[PATCH] qv4l2: avoid empty titles for the video control tabs

[PATCH] qv4l2: avoid empty titles for the video control tabs

[Frank Schäfer]

The video control class names are used as titles for the GUI-tabs.
The current code relies on the driver enumerating the control classes
properly when using V4L2_CTRL_FLAG_NEXT_CTRL.
But the UVC-driver (and likely others, too) don't do that, so we can end
up with an empty class name string.

Make sure we always have a control class title:
If the driver didn't enumrate a class along with the controls, call
VIDIOC_QUERYCTRL for the class explicitly.
If that fails, fall back to an internal string list.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
---
 utils/qv4l2/ctrl-tab.cpp |   15 ++++++++++++++-
 utils/qv4l2/v4l2-api.cpp |   25 +++++++++++++++++++++++++
 utils/qv4l2/v4l2-api.h   |    3 +++
 3 files changed, 42 insertions(+), 1 deletions(-)

diff --git a/utils/qv4l2/ctrl-tab.cpp b/utils/qv4l2/ctrl-tab.cpp
index 5bafbbd..6a4b630 100644
--- a/utils/qv4l2/ctrl-tab.cpp
+++ b/utils/qv4l2/ctrl-tab.cpp
@@ -133,7 +133,20 @@ void ApplicationWindow::addTabs()
 		m_col = m_row = 0;
 		m_cols = 4;
 
-		const v4l2_queryctrl &qctrl = m_ctrlMap[id];
+		v4l2_queryctrl &qctrl = m_ctrlMap[id];
+		/* No real control, it's just the control class description.
+		   Verify that the driver did enumerate the class properly 
+		   and add the class name if missing */
+		if (!strlen((char *)qctrl.name))
+		{
+			/* Try to request control class name from API */
+			qctrl.id = id;
+			qctrl.type = V4L2_CTRL_TYPE_CTRL_CLASS;
+			if (!queryctrl(qctrl) || !strlen((char *)qctrl.name))
+				/* Fall back to a local string list */
+				strcpy((char *)qctrl.name, ctrl_class_name(ctrl_class).toAscii());
+		}
+
 		QWidget *t = new QWidget(m_tabs);
 		QVBoxLayout *vbox = new QVBoxLayout(t);
 		QWidget *w = new QWidget(t);
diff --git a/utils/qv4l2/v4l2-api.cpp b/utils/qv4l2/v4l2-api.cpp
index 86cf388..5811cd7 100644
--- a/utils/qv4l2/v4l2-api.cpp
+++ b/utils/qv4l2/v4l2-api.cpp
@@ -638,3 +638,28 @@ bool v4l2::get_interval(v4l2_fract &interval)
 
 	return false;
 }
+
+QString v4l2::ctrl_class_name(__u32 ctrl_class)
+{
+	switch (ctrl_class) {
+	case V4L2_CTRL_CLASS_USER:
+		return "User Controls";
+	case V4L2_CTRL_CLASS_MPEG:
+		return "MPEG-compression Controls";
+	case V4L2_CTRL_CLASS_CAMERA:
+		return "Camera Controls";
+	case V4L2_CTRL_CLASS_FM_TX:
+		return "FM Transmitter Controls";
+	case V4L2_CTRL_CLASS_FLASH:
+		return "Flash Device Controls";
+	case V4L2_CTRL_CLASS_JPEG:
+		return "JPEG-compression Controls";
+	case V4L2_CTRL_CLASS_IMAGE_SOURCE:
+		return "Image Source Controls";
+	case V4L2_CTRL_CLASS_IMAGE_PROC:
+		return "Image Processing Controls";
+	case V4L2_CTRL_CLASS_DV:
+		return "Digital Video Controls";
+	}
+	return "Controls (unknown class)";
+}
diff --git a/utils/qv4l2/v4l2-api.h b/utils/qv4l2/v4l2-api.h
index 4c10466..74e69a8 100644
--- a/utils/qv4l2/v4l2-api.h
+++ b/utils/qv4l2/v4l2-api.h
@@ -163,6 +163,9 @@ public:
 
 	bool set_interval(v4l2_fract interval);
 	bool get_interval(v4l2_fract &interval);
+
+	QString ctrl_class_name(__u32 ctrl_class);
+
 private:
 	void clear() { error(QString()); }
 
-- 
1.7.7

Re: [PATCH] qv4l2: avoid empty titles for the video control tabs

[Hans Verkuil]

On Tue October 9 2012 16:46:04 Frank Schäfer wrote:
> The video control class names are used as titles for the GUI-tabs.
> The current code relies on the driver enumerating the control classes
> properly when using V4L2_CTRL_FLAG_NEXT_CTRL.
> But the UVC-driver (and likely others, too) don't do that, so we can end
> up with an empty class name string.
> 
> Make sure we always have a control class title:
> If the driver didn't enumrate a class along with the controls, call
> VIDIOC_QUERYCTRL for the class explicitly.
> If that fails, fall back to an internal string list.

NACK.

qv4l2 is for testing drivers, so I *want* to see if a driver doesn't provide
the control class name. They really should provide it, and it is not something
that should be papered over.

