plugin: add a tap bpm plugin

quodlibet/po/POTFILES.in

@@ -127,6 +127,7 @@ quodlibet/ext/songsmenu/playlist.py
 quodlibet/ext/songsmenu/refresh.py
 quodlibet/ext/songsmenu/replaygain.py
 quodlibet/ext/songsmenu/splitting.py
+quodlibet/ext/songsmenu/tapbpm.py
 quodlibet/ext/songsmenu/website_search.py
 quodlibet/ext/songsmenu/wikipedia.py
 quodlibet/formats/_audio.py

quodlibet/quodlibet/ext/songsmenu/tapbpm.py

@@ -0,0 +1,193 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 Didier Villevalois,
+#           2010 Christoph Reiter
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation
+
+from gi.repository import Gtk, GObject
+
+from quodlibet import _
+from quodlibet.plugins.songsmenu import SongsMenuPlugin
+from quodlibet.qltk import Icons
+from quodlibet.qltk.window import Dialog
+
+
+class TapBpmPanel(Gtk.VBox):
+    def __init__(self, parent, song):
+        super(Gtk.VBox, self).__init__()
+
+        self.dialog = parent
+        self.song = song
+        self.original_bpm = float(song["bpm"]) if "bpm" in song else 0.0
+
+        self.set_margin_bottom(6)
+        self.set_spacing(6)
+
+        box = Gtk.HBox()
+        box.set_spacing(6)
+        box.pack_start(Gtk.Label(_("BPM:")), False, True, 0)
+        self.bpm_label = Gtk.Label(_("n/a"))
+        self.bpm_label.set_xalign(0.5)
+        box.pack_start(self.bpm_label, True, True, 0)
+
+        self.reset_btn = Gtk.Button(label=_("Reset"))
+        self.reset_btn.connect('clicked', lambda *x: self.reset())
+        box.pack_end(self.reset_btn, False, True, 0)
+
+        self.pack_start(box, False, True, 0)
+
+        self.tap_btn = Gtk.Button(label=_("Tap"))
+        self.tap_btn.connect('button-press-event', self.tap)
+        self.pack_start(self.tap_btn, True, True, 0)
+
+        self.init_tap()
+        self.update()
+
+        self.show_all()
+
+    def update(self):
+        GObject.idle_add(self.do_update)
+
+    def do_update(self):
+        has_new_bpm = self.floating_bpm != self.original_bpm
+
+        self.dialog.set_response_sensitive(Gtk.ResponseType.OK, has_new_bpm)
+        self.reset_btn.set_sensitive(has_new_bpm)
+
+        if self.floating_bpm != 0.0:
+            self.bpm_label.set_text("%.1f" % self.floating_bpm)
+        else:
+            self.bpm_label.set_text(_("n/a"))
+
+    def tap(self, widget, event):
+        self.count_tap(event.time)
+        self.update()
+
+    def reset(self):
+        self.init_tap()
+        self.update()
+
+    def save(self):
+        self.song["bpm"] = "%.0f" % self.floating_bpm
+        self.song.write()
+
+    def init_tap(self):
+        self.bpm = 0.0
+        self.clicks = 0
+        self.last = 0
+        self.last_times = []
+        self.last_bpms = []
+        self.last_floating_bpms = []
+        self.last_floating_squares = []
+        self.bpms_sum = 0.0
+        self.squares_sum = 0.0
+        self.average_count = 0
+        self.min = 0
+        self.max = 0
+        self.floating_bpm = self.original_bpm
+        self.floating_square = 0.0
+        self.keep = 100
+
+        self.pause = 3
+        self.min_weight = 0.01
+
+    def count_tap(self, now):
+        now = now / 1000.
+        # reset?
+        if now - self.last > self.pause:
+            self.clicks = 0
+            self.bpm = 0.0
+
+            self.last_times = []
+            self.last_bpms = []
+            self.last_floating_bpms = []
+            self.last_floating_squares = []
+            self.bpms_sum = 0.0
+            self.squares_sum = 0.0
+            self.average_count = 0
+            self.min = 0
+            self.max = 0
+            self.floating_bpm = 0.0
+            self.floating_square = 0.0
+        elif now > self.last:
+            # Use previous 5 values to average BPM
+            bpms = []
+            bpms.append(60.0 / (now - self.last))
+            # and four out of the list
+            for i in xrange(1, 5):
+                if len(self.last_times) <= i:
+                    break
+                bpms.append((i + 1) * 60.0 / (now - self.last_times[-i]))
+
+            self.bpm = reduce(lambda x, y: x + y, bpms) / len(bpms)
+
+            # Exponentially weighted floating average
+            weight = (1.0 / self.clicks) ** .5
+            if weight < self.min_weight:
+                weight = self.min_weight
+            self.floating_bpm = \
+                self.floating_bpm * (1.0 - weight) \
+                + self.bpm * weight
+            self.floating_square = \
+                self.floating_square * (1.0 - weight) \
+                + self.bpm * self.bpm * weight
+
+            if self.bpm < self.min or self.average_count == 0:
+                self.min = self.bpm
+            if self.bpm > self.max or self.average_count == 0:
+                self.max = self.bpm
+            self.bpms_sum += self.bpm
+            self.squares_sum += self.bpm * self.bpm
+            self.average_count += 1
+
+            # Update history
+            self.last_times = self.last_times[-(self.keep - 1):] + [self.last]
+            self.last_bpms = self.last_bpms[-(self.keep - 1):] + [self.bpm]
+            self.last_floating_bpms = \
+                self.last_floating_bpms[-(self.keep - 1):] \
+                + [self.floating_bpm]
+            self.last_floating_squares = \
+                self.last_floating_squares[-(self.keep - 1):] \
+                + [self.floating_square]
+
+        self.last = now
+        self.clicks += 1
+
+
+class TapBpm(SongsMenuPlugin):
+    PLUGIN_ID = "Tap BPM"
+    PLUGIN_NAME = _("Tap BPM")
+    PLUGIN_DESC = _("Tap BPM for the selected song.")
+    PLUGIN_ICON = Icons.EDIT
+    PLUGIN_VERSION = "0.1"
+
+    def plugin_song(self, song):
+        self._window = window = \
+            Dialog(title=_("Tap BPM"), parent=self.plugin_window)
+
+        window.add_button(_("_Cancel"), Gtk.ResponseType.CANCEL)
+        window.add_icon_button(_("_Save"), Icons.DOCUMENT_SAVE,
+                             Gtk.ResponseType.OK)
+
+        window.set_default_size(300, 100)
+        window.set_border_width(6)
+        window.connect('response', self.response)
+
+        self._panel = TapBpmPanel(window, song)
+        window.vbox.pack_start(self._panel, False, True, 0)
+
+        window.vbox.show_all()
+        window.present()
+
+    def response(self, win, response):
+        self._window.hide()
+        self._window.destroy()
+        del self._window
+
+        if response != Gtk.ResponseType.OK:
+            return
+
+        # Save metadata
+        self._panel.save()