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Improve fallback scrollbar behaviour

tags/v0.9
Přemysl Janouch 1 year ago
parent
commit
3fd88d593c
Signed by: Přemysl Janouch <p@janouch.name> GPG Key ID: A0420B94F92B9493
2 changed files with 30 additions and 9 deletions
  1. 1
    1
      LICENSE
  2. 29
    8
      nncmpp.c

+ 1
- 1
LICENSE View File

@@ -1,4 +1,4 @@
Copyright (c) 2016 - 2017, Přemysl Janouch <p@janouch.name>
Copyright (c) 2016 - 2018, 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.

+ 29
- 8
nncmpp.c View File

@@ -1,7 +1,7 @@
/*
* nncmpp -- the MPD client you never knew you needed
*
* Copyright (c) 2016 - 2017, Přemysl Janouch <p@janouch.name>
* Copyright (c) 2016 - 2018, 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.
@@ -66,6 +66,7 @@ enum
#include "liberty/liberty.c"
#include "liberty/liberty-tui.c"

#include <math.h>
#include <locale.h>
#include <termios.h>
#ifndef TIOCGWINSZ
@@ -1171,6 +1172,29 @@ app_visible_items (void)
return MAX (0, app_fitting_items ());
}

struct scrollbar { long length, start; }
app_compute_scrollbar (long top, long total, long visible)
{
if (total < visible)
return (struct scrollbar) { 0, 0 };
if (visible == 1)
return (struct scrollbar) { 1, 0 };
if (visible == 2)
return (struct scrollbar) { 1, top >= total / 2 };

// 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 lenf = 1. + (visible - 2.) * visible / total, length = 0.;
long offset = 1. + (visible - 2.) * top / total + modf (lenf, &length);

if (top == 0)
return (struct scrollbar) { length, 0 };
if (top + visible >= total)
return (struct scrollbar) { length, visible - length };

return (struct scrollbar) { length, offset };
}

static void
app_draw_scrollbar (void)
{
@@ -1183,18 +1207,15 @@ 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)
{
// 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);

struct scrollbar bar = app_compute_scrollbar
(tab->item_top, tab->item_count, visible_items);
for (int row = 0; row < visible_items; row++)
{
move (g.header_height + row, COLS - 1);
if (row < start || row > start + length + 1)
if (row < bar.start || row >= bar.start + bar.length)
addch (' ' | APP_ATTR (SCROLLBAR));
else
addch (' ' | APP_ATTR (SCROLLBAR) | A_REVERSE);

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