Graph rate of temperature change

config/Windows/productionroaster.xml

 		var temperatureDisplays = new Array();
 		var columnNames = new Array();
 		var modbusdevices = new Array();
+		var rateCalculators = new Array();
+		var rateadapters = new Array();
+		var rateoffsets = new Array();
+		var ratezeros = new Array();
 		var indicatorPanel = findChildObject(this, 'indicators');
 		var annotationPanel = findChildObject(this, 'controlpanel');
 		var log = findChildObject(this, 'log');
 							indicatorPanel.addWidget(decorator);
 							rate.measurement.connect(indicator.setValue);
 							temperatureDisplays.push(indicator);
+							rateCalculators.push(rate);
 						}
 					}
 				}
 			emitter.measurement.connect(log.newMeasurement);
 			emitter.measurement.connect(graph.newMeasurement);
 		}
+		for(var i = channels.length; i < channels.length + rateCalculators.length; i++) {
+			var offset - new MeasurementTimeOffset(epoch);
+			rateoffsets.push(offset);
+			rateCalculators[i - channels.length].measurement.connect(offset.newMeasurement);
+			var adapter = new MeasurementAdapter(i + 1);
+			rateadapters.push(adapter);
+			offset.measurement.connect(adapter.newMeasurement);
+			var emitter = new ZeroEmitter(i + 1);
+			ratezeros.push(emitter);
+			rateCalculators[i - channels.length].measurement.connect(emitter.newMeasurement);
+			emitter.measurement.connect(graph.newMeasurement);
+		}
         start.clicked.connect(function() {
 			start.enabled = false;
 			hasTranslated = false;
 				adapters[i].measurement.connect(log.newMeasurement);
 				adapters[i].measurement.connect(graph.newMeasurement);
 			}
+			for(var i = 0; i < rateadapters.length; i++)
+			{
+				rateoffsets[i].setZeroTime(epoch);
+				ratezeros[i].emitZero();
+				rateadapters[i].measurement.connect(graph.newMeasurement);
+			}
 			timer.startTimer();
             if(typeof(currentBatchInfo) == 'undefined') { } else {
                 query = new QSqlQuery();
 				adapters[i].measurement.disconnect(log.newMeasurement);
 				adapters[i].measurement.disconnect(graph.newMeasurement);
 			}
+			for(var i = 0; i < rateadapters.length; i++)
+			{
+				rateadapters[i].measurement.disconnect(graph.newMeasurement);
+			}
             if(typeof(currentBatchInfo) == 'undefined') { } else {
                 lc = Number(QSettings.value("liveColumn"));
                 var duration = log.lastTime(lc);
 				zeroemitters[i].setColumn(c + i + 1);
 				log.setHeaderData(c + i + 1, columnNames[i]);
 			}
+			for(var i = 0; i < rateadapters.length; i++)
+			{
+				rateadapters[i].setColumn(c + i + 1 + adapters.length);
+				ratezeros[i].setColumn(c + i + 1 + adapters.length);
+			}
 			log.setHeaderData(c + columnNames.length + 1, "Note");
             stop.setTemperatureColumn(c + 1);
 			stop.setAnnotationColumn(c + columnNames.length + 1);

