Scilab Function

xchange - transform real to pixel coordinates

### Calling Sequence

  `[x1,y1,rect]=xchange(x,y,dir)`

### Parameters

- `x,y` : two matrices of size (n1,n2) (coordinates of a set of points).
- `x1,y1` : two matrices of size (n1,n2) (coordinates of the set of points).
- `rect` : a vector of size 4.

### Description

After having used a graphics function, `xchange` computes pixel coordinates from real coordinates and conversely, according to the value of the parameter `dir` : "f2i" (float to int) means real to pixel and "i2f" (int to float) means pixel to real. `x1` and `y1` are the new coordinates of the set of points defined by the old coordinates `x` and `y` .

`rect` is the coordinates in pixel of the rectangle in which the plot was done: [upper-left point, width, height].

### Examples

    t=[0:0.1:2*%pi]';
    plot2d(t,sin(t))
    [x,y,rect]=xchange(1,1,"f2i")
    [x,y,rect]=xchange(0,0,"i2f")

### Author

J.Ph.C.