highgui: ability to better control the fullscreen window

Signed-off-by: deadprogram <ron@hybridgroup.com>

highgui.cpp

@@ -13,6 +13,10 @@ void Window_IMShow(const char* winname, Mat mat) {
     cv::imshow(winname, *mat);
 }
 
+void Window_SetWindowProperty(const char* winname, int flag, double value) {
+    cv::setWindowProperty(winname, flag, value);
+}
+
 int Window_WaitKey(int delay = 0) {
     return cv::waitKey(delay);
 }

highgui.go

@@ -32,7 +32,7 @@ func NewWindow(name string) *Window {
 	cName := C.CString(name)
 	defer C.free(unsafe.Pointer(cName))
 
-	C.Window_New(cName, 1)
+	C.Window_New(cName, 2)
 
 	return &Window{name: name, open: true}
 }
@@ -56,6 +56,52 @@ func (w *Window) IsOpen() bool {
 	return w.open
 }
 
+// WindowFlag value for SetWindowProperty / GetWindowProperty.
+type WindowFlag float32
+
+const (
+	WindowNormal     WindowFlag = 0
+	WindowFullscreen            = 1
+	WindowAutosize              = 1
+	WindowFreeRatio             = 0x00000100
+	WindowKeepRatio             = 0
+)
+
+// WindowPropertyFlag flags for SetWindowProperty / GetWindowProperty.
+type WindowPropertyFlag int
+
+const (
+	// WindowPropertyFullscreen fullscreen property
+	// (can be WINDOW_NORMAL or WINDOW_FULLSCREEN).
+	WindowPropertyFullscreen WindowPropertyFlag = 0
+
+	// WindowPropertyAutosize is autosize property
+	// (can be WINDOW_NORMAL or WINDOW_AUTOSIZE).
+	WindowPropertyAutosize = 1
+
+	// WindowPropertyAspectRatio window's aspect ration
+	// (can be set to WINDOW_FREERATIO or WINDOW_KEEPRATIO).
+	WindowPropertyAspectRatio = 2
+
+	// WindowPropertyOpenGL opengl support.
+	WindowPropertyOpenGL = 3
+
+	// WindowPropertyVisible or not.
+	WindowPropertyVisible = 4
+)
+
+// SetWindowProperty changes parameters of a window dynamically.
+//
+// For further details, please see:
+// https://docs.opencv.org/3.3.1/d7/dfc/group__highgui.html#ga66e4a6db4d4e06148bcdfe0d70a5df27
+//
+func (w *Window) SetWindowProperty(flag WindowPropertyFlag, value WindowFlag) {
+	cName := C.CString(w.name)
+	defer C.free(unsafe.Pointer(cName))
+
+	C.Window_SetWindowProperty(cName, C.int(flag), C.double(value))
+}
+
 // IMShow displays an image Mat in the specified window.
 // This function should be followed by the WaitKey function which displays
 // the image for specified milliseconds. Otherwise, it won't display the image.

highgui.h

@@ -12,6 +12,7 @@ extern "C" {
 void Window_New(const char* winname, int flags);
 void Window_Close(const char* winname);
 void Window_IMShow(const char* winname, Mat mat);
+void Window_SetWindowProperty(const char* winname, int flag, double value);
 int Window_WaitKey(int);
 
 // Trackbar

highgui_test.go

@@ -19,6 +19,9 @@ func TestWindow(t *testing.T) {
 	if !window.IsOpen() {
 		t.Error("Window should have been open")
 	}
+
+	window.SetWindowProperty(WindowPropertyFullscreen, WindowFullscreen)
+
 	window.Close()
 	if window.IsOpen() {
 		t.Error("Window should have been closed")