api/drawing-functions.md

@@ -106,11 +106,17 @@ Calls the passed function for each point of the line formed by `[x0, y0]` and
 of the current point and a boolean variable which is set to `true` when the
 coordinates are inside the active layer.
 
+If the passed function returns `true` to it's call, `line_func()` will stop.
+
 Here is an example of a function passed to `line_func()`:
 ```javascript
-function	(x, y, is_on_layer) {
+function	my_line_drawing(x, y, is_on_layer) {
 	if (is_on_layer == true) {
+		if (my_layer[y][x] == ' ') {
 			my_layer[y][x] = '#';
+		} else {
+			return (true);
+		}
 	}
 }
 ```