Kshitij Suri <kshitij.s...@nutanix.com> writes:
> From: "kshitij.suri" <kshitij.s...@nutanix.com>
>
> 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.s...@nutanix.com>
> ---
> diff to v1:
> - Removed repeated alpha conversion operation.
> - Modified logic to mirror png conversion in vnc-enc-tight.c file.
> - Added a new CONFIG_PNG parameter for libpng support.
> - Changed input format to enum instead of string.
> - Improved error handling.
> hmp-commands.hx | 11 ++---
> monitor/hmp-cmds.c | 19 ++++++++-
> qapi/ui.json | 24 +++++++++--
> ui/console.c | 102 +++++++++++++++++++++++++++++++++++++++++++--
> 4 files changed, 144 insertions(+), 12 deletions(-)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 70a9136ac2..5eda4eeb24 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -244,17 +244,18 @@ ERST
>
> {
> .name = "screendump",
> - .args_type = "filename:F,device:s?,head:i?",
> - .params = "filename [device [head]]",
> - .help = "save screen from head 'head' of display device
> 'device' "
> - "into PPM image 'filename'",
> + .args_type = "filename:F,device:s?,head:i?,format:f?",
> + .params = "filename [device [head]] [format]",
> + .help = "save screen from head 'head' of display device
> 'device'"
> + "in specified format 'format' as image 'filename'."
> + "Currently only 'png' and 'ppm' formats are
> supported.",
> .cmd = hmp_screendump,
> .coroutine = true,
> },
>
> SRST
> ``screendump`` *filename*
> - Save screen into PPM image *filename*.
> + Save screen as an image *filename*, with default format of PPM.
> ERST
>
> {
> 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);
The second id != NULL looks wrong. Shouldn't it be head != NULL?
Not your patch's fault, of course.
> + 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);
> }
This isn't quite right.
qapi_enum_parse() is awkward to use.
If its second argument @input_format is null, it returns its third
argument -1.
Else, it @input_format is a valid enum string, it returns the
enumeration value, i.e. either IMAGE_FORMAT_PPM or IMAGE_FORMAT_PNG.
Else, it sets an error and returns its third argument -1.
If @input_format is null, I suspect your code jumps to
hmp_handle_error() with a null @err. Silently does nothing.
It should default to IMAGE_FORMAT_PPM instead.
I think you want something like this (completely untested):
val = qapi_enum_parse(&ImageFormat_lookup, input_format,
IMAGE_FORMAT_PPM, &err);
if (err) {
goto end;
}
qmp_screendump(filename, id != NULL, id, head != NULL, head,
input_format != NULL, val, &err);
>
> diff --git a/qapi/ui.json b/qapi/ui.json
> index 9354f4c467..a6d994ba2c 100644
> --- a/qapi/ui.json
> +++ b/qapi/ui.json
> @@ -73,12 +73,27 @@
> ##
> { 'command': 'expire_password', 'data': {'protocol': 'str', 'time': 'str'} }
>
> +##
> +# @ImageFormat:
> +#
> +# 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.
Let's improve this to
# Capture the contents of a screen and write it to a file.
> #
> -# @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 +102,8 @@
> # 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. (default: ppm) (Since
> 7.0)
> +#
> # Returns: Nothing on success
> #
> # Since: 0.14
> @@ -99,7 +116,8 @@
> #
> ##
> { 'command': 'screendump',
> - 'data': {'filename': 'str', '*device': 'str', '*head': 'int'},
> + 'data': {'filename': 'str', '*device': 'str', '*head': 'int',
> + '*format': 'ImageFormat'},
> 'coroutine': true }
>
> ##
[...]
> @@ -327,7 +413,8 @@ static void graphic_hw_update_bh(void *con)
> /* Safety: coroutine-only, concurrent-coroutine safe, main thread only */
> void coroutine_fn
> qmp_screendump(const char *filename, bool has_device, const char *device,
> - bool has_head, int64_t head, Error **errp)
> + bool has_head, int64_t head, bool has_format,
> + ImageFormat format, Error **errp)
Please break the line like
bool has_head, int64_t head,
bool has_format, ImageFormat format, Error **errp)
> {
> g_autoptr(pixman_image_t) image = NULL;
> QemuConsole *con;
> @@ -383,8 +470,17 @@ qmp_screendump(const char *filename, bool has_device,
> const char *device,
> * yields and releases the BQL. It could produce corrupted dump, but
> * it should be otherwise safe.
> */
> - if (!ppm_save(fd, image, errp)) {
> - qemu_unlink(filename);
> +
> + if (has_format && format == IMAGE_FORMAT_PNG) {
> + /* PNG format specified for screendump */
> + if (!png_save(fd, image, errp)) {
> + qemu_unlink(filename);
> + }
> + } else {
> + /* PPM format specified/default for screendump */
> + if (!ppm_save(fd, image, errp)) {
> + qemu_unlink(filename);
> + }
> }
> }
