---
title: "Conditions for point clipping"
subject: "Computer Graphics"
chapter: 3
key: "semester_5/computer_graphics:point-clipping-conditions"
source: https://www.bctengineer.com/q/semester_5/computer_graphics/point-clipping-conditions
site: BCT Engineering
---

# Conditions for point clipping

Computer Graphics · Chapter 3: Two –Dimensional Transformations

- Asked in: 2072 Kartik, 2 marks; 2070 Chaitra, 2 marks (asked 2 times)
- Video: [Introduction to Point Clipping | Computer Graphics](https://www.youtube.com/watch?v=1KW_H24KI9M) — Gate Smashers
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/computer_graphics/point-clipping-conditions
- Whole chapter: https://www.bctengineer.com/md/semester_5/computer_graphics/chapter-3

## Question

Write down the condition for point clipping.

## Short answer

A point P(x,y) is displayed only if xwmin <= x <= xwmax and ywmin <= y <= ywmax. If any inequality fails, the point is outside and clipped.

## Answer

A point P(x, y) is inside the clip window, and is displayed only if it satisfies:

**xwmin ≤ x ≤ xwmax  and  ywmin ≤ y ≤ ywmax**

If any one of these four inequalities fails, the point lies outside the window and is clipped (discarded).

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. A point (x,y) is displayed if:
   A. xwmin ≤ x ≤ xwmax and ywmin ≤ y ≤ ywmax
   B. x ≤ xwmin or y ≤ ywmin
   C. xwmin ≥ x ≥ xwmax
   D. only x is inside the window
   Answer: A. Both conditions must hold. (Key point: Condition)

2. If one inequality fails, the point is:
   A. displayed anyway
   B. clipped (discarded)
   C. moved to the nearest edge
   D. displayed in another colour
   Answer: B. It lies outside the window. (Key point: Failure)

3. For a window 0..100 in both axes, which point is displayed?
   A. (120, 50)
   B. (50, −1)
   C. (100, 50)
   D. (101, 101)
   Answer: C. The inequalities are inclusive, so edge points are inside. (Key point: Example)

## Related in Computer Graphics

- [Point clipping and Cohen-Sutherland (5,130)-(50,5)](https://www.bctengineer.com/question.md?key=semester_5%2Fcomputer_graphics%3Acohen-sutherland-point-clip-5-130) — Computer Graphics, chapter 3

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