From deb8ba223752d7b4a9aa85c4c8e608d01b792455 Mon Sep 17 00:00:00 2001
From: Christoph Rackwitz <christoph.rackwitz@gmail.com>
Date: Sun, 16 Dec 2018 05:50:32 +0100
Subject: [PATCH] fix for #4990: highgui w32 ogl: correct calculation of image
 coordinates from window coordinates

---
 modules/highgui/src/window_w32.cpp | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/modules/highgui/src/window_w32.cpp b/modules/highgui/src/window_w32.cpp
index e7141cb82c..130807e9e6 100644
--- a/modules/highgui/src/window_w32.cpp
+++ b/modules/highgui/src/window_w32.cpp
@@ -66,6 +66,7 @@
 #include <functional>
 #include "opencv2/highgui.hpp"
 #include <GL/gl.h>
+#include "opencv2/core/opengl.hpp"
 #endif
 
 static const char* trackbar_text =
@@ -1489,7 +1490,20 @@ MainWindowProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam )
           GetClientRect( window->hwnd, &rect );
 
           SIZE size = {0,0};
-          icvGetBitmapData( window, &size, 0, 0 );
+#ifdef HAVE_OPENGL
+          if (window->useGl)
+          {
+              cv::ogl::Texture2D* texObj = static_cast<cv::ogl::Texture2D*>(window->glDrawData);
+              size.cx = texObj->cols();
+              size.cy = texObj->rows();
+          }
+          else
+          {
+              icvGetBitmapData(window, &size, 0, 0);
+          }
+#else
+          icvGetBitmapData(window, &size, 0, 0);
+#endif
 
           window->on_mouse( event, pt.x*size.cx/MAX(rect.right - rect.left,1),
                                    pt.y*size.cy/MAX(rect.bottom - rect.top,1), flags,
@@ -1683,7 +1697,21 @@ static LRESULT CALLBACK HighGUIProc( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM
                 SIZE size = {0, 0};
 
                 GetClientRect( window->hwnd, &rect );
+
+#ifdef HAVE_OPENGL
+                if (window->useGl)
+                {
+                    cv::ogl::Texture2D* texObj = static_cast<cv::ogl::Texture2D*>(window->glDrawData);
+                    size.cx = texObj->cols();
+                    size.cy = texObj->rows();
+                }
+                else
+                {
+                    icvGetBitmapData(window, &size, 0, 0);
+                }
+#else
                 icvGetBitmapData( window, &size, 0, 0 );
+#endif
 
                 window->on_mouse( event, pt.x*size.cx/MAX(rect.right - rect.left,1),
                                          pt.y*size.cy/MAX(rect.bottom - rect.top,1), flags,