Bresenham's Line Drawing Algorithm

Bresenham's Line Drawing Algorithm is a simple and efficient method used to draw lines on a computer screen or any two-dimensional grid-based environment. It was developed by Jack E. Bresenham in 1962 while working at IBM. This algorithm finds the points of a discrete line that are closest to the ideal line connecting two given endpoints. Unlike other line drawing methods that require floating-point arithmetic, Bresenham's algorithm uses only integer arithmetic operations, making it computationally faster and suitable for hardware implementation.

The main concept behind Bresenham's algorithm is to utilize the idea of incremental error. The algorithm starts with one endpoint and then considers the pixel closest to the ideal line that passes through the next position. The decision to select the next pixel is based on the accumulated error at each step, which ensures the line remains as close to the ideal line as possible. This approach eliminates the need for floating-point calculations, which were computationally expensive when Bresenham's algorithm was developed.

The given C program demonstrates the implementation of Bresenham's Line Drawing Algorithm to draw a line between two endpoints. Let's go through the code step-by-step:

• The code starts with the necessary header files for input/output, mathematics, and graphics functions.

• The linebres function is declared to draw the line using Bresenham's algorithm.

In the main function:

1. The endpoints (x1, y1) and (x2, y2) are taken as input from the user.

2. The graphics window is initialized using initgraph.

3. The screen is cleared using cleardevice.

4. The linebres function is called to draw the line between the given endpoints.

5. The final line is drawn using line function to compare the results.

6. The graphics window is closed after pressing any key.

In the linebres function:

1. The function takes four parameters representing the coordinates of the two endpoints (x1, y1) and (x2, y2).

2. The difference in x and y coordinates is calculated as dx and dy, respectively.

3. The algorithm then decides whether to draw the line horizontally or vertically based on the values of dx and dy.

4. For horizontal lines (dx != 0), it uses incremental error to determine the next pixel position along the x-axis. The decision is made based on the error term 'p'.

5. For vertical lines (dx == 0), it uses the same error term 'p' to determine the next pixel position along the y-axis, while incrementing x when needed.

6. The putpixel function is used to plot each pixel on the screen with color 2 (arbitrary color identifier).

Bresenham's Line Drawing Algorithm is a powerful and efficient method for drawing lines in a grid-based environment. By utilizing integer arithmetic and incremental error, it avoids the need for costly floating-point calculations, making it highly suitable for hardware implementation. The provided C program showcases the implementation of Bresenham's algorithm and allows the user to input endpoints to draw lines.

• Bresenham's Line Drawing Algorithm efficiently draws lines using only integer arithmetic.

• The algorithm selects the closest pixel to the ideal line using incremental error.

• It eliminates the need for expensive floating-point calculations.

• The putpixel function is used to plot pixels on the screen.

• The algorithm works for lines with both positive and negative slopes.

• Computer Graphics Programs

  1. Fundamental Graphics Functions 

  2. DDA Line Algorithm 

  3. Bresenham's Line Drawing Algorithm 

  4. Bresenham's Circle Drawing Algorithm Using C Programming 

  5. Line Clipping Program Using C Programming 

  6. Text Animation Program Using C Programming 

  7. Midpoint Circle Algorithm 

• 2D Computer Graphics Programs

  1. 2D Scaling Program Using C Programming 

  2. 2D Rotation Program Using C Programming 

  3. 2D Translation Triangle Program Using C Programming 

  4. 2D Translation Rectangle Program Using C Programming 

• 3D Computer Graphics Programs

  1. 3D Translation Program Using C Programming 

  2. 3D Scaling Program Using C Programming 

  3. 3D Rotation Program Using C Programming