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: -=-=-=-=- 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); -=-=-=-=- 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: -=-=-=-=- 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 ]. -=-=-=-=- Second, they set line width, before any other action (like cairo_save). I do: -=-=-=-=- canvas pathTransform scaleBy: 200 @ 50. (can setStrokePaint: Color red) width: 0.1. can drawShape: path. -=-=-=-=- So, my result in Athens is like this: 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> escribió:
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
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