Re: Changing coordinates

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 16 Jun 2010 11:50:22 -0700 (PDT)

Message-ID:

<914e4a2f-f577-49e5-9269-e64390d057a3@g18g2000vbl.googlegroups.com>

Lew wrote:

From time immemorial screen coordinates have been expressed from the
top-left corner. You will go through a lot of useless effort
resisting this.

Rene' Descartes wrote:

But even before such immemorial times, physicists and mathematicians are
used to coordinates starting in the bottom left corner.

On computer screens? I think not.

Different domain of discourse, different rules.

My degree is in mathematics, but I don't try to fight the standard for
screen coordinates. I'm much happier that way. I recommend the same
to you.

Lew wrote:

Take the world for what it is and don't fight to jam it into your
preconceptions.

Rene' Descartes wrote:

And Y-flipping is something standard in every sensible graphics package.

Circular reasoning. You're proving your point by calling the
conclusion "sensible".

Usually one has some world coordinates, some "normalized device
coordinates" (NDC) and the raw device coordinates. Y-flipping is taken
care when passing from NDC to raw.

The OP is using libraries that work in terms of screen coordinates.
Ergo, they must use screen coordinates. Y-flipping is not relevant.

--
Lew