[css-images-3] Allow dithering in gradients. w3c#4793

Author: fantasai

css-images-3/Overview.bs

@@ -867,6 +867,13 @@ Defining Gradient Color {#gradient-colors}
 	along with its <a>starting point</a> and <a>ending point</a>;
 	see above.)
 
+	Colors throughout the gradient field are then determined
+	by tying them to specific points along the [=gradient line=]
+	as specified by the gradient function.
+	UAs may “dither” gradient colors slightly
+	(randomly alternate individual pixels with nearby colors on the gradient line)
+	to effect a smoother gradient.
+
 <h4 id=color-stop-syntax>
 Color Stop Lists</h4>
 
@@ -1877,6 +1884,8 @@ Changes Since the <a href="https://www.w3.org/TR/2019/CR-css-images-3-20191010/"
 		(<a href="https://github.com/w3c/csswg-drafts/issues/4572">Issue 4572</a>)
 	* Define that layout-affecting metadata occurring after the image data should be ignored
 		(<a href="https://github.com/w3c/csswg-drafts/issues/5165">Issue 5165</a>)
+	* Explicitly allow dithering in gradients
+		(<a href="https://github.com/w3c/csswg-drafts/issues/4793">Issue 4793</a>)
 	* Define that 'image-orientation' applies to both decorative and content images
 		(<a href="https://github.com/w3c/csswg-drafts/issues/5245">Issue 5245</a>)