User Guide

CHAPTER 13. FILTERS 160
Blur Radius The Blur Radius setting affects the maximum number of pixels considered
for blurring. The higher the setting, the higher the number of pixels that will be in-
cluded in the region analysis. Be aware that a higher setting will take considerably
longer to compute.
Max Delta The Max Delta slider affects the level of detail that will be blurred. A higher
setting here will produce more smoothing of the pixels in the radius.
See also
A common use for the Selective Gaussian Blur filter is smoothing areas affected by
populations of JPEG artifacts, or bad pixelization distortions.
Further information regarding blurring can be found on the Gaussian Blur - RLE and
Gaussian Blur - IIR pages.
13.133 Selection to Path
Overview
This tool transforms a selection into a path. See also
Further information regarding paths can be found on the Paths dialog page.
13.134 Semi-Flatten
Overview
The Semi-flatten filter helps those in need of a solution to anti-aliasing indexed im-
ages with transparency.
In order to use this filter, the user must set the background color in the toolbox to the
color that will be used for the destination of the image. For example, a black circle that
will be saved as an indexed image for placement on a green web page would preclude
a need to set the background color to the same color green as the web page.
With the background color set, the filter can be started. The filter will scan the edges
of the selected layer and color them in a similar fashion to anti-aliasing, but using the
selected background color instead of transparency.
13.135 SGI
Overview
GIMP can both read and write to the SGI file format. This format, by Silicon Graph-
ics Inc., supports black and white (usually with the extension .bw), color ( .rgb), and
color images with an alpha channel ( .rgba). You may also find SGI files in any of the
above formats with the extension .sgi. SGI images are normally only found on SGI
workstations. SGI Options
When saving an SGI image, GIMP will prompt you to specify a compression type.
RLE (Run Length Encoded) compression is recommended because it is a lossless for-
mat. The Aggressive RLE option may produce a smaller file size, but SGI applications
may not open the image correctly.