Hi Ian,
Yeah, that's why the spec hand-waves to transform the line too... but I
agree that that doesn't really work.
Do you have any suggestion of how to spec this better?
This is the most general arcTo situation:
setTransform(M0)
lineTo(x0, y0)
setTransform(M)
arcTo(x1, y1,
On Mon, Sep 3, 2012 at 8:58 AM, Ian Hickson i...@hixie.ch wrote:
Does it work if you just transform all the points and the line?
(Yeah, that's still way too vague. I'm not sure how to really specify
this in a manner that's both unambiguous and clear. Any suggestions?)
I am not 100% sure that
On Mon, 20 Aug 2012, Michael Day wrote:
The camvas arcTo method generates an arc that touches two tangent lines.
The first tangent line is from the last point in the previous subpath to
the first point passed to the arcTo method.
What happens in this situation:
ctx.lineTo(100, 100);
Hi Michael,
in your case, the first control point is not the same as the last point of
the subpath.
The 'scale(2,1)' set up a different coordinate system. You can rewrite your
code from this:
ctx.lineTo(100, 100);
ctx.scale(2, 1);
ctx.arcTo(100, 100, 100, 200, 100);
to this:
ctx.scale(2, 1);
Hi Rik,
The 'scale(2,1)' set up a different coordinate system. You can rewrite
your code from this:
ctx.lineTo(100, 100);
ctx.scale(2, 1);
ctx.arcTo(100, 100, 100, 200, 100);
to this:
ctx.scale(2, 1);
*ctx.lineTo(50, 100);*
ctx.arcTo(100, 100, 100, 200, 100);
Right,
On Mon, Aug 20, 2012 at 5:55 PM, Michael Day mike...@yeslogic.com wrote:
Hi Rik,
The 'scale(2,1)' set up a different coordinate system. You can rewrite
your code from this:
ctx.lineTo(100, 100);
ctx.scale(2, 1);
ctx.arcTo(100, 100, 100, 200, 100);
to this:
Hi Rik,
Yes, that is one way of implementing it. This is not specific to arcTo;
this happens with all drawing operators.
It is not quite the same with other drawing operators, for example:
ctx.setTransform(...T1...);
ctx.lineTo(100, 100);
ctx.setTransform(...T2...);
ctx.lineTo(100, 100);
On Mon, Aug 20, 2012 at 8:15 PM, Michael Day mike...@yeslogic.com wrote:
Hi Rik,
Yes, that is one way of implementing it. This is not specific to arcTo;
this happens with all drawing operators.
It is not quite the same with other drawing operators, for example:
Hi Rik,
Yes you can go to absolute canvas coordinates but you need to remember
that the radius is transformed too.
You cannot transform the three control points, and then generate the
arc. If you do this, you will always get circular arcs, whereas a
scale(2, 1) will produce an elliptical
Hi,
The camvas arcTo method generates an arc that touches two tangent lines.
The first tangent line is from the last point in the previous subpath to
the first point passed to the arcTo method.
What happens in this situation:
ctx.lineTo(100, 100);
ctx.scale(2, 1);
ctx.arcTo(100, 100, 100,
Firefox and Chrome do not do this, as can be seen by viewing the
attached HTML file.
Or since attachments are stripped, here is the file:
http://www.princexml.com/arcto.html
Cheers,
Michael
On Sat, 27 Dec 2008, Dirk Schulze wrote:
have two questions to the all points on a line part of canvas' arcTo.
A short example:
moveTo(50,0);
arcTo(100,0, 0,0, 10);
This should add a new, from p1 infinite far away, point to the subpath
and draw a straight line to it.
Two
On Sat, Dec 27, 2008 at 9:37 AM, Dirk Schulze vb...@gmx.de wrote:
Hi,
have two questions to the all points on a line part of canvas' arcTo.
A short example:
moveTo(50,0);
arcTo(100,0, 0,0, 10);
This should add a new, from p1 infinite far away, point to the subpath
and draw a straight
Philip Taylor ha scritto:
But I don't know if it makes sense from the perspective of someone
who's got to write an independent implementation of it. Does the above
explanation make more sense than the text in the spec? and if so, does
it seem implementable? If so, it seems best to keep the
On Wed, Jan 21, 2009 at 2:45 PM, Philip Taylor excors+wha...@gmail.com wrote:
On Sat, Dec 27, 2008 at 9:37 AM, Dirk Schulze vb...@gmx.de wrote:
Hi,
have two questions to the all points on a line part of canvas' arcTo.
A short example:
moveTo(50,0);
arcTo(100,0, 0,0, 10);
This should add
Hi,
have two questions to the all points on a line part of canvas' arcTo.
A short example:
moveTo(50,0);
arcTo(100,0, 0,0, 10);
This should add a new, from p1 infinite far away, point to the subpath
and draw a straight line to it.
Two questions.
1) If I add lineTo(50, 50); after arcTo(..).
I believe adding an infinite far away point is wrong and insteaed
nothing should be drawn at all and I would like to explain my reason:
Imagine 2 vectors. One from (x1, y1) to (x0, y0) and one from (x1, y1)
to (x2, y2).
For
moveTo(100, 0);
arcTo(150,0, 50, 0, 10);
the angle between the two
On 31/01/2008, Ian Hickson [EMAIL PROTECTED] wrote:
On Mon, 2 Jul 2007, Philip Taylor wrote:
If the point (x2, y2) is on the line defined by the points (x0, y0) and
(x1, y1) then the method must do nothing, as no arc would satisfy the
above constraints. - why would no arc satisfy the
On Sat, 2 Feb 2008, Philip Taylor wrote:
The circle can't touch tangentially at two distinct points, but
nothing said there had to be two distinct points.
IIRC it used to say another point. It's certainly more explicitly now.
About the updated specification:
the method must add a point
On Mon, 2 Jul 2007, Philip Taylor wrote:
As implemented, the operation of arcTo in Firefox (2, 3) and Opera (9.2,
9.5) is utterly unrelated to the spec and arguably crazy. At least Opera
has the right spirit and tries drawing arcs between points, though
they're the wrong points and they're
if the radius is finite.
Chris
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Philip Taylor
Sent: Monday, July 02, 2007 1:42 PM
To: WHATWG
Subject: [whatwg] Canvas arcTo
If the point (x2, y2) is on the line defined by the points (x0, y0)
and (x1, y1
As implemented, the operation of arcTo in Firefox (2, 3) and Opera
(9.2, 9.5) is utterly unrelated to the spec and arguably crazy. At
least Opera has the right spirit and tries drawing arcs between
points, though they're the wrong points and they're always
semicircles. Safari nearly matches the
Subject: [whatwg] Canvas arcTo
If the point (x2, y2) is on the line defined by the points (x0, y0)
and (x1, y1) then the method must do nothing, as no arc would satisfy
the above constraints. - why would no arc satisfy the constraints? If
P0, P1, P2 are collinear and non-coincident, then (I think) any
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