Feature/slint UI migration by Sqhh99 · Pull Request #4 · Sqhh99/webrtc-peerconnection-client

Sqhh99 · 2026-04-02T08:54:38Z

This pull request migrates the project’s UI from SDL3/ImGui to Slint, updates the build system to fetch and integrate Slint, and reorganizes media support/test code for clarity. It also introduces Rust as a build prerequisite (required by Slint), updates documentation, and improves dependency caching and validation in both CMake and CI/CD workflows.

UI Migration and Refactoring:

Replaces SDL3 and ImGui with Slint for the UI, updating all relevant code and build references (CMakeLists.txt, README.md, renaming/moving sdl_app.* to ui/slint_app.*, etc.). [1] [2] [3] [4]

Build System and Dependency Management:

Adds CMake logic to fetch Slint sources using FetchContent, disables unnecessary Slint features, and integrates Slint into the build process (cmake/FetchSlint.cmake, CMakeLists.txt). [1] [2] [3]
Updates CI/CD workflow and build.cmd to require Rust (version 1.88+), checks for its presence, and ensures the correct toolchain is used for building Slint. [1] [2] [3]

Project Structure and Code Organization:

Moves all test and media support code from the test/ directory into src/media_support/ and include/media_support/ for better organization and clarity, updating all includes accordingly. [1] [2] [3] [4] [5]

Documentation and Developer Experience:

Updates the README.md to reflect the new UI stack (Slint), the Rust requirement, and improved build notes regarding Slint source fetching. [1] [2] [3]

Build and Caching Improvements:

Enhances dependency caching in both GitHub Actions and the local build script to account for Slint and its version, preventing unnecessary rebuilds and ensuring reproducible builds. [1] [2] [3] [4]

These changes modernize the UI stack, improve build reliability, and make the codebase easier to maintain and extend.

…t layout and IDE-style stats

Copilot

Pull request overview

This PR migrates the Windows desktop client UI from SDL3/ImGui to Slint, updates the build/CI pipeline to fetch and build Slint (including Rust as a prerequisite), and reorganizes WebRTC “test” media helper code into a runtime media_support/ module.

Changes:

Replace the SDL3/ImGui UI with a Slint UI (new .slint components + SlintApp backend) and wire it into main.
Update rendering pipeline integration to push frames into Slint images (new SlintVideoRenderer bridge + enhanced VideoRenderer frame pacing/scaling).
Update build + CI scripts to fetch Slint via CMake FetchContent, cache dependencies, and require a Rust toolchain.

Reviewed changes

Copilot reviewed 32 out of 35 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
`ui/*.slint`	New Slint UI components (window layout, video stage, sidebar, overlays, logs).
`src/ui/backend/slint_app.cc` / `include/ui/slint_app.h`	New Slint UI backend replacing SDL app; binds controller callbacks and drives UI state.
`src/ui/backend/slint_video_renderer.cc` / `include/ui/slint_video_renderer.h`	Bridge that consumes `VideoRenderer` frames and updates Slint `Image` properties on the event loop.
`src/videorenderer.cc` / `include/videorenderer.h`	Adds output scaling, frame-rate limiting, and a “frame available” callback for UI redraw triggering.
`src/webrtcengine.cc`	Adjusts COM initialization strategy for Windows UI thread requirements.
`src/webrtcengine_media_pipeline.cc`	Updates includes to the new `media_support/*` paths.
`src/media_support/` + `include/media_support/`	Moves former WebRTC test helpers into runtime “media_support” module and updates includes.
`src/main.cc`	Switches app entrypoint from `SdlApp` to `SlintApp`.
`CMakeLists.txt` / `cmake/FetchSlint.cmake`	Fetches and configures Slint from source, links `Slint::Slint`, and adds `slint_target_sources`.
`build.cmd`	Adds Rust toolchain checks and improves stale-cache detection; passes Slint tag into CMake.
`.github/workflows/build.yml`	Installs Rust, adds Rust caching, and expands third-party caching key/scope for Slint.
`cmake/ui_paths.h.in`	Adds a template header (currently not wired up elsewhere).
`README.md`	Documents Slint UI migration and Rust toolchain prerequisite.

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Copilot · 2026-04-02T09:02:34Z

+
+SlintApp::~SlintApp() {
+  shutting_down_.store(true);
+  StopTimers();


SlintApp::~SlintApp() stops the VideoRenderer instances but never detaches them from SlintVideoRenderer. Since VideoRenderer::Stop() currently does not clear frame_available_callback_, any in-flight OnFrame() call could still invoke a callback that references video_renderer_bridge_ during/after destruction. DetachLocalRenderer()/DetachRemoteRenderer() should be called (or Stop() should clear the callback) to make shutdown robust against use-after-free races.

