WM-448: fix: place new windows on cursor's output instead of primary output

[deepin-wm]

修复多屏时新开窗口位置不正确

多屏环境下，新开的顶层窗口始终出现在主屏或左屏，而非光标所在的屏幕。

根因

存在两条代码路径导致新窗口位置错误：

路径一：addBySubContainer 使用 primaryOutput() 而非 cursorOutput()

RootSurfaceContainer::addBySubContainer() 在为无父窗口的顶层窗口分配 ownsOutput 时使用 primaryOutput()，导致所有新窗口被固定到主屏。

Workspace::updateSurfaceOwnsOutput() 的早退守卫 if (surface->ownsOutput() && outputs.contains(surface->ownsOutput()->output())) return; 在新窗口初始 getIntersectedOutputs 恰好返回含主屏的列表时会命中，旧代码因 ownsOutput=primary 早退后保留主屏（即 bug）。

路径二：updateSurfaceOwnsOutput 中 geometry-based 覆盖 cursor-based ownsOutput

仅修复路径一不够充分。当新窗口获得初始尺寸时：

1. addBySubContainer 设置 ownsOutput = cursorOutput()（如右屏）✅
2. 窗口获得初始尺寸 → geometryChanged 触发 → updateSurfaceOutputs → getIntersectedOutputs(QRect(0,0,w,h))
3. 窗口此时 position 仍为 (0,0)，在多屏布局中 (0,0) 落在左屏 → 返回左屏的 output
4. updateSurfaceOwnsOutput 发现 cursor output（右屏）不在 geometry-based outputs 列表中 → 不触发早退守卫 → outputs.first() → 覆盖为左屏 ❌

这就是窗口总是出现在左屏的原因。

修复

Commit 1：addBySubContainer 中 primaryOutput() → cursorOutput()

将无父窗口分支的 primaryOutput() 替换为 cursorOutput()，并在光标不在任何输出上时回退到 primaryOutput()：

auto output = parentSurface ? parentSurface->ownsOutput() : cursorOutput();
if (!output)
    output = primaryOutput();

Commit 2：updateSurfaceOwnsOutput 中防止 geometry-based 覆盖 cursor-based ownsOutput

当窗口 positionAutomatic() 为 true（即尚未被用户手动定位）且 ownsOutput 已设置时，优先保留现有 ownsOutput，而非使用 geometry-based outputs.first()：

if (surface->positionAutomatic() && surface->ownsOutput())
    output = surface->ownsOutput();
else if (!outputs.isEmpty())
    output = Helper::instance()->getOutput(outputs.first());

安全性分析

• 有父窗口（如 popup）分支不受影响，仍走 parentSurface->ownsOutput()
• getIntersectedOutputs 返回空（常见情形）时，早退守卫不触发，fallback 链本身已优先 cursorOutput()，行为不变
• 单屏环境下 cursorOutput() 与 primaryOutput() 等价，行为不变
• 光标处于输出布局空白区时回退主屏，与旧代码等价
• beginMoveResize 会将 positionAutomatic 设为 false，因此用户拖拽窗口到其他屏幕时，仍会使用 geometry-based 交集来更新 ownsOutput
• 输出断开时通过 moveSurfacesToOutput 显式设置 ownsOutput，不经过 updateSurfaceOwnsOutput

变更文件

• src/core/rootsurfacecontainer.cpp — addBySubContainer 中 primaryOutput() → cursorOutput() + 空值回退
• src/workspace/workspace.cpp — updateSurfaceOwnsOutput 中 positionAutomatic 守卫防止 geometry 覆盖

关联

Multica Issue: WM-448
PMS: https://pms.uniontech.com/bug-view-376719.html

Summary by Sourcery

Place new windows on the cursor's display while retaining existing behavior for parented and manually positioned windows.

Bug Fixes:

• Place newly created top-level windows on the display containing the cursor instead of always assigning them to the primary or left display.
• Preserve the cursor-selected output for automatically positioned windows so initial geometry updates do not overwrite it with a geometry-derived output.

