Re: [Dr. Geo] [Bug 1761420] Re: Rendering time of Point Morph

[hilaire]

Nice analysis!

Yep, the empty text morph label of point is very expensive. It was 
already identified, and fixed.

Regarding your idea about partial World update, it is neat. Dedicated 
methods should be implemented on the DrGeoCanvas class; it is really the 
one knowing about the state of the canvas.

We can have several messages:

#updateCanvasFrequency: integer

#updateCanvas

Two additional attributes for DrGeoCanvas are needed, 
updateCanvasFrequency and updateCanvasCounter

Round point are very expensive to render. The Cairo backend needs it to 
be render as arc. It could be optimized in the DrGPointMoprh with a 
cache Form. But I don't want to complicate its code. Now from Smalltalk 
Sketch, point are rendered by default as squares, which is likely even 
faster than cross.

About the point costume style, the setters need to be update 
individually too. For example the #color: message needs its own #changed 
message sent when the user edit its style from the GUI. How will you 
write #color:pointSize:shape setter and avoid code duplication at the 
same time? Writing private #color, #pointSize: #shape setters without 
the changed message. I am not sure what is the best practice? In the 
other hand, in the PI script, costume is initialized once per world 
update cycle, when a new the point is created. I am not sure it is a 
problem, is it? I have not measure its impact.

Good points!

Thanks

Hilaire

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https://bugs.launchpad.net/bugs/1761420

Title:
  Rendering time of Point Morph

Status in Dr. Geo II:
  Confirmed

Bug description:
  PointMorph are initialized with an empty label (text morph). 
  When a sketch comes with a lot of point, this emoty lable still slow down a 
lot the Athens canvas rendering.
  Solution: keep the textmorph as nil as long as there is not label attached to 
a point.

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