Touchscreen on raspberry with mixxx > 2.1.8

[mixxxbot]

Reported by: bhestia
Date: 2020-09-13T09:46:23Z
Status: Fix Released
Importance: High
Launchpad Issue: lp1895431
Tags: gui, raspberry, touchscreen

---

I've created a post also in the mixxx forum but i think this is a bug and is not correct to overcome it with a workaround.
I will copy-paste the message from the forum:

I’m using a raspberry and i have different touchscreens.
With mixxx versions < 2.1.8 (QT4) i had no problem at all.
Starting with mixxx 2.2 (QT5) all my thouscreens that act like touch devices stopped working.
The touchscreens that emulate a normal mouse still works, (in this kind of touchscreens if you drag over a web page the text will be selected as if you click and drag a real mouse).
The touchscreens that act as a touch devices are the one that, if in a web page you drag over the page, the page scroll, so a different behaviour with respect to a normal click-and-drag action done with a mouse.
Switching to mixxx > 2.1.8 had broke this compatibility, now all the touchscreens that raspbian handle like “touch devices” and not like “normal mouse” doesn’t work anymore.
How can i use the latest version of mixxx on this kind of devices?

[mixxxbot]

Commented by: bhestia
Date: 2020-09-13T13:48:44Z

---

Update: same problem not just on raspbian but also on ubuntu mate

[mixxxbot]

Commented by: ehendrikd
Date: 2020-10-07T01:09:28Z

---

After changing my RP4 screen to a Waveshare DSI touch screen I also found that:

• Menus could not be clicked
• Library tree and table items could not be clicked
• Any skin buttons could be clicked fine

Some debugging later I found that (counter intuitively) commenting out the following line:

mixxx/src/mixxx.cpp

Line 219 in c90e38b

setAttribute(Qt::WA_AcceptTouchEvents);

Fixed the issue and now the touchscreen works as expected. Are you in a position to compile Mixxx from source on your pi and confirm if this fixes the issue?

[mixxxbot]

Commented by: daschuer
Date: 2020-10-07T22:34:21Z

---

I can confirm this on Ubuntu Bionic.

Original this was introduced here to allow mutitouch.
#76

after removing this line
setAttribute(Qt::WA_AcceptTouchEvents)

multitouch still works here, so I guess qt has its own solution now and our own solution is broken.

Unfortunately after [Controls]", "touch_shift" for a right mouse click is now broken in the library. For the the buttons it is still working.

[mixxxbot]

Commented by: daschuer
Date: 2020-10-08T21:33:01Z

---

A PR #3164 is waiting for review that should fix the reported issues.

[mixxxbot]

Issue closed with status Fix Released.