Make places and roads accessible to VoiceOver #9950

1ec5 · 2017-09-11T01:13:32Z

After zooming in or out using VoiceOver’s one-finger upward or downward swipe gestures, MGLMapView now summarize the visible places and roads in addition to announcing the new zoom level. The places and roads are all part of the list of accessibility elements within the map view’s container, so the user can now navigate among these features to get a better sense of the map’s contents.

“Café du Monde: cafe”

“Orleans Ave: divided road, northwest to southeast”

“Denali: mountain, 20,313 feet”

These features work in any style that uses the Mapbox Streets source in at least one layer, and it’s mostly localizable (although some parts of the readout are dependent on open-ended OpenStreetMap tags, which are in English). For screen recordings of these features, see this blog post.

Along the way, the annotation accessibility element code has been refactored for better reliability, and the annotations are now sorted by proper geographic distance.

~~There remain a few problems with this feature, primarily that some of the roads seem to go in and out of the container chain:~~

[Accessibility] Went all the way up the container chain from @, but could not find any container that was one of the ordered children of @.  This may be acceptable if it happened right around a layout change, but it would be best to double check by swiping left/right to see if you can get to all elements.

More to come:

Fixes #4821.

/cc @fabian-guerra @friedbunny

friedbunny · 2017-10-11T00:04:33Z

I’m not very familiar with VoiceOver, but in terms of usability:

The settings button kept stealing focus when I tried to swipe zoom. Then I would have trouble tapping on any other element — map or UI. Swiping left would sometimes work. Other times, swiping through UI elements would never take me to the map view.
Performance seems pretty bad (at least, in a debug build) — when using the 100 views option and attempting to swipe between them, it can take several seconds to update to the next one.

fabian-guerra · 2017-10-11T00:25:35Z

platform/ios/src/MGLMapAccessibilityElement.m

+typedef struct {
+    MGLLocationRadians latitude;
+    MGLLocationRadians longitude;
+} MGLRadianCoordinate2D;


What is the difference between this struct and https://github.com/mapbox/mapbox-gl-native/blob/master/platform/darwin/src/MGLGeometry_Private.h#L17?

Ah, I completely forgot we had implemented this in #9110. Yes, I’ll add this to the to-do list.

Actually it was #8713 😜

fabian-guerra · 2017-10-11T00:26:43Z

platform/ios/src/MGLMapAccessibilityElement.m

+    MGLLocationRadians longitude;
+} MGLRadianCoordinate2D;
+
+MGLRadianCoordinate2D MGLRadianCoordinate2DMake(MGLLocationRadians latitude, MGLLocationRadians longitude) {


We already have defined this function in https://github.com/mapbox/mapbox-gl-native/blob/master/platform/darwin/src/MGLGeometry_Private.h#L25

fabian-guerra · 2017-10-11T00:29:02Z

platform/ios/src/MGLMapAccessibilityElement.m

+}
+
+/** Returns the direction from one coordinate to another. */
+CLLocationDirection MGLDirectionBetweenCoordinates(CLLocationCoordinate2D firstCoordinate, CLLocationCoordinate2D secondCoordinate) {


Is it possible reuse https://github.com/mapbox/mapbox-gl-native/blob/master/platform/darwin/src/MGLGeometry_Private.h#L122?

1ec5 · 2017-10-12T23:59:35Z

The settings button kept stealing focus when I tried to swipe zoom. Then I would have trouble tapping on any other element — map or UI. Swiping left would sometimes work. Other times, swiping through UI elements would never take me to the map view.

Tapping an element isn’t the normal mode of operation for VoiceOver. When the focus goes back to the first element on screen (which just happens to be the Settings button in iosapp), swipe rightward repeatedly to navigate through the accessibility elements. For best results, enable user location tracking.

Performance seems pretty bad (at least, in a debug build) — when using the 100 views option and attempting to swipe between them, it can take several seconds to update to the next one.

I wonder how this compares to master with VoiceOver enabled. Unfortunately, it is expected that performance with VoiceOver enabled is poorer than with VoiceOver disabled when there are many accessibility elements. In particular, the only difference between no annotations and 100 view-backed annotations should be the cost of querying the map for visible annotations; the map view leaves the annotation views in charge of providing accessibility information about themselves.

1ec5 · 2017-10-14T22:18:32Z

One thing I need to look into is that, after zooming in or out, the listed places and roads sometimes reflect the previous zoom level. I think this may be a race condition where feature querying kicks off before the map finishes loading at the new zoom level.

1ec5 · 2017-10-16T20:27:45Z

One thing I need to look into is that, after zooming in or out, the listed places and roads sometimes reflect the previous zoom level. I think this may be a race condition where feature querying kicks off before the map finishes loading at the new zoom level.

Fixed in 8e135a8.

fabian-guerra

LGTM 👍🏼

After zooming, MGLMapView’s accessibility value now indicates the number of visible roads and lists out a few places visible in the current viewport, starting with the features at the highest z-index (not necessarily the largest or the closest to the center of the view). Avoid saying that no annotations are visible.

Split out a separate header for the various accessibility elements tied to MGLMapView. Wrap place features in accessibility elements and insert them into the narration order after the visible annotations but before the attribution button. Refactored MGLMapView’s accessibility code to rely on ranges to avoid off-by-one errors.

Post a layout change notification when fully finishing a map render.

Also created a new MGLPlaceFeatureAccessibilityElement class.

