Merge pull request #4 from RolandDreger/extend-readme

Update readme.md

README.md

@@ -2,9 +2,21 @@
 
 With this script for Adobe InDesign you can determine the x-height of a text passage.
 
+## Script usage
+
+To measure the x-height, mark the relevant text passage in the layout of your InDesign document and click on the »Measure« button. The determined value is displayed in the script panel.
+
+<img width="629" alt="measure x-height" src="https://user-images.githubusercontent.com/19747449/85012596-889b9e00-b163-11ea-9fcd-626be9b8804a.png">
+
+For control purposes, the title bar shows you the font family that is used, the style and the size in points/millimeter.
+
+Of course, such a measurement is only meaningful if the text passage is represented by the corresponding font and not by a substitute font. A small yellow triangle indicates when a font is not available on the system. A warning also appears if the text frame and the font are scaled.
+
+<img width="629" alt="substitute font warning" src="https://user-images.githubusercontent.com/19747449/85012607-8afdf800-b163-11ea-9d83-7dca6df034e4.png">
+
 ## Website
 https://www.rolanddreger.net/de/503/x-hoehe-ermittlen
 
 ## License
 
-[MIT](http://www.opensource.org/licenses/mit-license.php)
+[MIT](http://www.opensource.org/licenses/mit-license.php)