Bug 103081 – [EFL][WK2] Mouse over on images on Google search shows artifacts

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit EFL

[Kenneth Rohde Christiansen]

SSIA

[Kenneth Rohde Christiansen]

Created attachment 175690 [details]
The issue

[Thiago Marcos P. Santos]

Do you see the same issue on the Qt minibrowser?

[Kenneth Rohde Christiansen]

(In reply to comment #2)
> Do you see the same issue on the Qt minibrowser?

I don't have it buildable right now. You need to move over at least two images for this issue to show

[Kalyan]

(In reply to comment #1)
> Created an attachment (id=175690) [details]
> The issue

The problem seems to be as follows:

We always seem to draw two layers being on top of each other. The first time you hover on a image the background is like a white layer. From there on the background is always the previous image (Atleast most of the times). I tried it on Firefox and chrome, I don't see any two layers there.

[Kalyan]

The following error is shown in command prompt when ever I hover over an image:

elm_label.c:400 elm_label_add() could not add 0x9859f68 as sub object of 0x91a1770

Any thoughts on why we might be getting this??

[Chris Dumez]

(In reply to comment #5)
> The following error is shown in command prompt when ever I hover over an image:
> 
> elm_label.c:400 elm_label_add() could not add 0x9859f68 as sub object of 0x91a1770
> 
> Any thoughts on why we might be getting this??

Yes, we know about this warning. It is caused by the tooltip code (printed every time we show a tooltip). However, since tooltips seem to show fine, we haven't really looked into it yet.

[Kenneth Rohde Christiansen]

(In reply to comment #4)
> (In reply to comment #1)
> > Created an attachment (id=175690) [details] [details]
> > The issue
> 
> The problem seems to be as follows:
> 
> We always seem to draw two layers being on top of each other. The first time you hover on a image the background is like a white layer. From there on the background is always the previous image (Atleast most of the times). I tried it on Firefox and chrome, I don't see any two layers there.

Actually it seems to create a layer and immediately destroy it

hover:
create layer 18
delete layer 18
create layer 19
unhover:
delete layer 19

[Kenneth Rohde Christiansen]

Created attachment 175962 [details]
Test case

This just adds the blurry border like on google, on hover and removed it on unhover. It is easy to see that resources are being reused.

[Kenneth Rohde Christiansen]

Funny fact, if I resize the window to create more content tiles (use WEBKIT_SHOW_COMPOSITING_DEBUG_VISUALS=1 for debugging) then the texture is reset

[Kenneth Rohde Christiansen]

Same test, make the window smaller than one tile, then resize it to at least 3 tiles in width... the 3rd tile in width is black, until scroll or hover on the image

[Kenneth Rohde Christiansen]

This bugs goes away every 3 seconds due to 

Source/WebKit2/WebProcess/WebPage/UpdateAtlas.h 

59     bool isInactive() const
60     {
61         const double inactiveSecondsTolerance = 3;
62         return m_inactivityInSeconds > inactiveSecondsTolerance;
63     }

So it definitely has something to do with the SharedSurface in WK2

[Kenneth Rohde Christiansen]

Ok, the bug is that we fail to clear the update atlas area when we will with transparent as the cairo context doesn't support that

https://bugs.webkit.org/show_bug.cgi?id=101911

[Kenneth Rohde Christiansen]

Solved by 101911

[Kalyan]

(In reply to comment #8)
> Created an attachment (id=175962) [details]
> Test case
> 
> This just adds the blurry border like on google, on hover and removed it on unhover. It is easy to see that resources are being reused.

Note:

We are using Drop Shadow with these images. I haven't checked the blur radius though. 

Anyway its fixed :)