src/graphsettings.w

+@* Graph widget configuration.
+
+\noindent There are many features of the graph in Typica which ought to be
+configurable. Most of these cannot be configured until changes are made to the
+graph widget. The original motivation for the class comes from a need to
+configure secondary axes.
+
+@<Class declarations@>=
+class GraphSettingsWidget : public QWidget
+{
+	Q_OBJECT
+	public:
+		GraphSettingsWidget();
+};
+
+@ At present there are three types of data that the graph might present. This
+will likely be expanded as support for additional unit types are added.
+
+Different measurement categories are presently organized into different tabs.
+This will potentially need to change later as more features are added and the
+tab set becomes excessively large but for now this is the best that I can
+think of. If anybody with UI design experience would like to propose something
+better I would be glad to consider it.
+
+@<GraphSettingsWidget implementation@>=
+GraphSettingsWidget::GraphSettingsWidget() : QWidget(NULL)
+{
+	QTabWidget *graphCategories = new QTabWidget;
+	GraphSettingsRelativeTab *relative = new GraphSettingsRelativeTab;
+	graphCategories->addTab(relative, tr("Relative Temperatures"));
+	QVBoxLayout *layout = new QVBoxLayout;
+	layout->addWidget(graphCategories);
+	setLayout(layout);
+}
+
+@ Relative temperature measurements are different from the absolute temperature
+measurements that fall on the primary axis in that it is likely that negative
+values will be presented. These may be important and should not be hidden off
+the bottom of the graph, but the most important values will be in a relatively
+small range of positive values. The particulars will depend on the settings
+used to construct the relative values and the style of coffee roasting. It is
+also possible to disable the graphing of relative temperature measurements.
+
+@<Class declarations@>=
+class GraphSettingsRelativeTab : public QWidget
+{
+	Q_OBJECT
+	public:
+		GraphSettingsRelativeTab();
+	public slots:
+		void updateEnableSetting(bool enable);
+		void updateColorSetting(const QString &color);
+		void updateAxisSetting(const QString &gridList);
+		void updateUnit(int unit);
+		void showColorPicker();
+	private:
+		QLineEdit *colorEdit;
+};
+
+@ The constructor sets up the interface and restores any previous values from
+settings.
+
+@<GraphSettingsWidget implementation@>=
+GraphSettingsRelativeTab::GraphSettingsRelativeTab() : QWidget(NULL),
+	colorEdit(new QLineEdit)
+{
+	QSettings settings;
+	QVBoxLayout *layout = new QVBoxLayout;
+	QCheckBox *enable = new QCheckBox(tr("Graph relative temperatures"));
+	enable->setChecked(settings.value("settings/graph/relative/enable", true).toBool());
+	updateEnableSetting(enable->isChecked());
+	connect(enable, SIGNAL(toggled(bool)), this, SLOT(updateEnableSetting(bool)));
+	layout->addWidget(enable);
+	QHBoxLayout *colorLayout = new QHBoxLayout;
+	QLabel *colorLabel = new QLabel(tr("Axis color:"));
+	colorEdit->setText(settings.value("settings/graph/relative/color", "#000000").toString());
+	updateColorSetting(colorEdit->text());
+	connect(colorEdit, SIGNAL(textChanged(QString)), this, SLOT(updateColorSetting(QString)));
+	QToolButton *colorPickerButton = new QToolButton();
+	colorPickerButton->setIcon(QIcon::fromTheme("applications-graphics"));
+	connect(colorPickerButton, SIGNAL(clicked()), this, SLOT(showColorPicker()));
+	colorLayout->addWidget(colorLabel);
+	colorLayout->addWidget(colorEdit);
+	colorLayout->addWidget(colorPickerButton);
+	colorLayout->addStretch();
+	layout->addLayout(colorLayout);
+	QHBoxLayout *unitLayout = new QHBoxLayout;
+	QLabel *unitLabel = new QLabel(tr("Unit"));
+	QComboBox *unitSelector = new QComboBox;
+	unitSelector->addItem(tr("Fahrenheit"));
+	unitSelector->addItem(tr("Celsius"));
+	unitSelector->setCurrentIndex(settings.value("settings/graph/relative/unit", 0).toInt());
+	updateUnit(unitSelector->currentIndex());
+	connect(unitSelector, SIGNAL(currentIndexChanged(int)), this, SLOT(updateUnit(int)));
+	unitLayout->addWidget(unitLabel);
+	unitLayout->addWidget(unitSelector);
+	unitLayout->addStretch();
+	layout->addLayout(unitLayout);
+	QHBoxLayout *axisLayout = new QHBoxLayout;
+	QLabel *axisLabel = new QLabel(tr("Grid line positions (comma separated):"));
+	QLineEdit *axisEdit = new QLineEdit;
+	axisEdit->setText(settings.value("settings/graph/relative/grid", "-300, -100, -10, 0, 10, 30, 50").toString());
+	updateAxisSetting(axisEdit->text());
+	connect(axisEdit, SIGNAL(textChanged(QString)), this, SLOT(updateAxisSetting(QString)));
+	axisLayout->addWidget(axisLabel);
+	axisLayout->addWidget(axisEdit);
+	layout->addLayout(axisLayout);
+	layout->addStretch();
+	setLayout(layout);
+}
+
+@ A set of methods updates the settings as they are adjusted.
+
+@<GraphSettingsWidget implementation@>=
+void GraphSettingsRelativeTab::updateEnableSetting(bool enabled)
+{
+	QSettings settings;
+	settings.setValue("settings/graph/relative/enable", enabled);
+}
+
+void GraphSettingsRelativeTab::updateColorSetting(const QString &color)
+{
+	QSettings settings;
+	settings.setValue("settings/graph/relative/color", color);
+}
+
+void GraphSettingsRelativeTab::updateAxisSetting(const QString &gridList)
+{
+	QSettings settings;
+	QString settingValue;
+	QStringList points = gridList.split(QRegExp("[\\s,]+"), QString::SkipEmptyParts);
+	QStringList numbers;
+	foreach(QString text, points)
+	{
+		bool okay = false;
+		text.toDouble(&okay);
+		if(okay)
+		{
+			numbers.append(text);
+		}
+	}
+	numbers.removeDuplicates();
+	settings.setValue("settings/graph/relative/grid", numbers.join(","));
+}
+
+void GraphSettingsRelativeTab::updateUnit(int unit)
+{
+	QSettings settings;
+	settings.setValue("settings/graph/relative/unit", unit);
+}
+
+@ When selecting a color, it is possible to either type the color into the line
+edit directly or use a color picker to select the color graphically. A tool
+button displays a color picker and pushes the selected color into the line edit
+which in turn updates the setting.
+
+@<GraphSettingsWidget implementation@>=
+void GraphSettingsRelativeTab::showColorPicker()
+{
+	QColor color = QColorDialog::getColor(QColor(colorEdit->text()), this);
+	colorEdit->setText(color.name());
+}

