FvwmPager: Snap small windows to page boundaries.

FvwmPager windows that are smaller than the minimum size dimensions are
set to the minimum size length. This can make windows appear in incorrect
positions since their size is relatively larger than other windows and the
page size. This makes it so small windows near a page boundary will snap
to the boundary and not appear they are on the wrong page. Fixes #541.

modules/FvwmPager/x_pager.c

@@ -226,8 +226,35 @@ static rectangle CalcGeom(PagerWindow *t, bool is_icon)
 
 	fvwmrec_to_pager(&rec, is_icon);
 
-	rec.width = max(MinSize, rec.width);
-	rec.height = max(MinSize, rec.height);
+	/* Set geometry to MinSize and snap to page boundary if needed */
+	if (rec.width < MinSize)
+	{
+		int page_w = desk_w;
+		if (is_icon)
+			page_w = icon.width;
+		page_w = page_w / m->virtual_scr.VxPages;
+
+		rec.width = MinSize;
+		if (rec.x > page_w - MinSize &&
+			(rec.x + rec.width)%page_w < MinSize)
+		{
+			rec.x = ((rec.x / page_w) + 1)*page_w - MinSize + 1;
+		}
+	}
+	if (rec.height < MinSize)
+	{
+		int page_h = desk_h;
+		if (is_icon)
+			page_h = icon.height;
+		page_h = page_h / m->virtual_scr.VyPages;
+
+		rec.height = MinSize;
+		if (rec.y > page_h - MinSize &&
+			(rec.y + rec.height)%page_h < MinSize)
+		{
+			rec.y = ((rec.y / page_h) + 1)*page_h - MinSize + 1;
+		}
+	}
 	return rec;
 }