Re: [PATCH v2 2/3] v4l2-ctl: Support V4L2_CTRL_TYPE_RECT

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

On Tue, Nov 05, 2024 at 09:30:43AM +0100, Hans Verkuil wrote:
> On 04/11/2024 02:24, Ming Qian(OSS) wrote:
> > On 2024/10/31 18:09, Laurent Pinchart wrote:
> >> On Thu, Oct 31, 2024 at 05:46:49PM +0800, Ming Qian(OSS) wrote:
> >>> On 2024/10/31 17:34, Laurent Pinchart wrote:
> >>>> On Thu, Oct 31, 2024 at 05:19:02PM +0800, Ming Qian(OSS) wrote:
> >>>>> On 2024/10/30 17:19, Hans Verkuil wrote:
> >>>>>> On 30/10/2024 10:03, Laurent Pinchart wrote:
> >>>>>>> On Wed, Oct 30, 2024 at 11:43:06AM +0900, ming.qian@oss.nxp.com wrote:
> >>>>>>>> From: Yunke Cao <yunkec@google.com>
> >>>>>>>>
> >>>>>>>> Tested with VIVID
> >>>>>>>>
> >>>>>>>>     ./v4l2-ctl -C rect -d 0
> >>>>>>>> rect: 300x400@200x100
> >>>>>>>>
> >>>>>>>>     ./v4l2-ctl -c rect=1000x2000@0x0
> >>>>>>>>     ./v4l2-ctl -C rect -d 0
> >>>>>>>> rect: 1000x2000@0x0
> >>>>>>>>
> >>>>>>>> Signed-off-by: Yunke Cao <yunkec@google.com>
> >>>>>>>> Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
> >>>>>>>> ---
> >>>>>>>>     utils/v4l2-ctl/v4l2-ctl-common.cpp | 12 ++++++++++++
> >>>>>>>>     1 file changed, 12 insertions(+)
> >>>>>>>>
> >>>>>>>> diff --git a/utils/v4l2-ctl/v4l2-ctl-common.cpp b/utils/v4l2-ctl/v4l2-ctl-common.cpp
> >>>>>>>> index 40667575fcc7..538e1951cf81 100644
> >>>>>>>> --- a/utils/v4l2-ctl/v4l2-ctl-common.cpp
> >>>>>>>> +++ b/utils/v4l2-ctl/v4l2-ctl-common.cpp
> >>>>>>>> @@ -614,6 +614,10 @@ static void print_value(int fd, const v4l2_query_ext_ctrl &qc, const v4l2_ext_co
> >>>>>>>>     		case V4L2_CTRL_TYPE_AREA:
> >>>>>>>>     			printf("%dx%d", ctrl.p_area->width, ctrl.p_area->height);
> >>>>>>>>     			break;
> >>>>>>>> +		case V4L2_CTRL_TYPE_RECT:
> >>>>>>>> +			printf("%ux%u@%dx%d", ctrl.p_rect->width, ctrl.p_rect->height,
> >>>>>>>
> >>>>>>> I find this notation ambiguous, it's not immediately clear when reading
> >>>>>>> 10x10@20x20 if we're looking at a 10x10 rectangle positioned at (20,20)
> >>>>>>> or the other way around. media-ctl use (20,20)/10x10 which I think would
> >>>>>>> be a better notation.
> >>>>>>
> >>>>>> Good point, I agree.
> >>>>>>
> >>>>>> Ming Qian, can you also update patch 1/4 of the kernel patch series to
> >>>>>> use the same formatting when logging the V4L2_CTRL_TYPE_RECT value?
> >>>>>>
> >>>>>> Regards,
> >>>>>>
> >>>>>> 	Hans
> >>>>>
> >>>>> There is a issue in v4l2-utils, that ',' is the ending flag in
> >>>>> v4l_getsubopt(), then I can't set the rect control,
> >>>>> for example:
> >>>>>
> >>>>> $v4l2-ctl -d 0 -c rect="(0,0)/1000x2000"
> >>>>> control '0)/1000x2000' without '='
> >>>>
> >>>> The should be fixable in v4l_getsubopt().
> >>>>
> >>>
> >>> I can see the following comments of v4l_getsubopt(),
> >>>
> >>>      Parse comma separated suboption from *OPTIONP and match against
> >>>      strings in TOKENS.
> >>>
> >>> I am not sure if we can change it.
> >>
> >> I think we can improve quotes handling by considering quoted substrings
> >> as a single value, ignoring commas. Hans any opinion ?
> 
> I think commas are hard to parse. Note that v4l_getsubopt is normally a
> #define for getsubopt from glibc. So you can't change the behavior of
> that function.

