2. You can see a point on the interface. The fixed point is called the rotation center and the angle is called the rotation angle.
3. Around the expansion, the distance from the corresponding point to the center of rotation is equal.
4, you can see the edge, the length of the corresponding line, the size of the corresponding angle is equal.
5. The size and shape of the figure have not changed before and after rotation.
Mathematically, figure rotation means that a new figure can be obtained by rotating the figure around the center point by a certain angle. The rotation can be clockwise or counterclockwise.
The following are some common graphic rotation methods and their characteristics:
Rotation of a point: For a given point, the position of the rotation point can be calculated by specifying the rotation center and rotation angle. This can be achieved by using a rotation matrix. The formula of rotation matrix varies according to the choice of rotation angle and coordinate axis.
Rotation of a straight line: For a straight line, the rotation of the straight line can be realized by rotating the points on the straight line to a new position. Similarly, you need to specify the rotation center and rotation angle, and use the rotation matrix to calculate the position of the rotation point.
Polygon Rotation: For polygons, you can rotate the whole polygon by rotating each vertex of the polygon to a new position. The rotated polygon keeps its original shape and size, but its direction has changed.
Center of rotation: It is very important to determine the center of rotation, because the drawing will rotate around this point. It can be a given point or the vertex or center of the graph itself.
Rotation angle: determines the rotation angle, which can be expressed in degrees or radians. You need to select the corresponding positive and negative angles according to the rotation direction (clockwise or counterclockwise).
Coordinate system: coordinate system that needs to be explicitly used in rotation calculation, such as Cartesian coordinate or polar coordinate. Graphic rotation is widely used in geometry, computer graphics and physics. Through rotation, we can study and describe all kinds of complex graphics and movements.