Add support for bitmap cursors

So far QtWayland did not support custom bitmap/pixmap QCursors.
This change adds support for them by creating a QWaylandShmBuffer and
copying the pixmap data into that buffer. The internal API to set
cursors images is changed to not only rely on wl_cursor_image, but also
allow to just set the buffer with a specific size and a hot spot.

The created WaylandShmBuffer is passed around as a shared pointer, so
that it can be automatically cleaned up once the cursor image is no
longer used on any seat.

Task-number: QTBUG-51604
Change-Id: I1f1ee87f03186c3d564468d3e8ea2a3141d7e2fb
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>
Reviewed-by: Johan Helsing <johan.helsing@theqtcompany.com>

1 files changed, 28 insertions, 1 deletions

diff --git a/src/client/qwaylandcursor.cpp b/src/client/qwaylandcursor.cpp
index 8dfc95c36..8d91e3896 100644
--- a/src/client/qwaylandcursor.cpp
+++ b/src/client/qwaylandcursor.cpp
@@ -85,7 +85,8 @@ struct wl_cursor_image *QWaylandCursor::cursorImage(Qt::CursorShape newShape)
     if (newShape < Qt::BitmapCursor) {
         waylandCursor = requestCursor((WaylandCursor)newShape);
     } else if (newShape == Qt::BitmapCursor) {
-        //TODO: Bitmap cursor logic
+        // cannot create a wl_cursor_image for a CursorShape
+        return Q_NULLPTR;
     } else {
         //TODO: Custom cursor logic (for resize arrows)
     }
@@ -105,12 +106,28 @@ struct wl_cursor_image *QWaylandCursor::cursorImage(Qt::CursorShape newShape)
     return image;
 }
 
+QSharedPointer<QWaylandBuffer> QWaylandCursor::cursorBitmapImage(const QCursor *cursor)
+{
+    if (cursor->shape() != Qt::BitmapCursor)
+        return QSharedPointer<QWaylandShmBuffer>();
+
+    const QImage &img = cursor->pixmap().toImage();
+    QSharedPointer<QWaylandShmBuffer> buffer(new QWaylandShmBuffer(mDisplay, img.size(), img.format()));
+    memcpy(buffer->image()->bits(), img.bits(), img.byteCount());
+    return buffer;
+}
+
 void QWaylandCursor::changeCursor(QCursor *cursor, QWindow *window)
 {
     Q_UNUSED(window)
 
     const Qt::CursorShape newShape = cursor ? cursor->shape() : Qt::ArrowCursor;
 
+    if (newShape == Qt::BitmapCursor) {
+        mDisplay->setCursor(cursorBitmapImage(cursor), cursor->hotSpot());
+        return;
+    }
+
     struct wl_cursor_image *image = cursorImage(newShape);
     if (!image) {
         return;
@@ -130,6 +147,16 @@ void QWaylandDisplay::setCursor(struct wl_buffer *buffer, struct wl_cursor_image
     }
 }
 
+void QWaylandDisplay::setCursor(const QSharedPointer<QWaylandBuffer> &buffer, const QPoint &hotSpot)
+{
+    /* Qt doesn't tell us which input device we should set the cursor
+     * for, so set it for all devices. */
+    for (int i = 0; i < mInputDevices.count(); i++) {
+        QWaylandInputDevice *inputDevice = mInputDevices.at(i);
+        inputDevice->setCursor(buffer, hotSpot);
+    }
+}
+
 QWaylandInputDevice *QWaylandDisplay::defaultInputDevice() const
 {
     return mInputDevices.isEmpty() ? 0 : mInputDevices.first();