Can't we ? Isn't it an internal function ?

> I propose this format for parsing instead:
> 
> widthxheight@(top;left)
> 
> e.g.: 1000x2000@(0;0)
> 
> According to this:
> https://www.dr-aart.nl/Geometry-coordinates.html
> 
> the ';' is the separator in countries where a decimal comma is used
> instead of a decimal point.
> 
> I prefer to have the position after the size of the rectangle, for two
> reasons: it feels more natural to talk about a 'rectangle of size S at position
> P', and it also makes it possible to allow a variant where only the size
> is given and the position will default to (0;0). I.e., we can support
> parsing either "widthxheight" or "widthxheight@(top;left)".
> 
> However, logging rectangles in the kernel should use a comma instead of a
> semicolon. Inside v4l-utils just consistently use the semicolon.
> 
> What do you think, Laurent?

We have a precedent of using (x,y)/WxH , both in the kernel and in
media-ctl. Breaking that with another syntax would cause trouble,
especially having different syntaxes between media-ctl and v4l2-ctl.
Think about the shell scripts that would need to convert from one syntax
to another for instance. I would very strongly like to avoid that.

> > How about omitting the commas between the brackets when parsing subopt?
> > 
> > 
> >>>>>>>> +			       ctrl.p_rect->left, ctrl.p_rect->top);
> >>>>>>>> +			break;
> >>>>>>>>     		default:
> >>>>>>>>     			printf("unsupported payload type");
> >>>>>>>>     			break;
> >>>>>>>> @@ -702,6 +706,9 @@ static void print_qctrl(int fd, const v4l2_query_ext_ctrl &qc,
> >>>>>>>>     	case V4L2_CTRL_TYPE_AREA:
> >>>>>>>>     		printf("%31s %#8.8x (area)   :", s.c_str(), qc.id);
> >>>>>>>>     		break;
> >>>>>>>> +	case V4L2_CTRL_TYPE_RECT:
> >>>>>>>> +		printf("%31s %#8.8x (rect)   :", s.c_str(), qc.id);
> >>>>>>>> +		break;
> >>>>>>>>     	case V4L2_CTRL_TYPE_HDR10_CLL_INFO:
> >>>>>>>>     		printf("%31s %#8.8x (hdr10-cll-info):", s.c_str(), qc.id);
> >>>>>>>>     		break;
> >>>>>>>> @@ -1279,6 +1286,11 @@ void common_set(cv4l_fd &_fd)
> >>>>>>>>     					sscanf(set_ctrl.second.c_str(), "%ux%u",
> >>>>>>>>     					       &ctrl.p_area->width, &ctrl.p_area->height);
> >>>>>>>>     					break;
> >>>>>>>> +				case V4L2_CTRL_TYPE_RECT:
> >>>>>>>> +					sscanf(set_ctrl.second.c_str(), "%ux%u@%dx%d",
> >>>>>>>> +					       &ctrl.p_rect->width, &ctrl.p_rect->height,
> >>>>>>>> +					       &ctrl.p_rect->left, &ctrl.p_rect->top);
> >>>>>>>> +					break;
> >>>>>>>>     				default:
> >>>>>>>>     					fprintf(stderr, "%s: unsupported payload type\n",
> >>>>>>>>     							qc.name);

-- 
Regards,

Laurent Pinchart