[Accepted with Revisions] SDL 0224 - Navigation Subscription Buttons

[theresalech]

Hello SDL community,

The review of "SDL 0224 - Navigation Subscription Buttons" begins now and runs through May 7, 2019. The proposal is available here:

https://github.com/smartdevicelink/sdl_evolution/blob/master/proposals/0224-navigation-subscription-buttons.md

Reviews are an important part of the SDL evolution process. All reviews should be sent to the associated Github issue at:

#712

What goes into a review?

The goal of the review process is to improve the proposal under review through constructive criticism and, eventually, determine the direction of SDL. When writing your review, here are some questions you might want to answer in your review:

• Is the problem being addressed significant enough to warrant a change to SDL?
• Does this proposal fit well with the feel and direction of SDL?
• If you have used competitors with a similar feature, how do you feel that this proposal compares to those?
• How much effort did you put into your review? A glance, a quick reading, or an in-depth study?
  Please state explicitly whether you believe that the proposal should be accepted into SDL.

More information about the SDL evolution process is available at

https://github.com/smartdevicelink/sdl_evolution/blob/master/process.md

Thank you,
Theresa Lech

Program Manager - Livio
theresa@livio.io

[Jack-Byrne]

I am thinking about other map/nav controls that the proposal could be missing.

What about:

• NAV_TILT (Toggle arial view vs angled view)
• NAV_ROTATE (Maybe separate buttons for clockwise/counterclockwise 90 degrees)
• NAV_HEADING (Lock orientation to north or to vehicle heading)

[joeygrover]

| 1. I am a little nervous adding this ability which could enable OEMs to put these buttons on-screen over the projected navigation app's screen and cause all sorts of compatibility issues (as the author laid out). So I think we have to make sure to add some notes to the Core certification guidelines that would reflect this.

|2. Should the Navigation Service have the button press added to it's handled RPCs with these new button types?

[joeljfischer]

|1. Yes, as I noted, these buttons should either be hard buttons, or be soft buttons that are located somewhere other than the map screen. They should never overlay the map screen.

|2. Yes, I believe that would make sense.

[tonyaug]

Regarding the below statement,

This should be considered an alternate way to interact with a map, while touches, pans, and pinches are the primary way to interact.

Mazda and many other OEMs still support hard button inputs along with or without the touch input. So in order to work with OEMs which still uses the hard buttons, the buttons names defined in this proposal should be used by the application. So I think that hard buttons should be considered with same priority as touch input.

Also, I would like to propose some more actions to this proposal.

User should be able to control all the functionalities of the Navigation app using the hard buttons. Currently this proposal suggests only the actions regarding the MAP screen.

For eg, user should be able to open menu of Navigation application, scroll through the menu and select any item in the menu. Adding some more functions such as below would be sufficient.

Function	Description
MENU	Open a consolidated list of menus in Navigation application
MOVE_FOCUS_NEXT_ITEM	Moving the focus to next item on the list screen
MOVE_FOCUS_PREVIOUS_ITEM	Moving the focus to previous item on the list screen
SELECT	Selecting the currently focused item
GO_BACK	Go back to the previous screen

In this scenario there is a case in which single hard button can be used for MAP operations and MENU operations.

For eg. a knob can be used for ZOOMING the MAP in MAP view and scrolling over the MENU items in MENU view. So the actions should be differentiated according to the screens. This can be achieved by using new enums such as

MAP_FULL_SCREEN_VIEW,
MAP_LIST_VIEW

By setting the enum MAP_FULL_SCREEN_VIEW indicates that the view is now MAP and hardware buttons can be used for MAP operations. If the enum MAP_LIST_VIEW is set, the view is MENU and hardware buttons can be used for MENU operations. This setting of enum should be done from the application if the application supports the hard buttons.

[joeljfischer]

Thank you for the review @tonyaug.

I'd like to clear a few things up.

This should be considered an alternate way to interact with a map, while touches, pans, and pinches are the primary way to interact.

Mazda and many other OEMs still support hard button inputs along with or without the touch input. So in order to work with OEMs which still uses the hard buttons, the buttons names defined in this proposal should be used by the application. So I think that hard buttons should be considered with same priority as touch input.

My statement above was intended to say that if a head unit supports touch, it should use touch as the primary input interaction, and only support the hard buttons as a secondary feature.

