On 04-09-12 10:50, Mark Crutch wrote:
The real problem is the number of filtered pixels to be calculated. A
box that's 100x100 pixels at one zoom level will be 50x50 or 500x500 at
others. Because filters are (generally) bitmap operations that apply to
each pixel in the filtered area (and beyond), more pixels means more
calculations, means slower redraws.
Never underestimate the power of a modern computer :) A typical PC is
able to fill your screen MANY, MANY times per second in terms of sheer
computational power. The only problem is getting the code to actually
run at full speed... In Inkscape's case we're doing more work than
necessary, and we're probably also not arranging the work in the most
efficient manner. And it is unfortunately non-trivial to do better (not
impossible, but it's definitely not a quick fix kind of thing).
(You are absolutely right that with something like blur you often need
to draw more than what is visible though.)