vendor: OpenCV 5.0.0 snapshot at 755e50675d97db9b7d449d8bd6b09888646f6c6e

2026-08-22 00:11:13 +08:00
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+Pose of a widget {#tutorial_widget_pose}
+================
+
+@prev_tutorial{tutorial_launching_viz}
+@next_tutorial{tutorial_transformations}
+
+Goal
+----
+
+In this tutorial you will learn how to
+
+-   Add widgets to the visualization window
+-   Use Affine3 to set pose of a widget
+-   Rotating and translating a widget along an axis
+
+Code
+----
+
+You can download the code from [here ](https://github.com/opencv/opencv_contrib/tree/master/modules/viz/samples/widget_pose.cpp).
+@include viz/samples/widget_pose.cpp
+
+Explanation
+-----------
+
+Here is the general structure of the program:
+
+-   Create a visualization window.
+    @code{.cpp}
+    /// Create a window
+    viz::Viz3d myWindow("Coordinate Frame");
+    @endcode
+-   Show coordinate axes in the window using CoordinateSystemWidget.
+    @code{.cpp}
+    /// Add coordinate axes
+    myWindow.showWidget("Coordinate Widget", viz::WCoordinateSystem());
+    @endcode
+-   Display a line representing the axis (1,1,1).
+    @code{.cpp}
+    /// Add line to represent (1,1,1) axis
+    viz::WLine axis(Point3f(-1.0f,-1.0f,-1.0f), Point3f(1.0f,1.0f,1.0f));
+    axis.setRenderingProperty(viz::LINE_WIDTH, 4.0);
+    myWindow.showWidget("Line Widget", axis);
+    @endcode
+-   Construct a cube.
+    @code{.cpp}
+    /// Construct a cube widget
+    viz::WCube cube_widget(Point3f(0.5,0.5,0.0), Point3f(0.0,0.0,-0.5), true, viz::Color::blue());
+    cube_widget.setRenderingProperty(viz::LINE_WIDTH, 4.0);
+    myWindow.showWidget("Cube Widget", cube_widget);
+    @endcode
+-   Create rotation matrix from rodrigues vector
+    @code{.cpp}
+    /// Rotate around (1,1,1)
+    rot_vec.at<float>(0,0) += CV_PI * 0.01f;
+    rot_vec.at<float>(0,1) += CV_PI * 0.01f;
+    rot_vec.at<float>(0,2) += CV_PI * 0.01f;
+
+    ...
+
+    Mat rot_mat;
+    Rodrigues(rot_vec, rot_mat);
+    @endcode
+-   Use Affine3f to set pose of the cube.
+    @code{.cpp}
+    /// Construct pose
+    Affine3f pose(rot_mat, Vec3f(translation, translation, translation));
+    myWindow.setWidgetPose("Cube Widget", pose);
+    @endcode
+-   Animate the rotation using wasStopped and spinOnce
+    @code{.cpp}
+    while(!myWindow.wasStopped())
+    {
+        ...
+
+        myWindow.spinOnce(1, true);
+    }
+    @endcode
+
+Results
+-------
+
+Here is the result of the program.
+
+\htmlonly
+<div align="center">
+<iframe width="420" height="315" src="https://www.youtube.com/embed/22HKMN657U0" frameborder="0" allowfullscreen></iframe>
+</div>
+\endhtmlonly