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[82.30.61.225]) by smtp.gmail.com with ESMTPSA id b16sm6004286wmj.32.2022.02.23.03.00.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Feb 2022 03:00:40 -0800 (PST) Date: Wed, 23 Feb 2022 11:00:38 +0000 From: "Dr. David Alan Gilbert" To: Kshitij Suri Subject: Re: [PATCH] Added parameter to take screenshot with screendump as PNG Message-ID: References: <20220222152758.207415-1-kshitij.suri@nutanix.com> MIME-Version: 1.0 In-Reply-To: <20220222152758.207415-1-kshitij.suri@nutanix.com> User-Agent: Mutt/2.1.5 (2021-12-30) Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, T_SCC_BODY_TEXT_LINE=-0.01, T_SPF_TEMPERROR=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: soham.ghosh@nutanix.com, thuth@redhat.com, prerna.saxena@nutanix.com, qemu-devel@nongnu.org, armbru@redhat.com, kraxel@redhat.com, eblake@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Kshitij Suri (kshitij.suri@nutanix.com) wrote: > Currently screendump only supports PPM format, which is un-compressed and not > standard. Added an "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 > --- > hmp-commands.hx | 11 ++-- > monitor/hmp-cmds.c | 4 +- > qapi/ui.json | 7 ++- > ui/console.c | 153 ++++++++++++++++++++++++++++++++++++++++++++- > 4 files changed, 165 insertions(+), 10 deletions(-) > > diff --git a/hmp-commands.hx b/hmp-commands.hx > index 70a9136ac2..2163337f35 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'." > + "Default format for screendump is PPM.", > .cmd = hmp_screendump, > .coroutine = true, > }, > > SRST > ``screendump`` *filename* > - Save screen into PPM image *filename*. > + Save screen as image *filename*. > ERST > > { > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c > index 2669156b28..3fb1394561 100644 > --- a/monitor/hmp-cmds.c > +++ b/monitor/hmp-cmds.c > @@ -1665,9 +1665,11 @@ 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 *format = qdict_get_str(qdict, "format"); > Error *err = NULL; > > - qmp_screendump(filename, id != NULL, id, id != NULL, head, &err); > + qmp_screendump(filename, id != NULL, id, id != NULL, head, > + format != NULL, format, &err); > hmp_handle_error(mon, err); > } I think that's OK from the HMP front, see some questions below. > diff --git a/qapi/ui.json b/qapi/ui.json > index 9354f4c467..9fdb56b60b 100644 > --- a/qapi/ui.json > +++ b/qapi/ui.json > @@ -76,7 +76,7 @@ > ## > # @screendump: > # > -# Write a PPM of the VGA screen to a file. > +# Write a screenshot of the VGA screen to a file. > # > # @filename: the path of a new PPM file to store the image > # > @@ -87,6 +87,9 @@ > # 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. Currently only PNG and > +# PPM are supported. > +# > # Returns: Nothing on success > # > # Since: 0.14 > @@ -99,7 +102,7 @@ > # > ## > { 'command': 'screendump', > - 'data': {'filename': 'str', '*device': 'str', '*head': 'int'}, > + 'data': {'filename': 'str', '*device': 'str', '*head': 'int', '*format': 'str'}, > 'coroutine': true } > > ## > diff --git a/ui/console.c b/ui/console.c > index 40eebb6d2c..7813b195ac 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_VNC_PNG > +#include "png.h" > +#endif > > #define DEFAULT_BACKSCROLL 512 > #define CONSOLE_CURSOR_PERIOD 500 > @@ -289,6 +292,137 @@ void graphic_hw_invalidate(QemuConsole *con) > } > } > > +#ifdef CONFIG_VNC_PNG > +/** > + * a8r8g8b8_to_rgba: Convert a8r8g8b8 to rgba format > + * > + * @dst: Destination pointer. > + * @src: Source pointer. > + * @n_pixels: Size of image. > + */ > +static void a8r8g8b8_to_rgba(uint32_t *dst, uint32_t *src, int n_pixels) > +{ > + uint8_t *dst8 = (uint8_t *)dst; > + int i; > + > + for (i = 0; i < n_pixels; ++i) { > + uint32_t p = src[i]; > + uint8_t a, r, g, b; > + > + a = (p & 0xff000000) >> 24; > + r = (p & 0x00ff0000) >> 16; > + g = (p & 0x0000ff00) >> 8; > + b = (p & 0x000000ff) >> 0; > + > + if (a != 0) { > + #define DIVIDE(c, a) \ > + do { \ > + int t = ((c) * 255) / a; \ > + (c) = t < 0 ? 0 : t > 255 ? 