[mutter] screen-cast: Track and always record cursors

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit b4a82471918b5cc5ca116dde0532b6bdfa84cb7b
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Jul 29 11:43:44 2020 +0200

    screen-cast: Track and always record cursors
    
    Always force-track the cursor position (so that the X11 backend can keep
    it up to date), and if the cursor wasn't part of the sampled
    framebuffer when reading pixels into CPU memory, draw it in an extra
    pass using cairo after the fact. The cairo based cursor painting only
    happens on the X11 backend, as we otherwise inhibit the hw cursor.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1391

 clutter/clutter/clutter-paint-context.h            |  1 +
 src/backends/meta-cursor-renderer.c                | 12 +++
 src/backends/meta-cursor-renderer.h                |  2 +
 src/backends/meta-screen-cast-area-stream-src.c    | 15 ++++
 src/backends/meta-screen-cast-monitor-stream-src.c | 87 ++++++++++++++++++++++
 src/backends/meta-screen-cast-stream-src.c         | 18 +++++
 src/backends/meta-screen-cast-stream-src.h         |  4 +
 src/backends/meta-screen-cast-window-stream-src.c  | 14 ++++
 src/backends/meta-stage.c                          | 23 +++++-
 9 files changed, 175 insertions(+), 1 deletion(-)
---
diff --git a/clutter/clutter/clutter-paint-context.h b/clutter/clutter/clutter-paint-context.h
index f781728c3b..8461b947ac 100644
--- a/clutter/clutter/clutter-paint-context.h
+++ b/clutter/clutter/clutter-paint-context.h
@@ -33,6 +33,7 @@ typedef enum _ClutterPaintFlag
 {
   CLUTTER_PAINT_FLAG_NONE = 0,
   CLUTTER_PAINT_FLAG_NO_CURSORS = 1 << 0,
+  CLUTTER_PAINT_FLAG_FORCE_CURSORS = 1 << 1,
 } ClutterPaintFlag;
 
 #define CLUTTER_TYPE_PAINT_CONTEXT (clutter_paint_context_get_type ())
diff --git a/src/backends/meta-cursor-renderer.c b/src/backends/meta-cursor-renderer.c
index c8bf6578d5..eacbf67244 100644
--- a/src/backends/meta-cursor-renderer.c
+++ b/src/backends/meta-cursor-renderer.c
@@ -409,6 +409,18 @@ meta_cursor_renderer_get_cursor (MetaCursorRenderer *renderer)
   return priv->displayed_cursor;
 }
 
+gboolean
+meta_cursor_renderer_is_overlay_visible (MetaCursorRenderer *renderer)
+{
+  MetaCursorRendererPrivate *priv =
+    meta_cursor_renderer_get_instance_private (renderer);
+
+  if (!priv->stage_overlay)
+    return FALSE;
+
+  return meta_overlay_is_visible (priv->stage_overlay);
+}
+
 void
 meta_cursor_renderer_add_hw_cursor_inhibitor (MetaCursorRenderer    *renderer,
                                               MetaHwCursorInhibitor *inhibitor)
diff --git a/src/backends/meta-cursor-renderer.h b/src/backends/meta-cursor-renderer.h
index 15b2bfca6e..386d029d08 100644
--- a/src/backends/meta-cursor-renderer.h
+++ b/src/backends/meta-cursor-renderer.h
@@ -67,6 +67,8 @@ void meta_cursor_renderer_force_update (MetaCursorRenderer *renderer);
 
 MetaCursorSprite * meta_cursor_renderer_get_cursor (MetaCursorRenderer *renderer);
 
