2015-07-17 17:57 GMT+02:00 Aliaksei Syrel <alex.syrel@gmail.com>:
Hi
Any ideas how one could blur an arbitrary shape using athens?
Cheers, Alex
Not possible. Not with Athens and not with cairo. (There was a discussion on cairos ml about drop shadows (and filter functions?, I am not sure) but I don't think there is something like that currently). Inkscape a vector/svg editor and viewer uses cairo but implements the svg filter rendering on its own. You can pre-render the cairo image and apply a filter function and use the result as a form paint. And you can cheat, and just compose multiple shape drawings with different alpha values, but of course, this is slow: | view star kernel s r root2pi | s := 3. r := 7. root2pi := (2 * Float pi) sqrt. kernel := (-1 * r to: r) collect: [ :i | 1 / (root2pi * s) * (-0.5 * (i / s) squared) exp ]. view := AthensSceneView new. star := {32.0 @ 44.04868495317364. 13.458980337503156 @ 57.519524250561204. 20.541019662496844 @ 35.72324841040037. 1.999999999999993 @ 22.252409113012813. 24.917960675006306 @ 22.25240911301281. 31.999999999999993 @ 0.4561332728519787. 39.08203932499369 @ 22.252409113012803. 62.0 @ 22.252409113012803. 43.458980337503164 @ 35.72324841040037. 50.54101966249685 @ 57.5195242505612}. view scene: [ :canvas | | path | path := canvas createPath: [ :builder | builder absolute; moveTo: star first. star allButFirstDo: [ :p | builder lineTo: p ]. builder close ]. canvas surface clear: Color white. canvas paintMode over. r negated to: r do: [ :i | | a | a := kernel at: r + i + 1. r negated to: r do: [ :j | | b | b := a * kernel at: r + j + 1. canvas setPaint: (Color black alpha: b). canvas pathTransform restoreAfter: [ | sx sy | sx := canvas pathTransform sx. sy := canvas pathTransform sy. canvas pathTransform translateBy: (i / sx) @ (j / sy). canvas drawShape: path ] ] ]. canvas pathTransform restoreAfter: [ canvas pathTransform translateBy: (5 @ 5) negated. canvas setPaint: Color red. canvas drawShape: path ] ]. view openInWindow
