Add Control Mod to Track Group Selection

[ALevansSamsung]

Track Groups did not previously act the same as Tracks when it came to selection. Control modifier should now preserve selection.

[cdamus]

I don't understand what this change is intended to accomplish. What am I as a reviewer supposed to test to verify the changes? I'm suspicious of the mention of Ctrl key in juxtaposition with the mouse pointer because on Mac platform this doesn't mean the same thing as on others: it summons the context menu.

[ALevansSamsung]

I don't understand what this change is intended to accomplish. What am I as a reviewer supposed to test to verify the changes? I'm suspicious of the mention of Ctrl key in juxtaposition with the mouse pointer because on Mac platform this doesn't mean the same thing as on others: it summons the context menu.

Currently when control clicking a track in the perfetto ui this changes the selected state of a track without clearing the previous state. This PR matches this functionality in the track groups as well. Track groups also removed the previous track selection state regardless of whether control was held.

[cdamus]

Currently when control clicking a track in the perfetto ui this changes the selected state of a track without clearing the previous state. This PR matches this functionality in the track groups as well. Track groups also removed the previous track selection state regardless of whether control was held.

I'm still not getting it. Track (group) selection is controlled by the little check boxes that appear when you drag out a selection rectangle over the tracks. What has this got to do with the Ctrl modifier? That isn't ordinarily used with check boxes, is it?

[ALevansSamsung]

When you click on track or track group label, the track header turns blue. This was meant to fix an issue where the user wanted to be able to click on a set of tracks to be able to combine them. What I did was add the ability to select tracks and use a plugin to access this information.

The PR on Sokatoa (https://github.com/android-graphics/sokatoa/pull/1470) would use this plugin point to be able to preselect the combination track dialog with this information. The Perfetto side of this was previous merged (#114), but the Sokatoa side of the PR got left in limbo. I started working on the Sokatoa side again and noticed an inconsistency in how the control modifier was working between track groups and tracks.

[cdamus]

BTW, if anything in Perfetto is counting on a mouse click event having the ctrlKey property set, then that won't work on Mac because this mouse event never happens. When clicking the mouse with Ctrl key down, the browser sends a contextmenu event to the DOM element, not any kind of mouse event.

On Mac platform probably what Perfetto should be looking for is the Command key to add to a selection. But I can't say for certain as I don't know what this selection scenario is for.

[cdamus]

When you click on track or track group label, the track header turns blue. This was meant to fix an issue where the user wanted to be able to click on a set of tracks to be able to combine them. What I did was add the ability to select tracks and use a plugin to access this information.

Ah, OK. Now I understand that this is all new selection behaviour in the Perfetto fork. It doesn't actually work as intended on Mac, so I cannot really test this.

[ALevansSamsung]

It looks like tree-widget, which also handles multiselection, has a specific case for MacOs when it comes to checking the ctrl mask.

    /**
     * Determine if the tree modifier aware event has a `ctrlcmd` mask.
     * @param event the tree modifier aware event.
     *
     * @returns `true` if the tree modifier aware event contains the `ctrlcmd` mask.
     */
    protected hasCtrlCmdMask(event: TreeWidget.ModifierAwareEvent): boolean {
        return isOSX ? event.metaKey : event.ctrlKey;
    }

[cdamus]

It looks like tree-widget, which also handles multiselection, has a specific case for MacOs when it comes to checking the ctrl mask.

Indeed, if Perfetto is after a similar multiselection behaviour, then that is the way to do it: with the Command key. It's a bit frustrating, isn't it, that these frameworks don't have appropriate abstractions for these platform variation points? We shouldn't have to be concerned in mouse handlers with which modifier key is depressed ... alas.

[ALevansSamsung]

It looks like tree-widget, which also handles multiselection, has a specific case for MacOs when it comes to checking the ctrl mask.

Indeed, if Perfetto is after a similar multiselection behaviour, then that is the way to do it: with the Command key. It's a bit frustrating, isn't it, that these frameworks don't have appropriate abstractions for these platform variation points? We shouldn't have to be concerned in mouse handlers with which modifier key is depressed ... alas.

I hoped it would be like how touchpads are handled and abstracted. A touchpad "zoom in" finger motion is treated as a control + scroll up in html. I found this out accidentally when setting up the mouse zoom for the texture widget.

[ALevansSamsung]

@cdamus I added a change to support multiselecting tracks on MacOS. Can you test this as none of us use Mac?

[cdamus]

Works great! Thanks @ALevansSamsung.

Aside: meta key? I haven't seen one of those since my work on Sun SparcStations at Nortel in the 90s 😉