1 files changed, 67 insertions, 0 deletions
diff --git a/compat/check-visible.cpp b/compat/check-visible.cpp
new file mode 100644
index 00000000..6030ad92
--- /dev/null
+++ b/compat/check-visible.cpp
@@ -0,0 +1,67 @@
+#include "check-visible.hpp"
+
+#if defined _WIN32
+
+#include "timer.hpp"
+
+#include <QMutexLocker>
+
+#include <windows.h>
+
+static constexpr int visible_timeout = 5000;
+
+static Timer timer;
+static QMutex mtx;
+static bool visible = true;
+
+never_inline OTR_COMPAT_EXPORT
+void set_is_visible(const QWidget& w, bool force)
+{
+    QMutexLocker l(&mtx);
+
+    if (!force && timer.elapsed_ms() < visible_timeout)
+        return;
+
+    timer.start();
+
+    const HWND id = (HWND) w.winId();
+    const QPoint pt = w.mapToGlobal({ 0, 0 });
+
+    const int W = w.width(), H = w.height();
+
+    const QPoint points[] =
+    {
+        pt,
+        pt + QPoint(W - 1, 0),
+        pt + QPoint(0, H - 1),
+        pt + QPoint(W - 1, H - 1),
+        pt + QPoint(W / 2, H / 2),
+    };
+
+    for (const QPoint& pt : points)
+        if (!!(visible = WindowFromPoint({ pt.x(), pt.y() }) == id))
+            break;
+}
+
+never_inline OTR_COMPAT_EXPORT
+bool check_is_visible()
+{
+    QMutexLocker l(&mtx);
+
+    return visible;
+}
+
+#else
+
+always_inline OTR_COMPAT_EXPORT
+void set_is_visible(const QWidget&)
+{
+}
+
+always_inline OTR_COMPAT_EXPORT
+bool check_is_visible()
+{
+    return true;
+}
+
+#endif