From e6ad337d633c145c48a5a4ae54968c14c16081c7 Mon Sep 17 00:00:00 2001
From: Jan Grulich <grulja@gmail.com>
Date: Wed, 19 Jun 2024 10:26:37 +0200
Subject: [PATCH] PipeWire capture: hide cursor when it goes off screen or is
 not visible

Set cursor position to (-1,-1) to indicate it's not valid when it goes
off the screen or it gets hidden by the compositor. Compositors indicate
invalid or hidden cursor by unsetting the cursor id in cursor metadata
and using spa_meta_cursor_is_valid() will tell us the needed information
for this.

Bug: chromium:346608851
Change-Id: I71b3222ca161b7fd8e964f4f4e12b9983179beba
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/355080
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Jan Grulich <grulja@gmail.com>
Cr-Commit-Position: refs/heads/main@{#42548}
---
 .../wayland/mouse_cursor_monitor_pipewire.cc  | 14 ++++--
 .../linux/wayland/shared_screencast_stream.cc | 48 +++++++++++--------
 2 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/modules/desktop_capture/linux/wayland/mouse_cursor_monitor_pipewire.cc b/modules/desktop_capture/linux/wayland/mouse_cursor_monitor_pipewire.cc
index 3d33b0fbb8..00b07f341b 100644
--- a/modules/desktop_capture/linux/wayland/mouse_cursor_monitor_pipewire.cc
+++ b/modules/desktop_capture/linux/wayland/mouse_cursor_monitor_pipewire.cc
@@ -40,6 +40,14 @@ void MouseCursorMonitorPipeWire::Capture() {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   RTC_DCHECK(callback_);
 
+  absl::optional<DesktopVector> mouse_cursor_position =
+      options_.screencast_stream()->CaptureCursorPosition();
+  // Invalid cursor or position
+  if (!mouse_cursor_position) {
+    callback_->OnMouseCursor(nullptr);
+    return;
+  }
+
   std::unique_ptr<MouseCursor> mouse_cursor =
       options_.screencast_stream()->CaptureCursor();
 
@@ -48,11 +56,7 @@ void MouseCursorMonitorPipeWire::Capture() {
   }
 
   if (mode_ == SHAPE_AND_POSITION) {
-    absl::optional<DesktopVector> mouse_cursor_position =
-        options_.screencast_stream()->CaptureCursorPosition();
-    if (mouse_cursor_position) {
-      callback_->OnMouseCursorPosition(mouse_cursor_position.value());
-    }
+    callback_->OnMouseCursorPosition(mouse_cursor_position.value());
   }
 }
 
diff --git a/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc b/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc
index 90273aba3e..047ad5a857 100644
--- a/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc
+++ b/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc
@@ -680,32 +680,38 @@ void SharedScreenCastStreamPrivate::ProcessBuffer(pw_buffer* buffer) {
     const struct spa_meta_cursor* cursor =
         static_cast<struct spa_meta_cursor*>(spa_buffer_find_meta_data(
             spa_buffer, SPA_META_Cursor, sizeof(*cursor)));
-    if (cursor && spa_meta_cursor_is_valid(cursor)) {
-      struct spa_meta_bitmap* bitmap = nullptr;
 
-      if (cursor->bitmap_offset)
-        bitmap =
-            SPA_MEMBER(cursor, cursor->bitmap_offset, struct spa_meta_bitmap);
+    if (cursor) {
+      if (spa_meta_cursor_is_valid(cursor)) {
+        struct spa_meta_bitmap* bitmap = nullptr;
 
-      if (bitmap && bitmap->size.width > 0 && bitmap->size.height > 0) {
-        const uint8_t* bitmap_data =
-            SPA_MEMBER(bitmap, bitmap->offset, uint8_t);
-        BasicDesktopFrame* mouse_frame = new BasicDesktopFrame(
-            DesktopSize(bitmap->size.width, bitmap->size.height));
-        mouse_frame->CopyPixelsFrom(
-            bitmap_data, bitmap->stride,
-            DesktopRect::MakeWH(bitmap->size.width, bitmap->size.height));
-        mouse_cursor_ = std::make_unique<MouseCursor>(
-            mouse_frame, DesktopVector(cursor->hotspot.x, cursor->hotspot.y));
+        if (cursor->bitmap_offset)
+          bitmap =
+              SPA_MEMBER(cursor, cursor->bitmap_offset, struct spa_meta_bitmap);
+
+        if (bitmap && bitmap->size.width > 0 && bitmap->size.height > 0) {
+          const uint8_t* bitmap_data =
+              SPA_MEMBER(bitmap, bitmap->offset, uint8_t);
+          BasicDesktopFrame* mouse_frame = new BasicDesktopFrame(
+              DesktopSize(bitmap->size.width, bitmap->size.height));
+          mouse_frame->CopyPixelsFrom(
+              bitmap_data, bitmap->stride,
+              DesktopRect::MakeWH(bitmap->size.width, bitmap->size.height));
+          mouse_cursor_ = std::make_unique<MouseCursor>(
+              mouse_frame, DesktopVector(cursor->hotspot.x, cursor->hotspot.y));
+
+          if (observer_) {
+            observer_->OnCursorShapeChanged();
+          }
+        }
+        mouse_cursor_position_.set(cursor->position.x, cursor->position.y);
 
         if (observer_) {
-          observer_->OnCursorShapeChanged();
+          observer_->OnCursorPositionChanged();
         }
-      }
-      mouse_cursor_position_.set(cursor->position.x, cursor->position.y);
-
-      if (observer_) {
-        observer_->OnCursorPositionChanged();
+      } else {
+        // Indicate an invalid cursor
+        mouse_cursor_position_.set(-1, -1);
       }
     }
   }