+gboolean meta_cursor_renderer_is_overlay_visible (MetaCursorRenderer *renderer);
+
 void meta_cursor_renderer_add_hw_cursor_inhibitor (MetaCursorRenderer    *renderer,
                                                    MetaHwCursorInhibitor *inhibitor);
 
diff --git a/src/backends/meta-screen-cast-area-stream-src.c b/src/backends/meta-screen-cast-area-stream-src.c
index d1fe0ae241..c5521422c6 100644
--- a/src/backends/meta-screen-cast-area-stream-src.c
+++ b/src/backends/meta-screen-cast-area-stream-src.c
@@ -343,6 +343,7 @@ meta_screen_cast_area_stream_src_enable (MetaScreenCastStreamSrc *src)
         g_signal_connect_after (cursor_tracker, "cursor-changed",
                                 G_CALLBACK (cursor_changed),
                                 area_src);
+      meta_cursor_tracker_track_position (cursor_tracker);
       G_GNUC_FALLTHROUGH;
     case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
       add_view_painted_watches (area_src,
@@ -350,6 +351,7 @@ meta_screen_cast_area_stream_src_enable (MetaScreenCastStreamSrc *src)
       break;
     case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
       inhibit_hw_cursor (area_src);
+      meta_cursor_tracker_track_position (cursor_tracker);
       add_view_painted_watches (area_src,
                                 META_STAGE_WATCH_AFTER_ACTOR_PAINT);
       break;
@@ -363,6 +365,7 @@ meta_screen_cast_area_stream_src_disable (MetaScreenCastStreamSrc *src)
 {
   MetaScreenCastAreaStreamSrc *area_src =
     META_SCREEN_CAST_AREA_STREAM_SRC (src);
+  MetaScreenCastStream *stream = meta_screen_cast_stream_src_get_stream (src);
   MetaBackend *backend = get_backend (area_src);
   MetaCursorTracker *cursor_tracker = meta_backend_get_cursor_tracker (backend);
   ClutterStage *stage;
@@ -389,6 +392,16 @@ meta_screen_cast_area_stream_src_disable (MetaScreenCastStreamSrc *src)
                           cursor_tracker);
 
   g_clear_handle_id (&area_src->maybe_record_idle_id, g_source_remove);
+
+  switch (meta_screen_cast_stream_get_cursor_mode (stream))
+    {
+    case META_SCREEN_CAST_CURSOR_MODE_METADATA:
+    case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
+      meta_cursor_tracker_untrack_position (cursor_tracker);
+      break;
+    case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
+      break;
+    }
 }
 
 static gboolean
@@ -418,6 +431,7 @@ meta_screen_cast_area_stream_src_record_to_buffer (MetaScreenCastStreamSrc  *src
       paint_flags |= CLUTTER_PAINT_FLAG_NO_CURSORS;
       break;
     case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
+      paint_flags |= CLUTTER_PAINT_FLAG_FORCE_CURSORS;
       break;
     }
 
