1 files changed, 98 insertions, 0 deletions
diff --git a/compat/check-visible.cpp b/compat/check-visible.cpp
new file mode 100644
index 00000000..621d941a
--- /dev/null
+++ b/compat/check-visible.cpp
@@ -0,0 +1,98 @@
+#include "check-visible.hpp"
+
+#include <QMutex>
+#include <QWidget>
+#include <QDebug>
+
+static QMutex lock;
+static bool visible = true;
+
+#if defined _WIN32
+
+#include "timer.hpp"
+#include "macros.h"
+
+static Timer timer;
+
+constexpr int visible_timeout = 1000;
+constexpr int invisible_timeout = 250;
+
+#include <windows.h>
+
+void set_is_visible(const QWidget& w, bool force)
+{
+    QMutexLocker l(&lock);
+
+    if (w.isHidden() || w.windowState() & Qt::WindowMinimized)
+    {
+        visible = false;
+        return;
+    }
+
+    {
+        int ndisplays = GetSystemMetrics(SM_CMONITORS);
+        if (ndisplays > 1)
+        {
+            visible = true;
+            return;
+        }
+    }
+
+    HWND hwnd = (HWND)w.winId();
+
+    if (!force && timer.elapsed_ms() < (visible ? visible_timeout : invisible_timeout))
+        return;
+
+    timer.start();
+
+    if (RECT r; GetWindowRect(hwnd, &r))
+    {
+        const int x = r.left, y = r.top;
+        const int w = r.right - x, h = r.bottom - y;
+
+        const POINT xs[] {
+            { x + w - 1, y + 1     },
+            { x + 1,     y + h - 1 },
+            { x + w - 1, y + h - 1 },
+            { x + 1,     y + 1     },
+            { x + w/2,   y + h/2   },
+        };
+
+        visible = false;
+
+        for (const POINT& pt : xs)
+            if (WindowFromPoint(pt) == hwnd)
+            {
+
+                visible = true;
+                break;
+            }
+    }
+    else
+    {
+        eval_once(qDebug() << "check-visible: GetWindowRect failed");
+        visible = true;
+    }
+}
+
+#else
+
+void set_is_visible(const QWidget& w, bool)
+{
+    QMutexLocker l(&lock);
+    visible = !(w.isHidden() || w.windowState() & Qt::WindowMinimized);
+}
+
+#endif
+
+bool check_is_visible()
+{
+    QMutexLocker l(&lock);
+    return visible;
+}
+
+void force_is_visible(bool value)
+{
+    QMutexLocker l(&lock);
+    visible = value;
+}