Suggested change

StopTimers();

StopTimers();

if (video_renderer_bridge_) {

video_renderer_bridge_->DetachLocalRenderer();

video_renderer_bridge_->DetachRemoteRenderer();

}

Copilot · 2026-04-02T09:02:35Z

@@ -33,15 +53,19 @@ void VideoRenderer::Stop() {
  }

  latest_frame_ = Frame{};
+  standby_frame_ = Frame{};
  latest_frame_.frame_id = next_frame_id_++;
  frame_dirty_ = true;
+  last_frame_time_ = std::chrono::steady_clock::time_point{};
 }


VideoRenderer::Stop() removes the sink and clears frame state, but it leaves frame_available_callback_ intact. If the renderer is stopped during shutdown while another thread is still delivering/finishing an OnFrame() call, the callback can still fire and call back into UI code that may already be tearing down. Consider clearing frame_available_callback_ inside Stop() (under the mutex) to avoid use-after-free risks during shutdown.

Copilot · 2026-04-02T09:02:35Z

+set "RUST_VERSION="
+for /f "tokens=2 delims= " %%I in ('rustc --version') do (
+    set "RUST_VERSION=%%I"
+    goto rust_version_found
+)
+
+:rust_version_found
+if not defined RUST_VERSION (
+    echo [build.cmd] Failed to parse the installed rustc version.
+    exit /b 1
+)
+
+for /f "tokens=1,2 delims=." %%I in ("%RUST_VERSION%") do (
+    set /a RUST_VERSION_MAJOR=%%I
+    set /a RUST_VERSION_MINOR=%%J
+)
+
+if %RUST_VERSION_MAJOR% GTR 1 exit /b 0
+if %RUST_VERSION_MAJOR% EQU 1 if %RUST_VERSION_MINOR% GEQ 88 exit /b 0
+
+echo [build.cmd] Rust %RUST_VERSION% is too old. Install Rust 1.88 or newer before building the Slint UI.


The Rust version parsing assumes rustc --version is strictly numeric (e.g. 1.88.0). For toolchains like 1.88.0-nightly (or other suffixes), set /a RUST_VERSION_MINOR=%%J will fail because %%J is not a pure integer. Consider stripping any non-numeric suffix before the numeric comparison, or using rustc -Vv and parsing release: instead.

Copilot · 2026-04-02T09:02:35Z

+#ifndef GENERATED_UI_PATHS_H_GUARD
+#define GENERATED_UI_PATHS_H_GUARD
+
+#define PEERCONNECTION_UI_DIR "@PEERCONNECTION_UI_DIR@"
+
+#endif  // GENERATED_UI_PATHS_H_GUARD


This template header is added but never referenced or generated anywhere in the repo (no configure_file() usage and no references to PEERCONNECTION_UI_DIR). If it’s intended to provide runtime UI paths, wire it into CMake (configure + install/copy) and include it from the relevant code; otherwise consider removing it to avoid dead build artifacts.

Suggested change

#ifndef GENERATED_UI_PATHS_H_GUARD

#define GENERATED_UI_PATHS_H_GUARD

#define PEERCONNECTION_UI_DIR "@PEERCONNECTION_UI_DIR@"

#endif // GENERATED_UI_PATHS_H_GUARD

/* Deprecated header template.

*

* This file was previously intended to be used as a CMake template

* (e.g. via configure_file) to provide a PEERCONNECTION_UI_DIR macro,

* but it is not currently wired into the build or referenced by code.

*

* It is intentionally left empty to avoid maintaining a dead build

* artifact while preserving the file path for any external tooling

* that might still reference it.

*/

sqhh99 and others added 6 commits April 1, 2026 23:59

feat: migrate desktop UI to slint

877170d

style(ui): redesign AppWindow to modern borderless layout with compac…

c719f67

…t layout and IDE-style stats

build: fetch slint from source

c0e63df

refactor: move slint video rendering to gpu textures

e291db6

perf: optimize slint shared pixel video rendering

6f09e67

refactor: reorganize ui and media support layout

c10e7ea

Sqhh99 requested a review from Copilot April 2, 2026 08:54

Copilot started reviewing on behalf of Sqhh99 April 2, 2026 08:55 View session

Copilot AI reviewed Apr 2, 2026

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Feature/slint UI migration#4

Feature/slint UI migration#4
Sqhh99 wants to merge 6 commits intomainfrom
feature/slint-ui-migration

Sqhh99 commented Apr 2, 2026

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-  StopTimers();
+  StopTimers();
+  if (video_renderer_bridge_) {
+    video_renderer_bridge_->DetachLocalRenderer();
+    video_renderer_bridge_->DetachRemoteRenderer();
+  }

-#ifndef GENERATED_UI_PATHS_H_GUARD
-#define GENERATED_UI_PATHS_H_GUARD
-#define PEERCONNECTION_UI_DIR "@PEERCONNECTION_UI_DIR@"
-#endif  // GENERATED_UI_PATHS_H_GUARD
+/* Deprecated header template.
+ *
+ * This file was previously intended to be used as a CMake template
+ * (e.g. via configure_file) to provide a PEERCONNECTION_UI_DIR macro,
+ * but it is not currently wired into the build or referenced by code.
+ *
+ * It is intentionally left empty to avoid maintaining a dead build
+ * artifact while preserving the file path for any external tooling
+ * that might still reference it.
+ */

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Pull request overview

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