Android Question Camera2: Auto_flash in Preview

[Karl Matzinger]

How can I enable flash in camera2: preview mode.
So that I can see before taking a picture in darkness.
tx
karl

 

[Erel]

I don't think that the flash is supposed to be turned on while in preview.

This code forces it to be on in preview mode (tested on a single device):

cam.AutoExposureMode = "OFF"
cam.PreviewSettingsMap.Put("FLASH_MODE", 2) 'TORCH
cam.StartPreview(MyTaskIndex, VideoMode)
cam.AutoExposureMode = "ON"
cam.PreviewSettingsMap.Put("FLASH_MODE", 2) 'TORCH
cam.StartPreview(MyTaskIndex, VideoMode)

 

[Karl Matzinger]

Hi Erel,
tx
in a first test it worked great

 

[Karl Matzinger]

Hi Erel,
Preview torch works great, but when taking a picture in darkness the ON_AUTO_FLASH isn't working - no flash and the taken picture is dark.
sorry for delay ...

I added 2 buttons

Sub btnLightOff_Click
   cam.AutoExposureMode = "OFF"
   cam.PreviewSettingsMap.Put("FLASH_MODE", 2) 'TORCH
   cam.StartPreview(MyTaskIndex, VideoMode)
End Sub

Sub btnLightOn_Click
   cam.AutoExposureMode = "ON"
   cam.PreviewSettingsMap.Put("FLASH_MODE", 2) 'TORCH
   cam.StartPreview(MyTaskIndex, VideoMode)
End Sub

Or did I wrong?

tx
karl

 

[Erel]

Please use [code]code here...[/code] tags when posting code.

Camera2 handling of the flash and auto exposure is surprisingly complicated. You need to play with combinations of auto exposure and flash modes. Start with the original example and see whether it works as you like it (without the preview flash).

 

[netsistemas]

for off light set '0' on FLASH_MODE

private Sub FlashEstado(LightOn As Boolean) As ResumableSub

    Try
       

        Estado = B4XFlash.Value
        cam.AutoExposureMode = IIf(LightOn, "ON","OFF")
        cam.PreviewSettingsMap.Put("FLASH_MODE", IIf(LightOn,2,0)) 'TORCH

           
        cam.StartPreview(MyTaskIndex, VideoMode)
        cam.AutoExposureMode =  IIf(LightOn, "ON","OFF")
        cam.PreviewSettingsMap.Put("FLASH_MODE", IIf(LightOn,2,0)) 'TORCH
   
   
   
        cam.StartPreview(MyTaskIndex, VideoMode)
       
        Return True
    Catch
        Log(LastException)
        Return False
    End Try

End Sub


End Sub