Clipping and Filling

1. Introduction

In computer graphics, objects may extend beyond the visible display area. Clipping removes invisible parts, and filling enhances the visual appearance by coloring interior regions.

• Improves visual correctness
• Optimizes rendering performance

2. Clipping

Clipping is the process of discarding the portions of graphics primitives that lie outside a specified boundary called the clipping window.

• Applies to points, lines, and polygons
• Reduces unnecessary drawing

3. Types of Clipping

• Point Clipping
• Line Clipping
• Polygon Clipping
• Text and Curve Clipping

4. Clipping Window

The clipping window defines the region of interest. Only the parts of objects inside this window are displayed.

• Rectangular window most common
• Defined by xmin, xmax, ymin, ymax

5. Filling

Filling is the process of coloring the interior of closed shapes such as polygons and circles to enhance visual representation.

• Used for solid objects
• Improves object visibility

6. Types of Filling

• Flood Fill
• Boundary Fill
• Scan-Line Polygon Fill

7. Clipping vs Filling

Clipping                     Filling
--------------------------   -----------------------------
Removes invisible parts      Colors interior regions
Applied before rendering     Applied after clipping
Used for visibility          Used for appearance

8. Importance of Clipping and Filling

• Ensures correct display output
• Improves rendering efficiency
• Essential for 2D and 3D graphics

9. Applications

• Window-based graphical interfaces
• CAD and design systems
• Game graphics and animation

Practice Questions

1. What is clipping?
2. Define filling in computer graphics.
3. List types of clipping.
4. Differentiate clipping and filling.
5. Why are clipping and filling important?

Practice Task