[HN Gopher] Reinventing Feathering for the Vectorian Era
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       Reinventing Feathering for the Vectorian Era
        
       Author : interpol_p
       Score  : 67 points
       Date   : 2025-04-04 01:13 UTC (3 days ago)
        
 (HTM) web link (rive.app)
 (TXT) w3m dump (rive.app)
        
       | cjbgkagh wrote:
       | The 2D Gaussian blur is separable into 2 1D convolutions which is
       | much faster than the 2D version so less of a performance issue.
        
         | tczMUFlmoNk wrote:
         | Not just that, but two 1D _iterated box blurs_ , requiring an
         | amount of work per pixel that is constant with respect to the
         | blur radius--as opposed to quadratic for the naive convolution,
         | or linear for the 2D-to-1D transformation with a full Gaussian
         | kernel.
         | 
         | http://elynxsdk.free.fr/ext-docs/Blur/Fast_box_blur.pdf
        
           | cjbgkagh wrote:
           | Neat didn't know that.
        
       | ajb wrote:
       | Not completely buying this. He's claiming that it's better to do
       | vector based feathering, but it's not at all clear that his
       | approach isn't just as computationally expensive, or more.
       | Filters do require a lot of calculations, but they are
       | embarrassingly parallel and also you get help from the
       | Convolution Theorem.
        
         | The5thElephant wrote:
         | Looking at the performance it's quite clearly much faster than
         | equivalent effects done in traditional web browser rendering or
         | in design tools.
        
       | zokier wrote:
       | I'm confused, can't you accomplish the same effect with simple
       | gradient (+ offset)?
        
         | tobr wrote:
         | What do you mean with a "simple" gradient? The difficult part
         | is that it has to follow not just the outline of the shape, but
         | also the average color of the shape around a certain point.
         | That must get very tricky with arbitrary shapes.
        
       | tobr wrote:
       | Right about when I'd expect it to get into the interesting
       | technical details, the article pivots to marketing fluff. Hoping
       | for a follow-up that dives in.
        
       | rikroots wrote:
       | You can achieve a gaussian blur effect using an infinite impulse
       | response thing[1]. Some very clever people at IBM came up with
       | the idea, and some other very clever people translated that code
       | to Javascript and stuck it on GitHub for the rest of the world to
       | use[2].
       | 
       | [1] - https://en.wikipedia.org/wiki/Infinite_impulse_response
       | 
       | [2] - https://github.com/nodeca/glur
        
       | B1FF_PSUVM wrote:
       | I'm a bad person who read too many old comics - I thought this
       | was a V _i_ ctorian history snippet about tar-less "tarring &
       | feathering", perhaps with honey for a gourmet twist ...
        
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       (page generated 2025-04-07 23:02 UTC)