[libcamera-devel] qcam: Fix logging of sequence number

3612 diff mbox series

The sequence number of captured frames is logged to the console with
padding to 6 characters to increase readability. The output is however
incorrect, as 123 is printed as 00012300000. This is caused by the
auto-space feature of QDebug, which inserts a space after every field.
This doesn't play well with stream format manipulation, as it ends up
padding the automatically inserted space the same way as the previous
argument.

This is a bug in Qt, work around it by formatting the sequence number
manually.

Fixes: 494da4467ddf ("qcam: Use Qt qInfo() and qWarning() logging facilities")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 src/qcam/main_window.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Hi Laurent,

Thanks for your work.

On 2020-04-29 22:31:56 +0300, Laurent Pinchart wrote:
> The sequence number of captured frames is logged to the console with
> padding to 6 characters to increase readability. The output is however
> incorrect, as 123 is printed as 00012300000. This is caused by the
> auto-space feature of QDebug, which inserts a space after every field.
> This doesn't play well with stream format manipulation, as it ends up
> padding the automatically inserted space the same way as the previous
> argument.
> 
> This is a bug in Qt, work around it by formatting the sequence number
> manually.
> 
> Fixes: 494da4467ddf ("qcam: Use Qt qInfo() and qWarning() logging facilities")
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

> ---
>  src/qcam/main_window.cpp | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
> index ed0cad417d62..d021fa9552de 100644
> --- a/src/qcam/main_window.cpp
> +++ b/src/qcam/main_window.cpp
> @@ -531,8 +531,8 @@ void MainWindow::processCapture()
>  	fps = lastBufferTime_ && fps ? 1000000000.0 / fps : 0.0;
>  	lastBufferTime_ = metadata.timestamp;
>  
> -	qInfo() << "seq:" << qSetFieldWidth(6) << qSetPadChar('0')
> -		<< metadata.sequence << reset
> +	qInfo().noquote()
> +		<< QString("seq: %1").arg(metadata.sequence, 6, 10, QLatin1Char('0'))
>  		<< "bytesused:" << metadata.planes[0].bytesused
>  		<< "timestamp:" << metadata.timestamp
>  		<< "fps:" << fixed << qSetRealNumberPrecision(2) << fps;
> -- 
> Regards,
> 
> Laurent Pinchart
> 
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel@lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel