[wpe-2.38] Spurious lines in zoomed content

[filipe-norte-red]

When applying a zoom factor to a page with images that form a gradient, spurious lines appear that are otherwise not present without the zoom factor.

Good case (zoom = 100%):

Bad case (zoom = 150%):

This can be reproduced with the attached test page: test.zip

Steps:

• Load the page. No spurious lines should be observed
• In inspector console, run: document.body.style.zoom = "150%"

This was only tested on 2.38 so far.

Note: The position of the lines depends on the size of the blocks / images used to create the gradient effect. In this particular case there is an overlap between 2 blocks that leads to the existence of the 2 lines. Should the size of the blocks be adjusted the position of the lines would change. The same test page renders ok on chrome on the pc.

[filipe-norte-red]

Hello @magomez Was wondering if you had the chance to have an initial look at this issue? Thanks

[magomez]

@filipe-norte-red yes, I started to look into it. I know it happens because the divs in the example overlap a bit, and the lines are shown exactly at the border of the overlapping area. I discarded it's a composition issue. My bet is that there's a rounding problem somewhere when applying to zoom to the divs size, but I'm still looking into it.

[magomez]

@filipe-norte-red I've just pushed 7d2a4ff147c6862f1cb19d5860f5a1e9a87c8152 to the wpe-2.38 branch. That fixes the problem for me. Could you please verify that it works for you as well and close this? Thanks!

[filipe-norte-red]

@magomez , many thanks for the fix! I confirm it fixes the issue!