Fix virtual output

[Groveer]

Summary by Sourcery

Improve virtual output management and output reconfiguration to provide a complete graphical control tool while keeping display topology, primary selection, layouts, and copy-mode state consistent across output changes.

New Features:

• Expand the virtual output example into a graphical display-management tool for mirroring, primary-output selection, color controls, and output configuration.
• Add wlroots output-management support for inspecting and applying output position, mode, refresh rate, rotation, scale, and enablement settings.

Bug Fixes:

• Fix virtual output lifecycle and synchronization when groups are created, modified, removed, or rebound.
• Preserve primary-output configuration, restore disabled-output surfaces, and avoid stale or overlapping output layouts during output changes.
• Improve copy-mode transitions when outputs are disabled or enabled and reject incomplete restoration of stale copy configurations.
• Make cursor relocation deterministic and prevent disabled outputs from being selected for cursor-based placement.

Enhancements:

• Add output-layout pinning to prevent automatic repositioning after output geometry changes.

Build:

• Generate the virtual output example against the Treeland output-management and wlroots output-management protocols.

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Groveer

The full list of commands accepted by this bot can be found here.

Details

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• debian/deepin/OWNERS

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[sourcery-ai]

Reviewer's Guide

The pull request turns the virtual-output example into a full interactive output-management client and expands the virtual-output protocol, while hardening compositor output topology transitions, layout positioning, cursor placement, primary-output persistence, and surface restoration across disable/enable and copy-mode changes.

Sequence diagram for copy-source disable and restoration

sequenceDiagram
    participant Client as OutputManagementClient
    participant Helper
    participant RootSurfaceContainer
    participant OutputManager
    participant Wlroots

    Client->>Helper: onOutputTestOrApply(config)
    Helper->>Helper: handleCopyModeSourceDisabled(disabledSource, requestedDisabled)
    alt surviving mirrors remain
        Helper->>Helper: promoteCopyOutputToSource(promotedMirror, surfaces, surfacesFrom, shouldRetarget)
        Helper->>RootSurfaceContainer: setPrimaryOutput(normalSource)
        Helper->>Helper: m_pendingOutputConfig.copyOutputIds = copyOutputIds
    else no mirror remains
        Helper->>Helper: convertCopyModeToExtension(disabledSource)
    end
    Helper->>Wlroots: commit output states
    Wlroots-->>Helper: commit callback
    Helper->>OutputManager: onOutputCommitFinished(config, success)
    alt successful re-enable in extension mode
        Helper->>Helper: surface->setPosition(savedPosition)
        Helper->>RootSurfaceContainer: updateSurfaceOutputs(surface)
    end

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Sequence diagram for virtual-output updates and protocol notifications

sequenceDiagram
    participant Client as WaylandClient
    participant Manager as VirtualOutputManagerInterfaceV1
    participant Binding as VirtualOutputInterfaceV1
    participant Config as VirtualOutputConfig

    Client->>Manager: create_virtual_output(resource, id, name, outputs)
    Manager->>Config: storeVirtualOutput(name, outputs, virtualOutput)
    Manager->>Manager: notifyVirtualOutputModified(name)
    Manager-->>Client: send_virtual_output_modified(resource, name)

    Client->>Manager: get_virtual_output(resource, name, id)
    Manager->>Binding: createVirtualOutput(resource, id, name)
    alt virtual output exists
        Manager->>Config: backfill virtualOutput binding
        Manager-->>Binding: sendOutputs(name, outputs)
    else virtual output was removed
        Manager-->>Binding: sendOutputs(name, empty outputs)
    end

    Manager->>Manager: updateVirtualOutput(name, outputs)
    Manager->>Binding: sendOutputs(name, outputs)
    Manager->>Manager: notifyVirtualOutputModified(name)
    Client->>Manager: destroy(resource)
    Manager->>Manager: wl_resource_destroy(resource)

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Flow diagram for safe output layout restoration

flowchart TD
    A[Output added or layout restored] --> B[Compute effective saved size]
    B --> C{Saved position overlaps enabled output?}
    C -- Yes --> D[Keep auto-added position]
    C -- No --> E["layout.move(output, savedPos)"]
    D --> F["layout.pin(output)"]
    E --> F
    F --> G[Output remains stable during sibling geometry changes]

    H[Output-management apply] --> I{Restored states overlap?}
    I -- Yes --> J[Reject restored topology]
    I -- No --> K[Apply restored states]

