-// The source image is cut off at the texel borders (so there is no interpolation
-// outside them), and then given a user-specific color; by default, full transparent.
+// The source image is cut off at the texture border, and then given a user-specific color;
+// by default, full transparent. You can give a fractional border size (non-integral
+// "top" or "left" offset) if you wish, which will give you linear interpolation of
+// both pixel data of and the border. Furthermore, you can offset where the border falls
+// by using the "border_offset_{top,bottom,left,right}" settings; this is particularly
+// useful if you use ResampleEffect earlier in the chain for high-quality fractional-pixel
+// translation and just want PaddingEffect to get the border right.