sergey Bylokhov
> >>> <Sergey.Bylokhov at oracle.com> wrote:
> >>>>
> >>>> On 12/03/2019 12:28, Sergey Malenkov wrote:
> >>>>> Hi Sergey,
> >>>>>
> >>>>> 1. macOS uses a regular Alt key as "Alternate Character Key". This is
> >>>>> the reason why JDK Toolkit defines Ctrl+Alt to select a mnemonic,
> >>>>> instead of simple Alt. See
> >>>>> https://sites.google.com/site/malenkov/java/141229
> >>>>
> >>>> Right, but introducing this flag for the "left alt" could cause even more
> >>>> issues, so this flag is set only for the right.
> >>>>
> >>>>> 3. Regression was caused by adding AltGr to key processing on Mac. But
> >>>>> I found more issues with inconsistent key processing on different
> >>>>> platforms. See http://sites.google.com/site/malenkov/java/190312
> >>>>
> >>>> Not sure that CAPS_LOCK is related.
> >>>>
> >>>>>
> >>>>>
> >>>>> On Tue, Mar 12, 2019 at 4:17 AM Sergey Bylokhov
> >>>>> <Sergey.Bylokhov at oracle.com> wrote:
> >>>>>>
> >>>>>> On 11/03/2019 17:37, Philip Race wrote:
> >>>>>>> The debate is about AltGraph which an ancient MS-DOSism for
> >>>>>>> asking for an ALTernate GRAPHics bitmap font - all pre-dates windows
> >>>>>>> and I am sure has never been applicable to any MacOS.
> >>>>>>
> >>>>>> It also about the "right alt" which is also know as "AltGraph". I guess currently
> >>>>>> it is implemented as "right alt" on Linux/macOS/windows.
> >>>>>>
> >>>>>> BTW on linux it is also named as "Alternative Characters Key":
> >>>>>> https://help.ubuntu.com/community/ComposeKey
> >>>>>>
> >>>>>>> So someone needs to properly explain why we would claim a Mac keyboard
> >>>>>>> is OK to generate a keycode it doesn't have and cause a slew of regressions
> >>>>>>> in the process ...>
> >>>>>>> If Mac doesn't distinguish these two, we should generate the same keycode for both.
> >>>>>>
> >>>>>> The macOS supports "right alt", otherwise it would not be possible to implement it in java:
> >>>>>> https://developer.apple.com/library/archive/technotes/tn2450/_index.html
> >>>>>>
> >>>>>>
> >>>>>>> One could suppose there is a difference else why two keys, but what is the right
> >>>>>>> thing to do here  that fixes all the problems. What exactly WAS the problem
> >>>>>>> with what was there in the first place ? And if changing it is correct why is it
> >>>>>>> causing regressions ?
> >>>>>>
> >>>>>> Regressions were caused by the bugs in the fix implementation, or am I missed something?
> >>>>>>
> >>>>>>
> >>>>>>>
> >>>>>>> -phil.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> On 3/12/19, 5:34 AM, Sergey Bylokhov wrote:
> >>>>>>>> Hi, Phil.
> >>>>>>>> On 11/03/2019 07:43, Philip Race wrote:
> >>>>>>>>> The reasoning that AltGraph might be useful to someone is a bit weak
> >>>>>>>>> and I don't think I'd want to support it via system property or build options.
> >>>>>>>>>
> >>>>>>>>> If its not a platform keyboard key, why do we need it ?
> >>>>>>>>
> >>>>>>>> The "AltGraph" key is also commonly referred to as "Right Alt", and
> >>>>>>>> it has been implemented on all platforms as a "Right Alt", it is convenient to
> >>>>>>>> distinguish the left/right alts.
> >>>>>>>>
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Best regards, Sergey.
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> Best regards, Sergey.
> >>>
> >>>
> >>>
> >>
> >>
> >> --
> >> Best regards, Sergey.
> >
> >
> >
> > --
> > Best regards,
> > Sergey A. Malenkov
>

-- 
Best regards,
Sergey A. Malenkov