Develop Reference

How to detect EAR with ArCore android

So I am trying to put a earing on a person with ArCore. But the Face ArCore mask does not cover ears best i can do is at 172 but its still far away from the ear.
this is my code
private fun getRegionPose(region: FaceRegion): Vector3? {
val buffer = augmentedFace?.meshVertices
if (buffer != null) {
return when (region) {
FaceRegion.EAR ->
Vector3(
buffer.get(177 * 3),
buffer.get(177 * 3 + 1),
buffer.get(177 * 3 + 2)
)
}
}
return null
}
override fun onUpdate(frameTime: FrameTime?) {
super.onUpdate(frameTime)
augmentedFace?.let { face ->
getRegionPose(FaceRegion.EAR)?.let {
mustacheNode?.localPosition = Vector3(it.x, it.y - 0.035f, it.z + 0.015f)
mustacheNode?.localScale = Vector3(0.07f, 0.07f, 0.07f)
}
}
}
Can some one help me please is there a way for me to go outside the bonds of the face lnadmakrs?

Well after a lot of research i found this example and it was what lead me to my answer. So i leave the tutorial here hopefouly it can help some one.
https://www.kodeco.com/523-augmented-reality-in-android-with-google-s-face-api#toc-anchor-003

Digital persona SDK - native problems

I am using in my app Digital Persona SDK for fingerprint identification.
When i use the identify function on less then 250 fmds it works fine.
Engine.Candidate candidates[] = m_engine.Identify(searchedFmd, 0, fmdArray, DEFAULT_THRESHOLD, 1); //fmdArray < 250
But with fmdArray > 250 it gives me a native runtime error:
A/art: art/runtime/indirect_reference_table.cc:132] JNI ERROR (app bug): local reference table overflow (max=512)
Now i runned this app on couple of android devices and came to conclusion that my app crushes with fmdArray > 250 when its running on android 7. But android 8 works fine. In 8 i can preform a check on even 4000 fmds and it works fine.
But i need to run this code in a specific device, that running android 7.
I tried to run it in couple of threads of 250 fmds only. But after single run there is another problem with the SDK. On the second run it doesnt works.
This is what i do:
First i get a fingerprint capture that i want to identify:
Reader.CaptureResult capture = m_reader.Capture(fidFormat, UrUSDK.DefaultImageProcessing, m_DPI, timeout);
// In second run, code after this line is not executed.
// My guees its not coming back from native. No exeptions. No errors.
...
Fmd scannedFmd = m_engine.CreateFmd(capture.image, fmdFormat);
...
int index = identifyFinger(fmds, scannedFmd);
...
private int identifyFinger(List<Fmd> fmdSearchArray, Fmd scannedFmd) {
List<List<Fmd>> lists = splitToChunks(fmdSearchArray);
AtomicInteger index = new AtomicInteger(-1);
List<Callable<Void>> threads = new ArrayList<>(lists.size());
AtomicInteger iteratorIndex = new AtomicInteger(0);
for (int i = 0; i < lists.size(); i++) {
int currentChunk = i;
Callable<Void> thread = () -> {
System.out.println(Thread.currentThread().getName() + " with chunk: " + iteratorIndex.getAndIncrement());
Fmd[] fmds = lists.get(currentChunk).toArray(new Fmd[IDENTIFY_BOUNDARY]);
try {
Engine.Candidate[] candidates = m_engine.Identify(scannedFmd, 0, fmds, threshold, 1);
if (candidates.length > 0) {
index.set(candidates[0].fmd_index + (currentChunk * IDENTIFY_BOUNDARY));
}
} catch (UareUException e) {
}
System.out.println(Thread.currentThread().getName() + " with chunk: " + currentChunk + " finished!");
return null;
};
threads.add(thread);
}
try {
List<Future<Void>> futures = executorService.invokeAll(threads);
System.out.println("All threads finished: " + index.get());
return index.get();
} catch (InterruptedException e) {
e.printStackTrace();
return -1;
}
}
...
private List<List<Fmd>> splitToChunks(List<Fmd> fmdSearchArray) {
int size = fmdSearchArray.size();
List<List<Fmd>> lists;
if (size > IDENTIFY_BOUNDARY) {
int chunks = size / IDENTIFY_BOUNDARY;
if (size % IDENTIFY_BOUNDARY > 0) {
chunks++;
}
lists = new ArrayList<>(chunks);
for (int i = 0; i < chunks; i++) {
if (i + 1 == chunks) {
lists.add(new ArrayList<>(fmdSearchArray.subList(i * IDENTIFY_BOUNDARY, size)));
break;
}
lists.add(new ArrayList<>(fmdSearchArray.subList(i * IDENTIFY_BOUNDARY, (i + 1) * IDENTIFY_BOUNDARY)));
}
} else {
lists = new ArrayList<>(1);
lists.add(fmdSearchArray);
}
return lists;
}
The problem with this code is that it runs once. But at another try it doesnt come back from the native code of Caprture call.
So my question is:
How i can overcome this and make it work from my java code?
Or at least what is the direction of the solution?

The root cause is that this Identify function holds on to at least two references per returned Candidate after pushing it to the result array. It should instead release the references after pushing, so its use of the (limited) local reference table remain constant. You should file a bug about that.
The simplest workaround for now is to cut your fmdArray into 250-sized chunks and call Identify for each chunk.

