Extended dimension expression (#68)

README.md

@@ -23,7 +23,7 @@ Usage
 
 - `:Goyo`
     - Toggle Goyo
-- `:Goyo [width]`
+- `:Goyo [dimension]`
     - Turn on or resize Goyo
 - `:Goyo!`
     - Turn Goyo off
@@ -31,12 +31,33 @@ Usage
 The window can be resized with the usual `[count]<CTRL-W>` + `>`, `<`, `+`,
 `-` keys.
 
+### Dimension expression
+
+The expected format of a dimension expression is
+`[WIDTH][XOFFSET][x[HEIGHT][YOFFSET]]`. `XOFFSET` and `YOFFSET` should be
+prefixed by `+` or `-`. Each component can be given in percantage.
+
+```vim
+" Width
+Goyo 120
+
+" Height
+Goyo x30
+
+" Both
+Goyo 120x30
+
+" In percentage
+Goyo 70%x50%
+
+" With offsets
+Goyo 50%+25%x50%-25%
+```
+
 Configuration
 -------------
 
 - `g:goyo_width` (default: 80)
-- `g:goyo_margin_top` (default: 4)
-- `g:goyo_margin_bottom` (default: 4)
 - `g:goyo_linenr` (default: 0)
 
 ### Callbacks