Reversing the JFrame Y coordinate?

Question

I've been working on a little side scroller for fun, and I always wondered how I would "reverse" the JFrame Y coordinates.

Instead of the Y coordinate starting from the top, it should start from the bottom.

I made a fancy diagram to make things more clear:

This is nothing that would be useful to me at thus point in time. But it would be good to know how to do it if for some reason I would need to do it.

This could be achieved by using an `AffineTransform` on the `Graphics` instance of the custom component. But beware that events and other such things won't be translated. — Andrew Thompson, Oct 23 '14 at 06:21
Also consider the approach outlined [here](http://stackoverflow.com/a/9373195/230513). — trashgod, Oct 23 '14 at 10:24

score 0 · Answer 1 · answered Oct 23 '14 at 05:34

0

you just need to subtract y from frame height.

answered Oct 23 '14 at 05:34

CharlieS

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score 0 · Answer 2 · answered Oct 23 '14 at 14:17

Try y-=yAmount or even y--; Let me explain, x and y start at 0, that is the top left corner, adding to x and/or y will put it lower to the right. Your image says that y should start there as 0 and to do that you can do int y2 = 0; int y = offsetY + y2; by doing that all you have to do is set y2, y and make sure that offsetY is set to your current y to make it a relative change.

Here is a few functions you could use

public void changePositionRelative(int xChange, int yChange){ x += xChange; y += yChange; }

public void resetPosition(){ x = offsetX; y = offsetY; }

Reversing the JFrame Y coordinate?

2 Answers2