309765 - Performance degradation associated with linearGradient at an angle

Status: VERIFIED INVALID

(Core :: SVG, defect)

Description

[JP Fiset]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b4) Gecko/20050908 Firefox/1.4
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b4) Gecko/20050908 Firefox/1.4

While manipulating SVG nodes via scripting, a great performance degradation is
experienced (more than an order of magnitude) if the related rendered objects
are superimposed over a linear gradient which is at an angle. Performance
degradation is not observed for linear gradient that are horizontal or vertical.

Note that this performance degradation is not experienced on a MacOSX
implementation that uses cairo 1.0.0.

Reproducible: Always

Steps to Reproduce:
1.Create a rectangle (1000x1000) with a linear gradient from 0,0 to 1000,1000
2.Create other objects (circles) over this rectangle
3.Animate the circles by attaching scripting events which change the colours of
the circle
4.Compare the performance with a similar approach, but where the linear gradient
goes from 0,0 to 0,1000 

Actual Results:  
Performance is degraded only for the linear gradients at an angle. Straight 
linear gradients (horizontal and vertical) and radial gradient (which would be
more complicated, one would assume) do not display any observable degradation.

Expected Results:  
The software should not have shown any performance degradation.

Comment 1

[JP Fiset]

Attachment: Test case

To compare performance between the different gradients, modify the rectangle by
associating its fill to 'gradient_0', 'gradient_1', 'gradient_2' and
'gradient_3'.

Comment 2

[JP Fiset]

I have downloaded a Win32 version of Firefox based on Cairo from
http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/experimental/mozilla1.8-svg-cairo1.0/firefox-1.5-svg-branch-cairo.zip

and tried the test case I have posted above. The performance degradation was not
experienced. So, this problem "might" have to do with GDI-based implementations.

Comment 3

[JP Fiset]

Attachment: More compelling test case

Better test case. In this one, you can select interactively the gradient of the
background, and compare performance without having to edit the SVG file.

Comment 4

[Peter van der Woude [:Peter6]]

Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8b5) Gecko/20051004
Firefox/1.4.1 ID:2005100415

It takes a few tenth of a sec to implement the gradient (tescase 2), but I have
an old amd850

i'd say that this is WFM

Comment 5

[Amos Hayes]

Hi Peter. This bug appears to show up in GDI+ builds only. I assume from your browser string that you're 
running a Cairo based Win32 build. Since the decision has been made to abandon GDI+ in favour of Cairo 
on Win32, perhaps this should be marked WONTFIX?

Comment 6

[Peter van der Woude [:Peter6]]

->INVA (was a gdiplus problem)

thanks Amos

Comment 7

[JP Fiset]

Performance degradation is no longer experienced. Tested with Firefox 2.0