Regards,

	Hans

> 
> Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
> ---
>  utils/qv4l2/ctrl-tab.cpp |   15 ++++++++++++++-
>  utils/qv4l2/v4l2-api.cpp |   25 +++++++++++++++++++++++++
>  utils/qv4l2/v4l2-api.h   |    3 +++
>  3 files changed, 42 insertions(+), 1 deletions(-)
> 
> diff --git a/utils/qv4l2/ctrl-tab.cpp b/utils/qv4l2/ctrl-tab.cpp
> index 5bafbbd..6a4b630 100644
> --- a/utils/qv4l2/ctrl-tab.cpp
> +++ b/utils/qv4l2/ctrl-tab.cpp
> @@ -133,7 +133,20 @@ void ApplicationWindow::addTabs()
>  		m_col = m_row = 0;
>  		m_cols = 4;
>  
> -		const v4l2_queryctrl &qctrl = m_ctrlMap[id];
> +		v4l2_queryctrl &qctrl = m_ctrlMap[id];
> +		/* No real control, it's just the control class description.
> +		   Verify that the driver did enumerate the class properly 
> +		   and add the class name if missing */
> +		if (!strlen((char *)qctrl.name))
> +		{
> +			/* Try to request control class name from API */
> +			qctrl.id = id;
> +			qctrl.type = V4L2_CTRL_TYPE_CTRL_CLASS;
> +			if (!queryctrl(qctrl) || !strlen((char *)qctrl.name))
> +				/* Fall back to a local string list */
> +				strcpy((char *)qctrl.name, ctrl_class_name(ctrl_class).toAscii());
> +		}
> +
>  		QWidget *t = new QWidget(m_tabs);
>  		QVBoxLayout *vbox = new QVBoxLayout(t);
>  		QWidget *w = new QWidget(t);
> diff --git a/utils/qv4l2/v4l2-api.cpp b/utils/qv4l2/v4l2-api.cpp
> index 86cf388..5811cd7 100644
> --- a/utils/qv4l2/v4l2-api.cpp
> +++ b/utils/qv4l2/v4l2-api.cpp
> @@ -638,3 +638,28 @@ bool v4l2::get_interval(v4l2_fract &interval)
>  
>  	return false;
>  }
> +
> +QString v4l2::ctrl_class_name(__u32 ctrl_class)
> +{
> +	switch (ctrl_class) {
> +	case V4L2_CTRL_CLASS_USER:
> +		return "User Controls";
> +	case V4L2_CTRL_CLASS_MPEG:
> +		return "MPEG-compression Controls";
> +	case V4L2_CTRL_CLASS_CAMERA:
> +		return "Camera Controls";
> +	case V4L2_CTRL_CLASS_FM_TX:
> +		return "FM Transmitter Controls";
> +	case V4L2_CTRL_CLASS_FLASH:
> +		return "Flash Device Controls";
> +	case V4L2_CTRL_CLASS_JPEG:
> +		return "JPEG-compression Controls";
> +	case V4L2_CTRL_CLASS_IMAGE_SOURCE:
> +		return "Image Source Controls";
> +	case V4L2_CTRL_CLASS_IMAGE_PROC:
> +		return "Image Processing Controls";
> +	case V4L2_CTRL_CLASS_DV:
> +		return "Digital Video Controls";
> +	}
> +	return "Controls (unknown class)";
> +}
> diff --git a/utils/qv4l2/v4l2-api.h b/utils/qv4l2/v4l2-api.h
> index 4c10466..74e69a8 100644
> --- a/utils/qv4l2/v4l2-api.h
> +++ b/utils/qv4l2/v4l2-api.h
> @@ -163,6 +163,9 @@ public:
>  
>  	bool set_interval(v4l2_fract interval);
>  	bool get_interval(v4l2_fract &interval);
> +
> +	QString ctrl_class_name(__u32 ctrl_class);
> +
>  private:
>  	void clear() { error(QString()); }
>  
> 

Re: [PATCH] qv4l2: avoid empty titles for the video control tabs

[Frank Schäfer]

Am 09.10.2012 17:24, schrieb Hans Verkuil:
> On Tue October 9 2012 16:46:04 Frank Schäfer wrote:
>> The video control class names are used as titles for the GUI-tabs.
>> The current code relies on the driver enumerating the control classes
>> properly when using V4L2_CTRL_FLAG_NEXT_CTRL.
>> But the UVC-driver (and likely others, too) don't do that, so we can end
>> up with an empty class name string.
>>
>> Make sure we always have a control class title:
>> If the driver didn't enumrate a class along with the controls, call
>> VIDIOC_QUERYCTRL for the class explicitly.
>> If that fails, fall back to an internal string list.
> NACK.
>
> qv4l2 is for testing drivers, so I *want* to see if a driver doesn't provide
> the control class name. They really should provide it, and it is not something
> that should be papered over.

Hehe, ok.
Then you might want to remove all the "papering-over" code a few lines
above, too ? ;)

Regards,
Frank

> Regards,
>
> 	Hans