QML Camera Flash not working properly (Android, iOS)

[ekkescorner]

trying to use QML Camera in Android / iOS App
run into a problem with the Flash

Flash Modes Auto, On, Off, FlashVideoLight are supported by my devices
Setting FlashAuto or FlashOn I can see that the Flash indeed was used from Android or iOS Camera
but captured Image is dark. seems not to be in sync with Flash and captured too early

anyone else run into this ?
as a workaround I can use FlashVideoLight and set it immediately before Image capture:

// on clicked Capture Button:
camera.flash.mode = Camera.FlashVideoLight
flashTimer.start()
....
Timer {
    id: flashTimer
    repeat: false
    interval: 200
    onTriggered: {
        camera.searchAndLock()
        camera.imageCapture.captureToLocation(dataUtil.capturedPhotoLocation())
    }
}
....
Camera {
    imageCapture {
        onImageCaptured: {
            camera.unlock()
            camera.flash.mode = Camera.FlashAuto
            photoPreview.source = preview  // Show the preview in an Image
        }
        onImageSaved: {
            console.log("SAVED PATH: "+camera.imageCapture.capturedImagePath)
        }
    }
}

works but is an ugly workaround
any ideas or should I open a Bug report ?

[ekkescorner]

@SGaist Qt 5.10.1, tried with iOS 11, Android 6, Android 7 on different devices
now found a Bug explaining why this happens: https://bugreports.qt.io/browse/QTBUG-37990

so the solution to fix this is:

// Capture Button:
        camera.searchAndLock()
        camera.imageCapture.captureToLocation(dataUtil.capturedPhotoLocation())
//
Camera {
        id: camera
        captureMode: Camera.CaptureStillImage
        flash.mode: Camera.FlashAuto
        imageCapture {
            onImageCaptured: {
                camera.unlock()
                // Show the preview in an Image
                photoPreview.source = preview
            }
            onImageSaved: {
                console.log("SAVED PATH: "+camera.imageCapture.capturedImagePath)
                // Hint: you should set the Image with the saved Image,
                // because if using a Flash the first preview will be too dark
                // see https://bugreports.qt.io/browse/QTBUG-37990
                photoPreview.source = "file://"+ camera.imageCapture.capturedImagePath
            }
        }
    } // camera

[SGaist]

Hi,

Looks like a bug.

What version of Qt are you using ?
Could you try that on different Android/iOS versions ?

[ekkescorner]

@SGaist Qt 5.10.1, tried with iOS 11, Android 6, Android 7 on different devices
now found a Bug explaining why this happens: https://bugreports.qt.io/browse/QTBUG-37990

so the solution to fix this is:

// Capture Button:
        camera.searchAndLock()
        camera.imageCapture.captureToLocation(dataUtil.capturedPhotoLocation())
//
Camera {
        id: camera
        captureMode: Camera.CaptureStillImage
        flash.mode: Camera.FlashAuto
        imageCapture {
            onImageCaptured: {
                camera.unlock()
                // Show the preview in an Image
                photoPreview.source = preview
            }
            onImageSaved: {
                console.log("SAVED PATH: "+camera.imageCapture.capturedImagePath)
                // Hint: you should set the Image with the saved Image,
                // because if using a Flash the first preview will be too dark
                // see https://bugreports.qt.io/browse/QTBUG-37990
                photoPreview.source = "file://"+ camera.imageCapture.capturedImagePath
            }
        }
    } // camera

[Nianoniaa]

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