---

Also, I would like to propose some more actions to this proposal.

User should be able to control all the functionalities of the Navigation app using the hard buttons. Currently this proposal suggests only the actions regarding the MAP screen.

For eg, user should be able to open menu of Navigation application, scroll through the menu and select any item in the menu. Adding some more functions such as below would be sufficient.

So, this requires several responses, but I think the criticism here is generally misguided.

1. Your suggestion of MAP_LIST_VIEW / MAP_FULL_SCREEN_VIEW is unclear. Do you mean new PredefinedLayout enums? If so, why do the NAV_FULLSCREEN_MAP and NAV_LIST templates not work?

2. Regarding the MENU suggestion, the recommendation is to use the default SDL menu system instead. See the SDL-0116 (Open Menu RPC) proposal for an unimplemented but accepted proposal to improve the menu button for navigation apps. If that is something you want, I would recommend bringing it up to be implemented in the next SDL version.

3. Regarding MOVE_FOCUS_NEXT_ITEM and PREVIOUS_ITEM, this was discussed in depth quite a while ago. The primary reason we do not recommend that this route be taken is because it puts a greater burden on app developers. They have to modify their UI to support focus highlighting. Furthermore, not every developer will modify focus the same way, so there will be inconsistency among apps. Furthermore, apps have no way of knowing when the focus leaves the map and moves to another part of the head unit UI.

   Therefore, we built the haptic rect system. That already exists and is the recommended method of moving focus. The OEM will then have to overlay the focus item highlighting and determining which item to highlight.

4. Regarding SELECT and GO_BACK, due to (3), these no longer make sense, because the app developer is not (and should not be) in charge of haptic highlighting. The OEM instead is supposed to "tap" the center of the haptic rect.

I believe that covers all of your concerns. I do not think any changes need to be made to this proposal.

[tonyaug]

Thank you for the reply @joeljfischer .

I am sorry for being naive about the comments.

We at Mazda intend to make SDL projection Navigation applications to work with only hard buttons. So this proposal is very crucial in that context. We were making a similar proposal. But most of the items in our proposal are already covered in this proposal. We thought it is good if we add our suggestions too in this proposal.

Regarding your comments,

1. It is okay to use the NAV_FULLSCREEN_MAP and NAV_LIST templates. The application need to set these values according to the screen change.

2. Please find my understanding about your comment,

the recommendation is to use the default SDL menu system instead

So the app developer will be adding the menu using the addCommand API. This menus will be hidden in Navigation projection case.

SDL-0116 (Open Menu RPC) proposal

As per this proposal by calling the API ShowAppMenu the hidden menu will become visible. This is done from the application.

Please confirm above understanding is correct or not.

In our scenario the MENU hard button will be pressed and the action will be notified to HU. Is it possible to the HU to call the API ShowAppMenu?

We were hoping the menu should be in the application. When user press the hard button to open the menu, application will open the menu and user can change the focus and select the menus using rotating and clicking the hard button.

3. I hope you mentioned the information in the below links by mentioning

Therefore, we built the haptic rect system

https://smartdevicelink.com/en/guides/android/mobile-navigation/supporting-haptic-input/
https://smartdevicelink.com/en/guides/iOS/video-streaming-for-navigation-apps/supporting-haptic-input/
https://smartdevicelink.com/en/docs/hmi/master/ui/sendhapticdata/

So as per comment 2 and 3 the app developer need to provide haptic rect data for each menu item. OEM need to highlight a rect when that rect is focused and inform application when the rect is pressed using the hard button. Please confirm my understanding?

Can you please provide more insight to the below sentence,

The OEM will then have to overlay the focus item highlighting and determining which item to highlight.

Is there any documentation on how OEM can achieve this when using the haptic inputs?

In this case also our understanding of the functionality was, application will be changing the focus of the menu item as per user action on the hard button. We were hoping that, there can be some guidelines defined in order to keep the consistency among different app developers.

4. Please consider the scenario, if there is a hard button for Back functionality, then as per user point of view pressing the button should change the screen to the previous screen. We think that this is a valid action to be added.

[joeljfischer]

|2. Yes, your understanding is correct, and that is the way I would recommend it work by far because the performance will be far greater. However, if the app wants to use a video projection menu, that is currently possible using the haptic rect system that currently exists.

|3. Your understanding appears to be correct.

