add canvas-based Meter object

3 files changed, 1093 insertions, 0 deletions

diff --git a/libs/canvas/canvas/meter.h b/libs/canvas/canvas/meter.h
new file mode 100644
index 0000000000..3a1a46cab2
--- /dev/null
+++ b/libs/canvas/canvas/meter.h
@@ -0,0 +1,192 @@
+/*
+    Copyright (C) 2003 Paul Davis
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef __push2_meter_h__
+#define __push2_meter_h__
+
+#include <map>
+#include <boost/tuple/tuple.hpp>
+#include <boost/tuple/tuple_comparison.hpp>
+
+#include <cairomm/pattern.h>
+#include <cairomm/region.h>
+
+#include "canvas/item.h"
+
+namespace ArdourCanvas {
+
+class Canvas;
+
+class Meter : public Item {
+  public:
+	enum Orientation {
+		Horizontal,
+		Vertical
+	};
+
+	Meter (Item* parent,
+	       long hold_cnt, unsigned long width, Orientation, int len=0,
+	       int clr0=0x008800ff, int clr1=0x008800ff,
+	       int clr2=0x00ff00ff, int clr3=0x00ff00ff,
+	       int clr4=0xffaa00ff, int clr5=0xffaa00ff,
+	       int clr6=0xffff00ff, int clr7=0xffff00ff,
+	       int clr8=0xff0000ff, int clr9=0xff0000ff,
+	       int bgc0=0x333333ff, int bgc1=0x444444ff,
+	       int bgh0=0x991122ff, int bgh1=0x551111ff,
+	       float stp0 = 55.0, // log_meter(-18);
+	       float stp1 = 77.5, // log_meter(-9);
+	       float stp2 = 92.5, // log_meter(-3); // 95.0, // log_meter(-2);
+	       float stp3 = 100.0,
+	       int styleflags = 3
+		);
+
+	Meter (ArdourCanvas::Canvas* canvas,
+	       long hold_cnt, unsigned long width, Orientation, int len=0,
+	       int clr0=0x008800ff, int clr1=0x008800ff,
+	       int clr2=0x00ff00ff, int clr3=0x00ff00ff,
+	       int clr4=0xffaa00ff, int clr5=0xffaa00ff,
+	       int clr6=0xffff00ff, int clr7=0xffff00ff,
+	       int clr8=0xff0000ff, int clr9=0xff0000ff,
+	       int bgc0=0x333333ff, int bgc1=0x444444ff,
+	       int bgh0=0x991122ff, int bgh1=0x551111ff,
+	       float stp0 = 55.0, // log_meter(-18);
+	       float stp1 = 77.5, // log_meter(-9);
+	       float stp2 = 92.5, // log_meter(-3); // 95.0, // log_meter(-2);
+	       float stp3 = 100.0,
+	       int styleflags = 3
+		);
+	virtual ~Meter ();
+	static void flush_pattern_cache();
+
+	void set (float level, float peak = -1);
+	void clear ();
+
+	float get_level() { return current_level; }
+	float get_user_level() { return current_user_level; }
+	float get_peak() { return current_peak; }
+
+	long hold_count() { return hold_cnt; }
+	void set_hold_count (long);
+	void set_highlight (bool);
+	bool get_highlight () { return highlight; }
+
+	void render (ArdourCanvas::Rect const &, Cairo::RefPtr<Cairo::Context>) const;
+	void compute_bounding_box() const;
+
+  private:
+
+	Cairo::RefPtr<Cairo::Pattern> fgpattern;
+	Cairo::RefPtr<Cairo::Pattern> bgpattern;
+	gint pixheight;
+	gint pixwidth;
+
+	float _stp[4];
+	int _clr[10];
+	int _bgc[2];
+	int _bgh[2];
+	int _styleflags;
+
+	Orientation orientation;
+	mutable Cairo::RectangleInt pixrect;
+	mutable Cairo::RectangleInt last_peak_rect;
+	unsigned long hold_cnt;
+	unsigned long hold_state;
+	bool bright_hold;
+	float current_level;
+	float current_peak;
+	float current_user_level;
+	bool highlight;
+
+	void init (int clr0, int clr1, int clr2, int clr3,
+	           int clr4, int clr5, int clr6, int clr7,
+	           int clr8, int clr9,
+	           int bgc0, int bgc1,
+	           int bgh0, int bgh1,
+	           float stp0, float stp1,
+	           float stp2, float stp3,
+	           int dimen, int len);
+
+	void vertical_expose (ArdourCanvas::Rect const & area, Cairo::RefPtr<Cairo::Context> context) const;
+	void queue_vertical_redraw (float old_level);
+
+	void horizontal_expose (ArdourCanvas::Rect const & area, Cairo::RefPtr<Cairo::Context> context) const;
+	void queue_horizontal_redraw (float old_level);
+
+	static bool no_rgba_overlay;
+
+	static Cairo::RefPtr<Cairo::Pattern> generate_meter_pattern (int, int, int *, float *, int, bool);
+	static Cairo::RefPtr<Cairo::Pattern> vertical_meter_pattern (int, int, int *, float *, int);
+	static Cairo::RefPtr<Cairo::Pattern> horizontal_meter_pattern (int, int, int *, float *, int);
+
+	static Cairo::RefPtr<Cairo::Pattern> generate_meter_background (int, int, int *, bool, bool);
+	static Cairo::RefPtr<Cairo::Pattern> vertical_background (int, int, int *, bool);
+	static Cairo::RefPtr<Cairo::Pattern> horizontal_background (int, int, int *, bool);
+
+	struct Pattern10MapKey {
+		Pattern10MapKey (
+				int w, int h,
+				float stp0, float stp1, float stp2, float stp3,
+				int c0, int c1, int c2, int c3,
+				int c4, int c5, int c6, int c7,
+				int c8, int c9, int st
+				)
+			: dim(w, h)
+			, stp(stp0, stp1, stp2, stp3)
+			, cols(c0, c1, c2, c3, c4, c5, c6, c7, c8, c9)
+			, style(st)
+		{}
+		inline bool operator<(const Pattern10MapKey& rhs) const {
+			return (dim < rhs.dim)
+				|| (dim == rhs.dim && stp < rhs.stp)
+				|| (dim == rhs.dim && stp == rhs.stp && cols < rhs.cols)
+				|| (dim == rhs.dim && stp == rhs.stp && cols == rhs.cols && style < rhs.style);
+		}
+		boost::tuple<int, int> dim;
+		boost::tuple<float, float, float, float> stp;
+		boost::tuple<int, int, int, int, int, int, int, int, int, int> cols;
+		int style;
+	};
+	typedef std::map<Pattern10MapKey, Cairo::RefPtr<Cairo::Pattern> > Pattern10Map;
+
+	struct PatternBgMapKey {
+		PatternBgMapKey (int w, int h, int c0, int c1, bool shade)
+			: dim(w, h)
+			, cols(c0, c1)
+			, sh(shade)
+		{}
+		inline bool operator<(const PatternBgMapKey& rhs) const {
+			return (dim < rhs.dim) || (dim == rhs.dim && cols < rhs.cols) || (dim == rhs.dim && cols == rhs.cols && (sh && !rhs.sh));
+		}
+		boost::tuple<int, int> dim;
+		boost::tuple<int, int> cols;
+		bool sh;
+	};
+	typedef std::map<PatternBgMapKey, Cairo::RefPtr<Cairo::Pattern> > PatternBgMap;
+
+	static Pattern10Map vm_pattern_cache;
+	static PatternBgMap vb_pattern_cache;
+	static Pattern10Map hm_pattern_cache;
+	static PatternBgMap hb_pattern_cache;
+	static int min_pattern_metric_size; // min dimension for axis that displays the meter level
+	static int max_pattern_metric_size; // max dimension for axis that displays the meter level
+};
+
+} /* namespace */
+
+#endif /* __push2_meter_h__ */
diff --git a/libs/canvas/meter.cc b/libs/canvas/meter.cc
new file mode 100644
index 0000000000..d71370ad48
--- /dev/null
+++ b/libs/canvas/meter.cc
@@ -0,0 +1,900 @@
+/*
+    Copyright (C) 2003-2016 Paul Davis
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    $Id$
+*/
+
+#include <iostream>
+#include <cmath>
+#include <algorithm>
+#include <cstring>
+
+#include <stdlib.h>
+
+#include <glibmm.h>
+
+#include <gtkmm2ext/utils.h>
+#include <gtkmm2ext/rgb_macros.h>
+
+#include "canvas/canvas.h"
+#include "canvas/colors.h"
+#include "canvas/meter.h"
+#include "canvas/utils.h"
+
+using namespace Glib;
+using namespace std;
+using namespace ArdourCanvas;
+using namespace Gtkmm2ext;
+
+int Meter::min_pattern_metric_size = 16;
+int Meter::max_pattern_metric_size = 1024;
+bool Meter::no_rgba_overlay = false;
+
+Meter::Pattern10Map Meter::vm_pattern_cache;
+Meter::PatternBgMap Meter::vb_pattern_cache;
+
+Meter::Pattern10Map Meter::hm_pattern_cache;
+Meter::PatternBgMap Meter::hb_pattern_cache;
+
+Meter::Meter (Item* parent, long hold, unsigned long dimen, Orientation o, int len,
+		int clr0, int clr1, int clr2, int clr3,
+		int clr4, int clr5, int clr6, int clr7,
+		int clr8, int clr9,
+		int bgc0, int bgc1,
+		int bgh0, int bgh1,
+		float stp0, float stp1,
+		float stp2, float stp3,
+		int styleflags
+		)
+	: Item (parent)
+	, pixheight(0)
+	, pixwidth(0)
+	, _styleflags(styleflags)
+	, orientation(o)
+	, hold_cnt(hold)
+	, hold_state(0)
+	, bright_hold(false)
+	, current_level(0)
+	, current_peak(0)
+	, highlight(false)
+{
+	init (clr0, clr1, clr2, clr3, clr4, clr5, clr6, clr7, clr8, clr9, bgc0, bgc1, bgh0, bgh1, stp0, stp1, stp2,  stp3, dimen, len);
+}
+
+Meter::Meter (Canvas* canvas, long hold, unsigned long dimen, Orientation o, int len,
