Figure 15.171. Example for the “Border Average” filter
This plug-in calculates the most often used color in a specified border
of the the active layer or selection. It can gather similar colors
together so that they become predominant. The calculated color becomes
the foreground color in the Toolbox. This filter is interesting when
you have to find a Web page color background that differs as little as
possible from your image border. The action of this filter is not
registered in Undo History and can't be deleted with Ctrl+Z : it
doesn't modify the image.
Examples illustrating the “Border Average” filter
Figure 15.173. Original image
Figure 15.174. “Number of Colors” is set to 8:
The bucket size is low. So the bucket number is high. All color shades
can be stored in different buckets. Here, the bucket containing red is
the most filled. The resulting color is a nearly pure
Red (254,2,2) and becomes the foreground color of the Toolbox.
Figure 15.175. “Number of Colors” is set to 64:
Here the bucket size is high, the number of buckets low. Similar colors
(here green) are stored in a same bucket. This “green”
bucket is now the most filled.
All colors in this bucket have the same values for the two most
significant bits: (00******;11******;00******). The remaining 6 bits
may have any values from 0 to 63 for the respective channel. So
in this bucket, color red channels range from 0 to 63, green channels
from 192 to 255, blue channels from 0 to 63. The resulting color is
Green (32,224,32), which, for every channel, is the average between the
limits of the channel range (63 + 0)/2, (255+192)/2 , (63+0)/2.