[Cuis-dev] [Ann] Major updates to VectorGraphics

[Juan Vuletich]

Hi Hilaire,

Thanks for the additional detail. Now I see what you mean.

I'm glad you found a way to translate your protocol to the one provided 
by the plugin.

WRT the blue sine function, the old behavior can be added back, but (as 
it was) only at the Smalltalk level. The implementation is too 
complicated to make it worth to add it to the plugin. But in Smalltalk, 
we can add it back if you want.

Thanks,

On 5/27/2025 3:39 PM, Hilaire Fernandes via Cuis-dev wrote:
>
> So far, your implementation of VectorGraphics engine followed the SVG 
> specification. I discovered that when I implemented the DrGeoSVGCanvas 
> to render a DrGeo sketch to a SVG file.
>
> Particularly in the style of the element, the dashArray attribute was 
> of same nature in VG and SVG:
>
>   1
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>   7
>   8
>   9
> 10
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> 17
> 	
> DrGSVGCanvas>>styleOf:  element  StrokeWidth:  strokeWidth  color:  strokeColor  strokeDashArray:  sda  fillColor:  fillColor
> "
> 	Apply style to a given element (node)
> "
> 	strokeWidth  ifNotNil:  [element  attributeAt:  #'stroke-width'  put:  strokeWidth  asString].
> 	strokeColor  ifNotNil:  [	element  attributeAt:  #stroke  put:
> 		(strokeColor  isTransparent  ifTrue:  ['transparent']ifFalse:	strokeColor  hexHtml)].
> 	sda  ifNotNil:  [
> 		element
> 			attributeAt:  #'stroke-dasharray'
> 			put:  (String  streamContents:  [:s  |  sda  do:  [:e  |  s  store:  e]separatedBy:  [s  space]])].
> "	sdao ifNotNil: [element attributeAt: #'stroke-dashoffset' put: sdao asString]."
> 	fillColor
> 		ifNotNil:  [
> 			element  attributeAt:  #fill  put:  fillColor  hexHtml.
> 			fillColor  isOpaque  ifFalse:  [element  attributeAt:  #'fill-opacity'  put:  fillColor  alpha  asString] ]
> 		ifNil:  [element  attributeAt:  #fill  put:  'none']
>
>
>
> From my understanding, now your implementation differs in the way 
> dashes are represented in SVG. It is just an observation not a complain.
> To minimize my code change, I implemented a backward compatible method 
> in AbstractVectorCanvas, it converts my dash (composed of only two 
> numbers) from the former format to your new format:
>
>   1
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> 	
> strokeWidth:  borderWidth  color:  borderColor  strokeDashArray:  dashedBorder  do:  pathCommandsBlock
> "
> dashedBorder = array of 2 elements, for example #(1 6), one pixel on, 6 off
> "
> 	dashedBorder
> 		ifNil:  [
> 			self
> 			strokeWidth:  borderWidth
> 			color:   borderColor
> 			do:  pathCommandsBlock]
> 		ifNotNil:  [
> 			self
> 			strokeWidth:  borderWidth
> 			color:   borderColor
> 			dashedStrokeBits:   (2  raisedTo:  dashedBorder  first)-  1   <<  dashedBorder  second
> 			do:  pathCommandsBlock  ]
>
>
>
> It works pretty well and keep DrGSVGCavnas working. It does not work 
> well for my Locus Morph though. A locus is a collection of points 
> connected by line. See the below the blue sinus curve should be 
> dashed. Of course it is related to the way the locus sample are 
> computed, some samples may be too close to each other to see the dash 
> painted.
> *Surprisingly for me, this problem was not present in your Smalltalk 
> previous implementation of dash. *
>
>
>
>
> When playing a bit with the Morph Locus parameters to alter the 
> sampling of the locus, we can reveal what is going on, see below.
> All this is not a bug in your implementation, but your previous 
> implementation could hide this problem related to sampling at a 
> dynamic rate, and it was pretty cool.
>
>
>
>
>
>
>
> Le 27/05/2025 à 17:53, Juan Vuletich a écrit :
>> Not sure what you mean. Can you give an example? Is there some quick 
>> test I can do that works without the updates?
>>
>> Thanks,
> -- 
> http://mamot.fr/@drgeo


-- 
Juan Vuletich
cuis.st
github.com/jvuletich
researchgate.net/profile/Juan-Vuletich
independent.academia.edu/JuanVuletich
patents.justia.com/inventor/juan-manuel-vuletich
linkedin.com/in/juan-vuletich-75611b3
twitter.com/JuanVuletich

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