@@ -458,6 +472,7 @@ meta_screen_cast_area_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc
       paint_flags |= CLUTTER_PAINT_FLAG_NO_CURSORS;
       break;
     case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
+      paint_flags |= CLUTTER_PAINT_FLAG_FORCE_CURSORS;
       break;
     }
   clutter_stage_paint_to_framebuffer (stage, framebuffer,
diff --git a/src/backends/meta-screen-cast-monitor-stream-src.c 
b/src/backends/meta-screen-cast-monitor-stream-src.c
index df8029aa94..cb6e81b288 100644
--- a/src/backends/meta-screen-cast-monitor-stream-src.c
+++ b/src/backends/meta-screen-cast-monitor-stream-src.c
@@ -343,6 +343,7 @@ meta_screen_cast_monitor_stream_src_enable (MetaScreenCastStreamSrc *src)
         g_signal_connect_after (cursor_tracker, "cursor-changed",
                                 G_CALLBACK (cursor_changed),
                                 monitor_src);
+      meta_cursor_tracker_track_position (cursor_tracker);
       G_GNUC_FALLTHROUGH;
     case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
       add_view_painted_watches (monitor_src,
@@ -350,6 +351,7 @@ meta_screen_cast_monitor_stream_src_enable (MetaScreenCastStreamSrc *src)
       break;
     case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
       inhibit_hw_cursor (monitor_src);
+      meta_cursor_tracker_track_position (cursor_tracker);
       add_view_painted_watches (monitor_src,
                                 META_STAGE_WATCH_AFTER_PAINT);
       break;
@@ -363,6 +365,7 @@ meta_screen_cast_monitor_stream_src_disable (MetaScreenCastStreamSrc *src)
 {
   MetaScreenCastMonitorStreamSrc *monitor_src =
     META_SCREEN_CAST_MONITOR_STREAM_SRC (src);
+  MetaScreenCastStream *stream = meta_screen_cast_stream_src_get_stream (src);
   MetaBackend *backend = get_backend (monitor_src);
   MetaCursorTracker *cursor_tracker = meta_backend_get_cursor_tracker (backend);
   ClutterStage *stage;
@@ -387,6 +390,79 @@ meta_screen_cast_monitor_stream_src_disable (MetaScreenCastStreamSrc *src)
                           cursor_tracker);
   g_clear_signal_handler (&monitor_src->cursor_changed_handler_id,
                           cursor_tracker);
+
+  switch (meta_screen_cast_stream_get_cursor_mode (stream))
+    {
+    case META_SCREEN_CAST_CURSOR_MODE_METADATA:
+    case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
+      meta_cursor_tracker_untrack_position (cursor_tracker);
+      break;
+    case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
+      break;
+    }
+}
+
+static void
+maybe_paint_cursor_sprite (MetaScreenCastMonitorStreamSrc *monitor_src,
+                           uint8_t                        *data)
+{
+  MetaScreenCastStreamSrc *src = META_SCREEN_CAST_STREAM_SRC (monitor_src);
+  MetaBackend *backend = get_backend (monitor_src);
+  MetaCursorRenderer *cursor_renderer =
+    meta_backend_get_cursor_renderer (backend);
+  MetaCursorSprite *cursor_sprite;
+  CoglTexture *sprite_texture;
+  int sprite_width, sprite_height, sprite_stride;
+  float sprite_scale;
+  uint8_t *sprite_data;
+  cairo_surface_t *sprite_surface;
+  graphene_rect_t sprite_rect;
+  int width, height, stride;
+  cairo_surface_t *surface;
+  cairo_t *cr;
+
+  cursor_sprite = meta_cursor_renderer_get_cursor (cursor_renderer);
+  if (!cursor_sprite)
+    return;
+
+  if (meta_cursor_renderer_is_overlay_visible (cursor_renderer))
+    return;
+
+  sprite_rect = meta_cursor_renderer_calculate_rect (cursor_renderer,
+                                                     cursor_sprite);
+  sprite_texture = meta_cursor_sprite_get_cogl_texture (cursor_sprite);
+  sprite_width = cogl_texture_get_width (sprite_texture);
+  sprite_height = cogl_texture_get_height (sprite_texture);
+  sprite_stride = sprite_width * 4;
+  sprite_scale = meta_cursor_sprite_get_texture_scale (cursor_sprite);
+  sprite_data = g_new0 (uint8_t, sprite_stride * sprite_height);
+  cogl_texture_get_data (sprite_texture,
+                         CLUTTER_CAIRO_FORMAT_ARGB32,
+                         sprite_stride,
+                         sprite_data);
+  sprite_surface = cairo_image_surface_create_for_data (sprite_data,
+                                                        CAIRO_FORMAT_ARGB32,
+                                                        sprite_width,
+                                                        sprite_height,
+                                                        sprite_stride);
+  cairo_surface_set_device_scale (sprite_surface, sprite_scale, sprite_scale);
+
+  stride = meta_screen_cast_stream_src_get_stride (src);
+  width = meta_screen_cast_stream_src_get_width (src);
+  height = meta_screen_cast_stream_src_get_height (src);
+  surface = cairo_image_surface_create_for_data (data,
+                                                 CAIRO_FORMAT_ARGB32,
+                                                 width, height, stride);
+
+  cr = cairo_create (surface);
+  cairo_set_source_surface (cr, sprite_surface,
+                            sprite_rect.origin.x,
+                            sprite_rect.origin.y);
+  cairo_paint (cr);
+  cairo_destroy (cr);
+  cairo_surface_destroy (sprite_surface);
+  cairo_surface_destroy (surface);
+  g_free (sprite_data);
 }
 
