Make rect_on_screen Qt4-compatible.

Use QDesktopWidget instead of QGuiApplication + QScreen. The former
exists in the Qt 4 API.

Ping-Bug: 11568
Change-Id: Icfbe9f78659b28efbc86061f94d946f70ab6dc41
Reviewed-on: https://code.wireshark.org/review/11604
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>

ui/qt/qt_ui_utils.cpp

@@ -36,14 +36,14 @@
 #include <wsutil/str_util.h>
 
 #include <QAction>
+#include <QApplication>
 #include <QDateTime>
 #include <QDesktopServices>
+#include <QDesktopWidget>
 #include <QDir>
 #include <QFileInfo>
 #include <QFontDatabase>
-#include <QGuiApplication>
 #include <QProcess>
-#include <QScreen>
 #include <QUrl>
 #include <QUuid>
 
@@ -235,8 +235,9 @@ void desktop_show_in_folder(const QString file_path)
 
 bool rect_on_screen(const QRect &rect)
 {
-    foreach (const QScreen *screen, QGuiApplication::screens()) {
-        if (screen->availableGeometry().contains(rect))
+    QDesktopWidget *desktop = qApp->desktop();
+    for (int i = 0; i < desktop->screenCount(); i++) {
+        if (desktop->availableGeometry(i).contains(rect))
             return true;
     }
 

ui/qt/qt_ui_utils.h

@@ -197,7 +197,7 @@ void desktop_show_in_folder(const QString file_path);
 /**
  * Test to see if a rect is visible on screen.
  *
- * @param rect
+ * @param rect The rect to test, typically a "recent.gui_geometry_*" setting.
  * @return true if the rect is completely enclosed by one of the display
  * screens, false otherwise.
  */