Clarified mipmap text

docs/en/manuals/gui-box.md

@@ -23,28 +23,26 @@ Box nodes are always rendered, even if they do not have a texture assigned to th
 
 ## Slice-9 texturing
 
-GUIs often feature elements that are context sensitive in regard to their size: panels and dialogs that need to be resized to fit the containing content. These will cause problems as soon as you apply texturing to the scaled node.
+GUIs often feature elements that are context sensitive in regard to their size: panels and dialogs that need to be resized to fit the containing content. These may cause visual problems when you apply texturing to the resized node.
 
-Normally, the engine scales the texture to fit the boundaries of a box node, but it is possible to limit what parts of the texture that should scale with the slice-9 feature:
+Normally, the engine scales the texture to fit the boundaries of a box node, but by defining slice-9 edge areas it is possible to limit what parts of the texture that should scale:
 
 ![GUI scaling](images/gui-box/scaling.png){srcset="images/gui-box/[email protected] 2x"}
 
-The *Slice9* box node property is used to control how the texture is sliced:
-
-The slicing is controlled by 4 numbers that specify the number of pixels that will not be regularly scaled, on each side of the texture.
+The *Slice9* box node consists of 4 numbers that specify the number of pixels for the left, top, right and bottom margin that should not be regularly scaled:
 
 ![Slice 9 properties](images/gui-box/slice9_properties.png){srcset="images/gui-box/[email protected] 2x"}
 
- The margins are set clockwise, starting on the left edge:
+The margins are set clockwise, starting on the left edge:
 
 ![Slice 9 sections](images/gui-box/slice9.png){srcset="images/gui-box/[email protected] 2x"}
 
-- Corner segments are never scaled, only moved.
-- Edge segments are scaled along one axis only.
-- The central texture area is scaled regularly, horizontally and vertically as needed.
+- Corner segments are never scaled.
+- Edge segments are scaled along a sigle axis. The left and right edge segments are scaled vertically. The top and bottom edge segments are scaled horizontally.
+- The central texture area is scaled horizontally and vertically as needed.
 
 Due to the way mipmapping works in the renderer, scaling of texture segments can sometimes exhibit artifacts. This happens when you _scale down_ segments below the original texture size. The renderer then selects a lower resolution mipmap for the segment, resulting in visual artifacts.
 
 ![Slice 9 mipmapping](images/gui-box/mipmap.png){srcset="images/gui-box/[email protected] 2x"}
 
-It is easy to avoid this problem, but it implies some constraints to the source texture: simply make sure that the texture's segments that will be scaled are small enough never to be scaled down, only up.
+To avoid this problem, make sure that the texture's segments that will be scaled are small enough never to be scaled down, only up.