+		int clr0, int clr1, int clr2, int clr3,
+		int clr4, int clr5, int clr6, int clr7,
+		int clr8, int clr9,
+		int bgc0, int bgc1,
+		int bgh0, int bgh1,
+		float stp0, float stp1,
+		float stp2, float stp3,
+		int styleflags
+		)
+	: Item (canvas)
+	, pixheight(0)
+	, pixwidth(0)
+	, _styleflags(styleflags)
+	, orientation(o)
+	, hold_cnt(hold)
+	, hold_state(0)
+	, bright_hold(false)
+	, current_level(0)
+	, current_peak(0)
+	, highlight(false)
+{
+	init (clr0, clr1, clr2, clr3, clr4, clr5, clr6, clr7, clr8, clr9, bgc0, bgc1, bgh0, bgh1, stp0, stp1, stp2,  stp3, dimen, len);
+}
+
+void
+Meter::init (int clr0, int clr1, int clr2, int clr3,
+             int clr4, int clr5, int clr6, int clr7,
+             int clr8, int clr9,
+             int bgc0, int bgc1,
+             int bgh0, int bgh1,
+             float stp0, float stp1,
+             float stp2, float stp3,
+             int dimen,
+             int len)
+{
+	last_peak_rect.width = 0;
+	last_peak_rect.height = 0;
+	last_peak_rect.x = 0;
+	last_peak_rect.y = 0;
+
+	no_rgba_overlay = ! Glib::getenv("NO_METER_SHADE").empty();
+
+	_clr[0] = clr0;
+	_clr[1] = clr1;
+	_clr[2] = clr2;
+	_clr[3] = clr3;
+	_clr[4] = clr4;
+	_clr[5] = clr5;
+	_clr[6] = clr6;
+	_clr[7] = clr7;
+	_clr[8] = clr8;
+	_clr[9] = clr9;
+
+	_bgc[0] = bgc0;
+	_bgc[1] = bgc1;
+
+	_bgh[0] = bgh0;
+	_bgh[1] = bgh1;
+
+	_stp[0] = stp0;
+	_stp[1] = stp1;
+	_stp[2] = stp2;
+	_stp[3] = stp3;
+
+	pixrect.x = 1;
+	pixrect.y = 1;
+
+	if (!len) {
+		len = 250;
+	}
+
+	if (orientation == Vertical) {
+		pixheight = len;
+		pixwidth = dimen;
+		fgpattern = vertical_meter_pattern (pixwidth + 2, pixheight + 2, _clr, _stp, _styleflags);
+		bgpattern = vertical_background (pixwidth + 2, pixheight + 2, _bgc, false);
+	} else {
+		pixheight = dimen;
+		pixwidth = len;
+		fgpattern = horizontal_meter_pattern (pixwidth + 2, pixheight + 2, _clr, _stp, _styleflags);
+		bgpattern = horizontal_background (pixwidth + 2, pixheight + 2, _bgc, false);
+	}
+
+	pixrect.width = pixwidth;
+	pixrect.height = pixheight;
+}
+
+void
+Meter::compute_bounding_box () const
+{
+	if (!_canvas) {
+		_bounding_box = boost::optional<Rect> ();
+		_bounding_box_dirty = false;
+		return;
+	}
+
+	Rect r (0, 0, pixwidth + 2, pixheight + 2);
+	_bounding_box = r;
+	_bounding_box_dirty = false;
+}
+
+
+Meter::~Meter ()
+{
+}
+
+void
+Meter::flush_pattern_cache () {
+	hb_pattern_cache.clear();
+	hm_pattern_cache.clear();
+	vb_pattern_cache.clear();
+	vm_pattern_cache.clear();
+}
+
+Cairo::RefPtr<Cairo::Pattern>
+Meter::generate_meter_pattern (int width, int height, int *clr, float *stp, int styleflags, bool horiz)
+{
+	guint8 r,g,b,a;
+	double knee;
+	const double soft =  3.0 / (double) height;
+	const double offs = -1.0 / (double) height;
+
+	cairo_pattern_t* pat = cairo_pattern_create_linear (0.0, 0.0, 0.0, height);
+
+	/*
+	  Cairo coordinate space goes downwards as y value goes up, so invert
+	  knee-based positions by using (1.0 - y)
+	*/
+
+	UINT_TO_RGBA (clr[9], &r, &g, &b, &a); // top/clip
+	cairo_pattern_add_color_stop_rgb (pat, 0.0,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	knee = offs + stp[3] / 115.0f; // -0dB
+
+	UINT_TO_RGBA (clr[8], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	UINT_TO_RGBA (clr[7], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee + soft,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	knee = offs + stp[2]/ 115.0f; // -3dB || -2dB
+
+	UINT_TO_RGBA (clr[6], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	UINT_TO_RGBA (clr[5], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee + soft,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	knee = offs + stp[1] / 115.0f; // -9dB
+
+	UINT_TO_RGBA (clr[4], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	UINT_TO_RGBA (clr[3], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee + soft,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	knee = offs + stp[0] / 115.0f; // -18dB
+
