How to set the camera flash on

alfah

Hi everybody,

Im working on the Qt Camera api. I've managed to open the viewfinder but cant set the flash on. Kindly help me on this one

Thank you

Alfah

kkrzewniak

Have a look at the QCameraExposure object thats assosiated with your QCamera instance. If you have some more questions feel free to ask.
Hint: QCameraExposure::FlashModes
Welcome to Devnet btw.

alfah

Thank you kkrzewniak,

The thing is, i couldn get how to use QcameraExposure::Flashmode.
I found "QCameraExposure::FlashOn 0x4 Flash is On." in the docs but how do you use it? Could you gimme an example?.
It is not a function right. Hope you don mind answering the basics. :)

regards,
alfah

mismail

Hi,
please look at this link

"http://www.developer.nokia.com/Community/Discussion/showthread.php?226102-How-can-I-use-camera-flash-as-a-tourch&p=851607#post851607":http://www.developer.nokia.com/Community/Discussion/showthread.php?226102-How-can-I-use-camera-flash-as-a-tourch&p=851607#post851607

alfah

:)

i did . . i does not give any solutions. . Theres gotta be some way to turn on the flash right??

regards,

lgeyer

[quote author="alfah" date="1310534091"]The thing is, i couldn get how to use QcameraExposure::Flashmode. I found "QCameraExposure::FlashOn 0x4 Flash is On." in the docs but how do you use it?[/quote]

For every enum in Qt there is usually a getter called enumName() and a setter setEnumName(). For the "QCameraExposure::FlashMode":http://doc.qt.nokia.com/qtmobility-1.1-tp/qcameraexposure.html#FlashMode-enum enum this will be "QCameraExposure::flashMode()":http://doc.qt.nokia.com/qtmobility-1.1-tp/qcameraexposure.html#flashMode and "QCameraExposure::setFlashMode()":http://doc.qt.nokia.com/qtmobility-1.1-tp/qcameraexposure.html#setFlashMode.

You will find a list of the possible flash modes in the same document:

bq. QCameraExposure::FlashOff
QCameraExposure::FlashOn
QCameraExposure::FlashAuto
QCameraExposure::FlashRedEyeReduction
QCameraExposure::FlashFill
QCameraExposure::FlashTorch
QCameraExposure::FlashSlowSyncFrontCurtain
QCameraExposure::FlashSlowSyncRearCurtain
QCameraExposure::FlashManual

To get the current flash mode use
@
QCamera* camera = new QCamera;
QCameraExposure* cameraExposure = camera.exposure();

FlashModes flashMode = cameraExposure->flashMode();
@
To set a flash mode (for example always on) use
@
QCamera* camera = new QCamera;
QCameraExposure* cameraExposure = camera.exposure();

cameraExposure->setFlashMode(QCameraExposure::FlashTorch);
@
Hint: see also "QCameraExposure::isAvailable()":http://doc.qt.nokia.com/qtmobility-1.1-tp/qcameraexposure.html#isAvailable.

alfah

Thanks Lukas.

That was indeed informative and the precisely what i needed .
But now there is a small problem. When i run the prog, i get this error
"QCameraExposure::QcameraExposure(Qcamera*) " is private!!!.. :(
Wat does it mean?, tht i've created an instance of QCameraExposure it as private??? of i should declare it as private??

Thank you.

lgeyer

There is no public constructor for the QCameraExposure object, which means that you cannot directly create an object of the QCameraExposure class (which itself is a design decision taken by the creator of the QCameraExposure class).

You will have to use "QCamera::exposure()":http://doc.qt.nokia.com/qtmobility-1.1-tp/qcamera.html#exposure instead to retrieve a QCameraExposure object.

The example might be a bit misleading - I corrected it so it should reflect real world code.

kkrzewniak

@QCameraExposure * QCamera::exposure () const@
Returns the camera exposure control object.
Sorry I'm a bit late :)

alfah

:) thanks lukas

bein a newbie am i dealin with tough stuff????? :(

cuz now i get jus one error and it says "

"request for member setFlashMode in cameraexpo, which is of non class type 'QCameraExposure' "

this is the code ive used in the function

{ QCamera *camera = new QCamera;
QCameraExposure *cameraexpo = camera->exposure();
cameraexpo.setFlashMode(QCameraExposure::FlashOn);

}

regards,

alfah

hey kkrzewniak

thank you, but i could not make head or tail of that oneliner code. :)

It returns a camera exposure ctrl obj? meanin?

regards,

P.S one basic question, is it necessary to switch on the camera to set flash on??

regards,

lgeyer

Have you included the QCameraExposure header?
@
#include <QCameraExposure>
@

loladiro

It's
@
cameraexpo->setFlashMode(QCameraExposure::FlashOn);
@
not
@
cameraexpo.setFlashMode(QCameraExposure::FlashOn);
@

alfah

@loladiro,
thanks! -> did the trick!! i finally got the prog running on c7 with out errors.

@lukas, loladiro, kkrzewniak

:( but then, when FlashOn was used i got the following msg
[Qt Message] camera error: "failed to set flash mode" :( :(

When i tried to use FlashTorch, i got
[Qt Message] Camera error: "Requested flash mode is not supported." :( :(

so wat next???

but there are apps which run in c7 which uses flash as torch!!!!!

thanks a lot for the help;

slava.chernikoff

Did anyone found a solution how to use camera LED as torch in Qt applications?

All suggested solutions like using setFlashMode(bla-bla-bla) doesn't work. But there are a lot of torches for Symbian and Meego... There are should be low-level platform for that trick I guess. But how to find it?

singaporeseo

take shot in bright place so that you don't need flash

slava.chernikoff

It's not about taking pictures. It about - how to use phone as torch.

jim_kaiser

To set the camera flash mode, you need to wait until the camera is initialized. So, connect a slot to the QCamera::statusChanged(QCamera::Status) and in your slot, set the flash mode when the camera is in QCamera::ActiveStatus. I don't know if the torch thingy would work but flash should.
The other app with the torch thingy could probably be using native Symbian code to do it.