On 2010-12-19 11:53, Teto wrote:
Hi!
First, I have to say that I do like inkscape, that I use everyday,sometimes just for fun. But, like all free softwares, it has few problems. Some are not important, others may become disabling. Obviously filters belong to the second category. Not because there are buggy (they aren't), but because the rendering engine is just too slow, when you are using few "big" filters in a big picture and you want to export in a big size, it takes centuries. I'm not complaining, I take a coffee during the export, but well... And it has other few problems like "what you see is not really what you get". More than this, useful features are missing: using filter in another filter, disable/mask an effect without remove it, things like that. Again, I'm not complaining, developing a soft like Inkscape is a hard stuff, and you, developers, do a great job.
If it's not WYSIWYG then there's a generally a bug (although minute variations can occur legitimately, due to rounding and such, those are rarely visible). And these do occur (Inkscape's filtering code is definitely not free of them), so don't hesitate to file a bug if you find an issue with one or more filters, or (most likely) a certain way of using them.
As for speed. Well, that's always an interesting issue :) Without sacrificing quality or using hand-written assembly or the graphics card a lot of filters are currently about as fast as they're going to get (although getting them a bit faster is still possible, and there's also some room left for improvement in "overhead"). There are also filters which are still coded in a "stupid" way and have lots of room for improvement (this includes the morphology filter). In general, if there is a specific filter you have an issue with: file a bug, and remember to also state your expectations.
... My idea can be useless, because the concept doesn't fit with the .svg specifications (I'm thinking about colors or edge thickness, for example, that are directly in the object definition, while filters are stored in svg:defs). Or compatibility with other softs that reading .svg. Or maybe you don't care. But implement this and many expensive professional vectorial tools will become "old-school" immediately ^^ ...
You're ideas are definitely not useless! They do indeed clash a bit with SVG's concepts, but hey, there is always SVG 2 :) Also, in some cases Inkscape can be made to work around SVG's limitations.
The most fundamental clash might be that SVG considers the fill and stroke of an object to be part of the same object, and cannot apply different filters to them. I'm also not sure that that makes sense (at least not within the current framework). If you're talking about stroking or filling as being a kind of "effect" that acts upon an abstract shape, then I think that could indeed make sense. Is there any application that does this? And/or can you make more detailed mockups of how you would like to see this kind of thing work in Inkscape?
Also, SVG doesn't really allow the use of making filters that can be reused in other filters (as far as I know), but this is so incredibly useful that we'll definitely figure something out (as Ivan wrote there is already some work underway).
... PS: About the actual filter tool: Maybe I missed something, but the tool "snapshot picture behind the object and use it" is missing, and could be useful for effects.
It sounds like you're looking to use BackgroundImage as source. This is supported, but does not work perfectly with all filters yet (basically it only works with filters that work per pixel, like the color matrix filter). It also has some other caveats, but that's a bit beyond the scope of this thread, if you're having trouble getting it to work, drop us a line.