Question

I have problem which I want to draw a function graph with any input I key in.However I not familiar with the y-coordinate in java.I wish my graph got negative value !Does anyone know how to make it?

Answer 1

By default origin i.e. (0,0) for java 2d graphics is at the upper left corner of your screen.

To translate it to center of your screen use the following method of Graphics class
http://docs.oracle.com/javase/1.4.2/docs/api/java/awt/Graphics.html

translate(int x, int y)

For eg.

 //if your graphics object is g:

g.translate(screen_width/2, screen_height/2);

//where
//screen_width is the width of your screen
//screen_height is the height of your screen