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Pointing and positioning techniques in Computer Graphics

In this article, we will learn about the pointing and positioning in computer graphics and its various techniques. We will be briefly describing both these topics in detail and will also talk about the tools related to each of them.
By Monika Sharma Last updated : April 05, 2024

Pointing and Positioning in Computer Graphics

The pointing and positioning in computer graphics are used for interaction with the screen. A pointing device is called a pointing tool. The pointing tool is a hardware device that is used to shift the cursor on the screen or the graphical user interface. A cursor is an indicator that is used to show the current position on the monitor or any other display device for user interaction on the screen. A cursor is a visible pointing device that the user controls with the mouse, touchpad, or any other input device. The pointing cursor is an arrow and the text entering cursor is a blinking underscore or a vertical bar.

Pointing and Positioning Techniques

Pointing techniques helps us to look at the items that are already on the screen and Positioning techniques refer to the position of the item on the screen to a new position, i.e., the old current position.

Pointing and Positioning Devices

There are many pointing and positioning devices that are discussed below,

1. Mouse
2. Joystick
3. Light pen
4. Graphics Tablet

1) Mouse

A mouse is a lightweight device that helps the user to control the cursor on the monitor or any other display device. The mouse moves on a flat surface. It is a small pointing device that rests on 2 small wheels whose axes are at right angle. Each wheel of the mouse is linked to a shaft encoder that gives an electrical signal for every incremental rotation of the wheel of the mouse. When the mouse is moved around on a flat surface, its movement in two orthogonal directions is translated into rotation of the wheels. These rotations can be measured by counting the signals received from the shaft encoders. The connected values may be held in registers accessible to the computer on written directly into the computer memory. But in present, nobody used the wheel mouse because the technology has evolved and laser mouse is available in the market. A laser mouse used the laser to detect the movement of the mouse. The laser mouse has 20 times more sensitivity than the traditional mouse. A mouse has 2 or 3 buttons that perform different actions. There are some actions that can be performed using a mouse:

1. Click
2. Double click
3. Drag
4. Right-click
5. Scroll

2) Joystick

A joystick consists of a small stick or handles that are used to move the screen cursor around. The distance that the stick is moved in any direction from its center position corresponds to the screen-cursor movement in that direction. Pressure-sensitive joysticks have a non-moveable stick. Pressure on the stick is measured with strain gauges and converted to the movement of the cursor in the direction specified. The main use of a joystick is in gaming. The cursor movement becomes very fast and smooth by using a joystick.

3) Light Pen

A light pen is a computer input device that helps the user to communicate or conjugate with the CRT display. The light pen looks exactly like a normal pen. It allows the user to point to displayed objects or draw on the monitor or any other display screen that supports light pen in a similar way to a touchscreen but with greater positional accuracy. It’s like drawing or pointing in a notebook by using a pen. We have to point or draw on a screen.

4) Graphics Tablet

A graphics tablet is an input device that helps the user to create hand-drawn images, animations, graphics with the help of a special type of pen. It is also known as a drawing tablet, a drawing pad, or a digital drawing pad.