255 : t; \ I can't see how 't' can be less than 0 here? > + } while (0) > + > + DIVIDE(r, a); > + DIVIDE(g, a); > + DIVIDE(b, a); > + #undef DIVIDE > + } > + > + *dst8++ = r; > + *dst8++ = g; > + *dst8++ = b; > + *dst8++ = a; > + } > +} Now, I'm not too much of a graphics person, but I'm a bit confused; this seems to be applying the alpha scaling to the r/g/b/ data - but then still including the alpha value in the output; doesn't that mean that the thing displaying the result will also apply the alpha scaling again? > +/** > + * png_save: Take a screenshot as PNG > + * > + * Saves screendump as a PNG file > + * > + * Returns true for success or false for error. > + * Inspired from png test utils from https://github.com/aseprite/pixman > + * > + * @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); > + int stride = width * 4; > + g_autofree uint32_t *src_data = g_malloc(height * stride); > + g_autofree uint32_t *dest_data = g_malloc(height * stride); > + g_autoptr(pixman_image_t) src_copy; > + g_autoptr(pixman_image_t) dest_copy; > + g_autofree png_struct *write_struct; > + g_autofree png_info *info_struct; > + g_autofree png_bytep *row_pointers = g_malloc(height * sizeof(png_bytep)); > + FILE *f = fdopen(fd, "wb"); > + int y; > + if (!f) { > + error_setg(errp, "Failed to create file from file descriptor"); > + return false; > + } > + > + src_copy = pixman_image_create_bits(PIXMAN_a8r8g8b8, width, height, > + src_data, stride); > + > + pixman_image_composite32(PIXMAN_OP_SRC, image, NULL, src_copy, 0, 0, 0, 0, > + 0, 0, width, height); Nothing in the rest of qemu uses pixman_image_composite*32* - all the rest uses the plain version; what's the difference? > + memcpy(dest_data, src_data, sizeof(*src_data)); Why if you're just about to nuke dest_data with the converted version? > + a8r8g8b8_to_rgba(dest_data, src_data, height * width); > + > + for (y = 0; y < height; ++y) { > + row_pointers[y] = (png_bytep)(src_data + y * width); > + } > + > + write_struct = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, > + NULL, NULL); > + if (!write_struct) { > + error_setg(errp, "PNG creation failed. Unable to write struct"); > + return false; > + } > + > + info_struct = png_create_info_struct(write_struct); > + > + if (!info_struct) { > + error_setg(errp, "PNG creation failed. Unable to write info"); > + return false; > + } > + > + png_init_io(write_struct, f); > + > + png_set_IHDR(write_struct, info_struct, width, height, 8, > + PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE, > + PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); > + > + png_write_info(write_struct, info_struct); > + > + png_write_image(write_struct, row_pointers); Had you considered using png_write_row and avoiding having to hold/allocate the destination and row_pointers at all? (In actual fact, can you steal the code in ui/vnc-enc-tight.c send_png_rect ? ) Dave > + png_write_end(write_struct, NULL); > + > + if (fclose(f) != 0) { > + error_setg(errp, "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 VNC PNG support for png screendump"); > + return false; > +} > + > +#endif /* CONFIG_VNC_PNG */ > + > static bool ppm_save(int fd, pixman_image_t *image, Error **errp) > { > int width = pixman_image_get_width(image); > @@ -327,7 +461,8 @@ 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, > + const char *format, Error **errp) > { > g_autoptr(pixman_image_t) image = NULL; > QemuConsole *con; > @@ -383,8 +518,22 @@ 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)) { > + > + if (has_format && strcmp(format, "png") == 0) { > + /* PNG format specified for screendump */ > + if (!png_save(fd, image, errp)) { > + qemu_unlink(filename); > + } > + } else if (!has_format || (has_format && strcmp(format, "ppm") == 0)) { > + /* PPM format specified/default for screendump */ > + if (!ppm_save(fd, image, errp)) { > + qemu_unlink(filename); > + } > + } else { > + /* Invalid specified for screendump */ > + error_setg(errp, "Invalid format provided for screendump."); > qemu_unlink(filename); > + return; > } > } > > -- > 2.22.3 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK