Sorry but I do not buy your argument. BlElement is in charge and it delegates it to BlShape. This is a quite common pattern and this is more logical that the object responsible for the shape drawing draw it in fact. It was like that in Bloc before so I do not see why this is not possible now. Le 25/2/16 13:37, Aliaksei Syrel a écrit :
All arbitrary shapes are being drawing in the same way and it is enough to have only one method. Allowing shape to render itself would lead to misunderstanding: bloc user would have to look into two places (element and shape) to find out where drawing actually happens.
On Feb 25, 2016 12:56 PM, "stepharo" <stepharo@free.fr <mailto:stepharo@free.fr>> wrote:
To me this is pre optimisation
I do not see why we cannot do
BlElement>>drawOnAthensCanvas: aCanvas
self shape drawOnAthensCanvas: aCanvas with: self
so far only localBounds from BlElement are used.
And to me this is really strange to have an object responsible for the drawing not doing it. It blurs the responsibility.
Stef
Le 25/2/16 10:39, Tudor Girba a écrit :
Hi,
Good question.
The reason we want to have the morph be responsible because subclasses might decide to draw in a different way regardless of the shape being used. This gives us the maximum freedom for more specific blocs. Still, this is something to experiment with once we have more complicated examples built with Bloc.
Cheers, Doru
On Feb 25, 2016, at 9:56 AM, stepharo <stepharo@free.fr <mailto:stepharo@free.fr>> wrote:
Hi Blockers
I do not really understand why drawOnAthensCanvas: is not defined on BlShape (especially when we see how many self space are defined in this method. And this is one of the few things I thought I understood from bloc (grouping the rendering in a separate object).
drawOnAthensCanvas: aCanvas "Actually render receiver on aCanvas in local bounds. Override to customize. aCanvas is an instance of AthensCanvas aCanvas must not be nil"
| pathTransform | pathTransform := aCanvas pathTransform. "First we fill" pathTransform restoreAfter: [ | path fillExtent fillTranslation | "We fill inside natural element's bounds" fillExtent := self shape path fillExtentFor: self shape inBounds: self localBounds. path := self shape path pathOn: aCanvas forExtent: fillExtent. "Translate fill if needed" fillTranslation := self shape path fillTranslationFor: self shape inBounds: self localBounds. pathTransform translateBy: fillTranslation. aCanvas setPaint: self shape fillPaint; drawShape: path ]. pathTransform restoreAfter: [ | path strokeExtent strokeTranslation | "We stroke inside natural element's bounds" strokeExtent := self shape path strokeExtentFor: self shape inBounds: self localBounds. path := self shape path pathOn: aCanvas forExtent: strokeExtent. "Translate stroke if needed" strokeTranslation := self shape path strokeTranslationFor: self shape inBounds: self localBounds. pathTransform translateBy: strokeTranslation. aCanvas setPaint: self shape strokePaint; drawShape: path ]
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