tests/cursor: Test Wayland client using wp_viewport for scaling

This test doesn't use a separate reference image, but verifies the
result is identical to that of the built in cursor.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3859>

src/tests/cursor-tests.c

@@ -32,6 +32,9 @@
 #include "tests/meta-wayland-test-driver.h"
 #include "tests/meta-wayland-test-utils.h"
 
+#define CURSOR_SCALE_METHOD_BUFFER_SCALE "buffer-scale"
+#define CURSOR_SCALE_METHOD_VIEWPORT "viewport"
+
 struct _MetaCrossOverlay
 {
   GObject parent;
@@ -278,6 +281,52 @@ meta_wait_for_window_cursor (void)
     g_main_context_iteration (NULL, TRUE);
 }
 
+static void
+test_client_cursor (ClutterStageView *view,
+                    const char       *scale_method,
+                    MetaCursor        cursor,
+                    const char       *ref_test_name,
+                    int               ref_test_seq,
+                    MetaReftestFlag   ref_test_flags)
+{
+  const char *cursor_name;
+  MetaWaylandTestClient *test_client;
+  MetaWindow *window;
+  MetaWindowActor *window_actor;
+
+  g_debug ("Testing cursor with client using %s", scale_method);
+
+  cursor_name = meta_cursor_get_name (cursor);
+  test_client =
+    meta_wayland_test_client_new_with_args (test_context,
+                                            "cursor-tests-client",
+                                            scale_method,
+                                            cursor_name,
+                                            NULL);
+  meta_wayland_test_driver_wait_for_sync_point (test_driver, 0);
+
+  window = meta_find_window_from_title (test_context,
+                                        "cursor-tests-surface");
+  g_assert_nonnull (window);
+  meta_wait_for_window_shown (window);
+  window_actor = meta_window_actor_from_window (window);
+  g_assert_nonnull (window_actor);
+  meta_wait_for_window_cursor ();
+
+  meta_ref_test_verify_view (view,
+                             ref_test_name,
+                             ref_test_seq,
+                             ref_test_flags);
+
+  meta_wayland_test_driver_emit_sync_event (test_driver, 0);
+
+  g_object_add_weak_pointer (G_OBJECT (window_actor),
+                             (gpointer *) &window_actor);
+  meta_wayland_test_client_finish (test_client);
+  while (window_actor)
+    g_main_context_iteration (NULL, TRUE);
+}
+
 static void
 meta_test_native_cursor_scaling (void)
 {
@@ -288,7 +337,6 @@ meta_test_native_cursor_scaling (void)
   ClutterActor *overlay_actor;
   ClutterStageView *view;
   MetaCursor cursor;
-  const char *cursor_name;
   struct {
     int width;
     int height;
@@ -330,10 +378,7 @@ meta_test_native_cursor_scaling (void)
 
   for (i = 0; i < G_N_ELEMENTS (test_cases); i++)
     {
-      MetaWaylandTestClient *test_client;
       g_autofree char *ref_test_name = NULL;
-      MetaWindow *window;
-      MetaWindowActor *window_actor;
 
       g_debug ("Testing monitor resolution %dx%d with scale %f and "
                "%s layout mode",
@@ -353,34 +398,16 @@ meta_test_native_cursor_scaling (void)
                                  0,
                                  meta_ref_test_determine_ref_test_flag ());
 
-      cursor_name = meta_cursor_get_name (cursor);
+      test_client_cursor (view,
-      test_client =
+                          CURSOR_SCALE_METHOD_BUFFER_SCALE,
-        meta_wayland_test_client_new_with_args (test_context,
+                          cursor,
-                                                "cursor-tests-client",
+                          ref_test_name, 1,
-                                                cursor_name,
-                                                NULL);
-      meta_wayland_test_driver_wait_for_sync_point (test_driver, 0);
-
-      window = meta_find_window_from_title (test_context,
-                                            "cursor-tests-surface");
-      g_assert_nonnull (window);
-      meta_wait_for_window_shown (window);
-      window_actor = meta_window_actor_from_window (window);
-      g_assert_nonnull (window_actor);
-      meta_wait_for_window_cursor ();
-
-      meta_ref_test_verify_view (view,
-                                 ref_test_name,
-                                 1,
                           meta_ref_test_determine_ref_test_flag ());
-
+      test_client_cursor (view,
-      meta_wayland_test_driver_emit_sync_event (test_driver, 0);
+                          CURSOR_SCALE_METHOD_VIEWPORT,
-
+                          cursor,
-      g_object_add_weak_pointer (G_OBJECT (window_actor),
+                          ref_test_name, 0,
-                                 (gpointer *) &window_actor);
+                          META_REFTEST_FLAG_NONE);
-      meta_wayland_test_client_finish (test_client);
-      while (window_actor)
-        g_main_context_iteration (NULL, TRUE);
     }
 
   clutter_actor_destroy (overlay_actor);

src/tests/wayland-test-clients/cursor-tests-client.c

@@ -22,9 +22,17 @@
 
 #include "wayland-test-client-utils.h"
 
