GUACAMOLE-288: Add support for multi-monitor connections. by corentin-soriano · Pull Request #560 · apache/guacamole-server

corentin-soriano · 2024-10-20T09:43:37Z

Allows as is to add multiple monitors of the same dimensions in RDP protocol if the server supports it.
I haven't looked at the VNC part yet.

Client side PR : apache/guacamole-client#1061

POC:

Pierre-Gronau-ndaal · 2025-04-15T18:56:39Z

it will be great if we bring that to main

necouchman · 2025-04-15T19:34:45Z

it will be great if we bring that to main

Yes, that is the plan, once the code is finalized and has been fully reviewed.

Vertganti · 2025-06-26T08:31:50Z

Frequently resizing a monitor window, e.g. by using Maximize and Restore down of the window in quick succession, can cause a RDP disconnect with the following message in the guacd logs:

GUAC_ASSERT in guac_rdp_gdi_desktop_resize() failed at gdi.c:172.

Assertion code

Is it possible to wait for the flush or just discard the affected window instead of crashing the connection?

corentin-soriano · 2025-07-07T07:16:54Z

Frequently resizing a monitor window, e.g. by using Maximize and Restore down of the window in quick succession, can cause a RDP disconnect with the following message in the guacd logs:
GUAC_ASSERT in guac_rdp_gdi_desktop_resize() failed at gdi.c:172.
Assertion code

Is it possible to wait for the flush or just discard the affected window instead of crashing the connection?

Which version of freerdp are you using?
If you are on v3, can you update it to at least version 3.8.0?

Vertganti · 2025-07-07T07:55:08Z

I'm using the Dockerfile from the repository which defaults to FreeRDP 2. The exact version is 2.11.7. I can try using FreeRDP 3 to see if that improves anything.

corentin-soriano · 2025-07-07T08:01:45Z

I'm using the Dockerfile form the repository which defaults to FreeRDP 2. The exact version is 2.11.7. I can try using FreeRDP 3 to see if that improves anything.

This is potentially a bug in FreeRDP. This assertion is mandatory in version 2.
Are you sure you can't reproduce this with a single monitor?

Vertganti · 2025-07-07T11:35:04Z

I'm using the Dockerfile form the repository which defaults to FreeRDP 2. The exact version is 2.11.7. I can try using FreeRDP 3 to see if that improves anything.

This is potentially a bug in FreeRDP. This assertion is mandatory in version 2. Are you sure you can't reproduce this with a single monitor?

I was able to reproduce it with one monitor with the FreeRDP 2 build.

EDIT: It does not reproduce with FreeRDP 3, independent of the number of monitors.

weberr13 · 2025-07-07T18:58:54Z

+    /* Make json string containing monitor information */
+    char json[JSON_BUFFER_SIZE];
+    int pos = 0;
+    pos += snprintf(json + pos, JSON_BUFFER_SIZE - pos, "{");


nit: While there may be concerns about grabbing an external dependency, when it comes to "never re-invent the wheel" any manual string manipulation to do json generation/parsing is king. Libraries like

https://github.com/nlohmann/json

will allow "C++ like" json parsing and generation that covers all the corner cases that JSON hides from the average user.

weberr13 · 2025-07-07T19:01:12Z

+        }
+
+        /* Append monitor information to JSON string */
+        pos += snprintf(json + pos, JSON_BUFFER_SIZE - pos,


A small piece of my soul is severed and sent to the depths of Hades every time I see sprintf generating json.

lirannisani · 2025-09-04T06:23:49Z

@necouchman @corentin-soriano
Thanks for adding this feature!
Do you plan to merge it into the main branch?

corentin-soriano · 2025-09-04T08:47:13Z

@necouchman @corentin-soriano Thanks for adding this feature! Do you plan to merge it into the main branch?

I still have some things to finalize before we can merge.
I haven't had time to continue lately but the subject has not been forgotten!

…ates.

…hen adding a new monitor.