+	UINT_TO_RGBA (clr[2], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	UINT_TO_RGBA (clr[1], &r, &g, &b, &a);
+	cairo_pattern_add_color_stop_rgb (pat, 1.0 - knee + soft,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	UINT_TO_RGBA (clr[0], &r, &g, &b, &a); // bottom
+	cairo_pattern_add_color_stop_rgb (pat, 1.0,
+	                                  r/255.0, g/255.0, b/255.0);
+
+	if ((styleflags & 1) && !no_rgba_overlay) {
+		cairo_pattern_t* shade_pattern = cairo_pattern_create_linear (0.0, 0.0, width, 0.0);
+		cairo_pattern_add_color_stop_rgba (shade_pattern, 0,   0.0, 0.0, 0.0, 0.15);
+		cairo_pattern_add_color_stop_rgba (shade_pattern, 0.4, 1.0, 1.0, 1.0, 0.05);
+		cairo_pattern_add_color_stop_rgba (shade_pattern, 1,   0.0, 0.0, 0.0, 0.25);
+
+		cairo_surface_t* surface;
+		cairo_t* tc = 0;
+		surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
+		tc = cairo_create (surface);
+		cairo_set_source (tc, pat);
+		cairo_rectangle (tc, 0, 0, width, height);
+		cairo_fill (tc);
+		cairo_pattern_destroy (pat);
+
+		cairo_set_source (tc, shade_pattern);
+		cairo_rectangle (tc, 0, 0, width, height);
+		cairo_fill (tc);
+		cairo_pattern_destroy (shade_pattern);
+
+		if (styleflags & 2) { // LED stripes
+			cairo_save (tc);
+			cairo_set_line_width(tc, 1.0);
+			cairo_set_source_rgba(tc, .0, .0, .0, 0.4);
+			//cairo_set_operator (tc, CAIRO_OPERATOR_SOURCE);
+			for (int i = 0; float y = 0.5 + i * 2.0; ++i) {
+				if (y >= height) {
+					break;
+				}
+				cairo_move_to(tc, 0, y);
+				cairo_line_to(tc, width, y);
+				cairo_stroke (tc);
+			}
+			cairo_restore (tc);
+		}
+
+		pat = cairo_pattern_create_for_surface (surface);
+		cairo_destroy (tc);
+		cairo_surface_destroy (surface);
+	}
+
+	if (horiz) {
+		cairo_surface_t* surface;
+		cairo_t* tc = 0;
+		surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, height, width);
+		tc = cairo_create (surface);
+
+		cairo_matrix_t m;
+		cairo_matrix_init_rotate (&m, -M_PI/2.0);
+		cairo_matrix_translate (&m, -height, 0);
+		cairo_pattern_set_matrix (pat, &m);
+		cairo_set_source (tc, pat);
+		cairo_rectangle (tc, 0, 0, height, width);
+		cairo_fill (tc);
+		cairo_pattern_destroy (pat);
+		pat = cairo_pattern_create_for_surface (surface);
+		cairo_destroy (tc);
+		cairo_surface_destroy (surface);
+	}
+	Cairo::RefPtr<Cairo::Pattern> p (new Cairo::Pattern (pat, false));
+
+	return p;
+}
+
+
+Cairo::RefPtr<Cairo::Pattern>
+Meter::generate_meter_background (int width, int height, int *clr, bool shade, bool horiz)
+{
+	guint8 r0,g0,b0,r1,g1,b1,a;
+
+	cairo_pattern_t* pat = cairo_pattern_create_linear (0.0, 0.0, 0.0, height);
+
+	UINT_TO_RGBA (clr[0], &r0, &g0, &b0, &a);
+	UINT_TO_RGBA (clr[1], &r1, &g1, &b1, &a);
+
+	cairo_pattern_add_color_stop_rgb (pat, 0.0,
+	                                  r1/255.0, g1/255.0, b1/255.0);
+
+	cairo_pattern_add_color_stop_rgb (pat, 1.0,
+	                                  r0/255.0, g0/255.0, b0/255.0);
+
+	if (shade && !no_rgba_overlay) {
+		cairo_pattern_t* shade_pattern = cairo_pattern_create_linear (0.0, 0.0, width, 0.0);
+		cairo_pattern_add_color_stop_rgba (shade_pattern, 0.0, 1.0, 1.0, 1.0, 0.15);
+		cairo_pattern_add_color_stop_rgba (shade_pattern, 0.6, 0.0, 0.0, 0.0, 0.10);
+		cairo_pattern_add_color_stop_rgba (shade_pattern, 1.0, 1.0, 1.0, 1.0, 0.20);
+
+		cairo_surface_t* surface;
+		cairo_t* tc = 0;
+		surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
+		tc = cairo_create (surface);
+		cairo_set_source (tc, pat);
+		cairo_rectangle (tc, 0, 0, width, height);
+		cairo_fill (tc);
+		cairo_set_source (tc, shade_pattern);
+		cairo_rectangle (tc, 0, 0, width, height);
+		cairo_fill (tc);
+
+		cairo_pattern_destroy (pat);
+		cairo_pattern_destroy (shade_pattern);
+
+		pat = cairo_pattern_create_for_surface (surface);
+
+		cairo_destroy (tc);
+		cairo_surface_destroy (surface);
+	}
+
+	if (horiz) {
+		cairo_surface_t* surface;
+		cairo_t* tc = 0;
+		surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, height, width);
+		tc = cairo_create (surface);
+
+		cairo_matrix_t m;
+		cairo_matrix_init_rotate (&m, -M_PI/2.0);
+		cairo_matrix_translate (&m, -height, 0);
+		cairo_pattern_set_matrix (pat, &m);
+		cairo_set_source (tc, pat);
+		cairo_rectangle (tc, 0, 0, height, width);
+		cairo_fill (tc);
+		cairo_pattern_destroy (pat);
+		pat = cairo_pattern_create_for_surface (surface);
+		cairo_destroy (tc);
+		cairo_surface_destroy (surface);
+	}
+
+	Cairo::RefPtr<Cairo::Pattern> p (new Cairo::Pattern (pat, false));
+
+	return p;
+}
+
+Cairo::RefPtr<Cairo::Pattern>
+Meter::vertical_meter_pattern (int width, int height, int *clr, float *stp, int styleflags)
+{
+	height = max(height, min_pattern_metric_size);
+	height = min(height, max_pattern_metric_size);
+
+	const Pattern10MapKey key (width, height,
+			stp[0], stp[1], stp[2], stp[3],
+			clr[0], clr[1], clr[2], clr[3],
+			clr[4], clr[5], clr[6], clr[7],
+			clr[8], clr[9], styleflags);
+
+	Pattern10Map::iterator i;
+	if ((i = vm_pattern_cache.find (key)) != vm_pattern_cache.end()) {
+		return i->second;
+	}
+	// TODO flush pattern cache if it gets too large
+
+	Cairo::RefPtr<Cairo::Pattern> p = generate_meter_pattern (width, height, clr, stp, styleflags, false);
+	vm_pattern_cache[key] = p;
+
+	return p;
+}
+
+Cairo::RefPtr<Cairo::Pattern>
+Meter::vertical_background (int width, int height, int *bgc, bool shade)
+{
+	height = max(height, min_pattern_metric_size);
+	height = min(height, max_pattern_metric_size);
+	height += 2;
+
+	const PatternBgMapKey key (width, height, bgc[0], bgc[1], shade);
+	PatternBgMap::iterator i;
+
+	if ((i = vb_pattern_cache.find (key)) != vb_pattern_cache.end()) {
+		return i->second;
+	}
+	// TODO flush pattern cache if it gets too large
+
+	Cairo::RefPtr<Cairo::Pattern> p = generate_meter_background (width, height, bgc, shade, false);
+	vb_pattern_cache[key] = p;
+
+	return p;
+}
+
+Cairo::RefPtr<Cairo::Pattern>
+Meter::horizontal_meter_pattern (int width, int height, int *clr, float *stp, int styleflags)
+{
+	width = max(width, min_pattern_metric_size);
+	width = min(width, max_pattern_metric_size);
+
+	const Pattern10MapKey key (width, height,
+			stp[0], stp[1], stp[2], stp[3],
+			clr[0], clr[1], clr[2], clr[3],
+			clr[4], clr[5], clr[6], clr[7],
+			clr[8], clr[9], styleflags);
+
+	Pattern10Map::iterator i;
+	if ((i = hm_pattern_cache.find (key)) != hm_pattern_cache.end()) {
+		return i->second;
+	}
+	// TODO flush pattern cache if it gets too large
+
+	Cairo::RefPtr<Cairo::Pattern> p = generate_meter_pattern (height, width, clr, stp, styleflags, true);
+
+	hm_pattern_cache[key] = p;
+	return p;
+}
+
+Cairo::RefPtr<Cairo::Pattern>
+Meter::horizontal_background (int width, int height, int *bgc, bool shade)
+{
+	width = max(width, min_pattern_metric_size);
+	width = min(width, max_pattern_metric_size);
+	width += 2;
+
+	const PatternBgMapKey key (width, height, bgc[0], bgc[1], shade);
+	PatternBgMap::iterator i;
+	if ((i = hb_pattern_cache.find (key)) != hb_pattern_cache.end()) {
+		return i->second;
+	}
+	// TODO flush pattern cache if it gets too large
+
+	Cairo::RefPtr<Cairo::Pattern> p = generate_meter_background (height, width, bgc, shade, true);
+
+	hb_pattern_cache[key] = p;
+
+	return p;
+}
+
+void
+Meter::set_hold_count (long val)
+{
+	if (val < 1) {
+		val = 1;
+	}
+
+	hold_cnt = val;
+	hold_state = 0;
+	current_peak = 0;
+
+	redraw ();
+}
+
+void
+Meter::render (ArdourCanvas::Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	if (orientation == Vertical) {
+		return vertical_expose (area, context);
+	} else {
+		return horizontal_expose (area, context);
+	}
+}
+
+void
+Meter::vertical_expose (ArdourCanvas::Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	gint top_of_meter;
+	Cairo::RectangleInt background;
+	Cairo::RectangleInt area_r;
+
+	area_r.x = area.x0;
+	area_r.y = area.y0;
+	area_r.width = area.width();
+	area_r.height = area.height();
+
+	context->set_source_rgb (0, 0, 0); // black
