El 14-04-2014, a las 8:21, Juraj Kubelka <juraj.kubelka@gmail.com> escribi��:

Thank you Stef,

the example helped me a lot to understand how to play with Athens.��

The solution is not what I am looking for. If someone starts to play with alpha canal, s/he will get unexpected results.

I have finally found an example in C language. It look like this:

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cairo_set_line_width (cr, 0.1);

cairo_save (cr);

cairo_scale (cr, 1, 0.2);

cairo_arc (cr, 1.5, 1.5, 1, 0, 2 * M_PI);

cairo_restore (cr);

�� �� �� �� cairo_set_source_rgba (cr, 0, 1, 0, 0.50);

cairo_stroke (cr);

-=-=-=-=-

<tips-ellipse.png>

I do not know how to write the same instructions with Athens.��

First, they draw one arc (cairo_arc (cr, 1.5, 1.5, 1, 0, 2 * M_PI);), I draw 4 arcs:

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canvas
createPath: [ :builder |��
builder
absolute;
moveTo: 0 @ 0.5;
ccwArcTo: 0.5 @ 0.0 angle: 90 degreesToRadians;
ccwArcTo: 0.0 @ -0.5 angle: 90 degreesToRadians;
ccwArcTo: -0.5 @ 0.0 angle: 90 degreesToRadians;
ccwArcTo: 0 @ 0.5 angle: 90 degreesToRadians ].

-=-=-=-=-

OK, now I can draw ellipse with just one arc:

-=-=-=-

canvas

createPath: [ :builder |��
builder
absolute;

moveTo: 0.5 @ 0;��

arcCenterX: 0 centerY: 0 radius: 0.5 startAngle: 0 endAngle: Float twoPi

-=-=-=-

Why is this method in private protocol? Why I should not use it?

Why I have to use ���moveTo:���? In C-example they do not use it. But I have to, otherwise there is an extra line on the canvas:

Well, I see in AthensCairoPathBuilder>>createPath:, there is call of "self moveToX: 0 Y: 0.���. If I remove it, I do not have to write ���moveTo: 0.5@0���. So, I understand why I have to write it in my code. The question is what is the purpose of "self moveToX: 0 Y: 0.���? I guess it simplify some situations, am I right? Which one?

There is actual Athens example:

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AthensSceneView new��scene: [ :can |
| path |
path := can��createPath: [ :builder |��
builder
absolute;

moveTo: 0.5 @ 0;
arcCenterX: 0 centerY: 0 radius: 0.5 startAngle: 0 endAngle: Float twoPi ].
can pathTransform��restoreAfter: [��
can pathTransform scaleBy: 200 @ 50.

(can��setStrokePaint: Color red) width: 0.1.
can��drawShape: ��path.

].
] ;
openInWindow

-=-=-=-

Thank you,

Juraj

Second, they set line width, before any other action (like cairo_save). I do:

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canvas pathTransform scaleBy: 200 @ 50.

(can setStrokePaint: Color red) width: 0.1.

can drawShape: ��path.

-=-=-=-=-

So, my result in Athens is like this:

<Captura de pantalla 2014-04-14 a la(s) 8.18.38.png>

Any idea? The example is explained��here, C source code is��here��(by clicking on the image in the��page).

Thank you,

Jura

El 12-04-2014, a las 4:01, Pharo4Stef <pharo4Stef@free.fr> escribi��:

AthensSceneView new
scene: [ :can |
| path |
path := can
createPath: [ :builder |
builder
absolute;
moveTo: 0 @ 0.5;
ccwArcTo: 0.5 @ 0.0 angle: 90 degreesToRadians;
ccwArcTo: 0.0 @ -0.5 angle: 90 degreesToRadians;
ccwArcTo: -0.5 @ 0.0 angle: 90 degreesToRadians;
ccwArcTo: 0 @ 0.5 angle: 90 degreesToRadians ].

can pathTransform
restoreAfter: [
can pathTransform scaleBy: 200 .
can
setPaint: Color red ;
drawShape: ��path.
"(athensCanvas setStrokePaint: strokePaint)
width: (self strokeWidth / self scale) asFloat."
can drawShape: ��path.].
can pathTransform
restoreAfter: [
can pathTransform scaleBy: 190 .
can
setPaint: Color blue ;
drawShape: ��path.
"(athensCanvas setStrokePaint: strokePaint)
width: (self strokeWidth / self scale) asFloat."
can drawShape: ��path

]
] ;
openInWindow


<Screen Shot 2014-04-12 at 09.01.09.pdf>