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How can I reverse the direction of the Y axis? [message #208925]

Thu, 09 February 2006 20:59

Eclipse User

Originally posted by: geoff_crowther.uk.ibm.com

BlankIn the GEF examples (e.g. Logic) the origin (0, 0) is at the top right
of the editor window. Positive Y values are below this origin, and negative
Y values are above. Is there any way to change this direction, so that
positive Y is upwards, preferably also changing the default location of the
origin to be the bottom left of the editor window? This would allow the
editor to match the conventional representation of an X,Y coordinate system.

Many thanks for your help.

Geoff Crowther

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Re: How can I reverse the direction of the Y axis? [message #208959 is a reply to message #208925]

Fri, 10 February 2006 00:53

Steven R. Shaw

Messages: 128
Registered: July 2009

Senior Member

GEF is consistent with SWT which is consistent with most OS windowing
systems which use the top left as a anchor for the point system. If you're
relying on some mathematic libraries or something that assumes different, it
should be a simple mapping to achieve the opposite (ViewPort extent - y
coordinate).

Regards,

Steve.

"geoffc" <geoff_crowther@uk.ibm.com> wrote in message
news:dsga83$pko$1@utils.eclipse.org...
> BlankIn the GEF examples (e.g. Logic) the origin (0, 0) is at the top
right
> of the editor window. Positive Y values are below this origin, and
negative
> Y values are above. Is there any way to change this direction, so that
> positive Y is upwards, preferably also changing the default location of
the
> origin to be the bottom left of the editor window? This would allow the
> editor to match the conventional representation of an X,Y coordinate
system.
>
> Many thanks for your help.
>
> Geoff Crowther
>
>

Report message to a moderator

Re: How can I reverse the direction of the Y axis? [message #208982 is a reply to message #208959]

Fri, 10 February 2006 09:03

TomÃ¡Å¡ Studva

Messages: 9
Registered: July 2009

Junior Member

I think good solution is to create such conversion methods. Maybe you find a good class where to place these methods as static. But I think if you subclass yor root editpart, you can change it there and have these coordinates by default.
Tomas Studva

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Re: How can I reverse the direction of the Y axis? [message #209045 is a reply to message #208925]

Fri, 10 February 2006 15:48

Eclipse User

Originally posted by: none.us.ibm.com

Rectangle rect = canvas.getClientArea();
Transform t = new Transform(Display.getCurrent());
t.translate(0f, (float)(rect.height - rect.y));
t.scale( 0f, -1f);
gc.setTransform(t);

"geoffc" <geoff_crowther@uk.ibm.com> wrote in message
news:dsga83$pko$1@utils.eclipse.org...
> BlankIn the GEF examples (e.g. Logic) the origin (0, 0) is at the top
> right
> of the editor window. Positive Y values are below this origin, and
> negative
> Y values are above. Is there any way to change this direction, so that
> positive Y is upwards, preferably also changing the default location of
> the
> origin to be the bottom left of the editor window? This would allow the
> editor to match the conventional representation of an X,Y coordinate
> system.
>
> Many thanks for your help.
>
> Geoff Crowther

Report message to a moderator

Re: How can I reverse the direction of the Y axis? [message #210329 is a reply to message #209045]

Sat, 25 February 2006 09:50

Eclipse User

Originally posted by: geoff_crowther.uk.ibm.com

Randy

Many thanks for your suggestion. Unfortunately I am new to GEF, and cannot
see where to hook this in to my application which is currently loosly based
on the "Logic" example application. Could you provide a few pointers for
me.

Thanks again

Geoff
"Randy Hudson" <none@us.ibm.com> wrote in message
news:dsicl5$5ei$1@utils.eclipse.org...
> Rectangle rect = canvas.getClientArea();
> Transform t = new Transform(Display.getCurrent());
> t.translate(0f, (float)(rect.height - rect.y));
> t.scale( 0f, -1f);
> gc.setTransform(t);
>
> "geoffc" <geoff_crowther@uk.ibm.com> wrote in message
> news:dsga83$pko$1@utils.eclipse.org...
> > BlankIn the GEF examples (e.g. Logic) the origin (0, 0) is at the top
> > right
> > of the editor window. Positive Y values are below this origin, and
> > negative
> > Y values are above. Is there any way to change this direction, so that
> > positive Y is upwards, preferably also changing the default location of
> > the
> > origin to be the bottom left of the editor window? This would allow the
> > editor to match the conventional representation of an X,Y coordinate
> > system.
> >
> > Many thanks for your help.
> >
> > Geoff Crowther
>
>

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