+	rounded_rectangle (context, 0, 0, pixwidth + 2, pixheight + 2, 2);
+	context->stroke ();
+
+	top_of_meter = (gint) floor (pixheight * current_level);
+
+	/* reset the height & origin of the rect that needs to show the pixbuf
+	 */
+
+	pixrect.height = top_of_meter;
+	pixrect.y = 1 + pixheight - top_of_meter;
+
+	background.x = 1;
+	background.y = 1;
+	background.width = pixrect.width;
+	background.height = pixheight - top_of_meter;
+
+	/* translate so that item coordinates match window coordinates */
+	Duple origin (0, 0);
+	origin = item_to_window (origin);
+	context->translate (origin.x, origin.y);
+
+	Cairo::RefPtr<Cairo::Region> r1 = Cairo::Region::create (area_r);
+	r1->intersect (background);
+
+	if (!r1->empty()) {
+		Cairo::RectangleInt i (r1->get_extents ());
+		context->rectangle (i.x, i.y, i.width, i.height);
+		context->set_source (bgpattern);
+		context->fill ();
+	}
+
+	Cairo::RefPtr<Cairo::Region> r2 = Cairo::Region::create (area_r);
+	r2->intersect (pixrect);
+
+	if (!r2->empty()) {
+		// draw the part of the meter image that we need. the area we draw is bounded "in reverse" (top->bottom)
+		Cairo::RectangleInt i (r2->get_extents ());
+		context->rectangle (i.x, i.y, i.width, i.height);
+		context->set_source (fgpattern);
+		context->fill ();
+	}
+
+	// draw peak bar
+
+	if (hold_state) {
+		last_peak_rect.x = 1;
+		last_peak_rect.width = pixwidth;
+		last_peak_rect.y = max(1, 1 + pixheight - (int) floor (pixheight * current_peak));
+		if (_styleflags & 2) { // LED stripes
+			last_peak_rect.y = max(0, (last_peak_rect.y & (~1)));
+		}
+		if (bright_hold || (_styleflags & 2)) {
+			last_peak_rect.height = max(0, min(3, pixheight - last_peak_rect.y - 1 ));
+		} else {
+			last_peak_rect.height = max(0, min(2, pixheight - last_peak_rect.y - 1 ));
+		}
+
+		context->set_source (fgpattern);
+		context->rectangle (last_peak_rect.x, last_peak_rect.y, last_peak_rect.width, last_peak_rect.height);
+
+		if (bright_hold && !no_rgba_overlay) {
+			context->fill_preserve ();
+			context->set_source_rgba (1.0, 1.0, 1.0, 0.3);
+		}
+		context->fill ();
+
+	} else {
+		last_peak_rect.width = 0;
+		last_peak_rect.height = 0;
+	}
+
+	context->translate (-origin.x, -origin.y);
+}
+
+void
+Meter::horizontal_expose (ArdourCanvas::Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
+{
+	gint right_of_meter;
+	Cairo::RectangleInt background;
+	Cairo::RectangleInt area_r;
+
+	/* convert expose area back to item coordinate space */
+	Rect area2 = window_to_item (area);
+
+
+	/* create a Cairo object so that we can use intersect and Region */
+	area_r.x = area2.x0;
+	area_r.y = area2.y0;
+	area_r.width = area2.width();
+	area_r.height = area2.height();
+
+	/* draw the edge (rounded corners) */
+	context->set_source_rgb (0, 0, 0); // black
+	rounded_rectangle (context, 0, 0, pixwidth + 2, pixheight + 2, 2);
+	context->stroke ();
+
+	/* horizontal meter extends from left to right. Compute the right edge */
+	right_of_meter = (gint) floor (pixwidth * current_level);
+
+	/* reset the width the rect that needs to show the pattern of the meter */
+	pixrect.width = right_of_meter;
+
+	/* compute a rect for the part of the meter that is all background */
+	background.x = 1 + right_of_meter;
+	background.y = 1;
+	background.width = pixwidth - right_of_meter;
+	background.height = pixheight;
+
+	/* translate so that item coordinates match window coordinates */
+	Duple origin (0, 0);
+	origin = item_to_window (origin);
+	context->translate (origin.x, origin.y);
+
+	Cairo::RefPtr<Cairo::Region> r;
+
+	r = Cairo::Region::create (area_r);
+	r->intersect (background);
+
+	if (!r->empty()) {
+		/* draw the background part */
+		Cairo::RectangleInt i (r->get_extents ());
+		context->set_source (bgpattern);
+		context->rectangle (i.x, i.y, i.width, i.height);
+		context->fill ();
+
+	}
+
+	r  = Cairo::Region::create (area_r);
+	r->intersect (pixrect);
+
+	if (!r->empty()) {
+		// draw the part of the meter image that we need.
