LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2016 - 2018, Přemysl Janouch <p@janouch.name>
+Copyright (c) 2016 - 2017, Přemysl Janouch <p@janouch.name>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted.

nncmpp.c

@@ -1,7 +1,7 @@
 /*
  * nncmpp -- the MPD client you never knew you needed
  *
- * Copyright (c) 2016 - 2018, Přemysl Janouch <p@janouch.name>
+ * Copyright (c) 2016 - 2017, Přemysl Janouch <p@janouch.name>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted.
@@ -66,7 +66,6 @@ enum
 #include "liberty/liberty.c"
 #include "liberty/liberty-tui.c"
 
-#include <math.h>
 #include <locale.h>
 #include <termios.h>
 #ifndef TIOCGWINSZ
@@ -1172,34 +1171,6 @@ app_visible_items (void)
 	return MAX (0, app_fitting_items ());
 }
 
-/// Figure out scrollbar appearance.  @a s is the minimal slider length as well
-/// as the scrollbar resolution per @a visible item.
-struct scrollbar { long length, start; }
-app_compute_scrollbar (struct tab *tab, long visible, long s)
-{
-	long top = tab->item_top, total = tab->item_count;
-	if (total < visible)
-		return (struct scrollbar) { 0, 0 };
-	if (visible == 1)
-		return (struct scrollbar) { s, 0 };
-	if (visible == 2)
-		return (struct scrollbar) { s, top >= total / 2 ? s : 0 };
-
-	// Only be at the top or bottom when the top or bottom item can be seen.
-	// The algorithm isn't optimal but it's a bitch to get right.
-	double available_length = s * visible - 2 - s + 1;
-
-	double lenf = s + available_length * visible / total, length = 0.;
-	long offset = 1 + available_length * top / total + modf (lenf, &length);
-
-	if (top == 0)
-		return (struct scrollbar) { length, 0 };
-	if (top + visible >= total)
-		return (struct scrollbar) { length, s * visible - length };
-
-	return (struct scrollbar) { length, offset };
-}
-
 static void
 app_draw_scrollbar (void)
 {
@@ -1212,14 +1183,18 @@ app_draw_scrollbar (void)
 	struct tab *tab = g.active_tab;
 	int visible_items = app_visible_items ();
 
-	hard_assert (tab->item_count != 0);
 	if (!g.use_partial_boxes)
 	{
-		struct scrollbar bar = app_compute_scrollbar (tab, visible_items, 1);
+		// Apparently here we don't want the 0.5 rounding constant
+		int length = (float) visible_items / (int) tab->item_count
+			* (visible_items - 1);
+		int start  = (float) tab->item_top / (int) tab->item_count
+			* (visible_items - 1);
+
 		for (int row = 0; row < visible_items; row++)
 		{
 			move (g.header_height + row, COLS - 1);
-			if (row < bar.start || row >= bar.start + bar.length)
+			if (row < start || row > start + length + 1)
 				addch (' ' | APP_ATTR (SCROLLBAR));
 			else
 				addch (' ' | APP_ATTR (SCROLLBAR) | A_REVERSE);
@@ -1227,11 +1202,19 @@ app_draw_scrollbar (void)
 		return;
 	}
 
-	struct scrollbar bar = app_compute_scrollbar (tab, visible_items, 8);
-	bar.length += bar.start;
+	// TODO: clamp the values, make sure they follow the right order
+	// We subtract half a character from both the top and the bottom, hence -1
+	// XXX: I'm not completely sure why we need that 0.5 constant in both
+	int length = (double) visible_items / tab->item_count
+		* (visible_items - 1) * 8 + 0.5;
+	int start  = (double) tab->item_top / tab->item_count
+		* (visible_items - 1) * 8 + 0.5;
 
-	int start_part = bar.start  % 8; bar.start  /= 8;
-	int end_part   = bar.length % 8; bar.length /= 8;
+	// Then we make sure the bar is at least one character high, hence +8
+	int end = start + length + 8;
+
+	int start_part = start % 8; start /= 8;
+	int end_part   = end   % 8; end   /= 8;
 
 	// Even with this, the solid part must be at least one character high
 	static const char *partials[] = { "█", "▇", "▆", "▅", "▄", "▃", "▂", "▁" };
@@ -1239,12 +1222,12 @@ app_draw_scrollbar (void)
 	for (int row = 0; row < visible_items; row++)
 	{
 		chtype attrs = APP_ATTR (SCROLLBAR);
-		if (row > bar.start && row <= bar.length)
+		if (row > start && row <= end)
 			attrs ^= A_REVERSE;
 
 		const char *c = " ";
-		if (row == bar.start)  c = partials[start_part];
-		if (row == bar.length) c = partials[end_part];
+		if (row == start) c = partials[start_part];
+		if (row == end)   c = partials[end_part];
 
 		move (g.header_height + row, COLS - 1);