 static gboolean
@@ -396,6 +472,7 @@ meta_screen_cast_monitor_stream_src_record_to_buffer (MetaScreenCastStreamSrc  *
 {
   MetaScreenCastMonitorStreamSrc *monitor_src =
     META_SCREEN_CAST_MONITOR_STREAM_SRC (src);
+  MetaScreenCastStream *stream = meta_screen_cast_stream_src_get_stream (src);
   ClutterStage *stage;
   MetaMonitor *monitor;
   MetaLogicalMonitor *logical_monitor;
@@ -405,6 +482,16 @@ meta_screen_cast_monitor_stream_src_record_to_buffer (MetaScreenCastStreamSrc  *
   stage = get_stage (monitor_src);
   clutter_stage_capture_into (stage, FALSE, &logical_monitor->rect, data);
 
+  switch (meta_screen_cast_stream_get_cursor_mode (stream))
+    {
+    case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
+      maybe_paint_cursor_sprite (monitor_src, data);
+      break;
+    case META_SCREEN_CAST_CURSOR_MODE_METADATA:
+    case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
+      break;
+    }
+
   return TRUE;
 }
 
diff --git a/src/backends/meta-screen-cast-stream-src.c b/src/backends/meta-screen-cast-stream-src.c
index 45eb3852f8..198cc68955 100644
--- a/src/backends/meta-screen-cast-stream-src.c
+++ b/src/backends/meta-screen-cast-stream-src.c
@@ -1058,6 +1058,24 @@ meta_screen_cast_stream_src_get_stride (MetaScreenCastStreamSrc *src)
   return priv->video_stride;
 }
 
+int
+meta_screen_cast_stream_src_get_width (MetaScreenCastStreamSrc *src)
+{
+  MetaScreenCastStreamSrcPrivate *priv =
+    meta_screen_cast_stream_src_get_instance_private (src);
+
+  return priv->stream_width;
+}
+
+int
+meta_screen_cast_stream_src_get_height (MetaScreenCastStreamSrc *src)
+{
+  MetaScreenCastStreamSrcPrivate *priv =
+    meta_screen_cast_stream_src_get_instance_private (src);
+
+  return priv->stream_height;
+}
+
 MetaScreenCastStream *
 meta_screen_cast_stream_src_get_stream (MetaScreenCastStreamSrc *src)
 {
diff --git a/src/backends/meta-screen-cast-stream-src.h b/src/backends/meta-screen-cast-stream-src.h
index 7e5ceace77..a2f681793f 100644
--- a/src/backends/meta-screen-cast-stream-src.h
+++ b/src/backends/meta-screen-cast-stream-src.h
@@ -80,6 +80,10 @@ gboolean meta_screen_cast_stream_src_pending_follow_up_frame (MetaScreenCastStre
 
 int meta_screen_cast_stream_src_get_stride (MetaScreenCastStreamSrc *src);
 
+int meta_screen_cast_stream_src_get_width (MetaScreenCastStreamSrc *src);
+
+int meta_screen_cast_stream_src_get_height (MetaScreenCastStreamSrc *src);
+
 MetaScreenCastStream * meta_screen_cast_stream_src_get_stream (MetaScreenCastStreamSrc *src);
 
 gboolean meta_screen_cast_stream_src_draw_cursor_into (MetaScreenCastStreamSrc  *src,
diff --git a/src/backends/meta-screen-cast-window-stream-src.c 
b/src/backends/meta-screen-cast-window-stream-src.c
index e80cd5e360..d41b6c41c9 100644
--- a/src/backends/meta-screen-cast-window-stream-src.c
+++ b/src/backends/meta-screen-cast-window-stream-src.c
@@ -23,6 +23,7 @@
 #include "backends/meta-screen-cast-window-stream-src.h"
 
