Re: [PATCH v2 2/2] Added parameter to take screenshot with screendump as PNG.

[Markus Armbruster]

Kshitij Suri <kshitij.suri@nutanix.com> writes:

> Currently screendump only supports PPM format, which is un-compressed and not
> standard. Added a "format" parameter to qemu monitor screendump capabilites
> to support PNG image capture using libpng. The param was added in QAPI schema
> of screendump present in ui.json along with png_save() function which converts
> pixman_image to PNG. HMP command equivalent was also modified to support the
> feature.
>
> Example usage:
> { "execute": "screendump", "arguments": { "filename": "/tmp/image",
> "format":"png" } }
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/718
>
> Signed-off-by: Kshitij Suri <kshitij.suri@nutanix.com>
> ---

[...]

> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> index 8c384dc1b2..9a640146eb 100644
> --- a/monitor/hmp-cmds.c
> +++ b/monitor/hmp-cmds.c
> @@ -1677,9 +1677,26 @@ hmp_screendump(Monitor *mon, const QDict *qdict)
>      const char *filename = qdict_get_str(qdict, "filename");
>      const char *id = qdict_get_try_str(qdict, "device");
>      int64_t head = qdict_get_try_int(qdict, "head", 0);
> +    const char *input_format  = qdict_get_str(qdict, "format");
>      Error *err = NULL;
> +    ImageFormat format;
>  
> -    qmp_screendump(filename, id != NULL, id, id != NULL, head, &err);
> +    int val = qapi_enum_parse(&ImageFormat_lookup, input_format, -1, &err);
> +    if (val < 0) {
> +        goto end;
> +    }
> +
> +    switch (val) {
> +    case IMAGE_FORMAT_PNG:
> +        format = IMAGE_FORMAT_PNG;
> +        break;
> +    default:
> +        format = IMAGE_FORMAT_PPM;
> +    }
> +
> +    qmp_screendump(filename, id != NULL, id, id != NULL, head,
> +                   input_format != NULL, format, &err);
> +end:
>      hmp_handle_error(mon, err);
>  }
>  
> diff --git a/qapi/ui.json b/qapi/ui.json
> index 9354f4c467..6aa0dd7c1b 100644
> --- a/qapi/ui.json
> +++ b/qapi/ui.json
> @@ -73,12 +73,27 @@
>  ##
>  { 'command': 'expire_password', 'data': {'protocol': 'str', 'time': 'str'} }
>  
> +##
> +# @ImageFormat:
> +#
> +# Available list of supported types.

This is just a hair better than "Lorem ipsum" :)

Suggest: Supported image format types.

> +#
> +# @png: PNG format
> +#
> +# @ppm: PPM format
> +#
> +# Since: 7.0
> +#
> +##
> +{ 'enum': 'ImageFormat',
> +  'data': ['ppm', 'png'] }
> +
>  ##
>  # @screendump:
>  #
> -# Write a PPM of the VGA screen to a file.
> +# Write a screenshot of the VGA screen to a file.

Is "VGA screen" accurate?  Or does this work for other displays, too?

>  #
> -# @filename: the path of a new PPM file to store the image
> +# @filename: the path of a new file to store the image
>  #
>  # @device: ID of the display device that should be dumped. If this parameter
>  #          is missing, the primary display will be used. (Since 2.12)
> @@ -87,6 +102,9 @@
>  #        parameter is missing, head #0 will be used. Also note that the head
>  #        can only be specified in conjunction with the device ID. (Since 
> 2.12)
>  #
> +# @format: image format for screendump is specified. ppm is the set as the
> +#          default format. (Since 7.0)

I figure you mean "is set as the default".  Suggest to replace the
sentence by "(default: ppm)".

> +#
>  # Returns: Nothing on success
>  #
>  # Since: 0.14
> @@ -99,7 +117,8 @@
>  #
>  ##
>  { 'command': 'screendump',
> -  'data': {'filename': 'str', '*device': 'str', '*head': 'int'},
> +  'data': {'filename': 'str', '*device': 'str', '*head': 'int',
> +           '*format': 'ImageFormat'},
>    'coroutine': true }
>  
>  ##

[...]