Plot 2d-image like data as heatmap

.gitignore

@@ -5,3 +5,4 @@ NixView.pro.user.18
 NixView.pro.user.3.2-pre1
 NixView.pro.user.5e84e8a
 *~
+.idea/

plotter/imageplotter.cpp

@@ -0,0 +1,149 @@
+#include "imageplotter.h"
+#include "ui_imageplotter.h"
+#include <QMenu>
+
+
+ImagePlotter::ImagePlotter(QWidget *parent) :
+        QWidget(parent), ui(new Ui::ImagePlotter), cmap() {
+    ui->setupUi(this);
+
+}
+
+ImagePlotter::~ImagePlotter() {
+    delete ui;
+}
+
+QCustomPlot *ImagePlotter::get_plot() {
+    return ui->plot;
+}
+
+struct DimInfo {
+    bool valid;
+    QString unit;
+    QString label;
+
+    QVector<double> ticks;
+    QCPRange range;
+};
+
+static DimInfo get_dim_info(const nix::DataArray &array, nix::ndsize_t dim_index) {
+    nix::Dimension d = array.getDimension(dim_index);
+    DimInfo info;
+    info.valid = false;
+
+    nix::NDSize shape = array.dataExtent();
+
+    if (d.dimensionType() == nix::DimensionType::Sample) {
+        nix::SampledDimension dim = d.asSampledDimension();
+        info.valid = true;
+        info.label = dim.label().get_value_or("").c_str();
+        info.unit = dim.unit().get_value_or("").c_str();
+        double si = dim.samplingInterval();
+        //todo: safe cast?
+        info.ticks.resize(static_cast<int>(shape[dim_index-1]));
+
+        double offset = dim.offset().get_value_or(0);
+        const int size = info.ticks.size();
+        for (int i = 0; i < size; i++) {
+            info.ticks[i] = offset + i * si;
+        }
+
+    } else if (d.dimensionType() == nix::DimensionType::Range) {
+        nix::RangeDimension dim = d.asRangeDimension();
+        info.valid = true;
+        info.label = dim.label().get_value_or("").c_str();
+        info.unit = dim.unit().get_value_or("").c_str();
+
+        info.ticks = QVector<double>::fromStdVector(dim.ticks());
+    }
+
+    const int size = info.ticks.size();
+    if (size > 0) {
+        info.range.lower = info.ticks[0];
+        info.range.upper = info.ticks[size - 1];
+    }
+
+    return info;
+}
+
+void ImagePlotter::draw(const nix::DataArray &array) {
+    if (array.dimensionCount() != 2) {
+        std::cerr << "ImagePlotter::draw can only draw 2D!" << std::endl;
+        return;
+    }
+
+    DimInfo yi = get_dim_info(array, 1); // rows == y
+    DimInfo xi = get_dim_info(array, 2); // cols == x
+
+    if (!(yi.valid && xi.valid)) {
+        std::cerr << "ImagePlotter::invalid dimensions found in array!" << std::endl;
+        return;
+    }
+
+    QCustomPlot *plot = get_plot();
+
+    plot->setInteractions(QCP::iRangeDrag|QCP::iRangeZoom); // this will also allow rescaling the color scale by dragging/zooming
+    plot->axisRect()->setupFullAxesBox(true);
+    plot->xAxis->setLabel(xi.label + " " + xi.unit);
+    plot->yAxis->setLabel(yi.label + " " + yi.unit);
+
+    QCPColorMap *colorMap = new QCPColorMap(plot->xAxis, plot->yAxis);
+    plot->addPlottable(colorMap);
+
+    int nx = xi.ticks.size();
+    int ny = yi.ticks.size();
+
+    colorMap->data()->setSize(nx, ny);
+    colorMap->data()->setRange(xi.range, yi.range);
+    colorMap->setInterpolate(false);
+
+    for (int xidx = 0; xidx < nx; xidx++) {
+        std::vector<double> data(static_cast<size_t>(nx));
+        //lets fetch a whole row (should be fast if data is
+        //  row-major, like hdf5)
+        //ny,   the number of rows in data-array
+        //xidx, the current column the fetch
+        // -> fetch all rows at column [xidx]
+        //                   count    offset
+        array.getData(data, {ny, 1}, {0, xidx});
+        for (int yidx = 0; yidx < ny; yidx++) {
+            // data[ydix], the data point of the row[yidx], col[xidx]
+            colorMap->data()->setCell(xidx, yidx, data[yidx]);
+        }
+    }
+
+    QCPColorScale *colorScale = new QCPColorScale(plot);
+    plot->plotLayout()->addElement(0, 1, colorScale);
+    colorScale->setType(QCPAxis::atRight);
+    colorMap->setColorScale(colorScale);
+    if (array.label()) {
+        colorScale->axis()->setLabel(array.label().get().c_str());
+    }
+    colorMap->setGradient(QCPColorGradient::gpSpectrum);
+    colorMap->rescaleDataRange();
+
+    QCPMarginGroup *marginGroup = new QCPMarginGroup(plot);
+    plot->axisRect()->setMarginGroup(QCP::msBottom|QCP::msTop, marginGroup);
+    colorScale->setMarginGroup(QCP::msBottom|QCP::msTop, marginGroup);
+
+    plot->rescaleAxes();
+}
+
+
+void ImagePlotter::add_events(const QVector<double> &x_data, const QVector<double> &y_data, const QString &name,
+                              bool y_scale) {
+
+}
+
+void ImagePlotter::add_segments(const QVector<double> &positions, const QVector<double> &extents, const QString &name) {
+
+}
+
+void ImagePlotter::set_label(const std::string &label) {
+
+}
+
+PlotterType ImagePlotter::plotter_type() const {
+    return PlotterType::Image;
+}
+