Regarding my comment:

The OEM will then have to overlay the focus item highlighting and determining which item to highlight.

Is there any documentation on how OEM can achieve this when using the haptic inputs?

There is no current documentation, because it's completely up to the OEM's HMI. There is no SDL API integration necessary to achieve this. Your HMI will have access to the rectangles that the developer claims can be highlighted and selected. It is then up to you to decide how to highlight those rectangles and which one to highlight when. When the user selects a rect, you send a tap to the app at the center of the rect.

In this case also our understanding of the functionality was, application will be changing the focus of the menu item as per user action on the hard button. We were hoping that, there can be some guidelines defined in order to keep the consistency among different app developers.

The application does not change its focus, therefore there are no guidelines. It's completely up to the OEM to ensure that focusing works the same within SDL as it does on the rest of the head unit.

|4. The problem is that there is no concept of "Back" in SDL. There is no standard SDL "go back to the previous screen." We could create it special for video projection apps, but it wouldn't work the same as elsewhere in SDL. Does anyone else have an opinion on a special back button for video projection navigation use cases when such a hard button exists in the car?

[theresalech]

During the 2019-05-07 meeting, the Steering Committee voted to defer this proposal, keeping it in review until our meeting on 2019-05-14. This will allow time for additional discussion on the issue between the author and SDLC members. It also was determined that the final proposal will incorporate this comment, with NAV_ROTATE including rotating left or right 90 degrees. The final proposal will also be updated to have button press added to the Navigation Service's handled RPCs with these new button types.

[tonyaug]

Hi @joeljfischer
Thank you for the reply.

Please find my comments.

|2. Thank you for confirming my understanding. But I am still not clear about the menu implementation.

Hope you have seen the below question from my previous comment,

In our scenario the MENU hard button will be pressed and the action will be notified to HU. Is it possible to the HU to call the API ShowAppMenu?

And your reply,

However, if the app wants to use a video projection menu, that is currently possible using the haptic rect system that currently exists.

My understanding from your comment is that the app developer need to place a haptic rect in the MAP view. OEM HMI need to focus the haptic rect and send button press to application when user press the MENU hard button. Then the application will open the menu screen by calling the API ShowAppMenu.

I think that, sending a function like MENU from HMI to application and application call the API ShowAppMenu can be more easy?

|3. I understand you comment. But one of the drawback of using the Haptic rect as mentioned in the documentation is that,

Currently, there are no RPCs for knowing which rect is highlighted, so your UI will have to remain static, without scrolling.

I think that this case conflicts with our requirements in the case of using the Haptic rect. All the available menus in the application should be available to the user to operate via hard controls. If an application have menus more than the number of the list items which can be displayed in the HMI (without scrolling), using haptic rect will not work. Kindly consider this case and provide your comment on this?

|4. We would really like to have the BACK button function. If the user opens the MENU view from MAP view, and press the BACK button, the screen should go back to the MAP view. Also I hope that with the current available APIs it is possible to perform the closing of MENU view from application.

[joeljfischer]

|2. I must have missed your comment:

In our scenario the MENU hard button will be pressed and the action will be notified to HU. Is it possible to the HU to call the API ShowAppMenu?

My understanding from your comment is that the app developer need to place a haptic rect in the MAP view. OEM HMI need to focus the haptic rect and send button press to application when user press the MENU hard button. Then the application will open the menu screen by calling the API ShowAppMenu.

I think that, sending a function like MENU from HMI to application and application call the API ShowAppMenu can be more easy?

I don't believe your understanding is correct here. The proposal SDL-0116 I referenced above gives the app a way to programmatically open the menu by telling the head unit to do so using ShowAppMenu. The head unit has always been able to open the menu (this is what they do when the user touches the menu button on any given head unit) by interacting with its own HMI to bring the app menu on screen. So you can certainly have a hard button to open the menu; when the button is pressed, you would simply tell your HMI to open the app menu.

The purpose of SDL-0116 is to give a video projection app a way to programatically open the menu from their side. This is so that they can have their own "menu" button on their video projection and open the app menu from that. But this would not affect you if you already have your own "menu" button, unless the app creates a video projection menu, which they are not encouraged to do.

