Verbose cursor audio region peak display

https://discourse.ardour.org/t/is-it-possible-to-view-audio-levels-in-db-by-moving-cursor-over-a-waveform/105199

gtk2_ardour/editor.cc

@@ -141,6 +141,7 @@
 #include "playlist_selector.h"
 #include "public_editor.h"
 #include "quantize_dialog.h"
+#include "region_peak_cursor.h"
 #include "region_layering_order_editor.h"
 #include "rgb_macros.h"
 #include "rhythm_ferret.h"
@@ -284,6 +285,7 @@ Editor::Editor ()
 	, _track_canvas_viewport (0)
 	, within_track_canvas (false)
 	, _verbose_cursor (0)
+	, _region_peak_cursor (0)
 	, tempo_group (0)
 	, meter_group (0)
 	, marker_group (0)
@@ -873,6 +875,7 @@ Editor::~Editor()
 	delete _drags;
 	delete nudge_clock;
 	delete _verbose_cursor;
+	delete _region_peak_cursor;
 	delete quantize_dialog;
 	delete _summary;
 	delete _group_tabs;
@@ -4714,6 +4717,7 @@ Editor::visual_changer (const VisualChange& vc)
 		update_video_timeline();
 	}
 
+	_region_peak_cursor->hide ();
 	_summary->set_overlays_dirty ();
 }
 

gtk2_ardour/editor.h

@@ -140,6 +140,7 @@ class PlaylistSelector;
 class PluginSelector;
 class ProgressReporter;
 class QuantizeDialog;
+class RegionPeakCursor;
 class RhythmFerret;
 class RulerDialog;
 class Selection;
@@ -848,6 +849,8 @@ private:
 	friend class VerboseCursor;
 	VerboseCursor* _verbose_cursor;
 
+	RegionPeakCursor* _region_peak_cursor;
+
 	void parameter_changed (std::string);
 	void ui_parameter_changed (std::string);
 

gtk2_ardour/editor_canvas.cc

@@ -58,6 +58,7 @@
 #include "editor_cursors.h"
 #include "mouse_cursors.h"
 #include "note_base.h"
+#include "region_peak_cursor.h"
 #include "ui_config.h"
 #include "verbose_cursor.h"
 
@@ -105,6 +106,7 @@ Editor::initialize_canvas ()
 	_track_canvas->add_scroller (*cg);
 
 	_verbose_cursor = new VerboseCursor (this);
+	_region_peak_cursor = new RegionPeakCursor (get_noscroll_group ());
 
 	/*a group to hold global rects like punch/loop indicators */
 	global_rect_group = new ArdourCanvas::Container (hv_scroll_group);
@@ -993,6 +995,7 @@ void
 Editor::tie_vertical_scrolling ()
 {
 	if (pending_visual_change.idle_handler_id < 0) {
+		_region_peak_cursor->hide ();
 		_summary->set_overlays_dirty ();
 	}
 }

gtk2_ardour/editor_mouse.cc

@@ -81,6 +81,7 @@
 #include "edit_note_dialog.h"
 #include "mouse_cursors.h"
 #include "editor_cursors.h"
+#include "region_peak_cursor.h"
 #include "verbose_cursor.h"
 #include "note.h"
 
@@ -2216,13 +2217,28 @@ Editor::motion_handler (ArdourCanvas::Item* /*item*/, GdkEvent* event, bool from
 		//drags change the snapped_cursor location, because we are snapping the thing being dragged, not the actual mouse cursor
 		return _drags->motion_handler (event, from_autoscroll);
 	} else {
-		//the snapped_cursor shows where an operation (like Split) is going to occur
 		bool ignored;
+		bool peaks_visible = false;
 		MusicSample where (0, 0);
 		if (mouse_sample (where.sample, ignored)) {
+
+			/* display peaks */
+			if (mouse_mode == MouseContent || ArdourKeyboard::indicates_snap (event->motion.state)) {
+				AudioRegionView* arv = dynamic_cast<AudioRegionView*>(entered_regionview);
+				if (arv) {
+					_region_peak_cursor->set (arv, where.sample, samples_per_pixel);
+					peaks_visible = true;
+				}
+			}
+
+			/* the snapped_cursor shows where an operation (like Split) is going to occur */
 			snap_to_with_modifier (where, event);
 			set_snapped_cursor_position (where.sample);
 		}
+
+		if (!peaks_visible) {
+			_region_peak_cursor->hide ();
+		}
 	}
 
 	return false;

gtk2_ardour/region_peak_cursor.cc

@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2020 Robin Gareus <robin@gareus.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "canvas/arrow.h"
+#include "canvas/tracking_text.h"
+
+#include "ardour/audioregion.h"
+#include "ardour/dB.h"
+
+#include "audio_region_view.h"
+#include "region_peak_cursor.h"
+#include "ui_config.h"
+
+#include "pbd/i18n.h"
+
+using namespace std;
+using namespace ARDOUR;
+
+RegionPeakCursor::RegionPeakCursor (ArdourCanvas::Item* parent)
+{
+	_canvas_text = new ArdourCanvas::Text (parent);
+	_canvas_text->set_outline (true);
+	_canvas_text->set_font_description (Pango::FontDescription (UIConfiguration::instance ().get_NormalMonospaceFont ()));
+	_canvas_text->set_ignore_events (true);
+
+	_canvas_line = new ArdourCanvas::Arrow (parent);
+	_canvas_line->set_show_head (0, true);
+	_canvas_line->set_show_head (1, true);
+	_canvas_line->set_ignore_events (true);
+
+	color_handler ();
+	UIConfiguration::instance ().ColorsChanged.connect (sigc::mem_fun (*this, &RegionPeakCursor::color_handler));
+}
+
+RegionPeakCursor::~RegionPeakCursor ()
+{
+#if 0
+	_canvas_text->unparent ();
+	delete _canvas_text;
+	_canvas_line->unparent ();
+	delete _canvas_line;
+#endif
+}
+
+void
+RegionPeakCursor::color_handler ()
+{
+	_canvas_text->set_color (UIConfiguration::instance ().color ("gtk_foreground"));
+}
+
+void
+RegionPeakCursor::show ()
+{
+	_canvas_line->show ();
+	_canvas_line->raise_to_top ();
+	_canvas_text->show ();
+	_canvas_text->raise_to_top ();
+	_canvas_text->parent ()->raise_to_top ();
+}
+
+void
+RegionPeakCursor::hide ()
+{
+	_canvas_text->hide ();
+	_canvas_line->hide ();
+}
+
+void
+RegionPeakCursor::set (AudioRegionView* arv, samplepos_t when, samplecnt_t samples_per_pixel)
+{
+	boost::shared_ptr<ARDOUR::AudioRegion> ar = boost::dynamic_pointer_cast<ARDOUR::AudioRegion> (arv->region ());
+	assert (ar);
+	assert (ar->n_channels () > 0);
+
+	sampleoffset_t s = when + ar->start () - ar->position ();
+	if (s < 0 || s > ar->length ()) {
+		hide ();
+		return;
+	}
+
+	PeakData p;
+	for (uint32_t chn = 0; chn < ar->n_channels (); ++chn) {
+		PeakData pc;
+		ar->read_peaks (&pc, 1, s, samples_per_pixel, chn, samples_per_pixel);
+		if (chn == 0) {
+			p.min = pc.min;
+			p.max = pc.max;
+		} else {
+			p.min = std::min (p.min, pc.min);
+			p.max = std::max (p.max, pc.max);
+		}
+	}
+
+	char tmp[128];
+	sprintf (tmp, "%s %+.2f %5.1f %s\n%s %+.2f %5.1f %s\n",
+	         _("Max:"), p.max,
+	         accurate_coefficient_to_dB (fabsf (p.max)), _("dBFS"),
+	         _("Min:"), p.min,
+	         accurate_coefficient_to_dB (fabsf (p.min)), _("dBFS"));
+
+	_canvas_text->set (tmp);
+
+	/* position relative to editor origin */
+	ArdourCanvas::Duple pos  = arv->get_canvas_group ()->item_to_window (_canvas_text->parent ()->position ());
+	double              xpos = pos.x + floor ((when - ar->position ()) / samples_per_pixel);
+
+	_canvas_text->set_x_position (xpos + 3);
+	_canvas_text->set_y_position (pos.y + 3);
+
+	_canvas_line->set_x (xpos - 0.5);
+	_canvas_line->set_y0 (pos.y);
+	_canvas_line->set_y1 (pos.y + arv->height ());
+
+	if (!visible ()) {
+		show ();
+	}
+}
+
+bool
+RegionPeakCursor::visible () const
+{
+	return _canvas_text->visible ();
+}

gtk2_ardour/region_peak_cursor.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2020 Robin Gareus <robin@gareus.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _gtk_ardour_region_peak_cursor_h_
+#define _gtk_ardour_region_peak_cursor_h_
+
+#include "ardour/types.h"
+#include "canvas/canvas.h"
+
+namespace ArdourCanvas
+{
+	class Text;
+	class Arrow;
+}
+
+class AudioRegionView;
+
+class RegionPeakCursor
+{
+public:
+	RegionPeakCursor (ArdourCanvas::Item*);
+	~RegionPeakCursor ();
+
+	void set (AudioRegionView*, samplepos_t, samplecnt_t);
+	void hide ();
+	bool visible () const;
+
+private:
+	void color_handler ();
+	void show ();
+
+	ArdourCanvas::Text*  _canvas_text;
+	ArdourCanvas::Arrow* _canvas_line;
+};
+
+#endif

gtk2_ardour/wscript

@@ -227,6 +227,7 @@ gtk2_ardour_sources = [
         'region_editor.cc',
         'region_gain_line.cc',
         'region_layering_order_editor.cc',
+        'region_peak_cursor.cc',
         'region_selection.cc',
         'region_view.cc',
         'return_ui.cc',