Placement from center

Discussion:

Stuart Axon

2010-10-15 23:45:27 UTC

The two transform modes we have are well and good, but it would be really useful
to have a placement mode that works like opengl, centered around the current
position.

This would mean that the following would place a large circle, with a small
circle centered on it:

fill(0.4)
ellipse(0, 0, 100, 100)
fill(0, 0, 0.4)
ellipse(0, 0, 50, 50)

I'd propose one of these to activate it:

placement(mode=CENTER)
transform(placement=CENTER)

Make sense ?
(Maybe I'm missing something here, but drawing from the center seems a bit
tricky right now)

Maybe I should make a new shoebot grammar to add the placement command though as
it's not strictly nodebox any more.

S++

Sebastian Oliva

2010-10-24 00:12:40 UTC

Permalink

Post by Stuart Axon
The two transform modes we have are well and good, but it would be really useful
to have a placement mode that works like opengl, centered around the current
position.
This would mean that the following would place a large circle, with a small
fill(0.4)
ellipse(0, 0, 100, 100)
fill(0, 0, 0.4)
ellipse(0, 0, 50, 50)
placement(mode=CENTER)
transform(placement=CENTER)
Make sense ?
(Maybe I'm missing something here, but drawing from the center seems a bit
tricky right now)
Maybe I should make a new shoebot grammar to add the placement command though as
it's not strictly nodebox any more.
S++

I think that could only work for Ovals and Squares, how can you draw a
path from "the center"; an easier implementation would be to enhance
the Oval or Square function to draw from the center.

Stuart Axon

2010-10-24 16:14:20 UTC

Permalink

Sent: Sun, October 24, 2010 12:12:40 AM
Subject: Re: [shoebot-devel] Placement from center

The two transform modes we have are well and good, but it would be really

useful

to have a placement mode that works like opengl, centered around the

current

position.
This would mean that the following would place a large circle, with a small
fill(0.4)
ellipse(0, 0, 100, 100)
fill(0, 0, 0.4)
ellipse(0, 0, 50, 50)
placement(mode=CENTER)
transform(placement=CENTER)
Make sense ?
(Maybe I'm missing something here, but drawing from the center seems a bit
tricky right now)
Maybe I should make a new shoebot grammar to add the placement command

though as

it's not strictly nodebox any more.
S++

I think that could only work for Ovals and Squares, how can you draw a
path from "the center"; an easier implementation would be to enhance
the Oval or Square function to draw from the center.

Centering already occurs in bezier path - their just re transformed so that
were based around the corner:

# Go to initial point (CORNER or CENTER):
transform = self._call_transform_mode(self._transform)

# Change the origin if nessacary
if self._get_pathmode() == CENTER:
xc, yc = self._get_center()
transform.translate(-xc, -yc)

The new parameter would probably affect the 2nd of these ifs. The tricky bit
might be how the different CENTER/CORNER stuff interacts and whether it
makes sense.

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ricardo lafuente

2010-10-24 16:22:40 UTC

Permalink

This sounds like it could be solved with functions similar to
Processing's rectMode() and ellipseMode(), see:
http://processing.org/reference/ellipseMode_.html
http://processing.org/reference/rectMode_.html

IIRC, i think Shoebot 0.3b has rectmode implemented.
I'm okay with adding this to the Shoebot grammar (+1 for keeping
separate from Nodebox), but this issue can also be dealt with with a few
translate() calls. I wonder what would be best: having the placement()
function, or a HOWTO on the docs on how to create paths originating from
the center.

Stuart Axon

2010-10-24 16:31:09 UTC

Permalink

Sent: Sun, October 24, 2010 4:22:40 PM
Subject: Re: [shoebot-devel] Placement from center

The two transform modes we have are well and good, but it would be really

useful

to have a placement mode that works like opengl, centered around the

current

though as

it's not strictly nodebox any more.

This sounds like it could be solved with functions similar to
http://processing.org/reference/ellipseMode_.html
http://processing.org/reference/rectMode_.html

how about just pathMode() ?
- Seems like it could be more general, and the name is probably
better than placement I came up with.

IIRC, i think Shoebot 0.3b has rectmode implemented.
I'm okay with adding this to the Shoebot grammar (+1 for keeping
separate from Nodebox), but this issue can also be dealt with with a few
translate() calls. I wonder what would be best: having the placement()
function, or a HOWTO on the docs on how to create paths originating from
the center.
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Stuart Axon

2010-10-24 16:35:51 UTC

Permalink

Sent: Sun, October 24, 2010 4:31:09 PM
Subject: Re: [shoebot-devel] Placement from center

Sent: Sun, October 24, 2010 4:22:40 PM
Subject: Re: [shoebot-devel] Placement from center

The two transform modes we have are well and good, but it would be really

useful

to have a placement mode that works like opengl, centered around the

current

position.
This would mean that the following would place a large circle, with a

small

fill(0.4)
ellipse(0, 0, 100, 100)
fill(0, 0, 0.4)
ellipse(0, 0, 50, 50)
placement(mode=CENTER)
transform(placement=CENTER)
Make sense ?
(Maybe I'm missing something here, but drawing from the center seems a

bit

tricky right now)
Maybe I should make a new shoebot grammar to add the placement command

though as

it's not strictly nodebox any more.

This sounds like it could be solved with functions similar to
http://processing.org/reference/ellipseMode_.html
http://processing.org/reference/rectMode_.html

how about just pathMode() ?
- Seems like it could be more general, and the name is probably
better than placement I came up with.

Thinking about it maybe pathMode CENTER would imply mode CENTER ?

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Shoebot-devel mailing list
http://lists.tinkerhouse.net/listinfo.cgi/shoebot-devel-tinkerhouse.net

ricardo lafuente

2010-10-24 17:16:05 UTC

Permalink

Post by Stuart Axon

how about just pathMode() ?
- Seems like it could be more general, and the name is probably
better than placement I came up with.

True, but how would rectmode/ellipsemode be adapted to bezier paths in
general?

Would this mean that the coords end up being relative to a center? I'm
still trying to wrap my head around this.

I think i mixed up two different concepts by relating your proposal to
Processing's rectMode/ellipsemode. Recapping:

rectMode and ellipseMode set what arguments rect() and ellipse() should
expect:
- CORNER (default): (x, y, width, height)
with (x, y) being the absolute coords of the top-left corner, unless you
use negative values for with and/or height -- e.g. with negative width
and height, (x,y) ends up being the bottom-left corner).
- CENTER: (cx, cy, width, height)
with (cx, cy) being the absolute coords of the CENTER of the
rectangle/ellipse. Width and height work the same as above.
- CORNERS: (x1, y1, x2, y2)
with (x1, y1) being the absolute coords of a corner, and (x2, y2) the
coords of the opposite corner.

On the other hand, your placement() concept would be more useful to
place paths relative to another point, if i understood correctly. This
can be easily achieved with translate(), isn't that so?
Since i'm unacquainted with OpenGL nitty-gritty, i'm not sure i got it,
so apologies in advance if this confusion is my fault.

Post by Stuart Axon
Thinking about it maybe pathMode CENTER would imply mode CENTER ?

You mean transformmode CENTER?