xgetmouse example

[johnny.heikell at kolumbus.fi]

Greetings,

Can anybody help me make sense of the script that is presented in connection with the function xgetmouse() in Scilab’s Help Browser (draw a rectangle in the Graphic Window)? I have the following questions:

1.	In the command  a = gca(); a.data_bounds = [0 0;100 100]  the numeric value of matrix elements do not seem to influence anything, they can be changed without noticeable effect. What are they for?
2.	According to Help\xclick, the first left vector element in the command  [b,xc,yc]=xclick;  is ibutton and should have a numeric value. So how can it be textual (b)? 
3.	The third vector element (-1) in the command  rep=[xc,yc,-1]  stands for “ibutton/pointer has moved” when we later have rep=xgetmouse(). However, it is also used as the condition in the while-do-end loop. So what exactly changes its value—the second click on the button?—and to which value is it changed? 
4.	The command  first=%f;  is used twice in the script, but it seems to be redundant because it can be deleted without any influence. Is that correct?

v/r Johnny Heikell

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Johnny Heikell
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