[Tcl-bugs] [ tktoolkit-Bugs-3431491 ] canvas create line slow for pure lists of double coordinates

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Bugs item #3431491, was opened at 2011-10-31 18:14
Message generated for change (Tracker Item Submitted) made by mhaidermako
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Category: 05. Canvas Items
Group: obsolete: 8.5.9
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Max Haider (mhaidermako)
Assigned to: Jeffrey Hobbs (hobbs)
Summary: canvas create line slow for pure lists of double coordinates

Initial Comment:
In our application, we noticed that "canvas create line" takes a considerable amount of time when the list of coordinates is not pre-shimmered before it enters the canvas. It looks like the list itself does not gain a string representation, but every double inside does gain a string representation and a type conversion to "pixel". A list of doubles with string representations appears to go around 25x faster than a list of pure doubles, at least with our particular systems and usage of the canvas. After some examination of Tk, I believe the string conversion happens in the conversion to the pixel type. I only tested this on 8.5.9.

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