So, to make a long response short, if you want a hard button to open the app menu, that's already possible. Your hard button just has to tell your HMI to open the app menu.

|3. This is correct. You cannot "scroll" purely using haptic rect. There would have to be an "up arrow" or "down arrow" button on screen that could be highlighted.

I can think of a use-case for a subscription button like NAV_SCROLL_DOWN or NAV_SCROLL_UP, but there are also drawbacks to such an approach, such as that the head unit would not know when it is appropriate to scroll down automatically, and the need for a dedicated hard button to scroll down instead of just moving the focus to the next item.

With that said, using the standard SDL templates for activities outside of the map view is, in my mind, strongly preferred for performance and UI cohesion reasons.

|4. See my comments on (2) for the ability to close the menu from a hard button. You can already do that by interacting with your HMI, just as other OEMs do when the user touches the "back" or "close" button on the menu screen.

Also I hope that with the current available APIs it is possible to perform the closing of MENU view from application.

I'm not entirely sure what you mean by this, but no, a proxy app cannot currently programmatically close the menu. This is a bad idea because it means that the app could accidentally close the menu when the user is not expecting it. There's no reason for such a feature to exist because closing the menu is always user-initiated and the HMI takes care of closing the menu in such a case.

So, I don't see a reason for a "back" hard button (even in navigation applications because they ought to be using the standard SDL templates outside of the map view wherever possible). That only place such a concept currently exists in SDL (such as the menu, or when an alert appears), there are already APIs in place to do this.

If this is still desired, I would request that you propose it in a separate proposal and provide your reasoning for it so that it can be a focused discussion and so that it does not delay this proposal further.

[tonyaug]

HI @joeljfischer
I am sorry for keeping the discussion this long.

|2. I think that I understand you comment. So if the app developer is using calling AddCommand and AddSubCommand to create the menus, then it can be opened from HMI by hard button without any prompt from the application. Please confirm?

Also regarding the below statement,

Your hard button just has to tell your HMI to open the app menu.

Can you provide any information on how to do this?

|3. Thank you for the suggestion. We will check this case with

SDL templates for activities outside of the map view

|4. we will check the back button case as per you comment.

|4. See my comments on (2) for the ability to close the menu from a hard button. You can already do that by interacting with your HMI, just as other OEMs do when the user touches the "back" or "close" button on the menu screen.

I have one more point to be noted. As I mentioned in this comment

In this scenario there is a case in which single hard button can be used for MAP operations and MENU operations.

For eg. a knob can be used for ZOOMING the MAP in MAP view and scrolling over the MENU items in MENU view.

I would like to confirm the use of NAV_FULLSCREEN_MAP and NAV_LIST templates. So that it is necessary for the HU to differentiate the action of hard buttons when MAP view and MENU view is displayed.

[joeljfischer]

|2.

Your hard button just has to tell your HMI to open the app menu.

Can you provide any information on how to do this?

That is outside of the scope of SDL. It would happen in any other way that you might signal your HMI a message when you press a button.

|4.

I would like to confirm the use of NAV_FULLSCREEN_MAP and NAV_LIST templates. So that it is necessary for the HU to differentiate the action of hard buttons when MAP view and MENU view is displayed.

I'm not sure what you mean here. The app would differentiate the buttons on the different screens to perform an appropriate action when they receive the button press.

[tonyaug]

Thank you @joeljfischer for your comments and suggestions. We think we can achieve our requirements as per your suggestion.

[theresalech]

The Steering Committee voted to accept this proposal with the following revisions:

• Incorporate this comment, with NAV_ROTATE including rotating left or right 90 degrees.
• Add button press to the Navigation Service's handled RPCs with these new button types.

Additionally, there was a question in the Steering Committee meeting about requiring applications to be compatible with this proposal. It was advised that this requirement is out of the scope of SDL, and OEMs would need to ask application developers to implement this proposal once it's available in the library for developers to implement.

[theresalech]

@joeljfischer please advise when a new PR has been entered to update the proposal to reflect the agreed upon revisions. I'll then merge the PR so the proposal is up to date, and update issues in the respective repositories for implementation. Thanks!

[theresalech]

Proposal has been updated to reflect revisions, and issues have been entered:

Core
RPC
HMI
iOS
Java Suite