Mis-rendering of parabola in Chrome on Mac El Capitan

jdgilbey shared this problem 5 years ago
Answered

I have a bizarre bug, exhibited by https://www.geogebra.org/m/1556391


On Chrome (Version 46.0.2490.86 (64-bit)), running on a MacBook Pro running El Capitan (OSX 10.11.1), when I zoom in using the red slider, the parabola is misdrawn. The parabola is defined as y=x^2, and attached is a screenshot to show an example of the parabola being miscalculated.


The GeoGebra file works correctly in the desktop app, it works correctly in Firefox and Safari, and on Chrome on a colleague's Mac running Yosemite.


It might therefore be a Chrome bug, or some nasty GeoGebra-Chrome interaction, or goodness knows what.


Julianae32cafb95657873ec8d8db19c443fa1

Comments (3)

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Thanks, we'll check (the problem occurs in Windows too). I think something's changed in Chrome recently as we fixed a similar problem last week.

https://jira.geogebra.org/b...

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Hi,


if you need to avoid the bug you can replace the conic by a function:

y=x^2 is drawn using bezier curves -- that seems to be buggy

f(x)=x^2 is drawn using line segments (generic algorithm for functions)


Also it seems this only happens if pixel ratio is >1, which happens on high density screens or when browser is zoomed on normal screen.


We'll keep digging.

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Last update: chrome developers fixed this in Chrome canary 49.

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