Merge pull request #14872 from AhiyaHiya:feature/topmost_window

* Added mechanism to set/toggle NORMAL window to TOPMOST window.

* highgui: remove unnecessary/legacy code

modules/highgui/include/opencv2/highgui.hpp

@@ -197,7 +197,8 @@ enum WindowPropertyFlags {
        WND_PROP_AUTOSIZE     = 1, //!< autosize property      (can be WINDOW_NORMAL or WINDOW_AUTOSIZE).
        WND_PROP_ASPECT_RATIO = 2, //!< window's aspect ration (can be set to WINDOW_FREERATIO or WINDOW_KEEPRATIO).
        WND_PROP_OPENGL       = 3, //!< opengl support.
-       WND_PROP_VISIBLE      = 4  //!< checks whether the window exists and is visible
+       WND_PROP_VISIBLE      = 4, //!< checks whether the window exists and is visible
+       WND_PROP_TOPMOST      = 5  //!< property to toggle normal window being topmost or not
      };
 
 //! Mouse Events see cv::MouseCallback

modules/highgui/src/precomp.hpp

@@ -116,6 +116,12 @@ double cvGetOpenGlProp_GTK(const char* name);
 
 double cvGetPropVisible_W32(const char* name);
 
+double cvGetPropTopmost_W32(const char* name);
+double cvGetPropTopmost_COCOA(const char* name);
+
+void cvSetPropTopmost_W32(const char* name, const bool topmost);
+void cvSetPropTopmost_COCOA(const char* name, const bool topmost);
+
 //for QT
 #if defined (HAVE_QT)
 CvRect cvGetWindowRect_QT(const char* name);

modules/highgui/src/window.cpp

@@ -42,6 +42,7 @@
 #include "precomp.hpp"
 #include <map>
 #include "opencv2/core/opengl.hpp"
+#include "opencv2/core/utils/logger.hpp"
 
 // in later times, use this file as a dispatcher to implementations like cvcap.cpp
 
@@ -83,6 +84,16 @@ CV_IMPL void cvSetWindowProperty(const char* name, int prop_id, double prop_valu
         #endif
     break;
 
+    case cv::WND_PROP_TOPMOST:
+        #if defined(HAVE_WIN32UI)
+            cvSetPropTopmost_W32(name, (prop_value != 0 ? true : false));
+        #elif defined(HAVE_COCOA)
+            cvSetPropTopmost_COCOA(name, (prop_value != 0 ? true : false));
+        #else
+            CV_LOG_WARNING(NULL, "Property WND_PROP_TOPMOST is not supported on current GUI backend");
+        #endif
+    break;
+
     default:;
     }
 }
@@ -162,6 +173,18 @@ CV_IMPL double cvGetWindowProperty(const char* name, int prop_id)
             return -1;
         #endif
     break;
+
+    case cv::WND_PROP_TOPMOST:
+        #if defined(HAVE_WIN32UI)
+            return cvGetPropTopmost_W32(name);
+        #elif defined(HAVE_COCOA)
+            return cvGetPropTopmost_COCOA(name);
+        #else
+            CV_LOG_WARNING(NULL, "Property WND_PROP_TOPMOST is not supported on current GUI backend");
+            return -1;
+        #endif
+    break;
+
     default:
         return -1;
     }

modules/highgui/src/window_cocoa.mm

@@ -712,6 +712,68 @@ void cvSetModeWindow_COCOA( const char* name, double prop_value )
     __END__;
 }
 
+double cvGetPropTopmost_COCOA(const char* name)
+{
+    double    result = -1;
+    CVWindow* window = nil;
+
+    CV_FUNCNAME("cvGetPropTopmost_COCOA");
+
+    __BEGIN__;
+    if (name == NULL)
+    {
+        CV_ERROR(CV_StsNullPtr, "NULL name string");
+    }
+
+    window = cvGetWindow(name);
+    if (window == NULL)
+    {
+        CV_ERROR(CV_StsNullPtr, "NULL window");
+    }
+
+    result = (window.level == NSStatusWindowLevel) ? 1 : 0;
+
+    __END__;
+    return result;
+}
+
+void cvSetPropTopmost_COCOA( const char* name, const bool topmost )
+{
+    CVWindow *window = nil;
+    NSAutoreleasePool* localpool = nil;
+    CV_FUNCNAME( "cvSetPropTopmost_COCOA" );
+
+    __BEGIN__;
+    if( name == NULL )
+    {
+        CV_ERROR( CV_StsNullPtr, "NULL name string" );
+    }
+
+    window = cvGetWindow(name);
+    if ( window == NULL )
+    {
+        CV_ERROR( CV_StsNullPtr, "NULL window" );
+    }
+
+    if ([[window contentView] isInFullScreenMode])
+    {
+        EXIT;
+    }
+
+    localpool = [[NSAutoreleasePool alloc] init];
+    if (topmost)
+    {
+        [window makeKeyAndOrderFront:window.self];
+        [window setLevel:CGWindowLevelForKey(kCGMaximumWindowLevelKey)];
+    }
+    else
+    {
+        [window makeKeyAndOrderFront:nil];
+    }
+    [localpool drain];
+    __END__;
+}
+
 void cv::setWindowTitle(const String& winname, const String& title)
 {
     CVWindow *window = cvGetWindow(winname.c_str());

modules/highgui/src/window_w32.cpp

@@ -40,6 +40,9 @@
 //M*/
 
 #include "precomp.hpp"
+
+using namespace cv;
+
 #include <windowsx.h> // required for GET_X_LPARAM() and GET_Y_LPARAM() macros
 
 #if defined _WIN32
@@ -538,6 +541,48 @@ void cvSetModeWindow_W32( const char* name, double prop_value)//Yannick Verdie
     __END__;
 }
 
+double cvGetPropTopmost_W32(const char* name)
+{
+    double result = -1;
+
+    CV_Assert(name);
+
+    CvWindow* window = icvFindWindowByName(name);
+    if (!window)
+        CV_Error(Error::StsNullPtr, "NULL window");
+
+    LONG style = GetWindowLongA(window->frame, GWL_EXSTYLE); // -20
+    if (!style)
+    {
+        std::ostringstream errorMsg;
+        errorMsg << "window(" << name << "): failed to retrieve extended window style using GetWindowLongA(); error code: " << GetLastError();
+        CV_Error(Error::StsError, errorMsg.str().c_str());
+    }
+
+    result = (style & WS_EX_TOPMOST) == WS_EX_TOPMOST;
+
+    return result;
+}
+
+void cvSetPropTopmost_W32(const char* name, const bool topmost)
+{
+    CV_Assert(name);
+
+    CvWindow* window = icvFindWindowByName(name);
+    if (!window)
+        CV_Error(Error::StsNullPtr, "NULL window");
+
+    HWND flag    = topmost ? HWND_TOPMOST : HWND_TOP;
+    BOOL success = SetWindowPos(window->frame, flag, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
+
+    if (!success)
+    {
+        std::ostringstream errorMsg;
+        errorMsg << "window(" << name << "): error reported by SetWindowPos(" << (topmost ? "HWND_TOPMOST" : "HWND_TOP") << "), error code:  " << GetLastError();
+        CV_Error(Error::StsError, errorMsg.str().c_str());
+    }
+}
+
 void cv::setWindowTitle(const String& winname, const String& title)
 {
     CvWindow* window = icvFindWindowByName(winname.c_str());