+typedef enum _CursorScaleMethod
+{
+  CURSOR_SCALE_METHOD_BUFFER_SCALE,
+  CURSOR_SCALE_METHOD_VIEWPORT,
+} CursorScaleMethod;
+
+static CursorScaleMethod scale_method;
 static char *cursor_name;
 
 static struct wl_surface *cursor_surface;
+static struct wp_viewport *cursor_viewport;
 
 static void
 on_pointer_enter (WaylandSurface    *surface,
@@ -40,6 +48,27 @@ on_pointer_enter (WaylandSurface    *surface,
   int num, denom;
   float scale;
   int ceiled_scale;
+  int effective_theme_size = 0;
+  float image_scale;
+  int hotspot_x = 0;
+  int hotspot_y = 0;
+
+  if (!cursor_surface)
+    cursor_surface = wl_compositor_create_surface (display->compositor);
+
+  switch (scale_method)
+    {
+    case CURSOR_SCALE_METHOD_BUFFER_SCALE:
+      g_clear_pointer (&cursor_viewport, wp_viewport_destroy);
+      break;
+    case CURSOR_SCALE_METHOD_VIEWPORT:
+      if (!cursor_viewport)
+        {
+          cursor_viewport = wp_viewporter_get_viewport (display->viewporter,
+                                                        cursor_surface);
+        }
+      break;
+    }
 
   theme_size = lookup_property_int (display, "cursor-theme-size");
   num = lookup_property_int (display, "scale-num");
@@ -47,27 +76,62 @@ on_pointer_enter (WaylandSurface    *surface,
   scale = (float) num / (float) denom;
   ceiled_scale = (int) ceilf (scale);
 
+  switch (scale_method)
+    {
+    case CURSOR_SCALE_METHOD_BUFFER_SCALE:
+      effective_theme_size = (int) (theme_size * ceilf (scale));
+      break;
+    case CURSOR_SCALE_METHOD_VIEWPORT:
+      effective_theme_size = (int) (theme_size * ceilf (scale));
+      break;
+    }
+
+  g_debug ("Using effective cursor theme size %d for logical size %d "
+           "and actual scale %f",
+           effective_theme_size, theme_size, scale);
+
   cursor_theme = wl_cursor_theme_load (NULL,
-                                       (int) (theme_size * ceilf (scale)),
+                                       effective_theme_size,
                                        display->shm);
   cursor = wl_cursor_theme_get_cursor (cursor_theme, cursor_name);
-
-  if (!cursor_surface)
-    cursor_surface = wl_compositor_create_surface (display->compositor);
-
   image = cursor->images[0];
   buffer = wl_cursor_image_get_buffer (image);
   g_assert_nonnull (buffer);
 
+  image_scale = ((float) image->width / theme_size);
+
+  switch (scale_method)
+    {
+    case CURSOR_SCALE_METHOD_BUFFER_SCALE:
+      hotspot_x = (int) roundf (image->hotspot_x / ceiled_scale);
+      hotspot_y = (int) roundf (image->hotspot_y / ceiled_scale);
+      break;
+    case CURSOR_SCALE_METHOD_VIEWPORT:
+      hotspot_x = (int) roundf (image->hotspot_x / image_scale);
+      hotspot_y = (int) roundf (image->hotspot_y / image_scale);
+      break;
+    }
+
   wl_pointer_set_cursor (pointer, serial,
                          cursor_surface,
-                         image->hotspot_x / ceiled_scale,
+                         hotspot_x, hotspot_y);
-                         image->hotspot_y / ceiled_scale);
   wl_surface_attach (cursor_surface, buffer, 0, 0);
-  wl_surface_damage (cursor_surface, 0, 0,
+  wl_surface_damage_buffer (cursor_surface, 0, 0,
                             image->width, image->height);
+
+  switch (scale_method)
+    {
+    case CURSOR_SCALE_METHOD_BUFFER_SCALE:
       wl_surface_set_buffer_scale (cursor_surface,
                                    ceiled_scale);
+      break;
+    case CURSOR_SCALE_METHOD_VIEWPORT:
+      wp_viewport_set_destination (cursor_viewport,
+                                   (int) roundf (image->width / image_scale),
+                                   (int) roundf (image->height / image_scale));
+      break;
+    }
+
   wl_surface_commit (cursor_surface);
 
   wl_cursor_theme_destroy (cursor_theme);
@@ -82,7 +146,14 @@ main (int    argc,
   g_autoptr (WaylandDisplay) display = NULL;
   g_autoptr (WaylandSurface) surface = NULL;
 
-  cursor_name = argv[1];
+  if (g_strcmp0 (argv[1], "buffer-scale") == 0)
+    scale_method = CURSOR_SCALE_METHOD_BUFFER_SCALE;
+  else if (g_strcmp0 (argv[1], "viewport") == 0)
+    scale_method = CURSOR_SCALE_METHOD_VIEWPORT;
+  else
+    g_error ("Missing scale method");
+
+  cursor_name = argv[2];
 
   display = wayland_display_new (WAYLAND_DISPLAY_CAPABILITY_TEST_DRIVER);
   surface = wayland_surface_new (display,