xchange

Arguments

x, y

two matrices of size (n1, n2) (coordinates of a set of points).

dir

a string, parameter used to specify the conversion type (See "Description" for details).

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].

Coordinates in pixels are relative to the top-left point of graphical area in figure (see axes_size in figure properties) unlike uicontrols positions which are relative to the bottom-left point of the graphical area (see examples below).

Examples

Data conversions

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

With uicontrols

plot(-10:10, -10:10);

sz = gcf().axes_size; // Used to change reference for positions
xpos = [-10 -10 0 10 10];
ypos = [-10 10 0 -10 10];

for i = 1:size(xpos, "*")
    [xp, yp] = xchange(xpos(i), ypos(i), "f2i");
    uicontrol("Style", "pushbutton", "Position", [xp, sz(2)-yp, 70, 20], "String", string(xpos(i)) + "/" + string(ypos(i)));
end