Mini Tutorial - Using the gradient Editor in GIMP
Originally Posted by Darth_Gimp
First get into the gradient editor:
Right Click to get the menu and select Replicate Segment (and pick 2). This gives two duplicates of the original segment.
Now change them so the left segment is all black and the right segment is all white. First Click on white arrow below the left side gradient to select just that segment (the bar will turn blue under the section the menu will now work with). Right Click and select "Right Endpoint Colour" and change it to black. Now select the right hand gradient portion (click the white arrow under it on the right) and change the left endpoint colour to white. You should now have a gradient made of a black bar and a white bar (I have circled the white arrow and braced the section this lets you edit by example):
Now decide how many bands you want. Lets say I want 10 (which will turn out to be 20 rows of tiles when the outline is stroked). Select both segments (shift click on the white triangles of both segment) then right click Replicate section and set the slider to 10. Now you get this:
To use it, just set the gradient tool to use Shaped (Angular) (and dial up the supersampling). It will fill a selection with the gradient following the
selection shape. You will get the ful gradient (10 stripes) from the edge to the "center" of the largest space. Here is an exmaple:
Now select the black (or white) with the Select by Colour Tool and perform a Edit->Stroke Selection with the tile brush!
Like I said, this is a bit of a workaround for gimp, as I believe photoshop lets you dynamically scale gradients. Gimp does not on any of the "Shaped" gradient fills.
Hope that helped!