- From: Rik Cabanier <cabanier@gmail.com>
- Date: Sun, 20 Nov 2011 20:44:18 -0800
- To: Cyril Concolato <Cyril.Concolato@cisra.canon.com.au>
- Cc: www-svg <www-svg@w3.org>, "public-fx@w3.org" <public-fx@w3.org>, "Alex Danilo (alex@abbra.com)" <alex@abbra.com>
- Message-ID: <CAGN7qDA--0idw42rexhh3dejR7tw7qTRhBpDLEpTpmYdhT14GQ@mail.gmail.com>
Hi Cyril, can you describe the structure in more detail? Is it: <g alpha-compositing='dst-atop'> <circle> <circle blending='plus'> </g> or <circle> <circle alpha-compositing='dst-atop' blending='plus'> or a different one? Rik On Sun, Nov 20, 2011 at 4:29 PM, Cyril Concolato < Cyril.Concolato@cisra.canon.com.au> wrote: > Hi Rik, Alex, > > > > Just to make sure I understand the proposal. What would happen if you > apply the ‘dst-atop’ compositing operator with partially transparent > objects together with say a ‘plus’ blending operator. I understand that the > ‘plus’ would only apply on the intersection but I’m not sure about the > maths. Would you compose the equations, in which order? It doesn’t look > like you can consider that the result of the (alpha-)compositing becomes > the source (or destination) of the (color-compositing) blending ,does it? > > > > Regards, > > Cyril > > > > > > *From:* Rik Cabanier [mailto:cabanier@gmail.com] > *Sent:* Friday, 18 November 2011 4:11 PM > > *To:* www-svg; public-fx@w3.org > *Subject:* [css-compositing] some proposals > > > > Last week I sent out some ideas to update the SVG composting spec: > http://www.w3.org/TR/SVGCompositing/. > > Some people suggested some improvements which I integrated. > > > > Here is the updated list of proposals: > > a. split up the spec in 2 sections: Porter-Duff & Blending. > > Porter-Duff are compositing primitives that describes how 2 images > (src+dst) can be merged. > > Porter-Duff will continue to use the existing comp-op property. > > > > Blending describes how the top image will 'blend' with its underlying > colors. The result of this is a new blended image. In the Adobe imaging > model and the existing SVG compositing spec it is assumed that this blended > image is composited with src-over. > > However, there are use cases where you might not want 'src-over'. To > facilitate other composting operators, we will introduce a new keyword > 'blend-mode'. > > > > b. simplify Porter-Duff > > -remove the clip-to-self property. The default behavior becomes > 'clip-to-self: object'. > > > > c. complete blend modes > > - add the following missing blend modes: hue, saturation, color & > luminosity > > - define 'normal' as the default blend mode > > > > d. update knockout > > - change the value to be more descriptive. The new value > ('replace'/'preserve') is confusing. > > - provide a better description + correct the compositing formula > > - knockout will only affect groups that use the new 'blend-mode' operator > > > > e. update enable-background > > - remove the ability to set up x, y, width & height. > > - clarify the description and refer to the filters spec which already > defines this parameter > > - replace the keyword with 'isolate' which is Adobe's equivalent. > 'isolate: isolated' = 'enable-background: new'. Keep the existing parameter > for backward compatibility. > > - Any comp-op apart from 'src-over' will establish a new stacking context. > > > > f. update all the formulas on the page > > - fix incorrect math > > - always do the math with pre-multiplied alpha. > > > > g. replace 'src'/'dst' in the spec with 'source'/'dest' > > > > Let me know if I missed something. > > > > Rik > > > > > The information contained in this email message and any attachments may > be confidential and may also be the subject to legal professional > privilege. If you are not the intended recipient, any use, interference > with, disclosure or copying of this material is unauthorised and > prohibited. If you have received this email in error, please immediately > advise the sender by return email and delete the information from your > system. >
Received on Monday, 21 November 2011 04:44:47 UTC