+		Cairo::RectangleInt i (r->get_extents ());
+		Duple d (i.x, i.y);
+		context->set_source (fgpattern);
+		context->rectangle (i.x, i.y, i.width, i.height);
+		context->fill ();
+	}
+
+	// draw peak bar
+
+	if (hold_state) {
+		last_peak_rect.y = 1;
+		last_peak_rect.height = pixheight;
+		const int xpos = floor (pixwidth * current_peak);
+		if (bright_hold || (_styleflags & 2)) {
+			last_peak_rect.width = min(3, xpos );
+		} else {
+			last_peak_rect.width = min(2, xpos );
+		}
+		last_peak_rect.x = 1 + max(0, xpos - last_peak_rect.width);
+
+		context->set_source (fgpattern);
+		context->rectangle (last_peak_rect.x, last_peak_rect.y, last_peak_rect.width, last_peak_rect.height);
+
+		if (bright_hold && !no_rgba_overlay) {
+			context->fill_preserve ();
+			context->set_source_rgba (1.0, 1.0, 1.0, 0.3);
+		}
+		context->fill ();
+
+	} else {
+		last_peak_rect.width = 0;
+		last_peak_rect.height = 0;
+	}
+
+	context->translate (-origin.x, -origin.y);
+}
+
+void
+Meter::set (float lvl, float peak)
+{
+	float old_level = current_level;
+	float old_peak = current_peak;
+
+	if (pixwidth <= 0 || pixheight <=0) return;
+
+	if (peak == -1) {
+		if (lvl >= current_peak) {
+			current_peak = lvl;
+			hold_state = hold_cnt;
+		}
+
+		if (hold_state > 0) {
+			if (--hold_state == 0) {
+				current_peak = lvl;
+			}
+		}
+		bright_hold = false;
+	} else {
+		current_peak = peak;
+		hold_state = 1;
+		bright_hold = true;
+	}
+
+	current_level = lvl;
+
+	const float pixscale = (orientation == Vertical) ? pixheight : pixwidth;
+#define PIX(X) floor(pixscale * (X))
+	if (PIX(current_level) == PIX(old_level) && PIX(current_peak) == PIX(old_peak) && (hold_state == 0 || peak != -1)) {
+		return;
+	}
+
+	if (orientation == Vertical) {
+		//queue_vertical_redraw (old_level);
+	} else {
+		//queue_horizontal_redraw (old_level);
+	}
+
+	redraw ();
+}
+
+void
+Meter::queue_vertical_redraw (float old_level)
+{
+	Cairo::RectangleInt rect;
+
+	gint new_top = (gint) floor (pixheight * current_level);
+
+	rect.x = 1;
+	rect.width = pixwidth;
+	rect.height = new_top;
+	rect.y = 1 + pixheight - new_top;
+
+	if (current_level > old_level) {
+		/* colored/pixbuf got larger, just draw the new section */
+		/* rect.y stays where it is because of X coordinates */
+		/* height of invalidated area is between new.y (smaller) and old.y
+		   (larger).
+		   X coordinates just make my brain hurt.
+		*/
+		rect.height = pixrect.y - rect.y;
+	} else {
+		/* it got smaller, compute the difference */
+		/* rect.y becomes old.y (the smaller value) */
+		rect.y = pixrect.y;
+		/* rect.height is the old.y (smaller) minus the new.y (larger)
+		*/
+		rect.height = pixrect.height - rect.height;
+	}
+
+	Cairo::RefPtr<Cairo::Region> region;
+	bool queue = false;
+
+	if (rect.height != 0) {
+
+		/* ok, first region to draw ... */
+
+		region = Cairo::Region::create (rect);
+		queue = true;
+	}
+
+	/* redraw the last place where the last peak hold bar was;
+	   the next expose will draw the new one whether its part of
+	   expose region or not.
