ISSUE-2343: Last Call Comment: 15.12 Filter primitive ‘feComposite’ formula

Last Call Comment: 15.12 Filter primitive ‘feComposite’ formula

State:

OPEN

Product:

SVG 1.1 F2 Last Call

Raised by:

Erik Dahlström

Opened on:

2010-06-29

Description:

about arithmetic operation of feComposite is mentioned:

'If the arithmetic operation is chosen, each result pixel is computed using
the following formula:
result = k1*i1*i2 + k2*i1 + k3*i2 + k4'

What is especially i1 and i2?
My assumption is, that it is the value of the corresponding channel of
the input indicated by the attributes in for i1 and in2 for i2?
If this is correct, my suggestion is to add something like:

',where i1 and i2 indicate the corresponding pixel channel values of
the input images, indicated by the attributes in for i1 and in2 for i2,
and k1, k2, k3, k4 indicate the values of the attributes with the
same name.'

Another suggestion to improve the understanding of the
other operations is to add formulas for the other operations
as well. This can help authors a lot, because the original
article from Porter and Duff is not trivial to find for all readers,
for example currently here an online version:
http://keithp.com/~keithp/porterduff/p253-porter.pdf

Additional suggestion for the related example:
Add a generic font-family -
Instead of font-family="Verdana" use for example
font-family="Verdana, sans-serif"

Original mail:
http://www.w3.org/mid/201006291243.33346.Dr.O.Hoffmann@gmx.de

Related Actions Items:

• ACTION-2819 on Anthony Grasso to Add proposed wording from ISSUE2343 and add an informative link to the compositing specification - due 2010-07-13, closed
• ACTION-2820 on Erik Dahlström to Create a test for feComposite with values outside the 0..1 range (in particular negative ones) - due 2010-07-13, closed

Related emails:

1. SVG/profiles/1.1F2/DoC disco.xsl,1.4,1.5 dump.html,1.3,1.4 (from cvsmail@w3.org on 2011-05-04)
2. RE: ISSUE-2343: 15.12 Filter primitive ‘feComposite’ formula [SVG 1.1 F2 Last Call] (from Anthony.Grasso@cisra.canon.com.au on 2010-12-10)
3. Re: {minutes} 9 December 2010 SVG WG telcon (from chris@w3.org on 2010-12-10)
4. SVG/profiles/1.1F2/master filters.html,1.39,1.40 refs.html,1.30,1.31 (from cvsmail@w3.org on 2010-12-09)
5. status update (from cam@mcc.id.au on 2010-11-25)
6. Agenda Nov 18 2010 SVG WG telcon (from ed@opera.com on 2010-11-17)
7. SVG/profiles/1.1F2/DoC getxml.html,NONE,1.1 disco.xsl,1.3,1.4 dump.html,1.2,1.3 dump.xml,1.1,NONE (from cvsmail@w3.org on 2010-08-02)
8. SVG/profiles/1.1F2/DoC disco.xsl,1.2,1.3 dump.html,1.1,1.2 (from cvsmail@w3.org on 2010-07-29)
9. Minutes July 6 2010 SVG WG telcon (from anthony.grasso@cisra.canon.com.au on 2010-07-07)
10. ISSUE-2343: 15.12 Filter primitive ‘feComposite’ formula [SVG 1.1 F2 Last Call] (from sysbot+tracker@w3.org on 2010-06-29)

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