Trying to make a Square like a potoshop

thefool

hii I was a novice programmer. i am from indonesia and I am very interested in the programming language processing.

I've watched several videos Daniel Shiffman about how to create a class, function, rect, circle, etc. but still not all that I have seen.

I am trying to create a function which can create a box shape as in potoshop

This is the result of my work

I may look fail :'( but I hope you can teach me how to write the code.

thx.... i am sorry if my english so bad

AverageJoe

https://processing.org/reference/constrain_.html
constrain(number, low, high);

Your code:
float mx = constrain(mouseX, mouseX, 200);

Because number == low, then mx == mouseX.
This means:
rect(mouseX, mouseY, mouseX, mouseY);

That is a rectangle less than one pixel...