Avoid animating single frame cursors

Currently to determine if a cursor is animated or not we check the
cursor theme delay.

This doesn't work in practice as by default many cursor themes have a
delay of 50 set even if they don't animate.

This comes from xcursorgen which specifies a delay of 50ms if there
isn't anything set in the config.
(https://github.com/freedesktop/xcursorgen/blob/master/xcursorgen.c#L92)

Given many themes will have a delay we should also check the number of
images in a given cursor.

In order to do that without a double lookup QWaylandCursor needed to
return the native wl_cursor, not wl_cursor_image and move the relevant
logic.

Change-Id: Ie782ace8054910ae76e61cab33ceca0377194929
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

3 files changed, 15 insertions, 16 deletions

diff --git a/src/client/qwaylandcursor.cpp b/src/client/qwaylandcursor.cpp
index 4356b23a0..1d3d88bea 100644
--- a/src/client/qwaylandcursor.cpp
+++ b/src/client/qwaylandcursor.cpp
@@ -219,7 +219,7 @@ wl_cursor *QWaylandCursorTheme::requestCursor(WaylandCursor shape)
     return nullptr;
 }
 
-::wl_cursor_image *QWaylandCursorTheme::cursorImage(Qt::CursorShape shape, uint millisecondsIntoAnimation)
+::wl_cursor *QWaylandCursorTheme::cursor(Qt::CursorShape shape)
 {
     struct wl_cursor *waylandCursor = nullptr;
 
@@ -237,15 +237,7 @@ wl_cursor *QWaylandCursorTheme::requestCursor(WaylandCursor shape)
         return nullptr;
     }
 
-    int frame = wl_cursor_frame(waylandCursor, millisecondsIntoAnimation);
-    ::wl_cursor_image *image = waylandCursor->images[frame];
-    ::wl_buffer *buffer = wl_cursor_image_get_buffer(image);
-    if (!buffer) {
-        qCWarning(lcQpaWayland) << "Could not find buffer for cursor";
-        return nullptr;
-    }
-
-    return image;
+    return waylandCursor;
 }
 
 QWaylandCursor::QWaylandCursor(QWaylandDisplay *display)
diff --git a/src/client/qwaylandcursor_p.h b/src/client/qwaylandcursor_p.h
index a4605f3d2..751ffa68b 100644
--- a/src/client/qwaylandcursor_p.h
+++ b/src/client/qwaylandcursor_p.h
@@ -75,7 +75,7 @@ class Q_WAYLAND_CLIENT_EXPORT QWaylandCursorTheme
 public:
     static QWaylandCursorTheme *create(QWaylandShm *shm, int size, const QString &themeName);
     ~QWaylandCursorTheme();
-    ::wl_cursor_image *cursorImage(Qt::CursorShape shape, uint millisecondsIntoAnimation = 0);
+    ::wl_cursor *cursor(Qt::CursorShape shape);
 
 private:
     enum WaylandCursor {
@@ -129,7 +129,6 @@ public:
     void setPos(const QPoint &pos) override;
 
     static QSharedPointer<QWaylandBuffer> cursorBitmapBuffer(QWaylandDisplay *display, const QCursor *cursor);
-    struct wl_cursor_image *cursorImage(Qt::CursorShape shape);
 
 private:
     QWaylandDisplay *mDisplay = nullptr;
diff --git a/src/client/qwaylandinputdevice.cpp b/src/client/qwaylandinputdevice.cpp
index a4098edd3..d812918e7 100644
--- a/src/client/qwaylandinputdevice.cpp
+++ b/src/client/qwaylandinputdevice.cpp
@@ -283,8 +283,8 @@ void QWaylandInputDevice::Pointer::updateCursorTheme()
     if (!mCursor.theme)
         return; // A warning has already been printed in loadCursorTheme
 
-    if (auto *arrow = mCursor.theme->cursorImage(Qt::ArrowCursor)) {
-        int arrowPixelSize = qMax(arrow->width, arrow->height); // Not all cursor themes are square
+    if (auto *arrow = mCursor.theme->cursor(Qt::ArrowCursor)) {
+        int arrowPixelSize = qMax(arrow->images[0]->width, arrow->images[0]->height); // Not all cursor themes are square
         while (scale > 1 && arrowPixelSize / scale < cursorSize())
             --scale;
     } else {
@@ -326,12 +326,20 @@ void QWaylandInputDevice::Pointer::updateCursor()
 
     // Set from shape using theme
     uint time = seat()->mCursor.animationTimer.elapsed();
-    if (struct ::wl_cursor_image *image = mCursor.theme->cursorImage(shape, time)) {
+
+    if (struct ::wl_cursor *waylandCursor = mCursor.theme->cursor(shape)) {
+        int frame = wl_cursor_frame(waylandCursor, time);
+        ::wl_cursor_image *image = waylandCursor->images[frame];
+
         struct wl_buffer *buffer = wl_cursor_image_get_buffer(image);
+        if (!buffer) {
+            qCWarning(lcQpaWayland) << "Could not find buffer for cursor" << shape;
+            return;
+        }
         int bufferScale = mCursor.themeBufferScale;
         QPoint hotspot = QPoint(image->hotspot_x, image->hotspot_y) / bufferScale;
         QSize size = QSize(image->width, image->height) / bufferScale;
-        bool animated = image->delay > 0;
+        bool animated = waylandCursor->image_count > 1 && image->delay > 0;
         getOrCreateCursorSurface()->update(buffer, hotspot, size, bufferScale, animated);
         return;
     }