 #include "backends/meta-backend-private.h"
+#include "backends/meta-cursor-tracker-private.h"
 #include "backends/meta-screen-cast-session.h"
 #include "backends/meta-screen-cast-window.h"
 #include "backends/meta-screen-cast-window-stream.h"
@@ -306,6 +307,8 @@ static void
 meta_screen_cast_window_stream_src_stop (MetaScreenCastWindowStreamSrc *window_src)
 
 {
+  MetaScreenCastStreamSrc *src = META_SCREEN_CAST_STREAM_SRC (window_src);
+  MetaScreenCastStream *stream = meta_screen_cast_stream_src_get_stream (src);
   MetaBackend *backend = get_backend (window_src);
   MetaCursorTracker *cursor_tracker = meta_backend_get_cursor_tracker (backend);
 
@@ -320,6 +323,16 @@ meta_screen_cast_window_stream_src_stop (MetaScreenCastWindowStreamSrc *window_s
                           cursor_tracker);
   g_clear_signal_handler (&window_src->cursor_changed_handler_id,
                           cursor_tracker);
+
+  switch (meta_screen_cast_stream_get_cursor_mode (stream))
+    {
+    case META_SCREEN_CAST_CURSOR_MODE_METADATA:
+    case META_SCREEN_CAST_CURSOR_MODE_EMBEDDED:
+      meta_cursor_tracker_untrack_position (cursor_tracker);
+      break;
+    case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
+      break;
+    }
 }
 
 static void
@@ -438,6 +451,7 @@ meta_screen_cast_window_stream_src_enable (MetaScreenCastStreamSrc *src)
         g_signal_connect_after (cursor_tracker, "cursor-changed",
                                 G_CALLBACK (cursor_changed),
                                 window_src);
+      meta_cursor_tracker_track_position (cursor_tracker);
       break;
     case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
       break;
diff --git a/src/backends/meta-stage.c b/src/backends/meta-stage.c
index af56a18f55..f2040362f7 100644
--- a/src/backends/meta-stage.c
+++ b/src/backends/meta-stage.c
@@ -25,6 +25,7 @@
 #include "backends/meta-stage-private.h"
 
 #include "backends/meta-backend-private.h"
+#include "backends/meta-cursor-tracker-private.h"
 #include "clutter/clutter-mutter.h"
 #include "meta/meta-backend.h"
 #include "meta/meta-monitor-manager.h"
@@ -127,7 +128,9 @@ meta_overlay_paint (MetaOverlay         *overlay,
   if (!overlay->texture)
     return;
 
-  if (!overlay->is_visible)
+  if (!overlay->is_visible &&
+      !(clutter_paint_context_get_paint_flags (paint_context) &
+        CLUTTER_PAINT_FLAG_FORCE_CURSORS))
     return;
 
   framebuffer = clutter_paint_context_get_framebuffer (paint_context);
@@ -207,10 +210,28 @@ meta_stage_paint (ClutterActor        *actor,
 
   g_signal_emit (stage, signals[ACTORS_PAINTED], 0);
 
+  if ((clutter_paint_context_get_paint_flags (paint_context) &
+       CLUTTER_PAINT_FLAG_FORCE_CURSORS))
+    {
+      MetaCursorTracker *cursor_tracker =
+        meta_backend_get_cursor_tracker (stage->backend);
+
+      meta_cursor_tracker_track_position (cursor_tracker);
+    }
+
   if (!(clutter_paint_context_get_paint_flags (paint_context) &
         CLUTTER_PAINT_FLAG_NO_CURSORS))
     g_list_foreach (stage->overlays, (GFunc) meta_overlay_paint, paint_context);
 
+  if ((clutter_paint_context_get_paint_flags (paint_context) &
+       CLUTTER_PAINT_FLAG_FORCE_CURSORS))
+    {
+      MetaCursorTracker *cursor_tracker =
+        meta_backend_get_cursor_tracker (stage->backend);
+
+      meta_cursor_tracker_untrack_position (cursor_tracker);
+    }
+
   if (view)
     {
       notify_watchers_for_mode (stage, view, paint_context,