Added: Analysis panel which shows the calculated frequency response of the filters for the selected device and channel.

Improved: GUIs of GraphicEQ and Copy command can now be resized
Improved: GraphicEQ GUI can now be zoomed separately in X and Y direction using mouse wheel on rulers. Also now shows values at mouse position.
Fixed: Original APO was not released when E-APO was shutting down, leading to a memory leak.

Editor/AnalysisPlotView.cpp

@@ -0,0 +1,80 @@
+/*
+	This file is part of EqualizerAPO, a system-wide equalizer.
+	Copyright (C) 2015  Jonas Thedering
+
+	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 <algorithm>
+
+#include "helpers/GainIterator.h"
+#include "AnalysisPlotScene.h"
+#include "AnalysisPlotView.h"
+
+using namespace std;
+
+AnalysisPlotView::AnalysisPlotView(QWidget* parent)
+	: FrequencyPlotView(parent)
+{
+}
+
+void AnalysisPlotView::drawBackground(QPainter* painter, const QRectF& rect)
+{
+	FrequencyPlotView::drawBackground(painter, rect);
+
+	painter->setRenderHint(QPainter::Antialiasing, true);
+	AnalysisPlotScene* s = qobject_cast<AnalysisPlotScene*>(scene());
+	std::vector<FilterNode>& nodes = s->getNodes();
+	GainIterator gainIterator(nodes);
+	QPainterPath path;
+	bool first = true;
+	double lastDb = -1000;
+	for(int x = rect.left() - 1; x <= rect.right() + 1; x++)
+	{
+		double hz = s->xToHz(x);
+		double db = gainIterator.gainAt(hz);
+		double y = s->dbToY(db);
+		if(db == lastDb)
+			y = floor(y) + 0.5;
+		lastDb = db;
+		if(first)
+		{
+			path.moveTo(x, y);
+			first = false;
+		}
+		else
+		{
+			path.lineTo(x, y);
+		}
+	}
+
+	path.lineTo(rect.right() + 1, rect.bottom() + 1);
+	path.lineTo(rect.left() - 1, rect.bottom() + 1);
+
+	double thresholdY = s->dbToY(0);
+	if(rect.top() < thresholdY)
+	{
+		QPainterPath rectPath;
+		rectPath.addRect(rect.left(), rect.top(), rect.width(), min(thresholdY - rect.top(), rect.height()));
+		QPainterPath clippingPath = path.intersected(rectPath);
+		painter->setPen(Qt::NoPen);
+		painter->setBrush(Qt::red);
+		painter->drawPath(clippingPath);
+		painter->setBrush(Qt::NoBrush);
+	}
+
+	painter->setPen(Qt::black);
+	painter->drawPath(path);
+}