radial gradients near the edges of the screen create visible banding

When using radial gradients, there seems to be an issue that the number of gradient steps is calculated wrong. It seems it's using the distance between gradient end and the screen border instead of the gradient start and gradient end.

Example code:

ctx.save()
ctx.radial_gradient(0, 0, 80, 0, 0, 115) # 5 colors
#ctx.radial_gradient(0, 0, 80, 0, 0, 116) # 4 colors
#ctx.radial_gradient(0, 0, 80, 0, 0, 117) # 3 colors
#ctx.radial_gradient(0, 0, 80, 0, 0, 118) # 2 colors
ctx.add_stop(0.0, (0.0, 0.0, 0.0), 1.0)
ctx.add_stop(1.0, (1.0, 0.0, 0.0), 1.0)
ctx.rectangle(-120, -120, 240, 240)
ctx.fill()
ctx.restore()

Increasing the size of the rectangle beyond the edges of the screen does not help

assigned to @pippin

added ctx label

I think I have seen this with some of desktop backends of ctx as well. Where it becomes apparent also in the middle of the rendered frame, since it is split the job in tiles and such edge-of buffer conditions are more regular.

This might be related to #62 (closed)

@pippin could u have another look at this now that #62 (closed) has been solved?

This also seems to be fixed now, please reopen if that was not the case.

closed