public static List <NSObject> toFeatureList(this IEnumerable <Pin> pins)
{
var features = new List <NSObject>();
foreach (var pin in pins)
{
// Skip if the pin is hidden
if (!pin.isVisible)
{
continue;
}
var feature = new MGLPointFeature {
Coordinate = new CLLocationCoordinate2D(pin.position.latitude, pin.position.longitude)
};
object[] offset = { pin.iconOffset.X, pin.iconOffset.Y }; //[x,y] coordinates Positive values indicate right and down
feature.Attributes = NSDictionary <NSString, NSObject> .FromObjectsAndKeys(
new object[] {
pin.image,
pin.heading,
pin.imageScaleFactor,
NSArray.FromObjects(offset),
pin.id
},
new object[] {
MapboxRenderer.pin_image_key,
MapboxRenderer.pin_rotation_key,
MapboxRenderer.pin_size_key,
MapboxRenderer.pin_offset_key,
MapboxRenderer.pin_id_key
}
);
features.Add(feature);
}
return(features);
}
/// <summary>
/// This has a problem, if the same pin updates a couple of times a second pin might jump suddenly to the
/// 2nd to latest position then smooth animate to the latest position, but I think this is ok logically since
/// By the time it's animating its final animation position is not really up to date.
/// </summary>
/// <param name="pin">Pin.</param>
private void animateLocationChange(Pin pin)
{
#region Simultaneous pin update
System.Threading.Tasks.Task.Run(async () => {
// If there exist a pin that caused this update
if (isPinAnimating)
return;
//// Wait for pin position assignment in the same call
isPinAnimating = true;
// Get all pins with the same key and same flat value (animatable pins)
var pinsWithSimilarKey = xMap.pins.Where(
(Pin arg) => arg.IsCenterAndFlat == pin.IsCenterAndFlat).ToArray();
Device.BeginInvokeOnMainThread(() => {
var geoJsonSource = (MGLShapeSource)nStyle.SourceWithIdentifier(mapLockedPinsSourceKey);
var visibleMovablePinCount = pinsWithSimilarKey.Count(p => p.isVisible);
var currentHeadingCollection = new double[visibleMovablePinCount];
var features = new NSObject[visibleMovablePinCount];
// Update the entire frame
MapBox.Extensions.MapExtensions.animatePin(
(double d) => {
System.Threading.Tasks.Task.Run(() => {
for (int i = 0; i < visibleMovablePinCount; i++) {
var p = pinsWithSimilarKey[i];
Position theCurrentAnimationJump = p.position;
double theCurrentHeading = p.heading;
// Only update the pin if it is the pin that cause this animation call
// OR the if it actually requested for a position update before this current animation has not been finished
if (pin == p || p.requestForUpdate) {
theCurrentAnimationJump = SphericalUtil.interpolate(p.previousPinPosition, p.position, d);
theCurrentHeading = SphericalUtil.computeHeading(p.previousPinPosition, p.position);
}
currentHeadingCollection[i] = theCurrentHeading;
var feature = new MGLPointFeature {
Coordinate = new CLLocationCoordinate2D(theCurrentAnimationJump.latitude,
theCurrentAnimationJump.longitude)
};
feature.Attributes = NSDictionary<NSString, NSObject>.FromObjectsAndKeys(
new object[] {
p.image,
theCurrentHeading,
p.imageScaleFactor,
p.id
},
new object[] {
MapboxRenderer.pin_image_key,
MapboxRenderer.pin_rotation_key,
MapboxRenderer.pin_size_key,
MapboxRenderer.pin_id_key
});
// Add to the new animation frame
features[i] = feature;
}
// Update the entire layer
Device.BeginInvokeOnMainThread(() => geoJsonSource.Shape = MGLShapeCollectionFeature.ShapeCollectionWithShapes(features));
});
},
async (d, b) => {
// DO NOT REMOVE, this is essential for the simultaneous pin location update to work
await System.Threading.Tasks.Task.Delay(500);
isPinAnimating = false;
// Stabilize the pins, at this moment all the pins are updated
for (int i = 0; i < visibleMovablePinCount; i++) {
var p = pinsWithSimilarKey[i];
// To avoid triggering heading property change event
p.PropertyChanged -= Pin_PropertyChanged;
p.requestForUpdate = false;
p.heading = currentHeadingCollection[i];
p.PropertyChanged += Pin_PropertyChanged;
}
}, 500);
});
});
#endregion
}