Solved

# How to extend a line starting from (x0,y0) and passing thru (x1,y1) upto (xn,yn)?

Posted on 2009-04-09
409 Views
Hi,

I have one center point (x0,y0) and some more points scattered on canvas (x1,y1), (x2,y2)...
I want to show a motion of a sprite in a straight line starting from (x0,y0) thru (x1,y1) till it reaches beyond the boundary of canvas.

In fact, the sprite might be present anywhere on canvas (x1,y1/x2,y2...) and from a central reference point (x0,y0) i want to show its motion in straight line till it reaches beyond the canvas boundary.

Many line drawing (pixel-by-pixel) algorithms give coordinates from x0,y0 to x1,y1 and not beyond that, however, i want to extend that line to (xn,yn) which could be anything depending upon (x0,y0) and (x1,y1)

Any ideas?
Algorithm?
line-extend-problem.gif
0
[X]
###### Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

• Help others & share knowledge
• Earn cash & points
• 2
• 2

LVL 84

Accepted Solution

ozo earned 20 total points
ID: 24105167
x = X0 + (X1-X0)*t
y = Y0 + (Y1-Y0)*t
0

Author Comment

ID: 24106026
Ozo:
Though I somehow calculated the value for "t" that suits my requirements by hit-n-trial - and the value i get is t>1 & t<2 (1.09/1.1/1.2..) what exactly this value should be?
What this "t" denotes??

The formula works like charm for any pixel in any quadrant.
0

Author Closing Comment

ID: 31568427
Even though the "t" remained mystery for me, I accept this solution since I managed to get my work done with the help of the given formula.

A little explanation would have claimed a higher grade.
0

LVL 84

Expert Comment

ID: 24161132
Sory, I didn't see your question,
t goes from 0 to 1 between the points, and then beyond 1 to extend the line
0

## Featured Post

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

### Suggested Solutions

What is RenderMan: RenderMan is a not any particular piece of software. RenderMan is an industry standard, defining set of rules that any rendering software should use, to be RenderMan-compliant. Pixar's RenderMan is a flagship implementation of …
Recently, in one of the tech-blogs I usually read, I saw a post about the best-selling video games through history. The first place in the list is for the classic, extremely addictive Tetris. Well, a long time ago, in a galaxy far far away, I was…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…
Attackers love to prey on accounts that have privileges. Reducing privileged accounts and protecting privileged accounts therefore is paramount. Users, groups, and service accounts need to be protected to help protect the entire Active Directory …
###### Suggested Courses
Course of the Month7 days, 20 hours left to enroll