It is known as **circumference** to the closed format line **curved** and flat appearance in which the **points** they are equidistant from the point **central** which is located on the same plane. This distance that separates the set of points and the central area is known as **radio** , while the line segment that makes up a pair of aligned radii is called **diameter** .

The diameter, as determined, is the largest distance that can be established between two points belonging to the same circumference. The length of this diameter, on the other hand, is twice the measure of the length of the radius.

Other elements that can be recognized when examining a circle are the **arc** (such as the name given to the curved segment of points that makes up every circle), the **rope** (that is, the **segment** which guarantees the union of two points), the **tangent line** (which makes contact at a single point) and the **secant line** (which marks contact in a couple of points).

In relation to the relative positions of the points with respect to the circumference, it must be said that a point can be **inside** (with respect to which the distance from the central zone to the point is smaller than the measure of the radius length), **belonging** (where the extension that separates the center of the point coincides with the length of the radius) or **Exterior** (where the separation between the center and the point exceeds the length of the radius).

Although in everyday language they are often used as synonyms, it should be noted that circumference and **circle** They don't mean the same thing. The circle, says the theory, is the geometric space based on the points that are part of a circle: this means that the circle constitutes the **perimeter** of a circle

The notion of circumference, therefore, is also used to name the **contour of a certain surface, area or terrain** . For example: *"Wiring allows keeping animals within the circumference of our property"*.

**Use of circumferences in graphic programming**

In video games, as well as in other types of **Applications** interactive graphics, it is necessary to tell the processor **what is the limit of the objects** that are observed on the screen, to avoid overlapping. A clear example is a character that runs through a maze and who, when walking against a wall, cannot cross it. For people who do not have any technical knowledge related to this topic, it may be difficult to understand that the program does not know that "a wall is solid and it is not possible to pass through it." But it is necessary to remember that, as they say in everyday speech, for a computer everything is "ones and zeros"; that is, it does not understand the characteristics of the bodies, nor the concepts of physics or **math**, but simply reproduces as a slave everything that is indicated.

To prevent an object from crossing a wall, for example, is that so-called **collision systems**, although its name may vary depending on the developer and language. Basically, it is a series of conventions and **functions** that establish how many types of interaction exist within the universe of the game and what consequence each case has. When implemented, what until now was a series of graphics without properties becomes a world that can be explored by walking, jumping, climbing, swimming, climbing stairs and going through narrow tunnels.

Traditionally, the types of collisions most used in video games are **the squares and the circumferences**, each one with **characteristics** and different purposes. It should be mentioned that they do not necessarily represent an object or be similarly, but that the decision to choose one or the other depends more on the type of interaction that element will have with the environment. If you want to define the body of a character such as Super Mario in a game in which the action takes place in 2 dimensions (the camera moves to the sides and not "to and from the screen"), probably the most appropriate option It is a rectangle, whose major sides will represent the height of the famous plumber, while the remaining two, both its width and depth, since it is a flat image.

At first glance, a human being has no rectangle shape, and depending on the degree of complexity, it is possible to use as many figures as desired to represent their **limits**. A circumference could be used for your head and hands, and rectangles for the rest of the parts of your body. The advantage of the circumference is that it allows very precise calculations of possible collisions from all directions without requiring much work from the processor and always performing the same check: if the distance between a given point of an external object and the center of the circumference is **equal to or less than radius**, so they are making contact.