@corentin-soriano

Ports the reusable, protocol-agnostic multi-monitor support added upstream in apache#560 (GUACAMOLE-288) by Corentin Soriano (@corentin-soriano): * guac_user_size_handler gains per-monitor x_position/top_offset * new "multimon-layout" default-layer parameter (a JSON monitor map) * __guac_handle_size parses the new size-instruction fields * guac_rect_shrink guards against divide-by-zero Every protocol's size handler is updated to the new signature; the new per-monitor arguments are ignored by all protocols except SPICE (see the following commit), preserving existing single-monitor behavior. Original work by @corentin-soriano, adapted for this fork: apache#560

@corentin-soriano

Builds on the ported libguac multi-monitor primitive to add client-driven multi-monitor support to the SPICE protocol, following the design of the RDP implementation in apache#560 (by @corentin-soriano) adapted to SPICE's model, where a QXL guest presents all heads as regions of a single combined framebuffer. * settings: new "secondary-monitors" parameter (max_secondary_monitors, default 0 = disabled) * the size handler tracks a per-monitor array (fixed, up to GUAC_SPICE_MAX_MONITORS) keyed by x_position, tiling monitors left-to-right and computing each monitor's left_offset; a non-positive size closes a secondary monitor * resize pushes the whole layout to the guest agent in a single monitors config (enabling/positioning active monitors and disabling removed ones) * on each combined-surface (re)create, the current layout is sent to the client as the "multimon-layout" parameter on the default layer so a multi-monitor client can split it into per-monitor windows * joining users are told the permitted secondary-monitor count via a "secondary-monitors" argv stream The monitor state uses a fixed array (no dynamic allocation), avoiding the pointer-ownership concerns raised in review of the upstream RDP change, and the default layer is referenced via GUAC_DEFAULT_LAYER rather than casting a guac_display_layer.

@corentin-soriano

Ports the reusable, protocol-agnostic multi-monitor support added upstream in apache#560 (GUACAMOLE-288) by Corentin Soriano (@corentin-soriano): * guac_user_size_handler gains per-monitor x_position/top_offset * new "multimon-layout" default-layer parameter (a JSON monitor map) * __guac_handle_size parses the new size-instruction fields * guac_rect_shrink guards against divide-by-zero Every protocol's size handler is updated to the new signature; the new per-monitor arguments are ignored by all protocols except SPICE (see the following commit), preserving existing single-monitor behavior. Original work by @corentin-soriano, adapted for this fork: apache#560

@corentin-soriano

Builds on the ported libguac multi-monitor primitive to add client-driven multi-monitor support to the SPICE protocol, following the design of the RDP implementation in apache#560 (by @corentin-soriano) adapted to SPICE's model, where a QXL guest presents all heads as regions of a single combined framebuffer. * settings: new "secondary-monitors" parameter (max_secondary_monitors, default 0 = disabled) * the size handler tracks a per-monitor array (fixed, up to GUAC_SPICE_MAX_MONITORS) keyed by x_position, tiling monitors left-to-right and computing each monitor's left_offset; a non-positive size closes a secondary monitor * resize pushes the whole layout to the guest agent in a single monitors config (enabling/positioning active monitors and disabling removed ones) * on each combined-surface (re)create, the current layout is sent to the client as the "multimon-layout" parameter on the default layer so a multi-monitor client can split it into per-monitor windows * joining users are told the permitted secondary-monitor count via a "secondary-monitors" argv stream The monitor state uses a fixed array (no dynamic allocation), avoiding the pointer-ownership concerns raised in review of the upstream RDP change, and the default layer is referenced via GUAC_DEFAULT_LAYER rather than casting a guac_display_layer.

@corentin-soriano

Ports the reusable, protocol-agnostic multi-monitor support added upstream in apache#560 (GUACAMOLE-288) by Corentin Soriano (@corentin-soriano): * guac_user_size_handler gains per-monitor x_position/top_offset * new "multimon-layout" default-layer parameter (a JSON monitor map) * __guac_handle_size parses the new size-instruction fields * guac_rect_shrink guards against divide-by-zero Every protocol's size handler is updated to the new signature; the new per-monitor arguments are ignored by all protocols except SPICE (see the following commit), preserving existing single-monitor behavior. Original work by @corentin-soriano, adapted for this fork: apache#560

