livetrax/libs/canvas/meter.cc

/*
    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;

	/* convert expose area back to item coordinate space */
	Rect area2 = window_to_item (area);

	area_r.x = area2.x0;
	area_r.y = area2.y0;
	area_r.width = area2.width();
	area_r.height = area2.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->set_source (bgpattern);
		context->rectangle (i.x, i.y, i.width, i.height);
		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->set_source (fgpattern);
		context->rectangle (i.x, i.y, i.width, i.height);
		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);
	}
}

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 ();
}