Fix: Change duration of news window scroll depending on GUI zoom.

src/news_gui.cpp

@@ -267,6 +267,7 @@ struct NewsWindow : Window {
 	const NewsItem *ni;   ///< News item to display.
 	static int duration;  ///< Remaining time for showing the current news message (may only be access while a news item is displayed).
 
+	static const uint TIMER_INTERVAL = 210; ///< Scrolling interval, scaled by line text line height. This value chosen to maintain the 15ms at normal zoom.
 	GUITimer timer;
 
 	NewsWindow(WindowDesc *desc, const NewsItem *ni) : Window(desc), ni(ni)
@@ -278,8 +279,6 @@ struct NewsWindow : Window {
 
 		this->flags |= WF_DISABLE_VP_SCROLL;
 
-		this->timer.SetInterval(15);
-
 		this->CreateNestedTree();
 
 		/* For company news with a face we have a separate headline in param[0] */
@@ -323,6 +322,11 @@ struct NewsWindow : Window {
 		PositionNewsMessage(this);
 	}
 
+	void OnInit() override
+	{
+		this->timer.SetInterval(TIMER_INTERVAL / FONT_HEIGHT_NORMAL);
+	}
+
 	void DrawNewsBorder(const Rect &r) const
 	{
 		GfxFillRect(r.left,  r.top,    r.right, r.bottom, PC_WHITE);