1 Launching Viz {#tutorial_launching_viz} 2 ============= 3 4 Goal 5 ---- 6 7 In this tutorial you will learn how to 8 9 - Open a visualization window. 10 - Access a window by its name. 11 - Start event loop. 12 - Start event loop for a given amount of time. 13 14 Code 15 ---- 16 17 You can download the code from [here ](https://github.com/Itseez/opencv/tree/master/samples/cpp/tutorial_code/viz/launching_viz.cpp). 18 @include samples/cpp/tutorial_code/viz/launching_viz.cpp 19 20 Explanation 21 ----------- 22 23 Here is the general structure of the program: 24 25 - Create a window. 26 @code{.cpp} 27 /// Create a window 28 viz::Viz3d myWindow("Viz Demo"); 29 @endcode 30 - Start event loop. This event loop will run until user terminates it by pressing **e**, **E**, 31 **q**, **Q**. 32 @code{.cpp} 33 /// Start event loop 34 myWindow.spin(); 35 @endcode 36 - Access same window via its name. Since windows are implicitly shared, **sameWindow** is exactly 37 the same with **myWindow**. If the name does not exist, a new window is created. 38 @code{.cpp} 39 /// Access window via its name 40 viz::Viz3d sameWindow = viz::get("Viz Demo"); 41 @endcode 42 - Start a controlled event loop. Once it starts, **wasStopped** is set to false. Inside the while 43 loop, in each iteration, **spinOnce** is called to prevent event loop from completely stopping. 44 Inside the while loop, user can execute other statements including those which interact with the 45 window. 46 @code{.cpp} 47 /// Event loop is over when pressed q, Q, e, E 48 /// Start event loop once for 1 millisecond 49 sameWindow.spinOnce(1, true); 50 while(!sameWindow.wasStopped()) 51 { 52 /// Interact with window 53 54 /// Event loop for 1 millisecond 55 sameWindow.spinOnce(1, true); 56 } 57 @endcode 58 59 Results 60 ------- 61 62 Here is the result of the program. 63 64  65