Not able to update Picker.SelectedIndex

I have an odd issue I can't explain the reason for it - maybe someone here can shed some light on it
I have a ticket scanning app in Xamarin Forms currently testing it on android
the interface allows you to:
type an order number and click the check order Button
use the camera scanner to scan which automatically triggers check order
use the barcode scanner to scan which automatically triggers check order
after the check order validation, user has to select the number of tickets from a drop down list and press confrim entry button
what I'm trying to do, is if the seats available on that ticket is just 1 - then automatically trigger confirm entry button functionality
problem that I have is that - some of my logic depends on setting the drop down index in code - for some reason it doesn't update - as seen in the debugger shot here
and this is the second tme I've noticed this today, earlier it was a var I was trying to assign a string and it kept coming up as null - eventually I replaced that code
is this a bug in xamarin ?
code has been simplified:
async void OnCheckOrderButtonClicked(object sender, EventArgs e)
{
await ValidateOrderEntry();
}
private async void scanCameraButton_Clicked(object sender, EventArgs e)
{
messageLabel.Text = string.Empty;
var options = new ZXing.Mobile.MobileBarcodeScanningOptions();
options.PossibleFormats = new List<ZXing.BarcodeFormat>() {
ZXing.BarcodeFormat.QR_CODE,ZXing.BarcodeFormat.EAN_8, ZXing.BarcodeFormat.EAN_13
};
var scanPage = new ZXingScannerPage(options);
scanPage.OnScanResult += (result) =>
{
//stop scan
scanPage.IsScanning = false;
Device.BeginInvokeOnMainThread(async () =>
{
//pop the page and get the result
await Navigation.PopAsync();
orderNoEntry.Text = result.Text;
//automatically trigger update
await ValidateOrderEntry();
});
};
await Navigation.PushAsync(scanPage);
}
private async Task ValidateOrderEntry()
{
//...other code....
checkInPicker.Items.Clear();
if (availablTickets == 1)
{
checkInPickerStack.IsVisible = true;
checkInPicker.SelectedIndex = 0;
messageLabel.Text = "Ticket OK! - " + orderNoEntry.Text;
messageLabel.TextColor = Color.Green;
//select the only element
checkInPicker.SelectedIndex = 0;
await PostDoorEntry();
}
//...other code....
}
private async Task PostDoorEntry()
{
int entryCount = checkInPicker.SelectedIndex + 1;
//... more code...
//...post api code..
}

Maybe I'm overlooking something, but you clear all the items a few lines above the one you are pointing out. That means there are no items in your Picker and thus you can't set the SelectedIndex to anything other than -1, simply because there are no items.

Make a TextView scroll its Content in a "bouncing" sort of fashion

Right now i am implementing a custom Renderer for my Xamarin.Forms Label with which i can make use of the marquee scrolling features of the TextView.
What i want to do now is change the scrolling mode of the text from just going to the left endlessly to "bouncing" from side to side. (Kind of like this question i found regarding this subject: How to make a label scroll a word back and forth?) I have not found any resources online that talk about this. I would be very happy if you could give me a general idea of where to look or what to do.
Thank you for your time
Here is my marquee Custom-Renderer:
protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
{
MarqueeLabel marqLabel = (MarqueeLabel)this.Element;
base.OnElementChanged(e);
if (marqLabel.shouldScroll)
{
Control.SetSingleLine(true);
Control.SetHorizontallyScrolling(true);
Control.Selected = true;
Control.Ellipsize = Android.Text.TextUtils.TruncateAt.Marquee;
Control.SetMarqueeRepeatLimit(-1);
}
}

If you can do the animations on the Xamarin.Forms level then you can save yourself quite a bit of work rather than implementing on each platform-specific level.
Try the following example that demonstrates some bouncing of a Label to and from the edges of the screen, as it may give you some ideas? Note it doesn't do it continuously in the example below.
StackLayout objStackLayout = new StackLayout()
{
Orientation = StackOrientation.Vertical,
};
Label objLabel = new Label();
objLabel.Text="Hello";
objLabel.HorizontalOptions = LayoutOptions.Start;
objStackLayout.Children.Add(objLabel);
Button objButton1 = new Button()
{
Text = "Animate"
};
objButton1.Clicked += (async (o2, e2) =>
{
double dblWidth = objStackLayout.Width - objLabel.Width;
//
await objLabel.TranslateTo(dblWidth, 0,1000, Easing.BounceIn);
await objLabel.TranslateTo(0,0,1000, Easing.BounceIn);
});
objStackLayout.Children.Add(objButton1);

This is not the good way to do that but I am sure this will solve your problem.
StackLayout objStackLayout = new StackLayout()
{
Orientation = StackOrientation.Vertical,
};
Label lblMarquee = new Label();
lblMarquee.Text = "This is marquee animation!!!";
lblMarquee.HorizontalOptions = LayoutOptions.Start;
objStackLayout.Children.Add(lblMarquee);
Button btnAnimate = new Button()
{
Text = "Stare Marquee Animation"
};
btnAnimate.Clicked += (async (o2, e2) =>
{
double dblWidth = objStackLayout.Width + lblMarquee.Width;
// Infinite loop
while (true)
{
lblMarquee.IsVisible = false;
await lblMarquee.TranslateTo(dblWidth / 2, 0, 500, Easing.SinIn);
lblMarquee.IsVisible = true;
await lblMarquee.TranslateTo(-(dblWidth / 2), 0, 10000, Easing.SinIn);
}
});
objStackLayout.Children.Add(btnAnimate);
Content = objStackLayout;
}
NOTE: You can remove the infinite loop and try the same with TPL that will be good way to handle never ending task instead of using infinite loop.

android emulator restarts itself (ADT)

When i invoke a function which is described below, android emulator restarts from beginning.
The function is like that
int index = 0;
Position myPostion;
Position destPosition = roadInstruction.getInstructionAt(index).getEndAddr();
while(index<roadInstruction.getNumInstruction())
{
myPostion = getMyPosition();
while(!hasArrivedToDestination(myPostion, destPosition ))
{
myPostion = getMyPosition();
}
++index;
}
What is the reason?
It maybe because of the inner while loop, but i am not sure.