- From: Rik Cabanier <cabanier@adobe.com>
- Date: Mon, 7 Feb 2011 12:09:20 -0800
- To: Erik Dahlstrom <ed@opera.com>, Chris Lilley <chris@w3.org>
- CC: Boris Zbarsky <bzbarsky@mit.edu>, Tavmjong Bah <tavmjong@free.fr>, Dirk Schulze <vbs85@gmx.de>, "www-svg@w3.org" <www-svg@w3.org>, Robert Longson <longsonr@gmail.com>
Hi Erik, Illustrator is turning these masks into opacity masks. In the PDF/AIM world this corresponds to a luminosity blend mode. All the colorspaces (=document + blend + object) are the same so the calculations are done on the original RGB values. I *think* this corresponds to linearRGB in the SVG world. I have to admit that the way SVG does color management is a little foreign to me since it's not ICC based... So, from the PDF spec: Luminosity: Creates a color with the luminosity of the source color and the hue and saturation of the backdrop color. This produces an inverse effect to that of the Color mode. B(Cb,Cs) = SetLum(Cb, Lum(Cs)) Cs = the boxes going from black to white + the image Cb = the red box Lum(Cs) = .3 *Cred + 0.59 * Cgreen + 0.11*Cblue Here: Lum(Cs) = the gray value So, the 'gray' value of the mask should be applied to the hue and saturation of the red box. > -----Original Message----- > From: Erik Dahlstrom [mailto:ed@opera.com] > Sent: Monday, February 07, 2011 5:44 AM > To: Chris Lilley; Rik Cabanier > Cc: Boris Zbarsky; Tavmjong Bah; Dirk Schulze; www-svg@w3.org; Robert > Longson > Subject: Re: [Moderator Action (size limit exceeded)] RE: SVG masks and > luminance calculations > > Forwarding yet another message on behalf of Jos Hirth: > > Adobe Illustrator CS3 also does it the sRGB way. (It's kinda unlikely that they > touched that code with CS4 or CS5.) > Screenshot: http://i.imgur.com/v1FWt.png > > Rik, can you confirm? This was testing with http://kaioa.com/svg/mask- > test.svgz. > > Cheers > /Erik > > On Sun, 06 Feb 2011 22:02:53 +0100, Rik Cabanier <cabanier@adobe.com> > wrote: > > > Alternatively, you can find the complete spec here: > > > http://www.adobe.com/content/dam/Adobe/en/devnet/pdf/pdfs/pdf_refer > enc > > e_1-7.pdf Page 523 has the formula for luminance.. > > > >> -----Original Message----- > >> From: Chris Lilley [mailto:chris@w3.org] > >> Sent: Saturday, February 05, 2011 2:59 AM > >> To: Rik Cabanier > >> Cc: Erik Dahlstrom; Boris Zbarsky; Tavmjong Bah; Dirk Schulze; www- > >> svg@w3.org; Robert Longson > >> Subject: Re: [Moderator Action (size limit exceeded)] RE: SVG masks > >> and luminance calculations > >> > >> On Friday, February 4, 2011, 6:46:01 PM, Rik wrote: > >> > >> RC> Assuming you're talking about luminosity masks, the formula for > >> RC> calculating them is defined in the PDF spec. > >> RC> I've attached the relevant pages to this mail. (Page 523 has the > >> RC> actual math.) > >> > >> The original email was rejected because the attachment was too large. > >> > >> The original attachment can be found at > >> http://lists.w3.org/Archives/Public/www-archive/2011Feb/att- > >> 0009/Pages_from_pdf_reference_1-7.pdf > >> > >> > >> -- > >> Chris Lilley Technical Director, Interaction Domain > >> W3C Graphics Activity Lead, Fonts Activity Lead Co-Chair, W3C > >> Hypertext CG Member, CSS, WebFonts, SVG Working Groups > > > > > -- > Erik Dahlstrom, Core Technology Developer, Opera Software Co-Chair, W3C > SVG Working Group Personal blog: http://my.opera.com/macdev_ed
Received on Monday, 7 February 2011 20:10:07 UTC