Hi Alex, The 'blend: layer' makes it so that only the graphic of group A are used when the multiply blend on B is calculated. Rik On Thu, Feb 24, 2011 at 4:13 PM, Alex Danilo <alex@abbra.com> wrote: > Hi Rick, > > Yes, that's correct. In SVG as specified, it could be > <g comp-op="multiply">...</g> or use inline style as you wrote > or applied to individual objects, etc. Although, there's no real > need for 'blend:layer' in your example, but the overall idea is > right. > > Alex > > --Original Message--: > > > > > >Hi Alex, > > > > > > > > > >to make sure I'm not confused. > > > > > >This is a filter: > > > ><svg version="1.1" xmlns="http://www.w3.org/2000/svg"> > > <defs> > > <filter id="srcLoadedOverlay"> > > <feImage xlink:href="url(#canvas0)" result="img1" /> > > <feImage xlink:href="url(#canvas1)" result="img2" /> > > <feImage xlink:href="url(#canvas2)" result="img3" /> > > <feBlend in="img1" in2="img2" result="blend1" mode="multiply" /> > > <feBlend in="blend1" in2="img3" mode="lighten" /> > > </filter> > > </defs> > ></svg> > > > >and this would be a property: > > > ><html> > > > >... > > > ><body> > > > >.... <- backdrop > > > ><div style="blend: layer;"> <- group A > > > > ... <- text, images, etc > > > > <div style="blend: multiply;"> <- group B > > > > .. <- text, images, etc > > > > </div> > > > ></div> > > > >Rik > > > >On Thu, Feb 24, 2011 at 3:53 PM, Alex Danilo <alex@abbra.com> wrote: > > > >Hi Anthony and all, > > > >--Original Message--: > >>Just adding to what Alex said (see below)... > >> > >> > >>>-----Original Message----- > > > >>><snip/> > >>> > >>>Perhaps that should serve as something to look at. This was researched > >>>extensively at the time, and a property works far better than the SVG > >>>filter mechanism when combining a lot of objects for blending. > >>> > >> > >>This is because the background is included twice when using filters to > perform compositing. This leads to incorrect results - the output tends to > be darker than expected. > > > >Ignoring side-effects, one of the main advantages of a property > >over a filter is no need for any sort of intermediate bitmap. > > > >The object being blended can be rasterized and alpha blended > >with the correct blend mode directly to the canvas. So the > >performance is significantly higher, especially if you are > >trying to composite lots of graphics on top of live HD video > >where memory bandwidth actually matters. > > > >Alex > > > > > > > > > > > >
Received on Monday, 28 February 2011 15:17:16 UTC