Explain the algorithms for line drawing.
The Line Drawing Algorithm is a graphical algorithm for representing line segments on discrete graphical media, such as printers and pixel-based media.”
A line drawing algorithm is a method for estimating a line segment on discrete graphical media such as pixel-based screens and printers in computer graphics. Line sketching on such media necessitates an approximation (in nontrivial cases). Lines are rasterised in one colour using basic methods. Spatial anti-aliasing is a sophisticated approach that allows for a better representation of numerous colour gradations.
To draw a line on a continuous medium, however, no algorithm is required. Cathode-ray oscilloscopes, for example, use analogue phenomena to create lines and curves.
The formula for a slope line interception is:
Y = mx + b
In this formula, m is the slope line and b is the line’s intercept of y. Two endpoints for the line segment are supplied in coordinates (x1, y1) and (x2, y2).
Properties of a Line Drawing Algorithm
These Algorithm has the following characteristics.
Input: At least one or more inputs must be accept a good algorithm.
Output: At least one output must produced an algorithm.
An algorithm should be precise: The algorithm’s each step must well-define.
Finiteness: Finiteness is require in an algorithm. It signifies that the algorithm will come to a halt once all of the steps have been complete.
Correctness: An algorithm must implemented correctly.
Uniqueness: The result of an algorithm should be based on the given input, and all steps of the algorithm should be clearly and uniquely defined.
Effectiveness: An algorithm’s steps must be correct and efficient.
Easy to understand: Learners must be able to understand the solution in a more natural way thanks to an algorithm.
Types of Line Drawing Algorithm
For drawing a line, the following algorithms are use:
DDA (Digital Differential Analyzer) Line Drawing Algorithm
Bresenham’s Line Drawing Algorithm
Digital Differential Algorithm ( DDA)
A DDA Algorithm, also known as a Digital Differential Algorithm, is an incremental conversion method. Moreover, The usage of the results from the preceding stage in each calculation distinguishes this method.
Advantages of Digital Differential Analyzer
Firstly, It’s a straightforward algorithm to implement.
The direct line equation is a slower algorithm.
In the Digital Differential Analyzer, we are unable to apply the multiplication approach.
When a point changes its location, the Digital Differential Analyzer method alerts us about the overflow.
DDA Algorithm Limitations
Firstly, It takes a long time to do floating point arithmetic and rounding points.
A round-off mistake may cause the measured pixel location to deviate from the true long-line segment path.
The Bresenham Line Algorithm
In 1962, “Jack Elton Bresenham” proposed this algorithm. This algorithm aids in the conversion of a line’s scan. It’s a strong, useful, and precise method. Furthermore, To draw a line, we employ incremental integer calculations. Addition, subtraction, and multiplication are among the integer calculations.
In addition, We must determine the slope (m) between the starting point and the final point in Bresenham’s Line Drawing procedure.
Advantages of Bresenham’s Line Drawing Algorithm
The following are the benefits of the Bresenham line algorithm:
- An incremental algorithm that is quick.
- Only integer computations are used in this.
Disadvantages of Bresenham’s Line Drawing Algorithm
Bresenham’s Line Drawing Algorithm only aids in the creation of fundamental lines.
The drawn line is not smooth as a result.