plotter/imageplotter.h

@@ -0,0 +1,41 @@
+#ifndef IMAGEPLOTTER_H
+#define IMAGEPLOTTER_H
+
+#include <QWidget>
+#include "plotter.h"
+#include <nix.hpp>
+#include "colormap.hpp"
+
+namespace Ui {
+    class ImagePlotter;
+}
+
+class ImagePlotter : public QWidget, public Plotter {
+Q_OBJECT
+public:
+
+    virtual void add_events(const QVector<double> &x_data, const QVector<double> &y_data, const QString &name,
+                            bool y_scale) override;
+
+    virtual void add_segments(const QVector<double> &positions, const QVector<double> &extents,
+                              const QString &name) override;
+
+    virtual void set_label(const std::string &label) override;
+
+    virtual PlotterType plotter_type() const override;
+
+
+public:
+    explicit ImagePlotter(QWidget *parent = 0);
+    ~ImagePlotter();
+
+    void draw(const nix::DataArray &array);
+
+private:
+    Ui::ImagePlotter *ui;
+    ColorMap cmap;
+
+    QCustomPlot* get_plot();
+};
+
+#endif //IMAGEPLOTTER_H

plotter/imageplotter.ui

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>ImagePlotter</class>
+ <widget class="QWidget" name="ImagePlotter">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Ignored" vsizetype="Ignored">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <property name="autoFillBackground">
+   <bool>false</bool>
+  </property>
+  <property name="styleSheet">
+   <string notr="true"/>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="spacing">
+    <number>3</number>
+   </property>
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
+    <number>0</number>
+   </property>
+   <item>
+    <widget class="QCustomPlot" name="plot" native="true">
+     <property name="sizePolicy">
+      <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
+       <horstretch>0</horstretch>
+       <verstretch>0</verstretch>
+      </sizepolicy>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QCustomPlot</class>
+   <extends>QWidget</extends>
+   <header>qcustomplot.h</header>
+   <container>1</container>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>

plotter/plotter.h

@@ -234,8 +234,7 @@ class Plotter {
                 if (array.getDimension(2).dimensionType() == nix::DimensionType::Set) {
                     return PlotterType::Line;
                 } else {
-                    // handle 2D image/heatmap plotting not supported, yet TODO
-                    return PlotterType::Unsupported;
+                    return PlotterType::Image;
                 }
             } else {
                 if (array.getDimension(2).dimensionType() == nix::DimensionType::Sample ||

plotwidget.cpp

@@ -2,6 +2,7 @@
 #include "ui_plotwidget.h"
 #include "plotter/lineplotter.h"
 #include "plotter/categoryplotter.h"
+#include "plotter/imageplotter.h"
 #include "common/Common.hpp"
 
 PlotWidget::PlotWidget(QWidget *parent) :
@@ -59,19 +60,28 @@ void PlotWidget::delete_widgets_from_layout() {
 
 
 Plotter* PlotWidget::process(const nix::DataArray &array) {
-    if (Plotter::suggested_plotter(array) == PlotterType::Line) {
+    PlotterType suggestion = Plotter::suggested_plotter(array);
+
+    if (suggestion == PlotterType::Line) {
         delete_widgets_from_layout();
         LinePlotter *lp = new LinePlotter();
         ui->scrollAreaWidgetContents->layout()->addWidget(lp);
         lp->draw(array);
         return lp;
-    } else if (Plotter::suggested_plotter(array) == PlotterType::Category) {
+    } else if (suggestion == PlotterType::Category) {
         delete_widgets_from_layout();
         CategoryPlotter *cp = new CategoryPlotter();
         ui->scrollAreaWidgetContents->layout()->addWidget(cp);
         cp->draw(array);
         return cp;
+    } else if (suggestion == PlotterType::Image) {
+        delete_widgets_from_layout();
+        ImagePlotter *ip = new ImagePlotter();
+        ui->scrollAreaWidgetContents->layout()->addWidget(ip);
+        ip->draw(array);
+        return ip;
     }
+
     return nullptr;
 }