Display annotation comments as tooltips

When the mouse is moved over a SigMF annotation rectangle on the
waterfall, a tooltip showing the annotation comment is displayed
(if the annotation has a comment field).

This feature can be enabled/disabled with a checkbox, in the same
way as annotations. If annotations are disabled, the annotation comments
checkbox is grayed out and the tooltips are not shown.

Signed-off-by: Daniel Estévez <daniel@destevez.net>

Author: daniestevez

src/inputsource.cpp

@@ -340,7 +340,9 @@ void InputSource::readMetaData(const QString &filename)
 
                 auto label = sigmf_annotation["core:label"].toString();
 
-                annotationList.emplace_back(sampleRange, frequencyRange, label);
+                auto comment = sigmf_annotation["core:comment"].toString();
+
+                annotationList.emplace_back(sampleRange, frequencyRange, label, comment);
             }
         }
     }

src/mainwindow.cpp

@@ -51,6 +51,8 @@ MainWindow::MainWindow()
     connect(dock->cursorsCheckBox, &QCheckBox::stateChanged, plots, &PlotView::enableCursors);
     connect(dock->scalesCheckBox, &QCheckBox::stateChanged, plots, &PlotView::enableScales);
     connect(dock->annosCheckBox, &QCheckBox::stateChanged, plots, &PlotView::enableAnnotations);
+    connect(dock->annosCheckBox, &QCheckBox::stateChanged, dock, &SpectrogramControls::enableAnnotations);
+    connect(dock->commentsCheckBox, &QCheckBox::stateChanged, plots, &PlotView::enableAnnotationCommentsTooltips);
     connect(dock->cursorSymbolsSpinBox, static_cast<void (QSpinBox::*)(int)>(&QSpinBox::valueChanged), plots, &PlotView::setCursorSegments);
 
     // Connect dock outputs

src/plotview.cpp

@@ -32,6 +32,7 @@
 #include <QRadioButton>
 #include <QScrollBar>
 #include <QSpinBox>
+#include <QToolTip>
 #include <QVBoxLayout>
 #include "plots.h"
 
@@ -50,6 +51,7 @@ PlotView::PlotView(InputSource *input) : cursors(this), viewRange({0, 0})
     enableScales(true);
 
     enableAnnotations(true);
+    enableAnnotationCommentsTooltips(true);
 
     addPlot(spectrogramPlot);
 
@@ -62,6 +64,39 @@ void PlotView::addPlot(Plot *plot)
     connect(plot, &Plot::repaint, this, &PlotView::repaint);
 }
 
+void PlotView::mouseMoveEvent(QMouseEvent *event)
+{
+    updateAnnotationTooltip(event);
+    QGraphicsView::mouseMoveEvent(event);
+}
+
+void PlotView::mouseReleaseEvent(QMouseEvent *event)
+{
+    // This is used to show the tooltip again on drag release if the mouse is
+    // hovering over an annotation.
+    updateAnnotationTooltip(event);
+    QGraphicsView::mouseReleaseEvent(event);
+}
+
+void PlotView::updateAnnotationTooltip(QMouseEvent *event)
+{
+    // If there are any mouse buttons pressed, we assume
+    // that the plot is being dragged and hide the tooltip.
+    bool isDrag = event->buttons() != Qt::NoButton;
+    if (!annotationCommentsEnabled
+        || !spectrogramPlot->isAnnotationsEnabled()
+        || isDrag)  {
+        QToolTip::hideText();
+    } else {
+        QString* comment = spectrogramPlot->mouseAnnotationComment(event);
+        if (comment != nullptr) {
+            QToolTip::showText(event->globalPos(), *comment);
+        } else {
+            QToolTip::hideText();
+        }
+    }
+}
+
 void PlotView::contextMenuEvent(QContextMenuEvent * event)
 {
     QMenu menu;
@@ -612,6 +647,13 @@ void PlotView::enableAnnotations(bool enabled)
     viewport()->update();
 }
 
+void PlotView::enableAnnotationCommentsTooltips(bool enabled)
+{
+    annotationCommentsEnabled = enabled;
+
+    viewport()->update();
+}
+
 int PlotView::sampleToColumn(size_t sample)
 {
     return sample / samplesPerColumn();

src/plotview.h

@@ -47,6 +47,7 @@ public slots:
     void enableCursors(bool enabled);
     void enableScales(bool enabled);
     void enableAnnotations(bool enabled);
+    void enableAnnotationCommentsTooltips(bool enabled);
     void invalidateEvent() override;
     void repaint();
     void setCursorSegments(int segments);
@@ -55,6 +56,8 @@ public slots:
     void setPowerMax(int power);
 
 protected:
+    void mouseMoveEvent(QMouseEvent *event) override;
+    void mouseReleaseEvent(QMouseEvent *event) override;
     void contextMenuEvent(QContextMenuEvent * event) override;
     void paintEvent(QPaintEvent *event) override;
     void resizeEvent(QResizeEvent * event) override;
@@ -80,6 +83,7 @@ public slots:
     double sampleRate = 0.0;
     bool timeScaleEnabled;
     int scrollZoomStepsAccumulated = 0;
+    bool annotationCommentsEnabled;
 
     void addPlot(Plot *plot);
     void emitTimeSelection();
@@ -91,6 +95,7 @@ public slots:
     void updateViewRange(bool reCenter);
     void updateView(bool reCenter = false, bool expanding = false);
     void paintTimeScale(QPainter &painter, QRect &rect, range_t<size_t> sampleRange);
+    void updateAnnotationTooltip(QMouseEvent *event);
 
     int sampleToColumn(size_t sample);
     size_t columnToSample(int col);

src/samplesource.h

@@ -33,9 +33,12 @@ class Annotation
     range_t<size_t> sampleRange;
     range_t<double> frequencyRange;
     QString label;
+    QString comment;
 