[deepin-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: deepin-wm

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

Details

Needs approval from an approver in each of these files:

• debian/deepin/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Fix multi-monitor placement by initially assigning new top-level windows to the cursor’s output, while preserving parent-output behavior and switching to geometry-based tracking after the window is moved.

Sequence diagram for cursor-based new window output assignment

sequenceDiagram
    participant WindowManager
    participant RootSurfaceContainer
    participant Workspace
    participant Cursor
    participant Outputs

    WindowManager->>RootSurfaceContainer: addBySubContainer(sub, surface)
    RootSurfaceContainer->>RootSurfaceContainer: parentSurface()
    alt top-level window
        RootSurfaceContainer->>Cursor: cursorOutput()
        Cursor-->>RootSurfaceContainer: cursor output or null
        opt cursor output unavailable
            RootSurfaceContainer->>Outputs: primaryOutput()
            Outputs-->>RootSurfaceContainer: primary output
        end
    else child window
        RootSurfaceContainer->>RootSurfaceContainer: ownsOutput()
    end
    RootSurfaceContainer->>Workspace: updateSurfaceOwnsOutput(surface)
    alt positionAutomatic and ownsOutput exists
        Workspace->>Workspace: ownsOutput()
    else geometry-based tracking
        Workspace->>Workspace: getIntersectedOutputs(outputs)
    end

Loading

State diagram for window output tracking after placement

stateDiagram-v2
    [*] --> CursorOutputAssigned: new top-level window
    CursorOutputAssigned --> CursorOutputAssigned: positionAutomatic()
    CursorOutputAssigned --> GeometryOutputTracking: beginMoveResize()
    GeometryOutputTracking --> GeometryOutputTracking: getIntersectedOutputs(outputs)
    CursorOutputAssigned --> PrimaryOutputFallback: cursorOutput unavailable
    PrimaryOutputFallback --> CursorOutputAssigned: window created

Loading

File-Level Changes

Change	Details	Files
Assign new top-level windows to the output containing the cursor, with a primary-output fallback.	Use cursorOutput() for parentless surfaces and retain parent-owned output assignment for child surfaces. Fall back to primaryOutput() when the cursor is not over an output.	src/core/rootsurfacecontainer.cpp
Preserve cursor-based ownership for automatically positioned windows until the user moves them, then resume geometry-based output tracking.	Prefer an existing ownsOutput for automatically positioned surfaces to avoid initial geometry overriding cursor placement. Use intersected outputs after user movement, with cursor output as the final fallback.	src/core/workspace/workspace.cpp

Possibly linked issues

• #Multiple screen issues: PR directly fixes the unchecked issue by assigning new top-level windows to the cursor’s output with primary fallback.

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it. You can also reply to a
  review comment with @sourcery-ai issue to create an issue from it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time. You can also comment
  @sourcery-ai title on the pull request to (re-)generate the title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time exactly where you
  want it. You can also comment @sourcery-ai summary on the pull request to
  (re-)generate the summary at any time.
• Generate reviewer's guide: Comment @sourcery-ai guide on the pull
  request to (re-)generate the reviewer's guide at any time.
• Resolve all Sourcery comments: Comment @sourcery-ai resolve on the
  pull request to resolve all Sourcery comments. Useful if you've already
  addressed all the comments and don't want to see them anymore.
• Dismiss all Sourcery reviews: Comment @sourcery-ai dismiss on the pull
  request to dismiss all existing Sourcery reviews. Especially useful if you
  want to start fresh with a new review - don't forget to comment
  @sourcery-ai review to trigger a new review!

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.

[sourcery-ai]

Hey - I've reviewed your changes and they look great!

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

[deepin-bot]

TAG Bot

New tag: 0.10.0
DISTRIBUTION: unstable
Suggest: synchronizing this PR through rebase #1392

[wineee]

为什么改这里