[FEAT] Review mouse wheel zoom support for macOS

[tbouffard]

Is your feature request related to a problem? Please describe.
In [email protected], on macOS, the zoom can be triggered with both CTRL as for other os but also with CMD.
We only automatically tests with the CTRL way.

Describe the solution you'd like

Decide if we only want to trigger zoom on CMD, only on CTRL (as for other os) or both --> CTRL only (see #773 (comment))

Additional context
During tests of the initial implementation (#734), it seemed that the zoom didn't work on both Firefox and Safari. Tests on Chromium are passing.
Let recheck this --> this is working, see #773 (comment)

[csouchet]

Mac OS

Firefox

• CTRL + mouse wheel => OK, but Browser Zoom
• CMD + mouse wheel => OK, but Browser Zoom

=> Browser Zoom, even the button is zoom/dezoom (cursor position on task)

Safari

• CTRL + mouse wheel => KO
• CMD + mouse wheel => KO

Chrome

• CTRL + mouse wheel => KO
• CMD + mouse wheel => KO

[csouchet]

I think I found why my tests don't work.

• If I make them with http://localhost:10001/navigation-diagram.html, on all browsers, with CTRL or CMD, they work.
• If I make them with http://localhost:10001, on all browsers, with CTRL or CMD, they don't work.

Is it normal not to have the navigation & zoom activated in the demo page ?

[tbouffard]

The demo page currently uses a bpmn container with a floating size. This doesn't work well with panning and zoom, that's why panning and zoom are not activated in this page and a new page with fixed size container has been created.
See:

• zoom: [FEAT] Zoom in and Zoom out with Ctrl+mouse wheel #730 (comment)
• panning: [FEAT] Add Pan capability to the diagram display #590 (comment)

[UPDATE] in 0.8.0 version, the demo page has been reworked. zoom and panning are activated by default and correctly work. See #896

[tbouffard]

We have received feedback #1238 (comment) about the magic mouse usage.
In that case, the zoom is not progressive, the scale increases from 1 to 5 (this is an example) without passing by scale 2, 3 and 4
Everything acts as if the mouse sends a lot of mouse wheel events very quickly. A regular mouse sends the events progressively letting the zoom scale change progressively.

[tbouffard]

We have decided to only keep the CTRL button to trigger the zoom for now.
We initially decided to use a button in addition to the mouse wheel as we wanted to also support diagram move with mouse interactions (see process-analytics/bpmn-visualization-addons#168). In the future, we may decide to change the way zoom is managed when using the mouse if we don't implement the 'navigation by mouse' feature.