On 4/3/07, bulia byak <buliabyak@...155...> wrote:
On 4/2/07, Bryce Harrington <bryce@...983...> wrote:
No, it's a non-linear (exponential?) relation that was arrived at through feedback from user testing and experimentation.
No. There was only one user advocating the exponential scale, but his patch did not convince me. Anyone is welcome to try out the patch in our patch tracker; if the majority votes for it I'll go with it.
So currently, the scale is linear, and the range is explained in the 0.45 release notes:
The blur value is a percentage, with 100% corresponding to a blurring radius (standard deviation of Gaussian function) of 1/8 of the object's bounding box' perimeter (that is, for a square, a blur of 100% will have the radius equal to half a side, which turns any shape into an amorphous cloud).
http://wiki.inkscape.org/wiki/index.php/ReleaseNotes045#SVG_filters:_Gaussia...
As far as explaining what the number means, I think the existing explanation you just gave of "a percentage of a fraction of the bounding box" is fairly simple and makes it easy to guess what a reasonable value would be. Making it instead into "a nonlinear mapping of a percentage of a fraction of the bounding box" would make it difficult to guess good values.
But it might be useful for the slider to behave in a logarithmic way, while still showing the % number with the same meaning it currently has. Values like 0.1 through 0.5 seem to be useful for adding different amounts of light fringe, whereas the visual difference between 20.1 and 20.5 is pretty much Nil. So the slider would be more useful if the left third mapped, say, from 0 to 1, middle third from 1 to 10, and last third about 10-100.
Very nice feature though, this blurring. Does it by any chance use this: http://incubator.quasimondo.com/processing/fast_blur_deluxe.php ?