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 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 | 12 +++++-
qapi/ui.json | 24 +++++++++--
ui/console.c | 101 +++++++++++++++++++++++++++++++++++++++++++--
4 files changed, 136 insertions(+), 12 deletions(-)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 8476277aa9..19b7cab595 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -244,11 +244,12 @@ 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'",
- .cmd = hmp_screendump,
+ .args_type = "filename:F,format:s?,device:s?,head:i?",
+ .params = "filename [format] [device [head]]",
+ .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,
},
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 634968498b..2442bfa989 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -1720,9 +1720,19 @@ 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_try_str(qdict, "format");
Error *err = NULL;
+ ImageFormat format;
- qmp_screendump(filename, id != NULL, id, id != NULL, head, &err);
+ format = qapi_enum_parse(&ImageFormat_lookup, input_format,
+ IMAGE_FORMAT_PPM, &err);
+ if (err) {
+ goto end;
+ }
+
+ 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 664da9e462..e8060d6b3c 100644
--- a/qapi/ui.json
+++ b/qapi/ui.json
@@ -157,12 +157,27 @@
##
{ 'command': 'expire_password', 'boxed': true, 'data':
'ExpirePasswordOptions' }
+##
+# @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.
+# 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)
@@ -171,6 +186,8 @@
# 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
@@ -183,7 +200,8 @@
#
##
{ 'command': 'screendump',
- 'data': {'filename': 'str', '*device': 'str', '*head': 'int'},
+ 'data': {'filename': 'str', '*device': 'str', '*head': 'int',
+ '*format': 'ImageFormat'},
'coroutine': true }
##
diff --git a/ui/console.c b/ui/console.c
index da434ce1b2..f42f64d556 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -37,6 +37,9 @@
#include "exec/memory.h"
#include "io/channel-file.h"
#include "qom/object.h"
+#ifdef CONFIG_PNG
+#include <png.h>
+#endif
#define DEFAULT_BACKSCROLL 512
#define CONSOLE_CURSOR_PERIOD 500
@@ -291,6 +294,89 @@ void graphic_hw_invalidate(QemuConsole *con)
}
}
+#ifdef CONFIG_PNG
+/**
+ * png_save: Take a screenshot as PNG
+ *
+ * Saves screendump as a PNG file
+ *
+ * Returns true for success or false for error.
+ *
+ * @fd: File descriptor for PNG file.
+ * @image: Image data in pixman format.
+ * @errp: Pointer to an error.
+ */
+static bool png_save(int fd, pixman_image_t *image, Error **errp)
+{
+ int width = pixman_image_get_width(image);
+ int height = pixman_image_get_height(image);
+ g_autofree png_struct *png_ptr = NULL;
+ g_autofree png_info *info_ptr = NULL;
+ g_autoptr(pixman_image_t) linebuf =
+ qemu_pixman_linebuf_create(PIXMAN_a8r8g8b8, width);
+ uint8_t *buf = (uint8_t *)pixman_image_get_data(linebuf);
+ FILE *f = fdopen(fd, "wb");
+ int y;
+ if (!f) {
+ error_setg_errno(errp, errno,
+ "Failed to create file from file descriptor");
+ return false;
+ }
+
+ png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+ NULL, NULL);
+ if (!png_ptr) {
+ error_setg(errp, "PNG creation failed. Unable to write struct");
+ fclose(f);
+ return false;
+ }
+
+ info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr) {
+ error_setg(errp, "PNG creation failed. Unable to write info");
+ fclose(f);
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ return false;
+ }
+
+ png_init_io(png_ptr, f);
+
+ png_set_IHDR(png_ptr, info_ptr, width, height, 8,
+ PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
+ PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ png_write_info(png_ptr, info_ptr);
+
+ for (y = 0; y < height; ++y) {
+ qemu_pixman_linebuf_fill(linebuf, image, width, 0, y);
+ png_write_row(png_ptr, buf);
+ }
+ qemu_pixman_image_unref(linebuf);
+
+ png_write_end(png_ptr, NULL);
+
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+ if (fclose(f) != 0) {
+ error_setg_errno(errp, errno,
+ "PNG creation failed. Unable to close file");
+ return false;
+ }
+
+ return true;
+}
+
+#else /* no png support */
+
+static bool png_save(int fd, pixman_image_t *image, Error **errp)
+{
+ error_setg(errp, "Enable PNG support with libpng for screendump");
+ return false;
+}
+
+#endif /* CONFIG_PNG */
+
static bool ppm_save(int fd, pixman_image_t *image, Error **errp)
{
int width = pixman_image_get_width(image);
@@ -329,7 +415,8 @@ 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)
{
g_autoptr(pixman_image_t) image = NULL;
QemuConsole *con;
@@ -385,8 +472,16 @@ 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);
+ }
}
}