src/rate.w

 instead of on the data we wish we had should result in better stability in the
 derived series.
 
+The measurement will carry the fact that it is a relative measurement.
+
 @<Calculate rate of change@>=
 double mdiff = cache.back().temperature() - cache.front().temperature();
 double tdiff = cache.front().time().msecsTo(cache.back().time()) / 1000.0;
 double dps = mdiff / tdiff;
 double scale = dps * st;
-emit measurement(Measurement(scale, cache.back().time(), cache.back().scale()));
+Measurement value(scale, cache.back().time(), cache.back().scale());
+value.insert("relative", true);
+emit measurement(value);
 
 @ The rest of the class implementation is trivial.
 

src/resources.qrc

         <file>resources/fonts/texgyrepagella-bolditalic.otf</file>
         <file>resources/fonts/texgyrepagella-italic.otf</file>
         <file>resources/fonts/texgyrepagella-regular.otf</file>
+        <file>resources/icons/tango/16x16/categories/applications-graphics.png</file>
+        <file>resources/icons/tango/22x22/categories/applications-graphics.png</file>
+        <file>resources/icons/tango/32x32/categories/applications-graphics.png</file>
+        <file>resources/icons/tango/scalable/categories/applications-graphics.svg</file>
     </qresource>
 </RCC>

src/settings.w

 	QTabWidget *settingsTab = new QTabWidget;
 	DeviceConfigurationWindow *deviceSettings = new DeviceConfigurationWindow;
 	settingsTab->addTab(deviceSettings, tr("Roasters"));
+	GraphSettingsWidget *graphSettings = new GraphSettingsWidget;
+	settingsTab->addTab(graphSettings, tr("Graph"));
 	setCentralWidget(settingsTab);
 }
 
 @<Set up the scripting engine@>=
 constructor = engine->newFunction(constructSettingsWindow);
 value = engine->newQMetaObject(&DeviceConfigurationWindow::staticMetaObject, constructor);
-engine->globalObject().setProperty("SettingsWindow", value);
+engine->globalObject().setProperty("SettingsWindow", value);
+
+@i graphsettings.w