avoid crazy costs of looking up and constructing color modifier every time, and cache color values for MIDI notes

1 files changed, 36 insertions, 10 deletions

diff --git a/gtk2_ardour/note_base.cc b/gtk2_ardour/note_base.cc
index 2e900c354e..915866ef61 100644
--- a/gtk2_ardour/note_base.cc
+++ b/gtk2_ardour/note_base.cc
@@ -46,11 +46,17 @@ const uint32_t NoteBase::midi_channel_colors[16] = {
 
 bool             NoteBase::_color_init = false;
 Gtkmm2ext::Color NoteBase::_selected_col = 0;
+Gtkmm2ext::SVAModifier NoteBase::color_modifier;
+Gtkmm2ext::Color NoteBase::velocity_color_table[128];
 
 void
 NoteBase::set_colors ()
 {
+	for (uint8_t i = 0; i < 128; ++i) {
+		velocity_color_table[i] = 0; /* out of bounds because zero alpha makes no sense  */
+	}
 	_selected_col = UIConfiguration::instance().color ("midi note selected outline");
+	color_modifier = UIConfiguration::instance().modifier ("midi note");
 }
 
 NoteBase::NoteBase(MidiRegionView& region, bool with_events, const boost::shared_ptr<NoteType> note)
@@ -324,15 +330,35 @@ NoteBase::big_enough_to_trim () const
 Gtkmm2ext::Color
 NoteBase::meter_style_fill_color(uint8_t vel, bool /* selected */)
 {
-	if (vel < 32) {
-		return UINT_INTERPOLATE(UIConfiguration::instance().color_mod ("midi meter color0", "midi note"), UIConfiguration::instance().color_mod ("midi meter color1", "midi note"), (vel / 32.0));
-	} else if (vel < 64) {
-		return UINT_INTERPOLATE(UIConfiguration::instance().color_mod ("midi meter color2", "midi note"), UIConfiguration::instance().color_mod ("midi meter color3", "midi note"), ((vel-32) / 32.0));
-	} else if (vel < 100) {
-		return UINT_INTERPOLATE(UIConfiguration::instance().color_mod ("midi meter color4", "midi note"), UIConfiguration::instance().color_mod ("midi meter color5", "midi note"), ((vel-64) / 36.0));
-	} else if (vel < 112) {
-		return UINT_INTERPOLATE(UIConfiguration::instance().color_mod ("midi meter color6", "midi note"), UIConfiguration::instance().color_mod ("midi meter color7", "midi note"), ((vel-100) / 12.0));
-	} else {
-		return  UINT_INTERPOLATE(UIConfiguration::instance().color_mod ("midi meter color8", "midi note"), UIConfiguration::instance().color_mod ("midi meter color9", "midi note"), ((vel-112) / 17.0));
+	/* note that because vel is uint8_t, we don't need bounds checking for
+	   the color lookup table.
+	*/
+
+	if (velocity_color_table[vel] == 0) {
+
+		Gtkmm2ext::Color col;
+
+		if (vel < 32) {
+			col = UINT_INTERPOLATE(UIConfiguration::instance().color ("midi meter color0"), UIConfiguration::instance().color ("midi meter color1"), (vel / 32.0));
+			col = Gtkmm2ext::change_alpha (col, color_modifier.a());
+		} else if (vel < 64) {
+			col = UINT_INTERPOLATE(UIConfiguration::instance().color ("midi meter color2"), UIConfiguration::instance().color ("midi meter color3"), ((vel-32) / 32.0));
+			col = Gtkmm2ext::change_alpha (col, color_modifier.a());
+		} else if (vel < 100) {
+			col = UINT_INTERPOLATE(UIConfiguration::instance().color ("midi meter color4"), UIConfiguration::instance().color ("midi meter color5"), ((vel-64) / 36.0));
+			col = Gtkmm2ext::change_alpha (col, color_modifier.a());
+		} else if (vel < 112) {
+			col = UINT_INTERPOLATE(UIConfiguration::instance().color ("midi meter color6"), UIConfiguration::instance().color ("midi meter color7"), ((vel-100) / 12.0));
+			col = Gtkmm2ext::change_alpha (col, color_modifier.a());
+		} else {
+			col =  UINT_INTERPOLATE(UIConfiguration::instance().color ("midi meter color8"), UIConfiguration::instance().color ("midi meter color9"), ((vel-112) / 17.0));
+			col = Gtkmm2ext::change_alpha (col, color_modifier.a());
+		}
+
+		velocity_color_table[vel] = col;
+		return col;
 	}
+
+	return velocity_color_table[vel];
 }
+