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File-Level Changes

Change	Details	Files
Rebuild the virtual-output example into an interactive display-management client.	Add Treeland color-control and primary-output bindings. Add wlroots output-management bindings for head discovery and configuration. Replace command-line cloning with a Qt UI for screen selection, mirroring, enablement, geometry, mode, refresh, rotation, scale, brightness, color temperature, and primary-output control. Track virtual-output groups and refresh state when the compositor reports modifications.	examples/test_virtual_output/CMakeLists.txt examples/test_virtual_output/main.cpp examples/test_virtual_output/virtualclient.cpp examples/test_virtual_output/virtualclient.h examples/test_virtual_output/wlroutputmanager.cpp examples/test_virtual_output/wlroutputmanager.h
Extend the virtual-output protocol implementation to support lifecycle and modification notifications.	Upgrade the manager interface to version 3 and handle empty output lists safely. Emit modification events when virtual-output groups are created, updated, or removed. Implement manager-resource destruction and safely handle groups that disappear between listing and lookup. Rebind newly requested virtual-output resources to current server-side configurations.	examples/test_virtual_output/virtualoutputmanager.cpp examples/test_virtual_output/virtualoutputmanager.h src/modules/virtual-output/virtualoutputmanagerinterfacev1.cpp src/modules/virtual-output/virtualoutputmanagerinterfacev1.h
Make output layout and cursor behavior resilient to stale or changing output topology.	Pin automatically positioned outputs after placement to prevent wlroots reflow. Avoid restoring saved positions that overlap enabled outputs and de-overlap extension-mode states. Move the cursor to the closest remaining layout point when it leaves all outputs. Ignore disabled outputs during cursor hit testing.	src/core/rootsurfacecontainer.cpp src/core/rootsurfacecontainer.h src/seat/helper.cpp waylib/src/server/kernel/woutputlayout.cpp waylib/src/server/kernel/woutputlayout.h
Improve copy-mode transitions, output disable/enable handling, and persistence.	Promote surviving mirrors when a copy source is disabled, or collapse copy mode when insufficient mirrors remain. Convert mirror outputs to normal outputs for extension-mode transitions and mixed topologies. Persist rebuilt copy groups only after all output commits succeed. Restore disabled-output surfaces and clear snapshots on re-enable. Persist primary-output restoration and reject incomplete stale copy configurations.	src/output/outputmanager.cpp src/seat/helper.cpp src/seat/helper.h

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[sourcery-ai]

Hey - I've found 2 issues

Prompt for AI Agents

Please address the comments from this code review:

## Individual Comments

### Comment 1
<location path="src/modules/virtual-output/virtualoutputmanagerinterfacev1.cpp" line_range="256-259" />
<code_context>
-    const QByteArray arrSend = config.outputs.join('\0').toLatin1();
-    virtualOutput->sendOutputs(name, arrSend);
+    if (it != m_configs.end()) {
+        // Backfill so updateVirtualOutput() pushes to this newest binding
+        // instead of a stale (possibly disconnected) proxy.
+        it.value().virtualOutput = virtualOutput;
+        virtualOutput->sendOutputs(name, it.value().outputs.join('\0').toLatin1());
+    } else {
+        virtualOutput->sendOutputs(name, QByteArray());
</code_context>
<issue_to_address>
**issue (bug_risk):** Rebinding `m_configs[name].virtualOutput` to the newest proxy does not make the destroy cleanup proxy-specific: when the older proxy is later destroyed, its `beforeDestroy` handler unconditionally removes `m_configs[name]`, including the configuration now bound to the newer proxy.

**Triggers:** When a client calls `get_virtual_output` for an existing group more than once and then destroys the older proxy.

**Suggested fix:** Capture the proxy in the cleanup callback and remove the config only when `m_configs[name].virtualOutput` still points to that proxy.
</issue_to_address>

### Comment 2
<location path="src/modules/virtual-output/virtualoutputmanagerinterfacev1.cpp" line_range="261" />
<code_context>
+        it.value().virtualOutput = virtualOutput;
+        virtualOutput->sendOutputs(name, it.value().outputs.join('\0').toLatin1());
+    } else {
+        virtualOutput->sendOutputs(name, QByteArray());
+    }
 }
</code_context>
<issue_to_address>
**issue (bug_risk):** The vanished-group path sends an empty outputs array, but the example client's `VirtualOutput::treeland_virtual_output_v1_outputs` handler returns without emitting `outputsReceived` when the array is empty, so the client never observes the required empty outputs event.

**Triggers:** When a listed virtual-output group disappears before the client calls `get_virtual_output`.

**Suggested fix:** Emit `outputsReceived(name, {})` for an empty array instead of returning before the signal emission.
</issue_to_address>

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