@corentin-soriano

Builds on the ported libguac multi-monitor primitive to add client-driven multi-monitor support to the SPICE protocol, following the design of the RDP implementation in apache#560 (by @corentin-soriano) adapted to SPICE's model, where a QXL guest presents all heads as regions of a single combined framebuffer. * settings: new "secondary-monitors" parameter (max_secondary_monitors, default 0 = disabled) * the size handler tracks a per-monitor array (fixed, up to GUAC_SPICE_MAX_MONITORS) keyed by x_position, tiling monitors left-to-right and computing each monitor's left_offset; a non-positive size closes a secondary monitor * resize pushes the whole layout to the guest agent in a single monitors config (enabling/positioning active monitors and disabling removed ones) * on each combined-surface (re)create, the current layout is sent to the client as the "multimon-layout" parameter on the default layer so a multi-monitor client can split it into per-monitor windows * joining users are told the permitted secondary-monitor count via a "secondary-monitors" argv stream The monitor state uses a fixed array (no dynamic allocation), avoiding the pointer-ownership concerns raised in review of the upstream RDP change, and the default layer is referenced via GUAC_DEFAULT_LAYER rather than casting a guac_display_layer.

corentin-soriano marked this pull request as draft October 20, 2024 09:43

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from 78954b5 to d829739 Compare October 20, 2024 10:05

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch 5 times, most recently from 8374544 to 683800f Compare November 4, 2024 16:33

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from 683800f to 62c8b1e Compare January 9, 2025 09:00

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from 62c8b1e to 4ee5e1b Compare January 21, 2025 09:32

corentin-soriano mentioned this pull request Feb 15, 2025

GUACAMOLE-288: Add support for multi-monitor connections on RDP. apache/guacamole-client#1061

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neandrake reviewed Feb 21, 2025

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Comment thread src/protocols/rdp/channels/disp.c Outdated

Comment thread src/protocols/rdp/channels/disp.c Outdated

Comment thread src/protocols/rdp/channels/disp.c Outdated

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from 4ee5e1b to ac08c95 Compare February 22, 2025 15:41

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corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from eda5067 to 5294c1b Compare June 17, 2025 15:49

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weberr13 reviewed Jul 7, 2025

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Comment thread src/protocols/rdp/channels/disp.c

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necouchman mentioned this pull request Sep 24, 2025

Multi screen #616

Closed

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from 5294c1b to 5989c14 Compare November 3, 2025 11:40

corentin-soriano added 6 commits November 6, 2025 09:40

GUACAMOLE-288: Receive the monitors count in resize channel.

ce4c852

GUACAMOLE-288: Handle multiple monitors in RDP via resize display upd…

8dbcc6f

…ates.

GUACAMOLE-288: Add parameter to limit the usage of multiple monitors.

bb70e8f

GUACAMOLE-288: Allow windows to have different dimensions.

f6ace69

GUACAMOLE-288: Send monitor layout via layer set parameter.

a30923f

GUACAMOLE-288: Send mouse icon after resize to ensure it is visible w…

ce23d60

…hen adding a new monitor.

corentin-soriano force-pushed the GUACAMOLE-288_multi_monitors branch from 5989c14 to ce23d60 Compare November 6, 2025 08:40

nvdhau-v2cloud mentioned this pull request Jun 23, 2026

GUACAMOLE-288: Multi-monitor server support — RDP disp channel, libguac copy decomposition, size offset corentin-soriano/guacamole-server#4

Open

ciroiriarte mentioned this pull request Jul 4, 2026

SPICE: support multiple monitors (secondary display channels) ciroiriarte/guacamole-server#6

Closed

nvdhau-v2cloud mentioned this pull request Jul 4, 2026

VAN-509: GUACAMOLE-288 multi monitor v2cloud/guacamole-server#2

Merged

ciroiriarte mentioned this pull request Jul 10, 2026

GUACAMOLE-261: Add native SPICE protocol support (libguac-client-spice) #688

Open

ciroiriarte mentioned this pull request Jul 20, 2026

GUACAMOLE-288: Six fixes for the multi-monitor branch (incl. two WIP items) corentin-soriano/guacamole-client#3

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