Added stripes() function to CSS Images 4

Author: SebastianZ

css-images-4/Overview.bs

@@ -1117,7 +1117,45 @@ Cycle Detection</h4>
 	any ''element()'' functions participating in the cycle are <a>invalid images</a>.
 
 
+<!--
+ ██████  ████████ ████████  ████ ████████  ███████  ██████    ███ ███
+██    ██    ██    ██     ██  ██  ██     ██ █       ██    ██  ██     ██
+██          ██    ██     ██  ██  ██     ██ █       ██       ██       ██
+ ██████     ██    ████████   ██  ████████  █████    ██████  ██       ██
+      ██    ██    ██   ██    ██  ██        █             ██ ██       ██
+██    ██    ██    ██    ██   ██  ██        █       ██    ██  ██     ██
+ ██████     ██    ██     ██ ████ ██        ███████  ██████    ███ ███
+-->
+
+Stripes: the ''stripes()'' notation {#stripes-function}
+----------------------------------------------------------------------
+
+	The ''stripes()'' function allows to define a number of stripes of
+	different colors with different widths. How those stripes are actually
+	painted depends on the context the function is used in.
+
+	The syntax for ''stripes()'' is defined as:
+
+	<pre class=prod>
+		<dfn>stripes()</dfn> = stripes( [ <<color>> && [ <<length-percentage>> | <<flex>>]? ]# )
+	</pre>
+
+	The function represents a 1-dimensional image generated by a list
+	of colors and an optional thickness for each of them.
+
+	A <<percentage>> or <<flex>> value refers to the total length of the image
+	in the used context.
+	The <<percentage>> must be between ''0%'' and ''100%'' inclusive;
+	any other value is invalid.
+
+	If the thickness of a stripe is omitted, it is meant to be ''1fr''.
 
+	If the width of the context the function is used in exceeds the total
+	thickness of the stripes, the rest is painted transparent. I.e. it behaves
+	as if there were an additional last ''transparent'' stripe.
+	If the width of the context the function is used in is smaller than the
+	total thickness of the stripes, the stripes are clipped starting from the
+	last defined color.
 
 <!--
  ██████   ████████     ███    ████████  ████ ████████ ██    ██ ████████  ██████