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il...@google.com
Can you please describe exactly what method call you're making on ExifInterface? I would expect this to work for exifInterface.setAttribute(TAG_EXPOSURE_TIME, "1/1600") but not exifInterface.setAttribute(TAG_EXPOSURE_TIME, "0.000625").
kr...@gmail.com
```
val sourceExif = ExifInterface(sourceFilePath)
val destinationExif = ExifInterface(destinationFilePath)
exifTagsList
.associateWith { sourceExif.getAttribute(it) }
.forEach { (tag, value) ->
destinationExif.setAttribute(tag, value)
}
destinationExif.saveAttributes()
```
Where exifTagsList contains the tags I need, e.g. ExifInterface.TAG_EXPOSURE_TIME.
I'm not sure if it's okay to simply read all attributes as String and write them as String, but it worked fine for all tags, except this one.
The attribute value I get for `getAttribute(TAG_EXPOSURE_TIME)` is a String `6.25E-4`. This should be parsed correctly as double value of `0,000625`, which is equal to the actual photo exposure time of `1/1600`.
The problem here is IMO the lack of precision - for higher exposure times like 1/100, 1/50, etc. it works fine. It doesn't for smaller values like 1/1600 or 1/3200.
When you run this code, you will get 1/1666 instead of 1/1600, which I suppose is lack of precision, as 1/1666 = 0,0006:
`exifInterface.setAttribute(TAG_EXPOSURE_TIME, "6.25E-4")`
I tried `exifInterface.setAttribute(TAG_EXPOSURE_TIME, "1/1600")` but it didn't work for me. Probably the interface expects a value that it can parse as double. According to ExifInterface documentation:
> TAG_EXPOSURE_TIME
> Type is double.
il...@google.com
Thanks, I think part of the cause of the problem you're seeing is that exifInterface.getAttribute(TAG_EXPOSURE_TIME) is returning "6.25E-4" while setAttribute(TAG_EXPOSURE_TIME, value) is ideally expecting "1/1600".
Turns out there is code to handle the case of passing a decimal string to setAttribute, by converting it to a Rational representation of { int numerator, int denominator }, but it (arbitrarily)
Rational(double value) {
this(/* numerator= */ (long) (value * 10000), /* denominator */ 10000);
}
It looks like this code has been present for a long time, seems it was present in ExifInterface added in 2016
So I think there's an obvious improvement we can make here:
-
Fix the
double->Rationalconversion to support more precision. Ideally we would first try a denominator of1 / value(since this would give an exact result in the case of this bug, and probably most other cases since shutter speeds that are less than 1 are usually1/something), something like:Rational createRationalFromDouble(double value) { double inverse = 1 / value; if (isMathematicalInteger(value)) { return new Rational(1, (long) inverse); } // Not sure what we can do here }For the
elsecase, maybe we could do something clever with continued fractions:https://en.wikipedia.org/wiki/Continued_fraction
It feels like we should also align the format that getAttribute returns with the format setAttribute expects, in order to explicitly support the copying use-case you've described. That would mean changing getAttribute to return "1/1600" in this case. Unfortunately that is a breaking change for any existing code that is doing Double.parseDouble(exifInterface.getAttribute(TAG_EXPOSURE_TIME)), so not feasible. If we were to introduce this it would need to be a separate method.
il...@google.com
il...@google.com
Please also take into account values larger than 1. I think the exposure time might be for example 1,5 second or 15 seconds.
Description
Version used: 1.0.0-alpha06
Devices/Android versions reproduced on: Android 8.1.0, Samsung Galaxy J5 (I don't think it's device related)
Navigation library doesn't handle deep links properly when there are 2 deep links registered and the second one is an "extension" of the previous one. Let me give a simplified example to make it more clear:
<fragment android:name="com.example.EventFragment">
<argument
android:name="eventId"
app:argType="string" />
<action
android:id="@+id/exhibitorDetails"
app:destination="@id/exhibitorDetails" />
<deepLink app:uri="example://events/{eventId}" />
</fragment>
<activity android:id="@+id/exhibitorDetails"
android:name="com.example.ExhibitorsActivity">
<!-- I know, not a single Activity app. But that's the case. -->
<argument
android:name="exhibitorId"
app:argType="string" />
<deepLink app:uri="example://events/{eventId}/exhibitors/{exhibitorId}" />
</activity>
When I use a link: example://events/event123/exhibitors/exhibitor123 I expect navigation library to navigate to an ExhibitorsActivity. Instead, it navigates to EventFragment. Furthermore, an eventId passed to a fragment is invalid, in this case, it's: "event123/exhibitors/exhibitor123".
I believe it's a bug of regex: in my example, passed link matches both regexes: example://events/{eventId} and example://events/{eventId}/exhibitors/{exhibitorId}.