Thank you Michael, Jose, Florian, and Markus
In my mind the "Too many touch points reported" exception fix (#394)
appears to not be the correct fix for that issue and is what caused this
regression.
There seems to be two possible paths forward, either revert #394 or
integrate this. In both cases the "Too many touch points reported" issue
will need to be readdressed.
It would be nice to see this move forward somehow.
Thanks again,
Jurgen
On Tue, 04 Jun 2024 18:28:47 +0200, Markus Mack <mm...@openjdk.org> wrote:
On Tue, 21 May 2024 14:25:51 GMT, Michael Strauß <mstra...@openjdk.org>
wrote:
This PR fixes a bug
([JDK-8289115](https://bugs.openjdk.org/browse/JDK-8289115)) that was
introduced with #394, which changed the following line in the
`NotifyTouchInput` function (ViewContainer.cpp):
- const bool isDirect = true;
+ const bool isDirect = IsTouchEvent();
`IsTouchEvent` is a small utility function that uses the Windows SDK
function `GetMessageExtraInfo` to distinguish between mouse events and
pen events as described in this article:
https://learn.microsoft.com/en-us/windows/win32/tablet/system-events-and-mouse-messages
I think that using this function to distinguish between touchscreen
events and pen events is erroneous. The linked article states:
_"When your application receives a **mouse message** (such as
WM_LBUTTONDOWN) [...]"_
But we are not receiving a mouse message in `NotifyTouchInput`, we are
receiving a `WM_TOUCH` message.
I couldn't find any information on whether this API usage is also
supported for `WM_TOUCH` messages, but my testing shows that that's
probably not the case (I tested this with a XPS 15 touchscreen laptop,
where `GetMessageExtraInfo` returns 0 for `WM_TOUCH` messages).
My suggestion is to check the `TOUCHEVENTF_PEN` flag of the
`TOUCHINPUT` structure instead:
const bool isDirect = (ti->dwFlags & TOUCHEVENTF_PEN) == 0;
I attempted to test this with the sample app in
[JDK-8249737](https://bugs.openjdk.org/browse/JDK-8249737) and
[Microsoft.Windows.Simulator](https://stackoverflow.com/questions/40274660/windows-10-how-do-i-test-touch-events-without-a-touchscreen)
using the simulator's "Basic touch mode".
The "Too many touch points reported" exception seems to be thrown
consistently with
`const bool isDirect = true;` (original before #394)
and `const bool isDirect = (ti->dwFlags & TOUCHEVENTF_PEN) == 0;` (this
PR)
I didn't see the exception with `const bool isDirect = IsTouchEvent();`
(#394)
and `const bool isDirect = false` (which is probably what IsTouchEvent()
returns here).
Not sure what this simulator actually sends, but someone more
knowledgeable might want to have a look at what's happening.
-------------
PR Comment: https://git.openjdk.org/jfx/pull/1459#issuecomment-2147933056
