[BUG] Release v2.7.3 scatter plot CanvasGradient

[chouhy]

I believe in v2.7.3, something goes wrong.
I tried to apply CanvasGradient color to scatter plot and it just doesn't work.

At last, I changed to v2.7.2 and it worked.

v2.7.2
https://jsfiddle.net/b1embnd2/14/
v2.7.3
https://jsfiddle.net/b1embnd2/15/

Construction of the graph is completely same, the only difference is the version of chart.js.

[nagix]

Since v2.7.3, the origin of coordinates for CanvasGradient has become relative (#5319). In other words, the center of each point is (0, 0) for CanvasGradient.

[chouhy]

Since v2.7.3, the origin of coordinates for CanvasGradient has become relative (#5319). In other words, the center of each point is (0, 0) for CanvasGradient.

I don't get what you mean. The center of each point has nothing to do with CanvasGradient.
In v2.7.3, CanvasGradient seems to apply color gradient INSIDE every point, i.e. https://jsfiddle.net/b1embnd2/22/ .
This is definitely not the correct behavior.
In previous version, the behavior of CanvasGradient acted like this.

[nagix]

Ok, this seems a common use case.

@simonbrunel #5319 uses ctx.translate and changed to draw points at (0, 0) to support rotation, but it causes this degradation. One solution would be to calculate each drawing point without ctx.translate or ctx.rotate, but I'm concerned that it could impact the rendering performance. Any ideas?

[simonbrunel]

I don't know what's the best solution and I agree that calculating ourselves the rotated coordinates can have impact on performances. But we could try to benchmark how bad is it and see if it's an acceptable direction.