Sort annotation accessibility elements by screen distance, not the hypotenuse of coordinates, which can yield incorrect results when the map is rotated or tilted or when the user is located at high latitudes. Sort place feature accessibility elements by screen distance as well.

…eature accessibility element

Improved accessibility performance after changing the map camera. MGLMapView no longer queries the map for place features once per place feature.

Wrap visible road features in accessibility elements described by the road name, route number, and general direction of travel.

Also fixed an issue causing road feature accessibility elements to get treated like place feature accessibility elements.

Announce the direction of a divided road based on the direction of its first polyline.

A 100-millisecond delay is enough for the post-zooming announcement to reflect the new zoom level rather than the previous zoom level.

Adopted MGLGeometry_Private.h in the accessibility code, forcing a conversion to Objective-C++. Avoid inlining some of the more complex geometric functions.

NSLocale.scriptCode is only set when the locale identifier explicitly specifies a script. Use NSOrthography to identify the dominant orthography regardless of locale. Also added a unit test of feature accessibility element labels.

A road feature’s accessibility value now indicates whether the road is a one-way road.

1ec5 · 2017-11-03T01:21:42Z

b585ccf and 096d486 add unit tests of the features’ accessibility labels and values.

1ec5 added accessibility Integration with screen readers and other assistive technology iOS Mapbox Maps SDK for iOS MapKit parity For feature parity with MapKit on iOS or macOS labels Sep 11, 2017

1ec5 self-assigned this Sep 11, 2017

1ec5 mentioned this pull request Sep 11, 2017

Announce zoom level and visible features after zooming via VoiceOver #4821

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1ec5 requested review from friedbunny and fabian-guerra September 11, 2017 01:25

1ec5 force-pushed the 1ec5-a11y-features-4821 branch from 1464eac to 66e0f5b Compare September 18, 2017 16:30

1ec5 added this to the ios-v3.7.0 milestone Sep 18, 2017

1ec5 force-pushed the 1ec5-a11y-features-4821 branch from 9cfa995 to e7112fb Compare September 28, 2017 20:00

1ec5 changed the base branch from release-ios-v3.6.0-android-v5.1.0 to master September 28, 2017 20:00

boundsj self-requested a review October 2, 2017 16:10

1ec5 force-pushed the 1ec5-a11y-features-4821 branch from e7112fb to d913f4b Compare October 6, 2017 04:20

1ec5 changed the base branch from master to release-agua October 6, 2017 04:20

fabian-guerra reviewed Oct 11, 2017

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1ec5 added the beta blocker Blocks the next beta release label Oct 26, 2017

1ec5 force-pushed the 1ec5-a11y-features-4821 branch from 54bb912 to 0546cda Compare October 27, 2017 18:10

1ec5 requested a review from fabian-guerra October 27, 2017 23:16

fabian-guerra approved these changes Nov 1, 2017

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1ec5 added 7 commits November 2, 2017 15:19

[ios] Post layout change notification when fully rendered

21dd42a

Post a layout change notification when fully finishing a map render.

[ios, macos] Moved MGLVectorSource+MGLAdditions to more specific group

c17011f

[ios] Localize accessibility feature names

226033a

[ios] Find place feature accessibility elements by identifier

56088bf

[ios] Refactored accessibility traits

91d5635

Also created a new MGLPlaceFeatureAccessibilityElement class.

1ec5 added 14 commits November 2, 2017 15:19

[ios] Create a place feature accessibility element, not an abstract f…

539ec4d

…eature accessibility element

[ios] Only query for visible place features once per camera

de52d40

Improved accessibility performance after changing the map camera. MGLMapView no longer queries the map for place features once per place feature.

[ios] Made roads accessible

7a1fdd8

Wrap visible road features in accessibility elements described by the road name, route number, and general direction of travel.

[ios] Cleaned up radian conversions

788482e

[ios] Thickened road accessibility elements

ac7ce2f

[ios] Made unioned roads accessible

0cf4b96

[ios] Consistently sort accessibility elements

04ba3e2

Also fixed an issue causing road feature accessibility elements to get treated like place feature accessibility elements.

[ios] Announce direction of divided roads

b475f4c

Announce the direction of a divided road based on the direction of its first polyline.

[ios] Refined announced elevation units

160da06

[ios] Romanize feature names

83acd62

[ios] Updated changelog

4e5aecb

[ios] Delay zoom announcement

862f4fa

A 100-millisecond delay is enough for the post-zooming announcement to reflect the new zoom level rather than the previous zoom level.

[ios] Consolidated geometry functions

b8e7ef5

Adopted MGLGeometry_Private.h in the accessibility code, forcing a conversion to Objective-C++. Avoid inlining some of the more complex geometric functions.

1ec5 force-pushed the 1ec5-a11y-features-4821 branch from 0546cda to b8e7ef5 Compare November 2, 2017 22:20

1ec5 added 3 commits November 2, 2017 17:54

[ios] Added tests for place, road accessibility values

096d486

[ios] Announce one-way roads

08ff142

A road feature’s accessibility value now indicates whether the road is a one-way road.

1ec5 merged commit 2955fb5 into release-agua Nov 3, 2017

1ec5 deleted the 1ec5-a11y-features-4821 branch November 3, 2017 19:17

1ec5 mentioned this pull request Jun 28, 2018

Navigation iOS SDK Accessibility mapbox/mapbox-navigation-ios#1521

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Make places and roads accessible to VoiceOver #9950

Make places and roads accessible to VoiceOver #9950

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Make places and roads accessible to VoiceOver #9950

Make places and roads accessible to VoiceOver #9950

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