3
$\begingroup$

As often happens I'm not sure of the name of what I'm trying to do, so I'm having difficulty searching it. I know this is basic algebra, but my math is null so I'm struggling with it greatly.

I have a coordinate system that starts from 0,0 in the bottom left corner, and ends in 1,1 in the top right corner. I must "translate" from coordinates to pixels and viceversa. I'm including a diagram to clarify what I'm trying to do.

I'm trying to do this with Javascript, but I guess it's irrelevant. A formula is enough to get me started.

Thanks!

enter image description here

  • 0
    An interesting related issue for you may what pixels correspond to the points on a particular straight line. One approach to this is known as Bresenham's Algorithm: http://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm2011-02-16

1 Answers 1

5

Your coordinates look odd, but going from co-ordinates to pixels, you probably want something like $f(x,y) = (190y+5,195-190x)$ and going from pixels to coordinates $g(a,b) = \left(\frac{195-b}{190},\frac{a-5}{190},\right)$ but you may need to adjust this slightly to deal with what happens on the edges

  • 0
    Thanks! I've implemented it and it's working perfectly.2011-02-16