+	*/
+
+	if (last_peak_rect.width * last_peak_rect.height != 0) {
+		if (!queue) {
+			region = Cairo::Region::create ();
+			queue = true;
+		}
+		region->do_union (last_peak_rect);
+	}
+
+	if (hold_state && current_peak > 0) {
+		if (!queue) {
+			region = Cairo::Region::create ();
+			queue = true;
+		}
+		rect.x = 1;
+		rect.y = max(1, 1 + pixheight - (int) floor (pixheight * current_peak));
+		if (_styleflags & 2) { // LED stripes
+			rect.y = max(0, (rect.y & (~1)));
+		}
+		if (bright_hold || (_styleflags & 2)) {
+			rect.height = max(0, min(3, pixheight - last_peak_rect.y -1 ));
+		} else {
+			rect.height = max(0, min(2, pixheight - last_peak_rect.y -1 ));
+		}
+		rect.width = pixwidth;
+		region->do_union (rect);
+	}
+
+	if (queue) {
+		if (visible() && _bounding_box && _canvas) {
+			Cairo::RectangleInt iri = region->get_extents();
+			Rect ir (iri.x, iri.y, iri.x + iri.width, iri.y + iri.height);
+			_canvas->request_redraw (item_to_window (ir));
+		}
+	}
+}
+
+void
+Meter::queue_horizontal_redraw (float old_level)
+{
+	Cairo::RectangleInt rect;
+
+	gint new_right = (gint) floor (pixwidth * current_level);
+
+	rect.height = pixheight;
+	rect.y = 1;
+
+	if (current_level > old_level) {
+		rect.x = 1 + pixrect.width;
+		/* colored/pixbuf got larger, just draw the new section */
+		rect.width = new_right - pixrect.width;
+	} else {
+		/* it got smaller, compute the difference */
+		rect.x = 1 + new_right;
+		/* rect.height is the old.x (smaller) minus the new.x (larger) */
+		rect.width = pixrect.width - new_right;
+	}
+
+	Cairo::RefPtr<Cairo::Region> region;
+	bool queue = false;
+
+	if (rect.height != 0) {
+
+		/* ok, first region to draw ... */
+
+		region = Cairo::Region::create (rect);
+		queue = true;
+	}
+
+	/* redraw the last place where the last peak hold bar was;
+	   the next expose will draw the new one whether its part of
+	   expose region or not.
+	*/
+
+	if (last_peak_rect.width * last_peak_rect.height != 0) {
+		if (!queue) {
+			region = Cairo::Region::create ();
+			queue = true;
+		}
+		region->do_union (last_peak_rect);
+	}
+
+	if (hold_state && current_peak > 0) {
+		if (!queue) {
+			region = Cairo::Region::create ();
+			queue = true;
+		}
+		rect.y = 1;
+		rect.height = pixheight;
+		const int xpos = floor (pixwidth * current_peak);
+		if (bright_hold || (_styleflags & 2)) {
+			rect.width = min(3, xpos);
+		} else {
+			rect.width = min(2, xpos);
+		}
+		rect.x = 1 + max(0, xpos - rect.width);
+		region->do_union (rect);
+	}
+
+	if (queue) {
+		if (visible() && _bounding_box && _canvas) {
+			Cairo::RectangleInt iri = region->get_extents();
+			Rect ir (iri.x, iri.y, iri.x + iri.width, iri.y + iri.height);
+			_canvas->request_redraw (item_to_window (ir));
+		}
+	}
+}
+
+void
+Meter::set_highlight (bool onoff)
+{
+	if (highlight == onoff) {
+		return;
+	}
+	highlight = onoff;
+	if (orientation == Vertical) {
+		bgpattern = vertical_background (pixwidth + 2, pixheight + 2, highlight ? _bgh : _bgc, highlight);
+	} else {
+		bgpattern = horizontal_background (pixwidth + 2, pixheight + 2, highlight ? _bgh : _bgc, highlight);
+	}
+	redraw ();
+}
+
+void
+Meter::clear ()
+{
+	current_level = 0;
+	current_peak = 0;
+	hold_state = 0;
+	redraw ();
+}
diff --git a/libs/canvas/wscript b/libs/canvas/wscript
index 0038b783c6..fa6dabb080 100644
--- a/libs/canvas/wscript
+++ b/libs/canvas/wscript
@@ -46,6 +46,7 @@ canvas_sources = [
         'line.cc',
         'line_set.cc',
         'lookup_table.cc',
+        'meter.cc',
         'outline.cc',
         'pixbuf.cc',
         'poly_item.cc',