-    Annotation(range_t<size_t> sampleRange, range_t<double>frequencyRange, QString label)
-        : sampleRange(sampleRange), frequencyRange(frequencyRange), label(label) {}
+    Annotation(range_t<size_t> sampleRange, range_t<double>frequencyRange, QString label,
+               QString comment)
+      : sampleRange(sampleRange), frequencyRange(frequencyRange), label(label),
+        comment(comment) {}
 };
 
 template<typename T>

src/spectrogramcontrols.cpp

@@ -99,6 +99,8 @@ SpectrogramControls::SpectrogramControls(const QString & title, QWidget * parent
 
     annosCheckBox = new QCheckBox(widget);
     layout->addRow(new QLabel(tr("Display Annotations:")), annosCheckBox);
+    commentsCheckBox = new QCheckBox(widget);
+    layout->addRow(new QLabel(tr("Display annotation comments tooltips:")), commentsCheckBox);
 
     widget->setLayout(layout);
     setWidget(widget);
@@ -134,6 +136,7 @@ void SpectrogramControls::setDefaults()
     cursorSymbolsSpinBox->setValue(1);
 
     annosCheckBox->setCheckState(Qt::Checked);
+    commentsCheckBox->setCheckState(Qt::Checked);
 
     // Try to set the sample rate from the last-used value
     QSettings settings;
@@ -235,3 +238,8 @@ void SpectrogramControls::zoomOut()
 {
     zoomLevelSlider->setValue(zoomLevelSlider->value() - 1);
 }
+
+void SpectrogramControls::enableAnnotations(bool enabled) {
+    // disable annotation comments checkbox when annotations are disabled
+    commentsCheckBox->setEnabled(enabled);
+}

src/spectrogramcontrols.h

@@ -44,6 +44,7 @@ public slots:
     void timeSelectionChanged(float time);
     void zoomIn();
     void zoomOut();
+    void enableAnnotations(bool enabled);
 
 private slots:
     void fftSizeChanged(int value);
@@ -74,4 +75,5 @@ private slots:
     QLabel *symbolPeriodLabel;
     QCheckBox *scalesCheckBox;
     QCheckBox *annosCheckBox;
+    QCheckBox *commentsCheckBox;
 };

src/spectrogramplot.cpp

@@ -169,6 +169,8 @@ void SpectrogramPlot::paintAnnotations(QPainter &painter, QRect &rect, range_t<s
     painter.setPen(pen);
     QFontMetrics fm(painter.font());
 
+    visibleAnnotationLocations.clear();
+
     for (int i = 0; i < inputSource->annotationList.size(); i++) {
         Annotation a = inputSource->annotationList.at(i);
 
@@ -195,12 +197,27 @@ void SpectrogramPlot::paintAnnotations(QPainter &painter, QRect &rect, range_t<s
             // Draw the label 2 pixels above the box
             painter.drawText(x, y - 2, a.label);
             painter.drawRect(x, y, width, height);
+
+            visibleAnnotationLocations.emplace_back(a, x, y, width, height);
         }
     }
 
     painter.restore();
 }
 
+QString *SpectrogramPlot::mouseAnnotationComment(const QMouseEvent *event) {
+    auto pos = event->pos();
+    int mouse_x = pos.x();
+    int mouse_y = pos.y();
+
+    for (auto& a : visibleAnnotationLocations) {
+        if (a.isInside(mouse_x, mouse_y)) {
+            return &a.annotation.comment;
+        }
+    }
+    return nullptr;
+}
+
 void SpectrogramPlot::paintMid(QPainter &painter, QRect &rect, range_t<size_t> sampleRange)
 {
     if (!inputSource || inputSource->count() == 0)
@@ -395,6 +412,11 @@ void SpectrogramPlot::enableAnnotations(bool enabled)
    sigmfAnnotationsEnabled = enabled;
 }
 
+bool SpectrogramPlot::isAnnotationsEnabled(void)
+{
+    return sigmfAnnotationsEnabled;
+}
+
 bool SpectrogramPlot::tunerEnabled()
 {
     return (tunerTransform->subscriberCount() > 0);

src/spectrogramplot.h

@@ -20,6 +20,7 @@
 #pragma once
 
 #include <QCache>
+#include <QString>
 #include <QWidget>
 #include "fft.h"
 #include "inputsource.h"
@@ -30,8 +31,10 @@
 #include <memory>
 #include <array>
 #include <math.h>
+#include <vector>
 
 class TileCacheKey;
+class AnnotationLocation;
 
 class SpectrogramPlot : public Plot
 {
@@ -49,6 +52,8 @@ class SpectrogramPlot : public Plot
     bool tunerEnabled();
     void enableScales(bool enabled);
     void enableAnnotations(bool enabled);
+    bool isAnnotationsEnabled();
+    QString *mouseAnnotationComment(const QMouseEvent *event);
 
 public slots:
     void setFFTSize(int size);
@@ -62,6 +67,7 @@ public slots:
     static const int tileSize = 65536; // This must be a multiple of the maximum FFT size
 
     std::shared_ptr<SampleSource<std::complex<float>>> inputSource;
+    std::vector<AnnotationLocation> visibleAnnotationLocations;
     std::unique_ptr<FFT> fft;
     std::unique_ptr<float[]> window;
     QCache<TileCacheKey, QPixmap> pixmapCache;
@@ -110,3 +116,23 @@ class TileCacheKey
     int zoomLevel;
     size_t sample;
 };
+
+class AnnotationLocation
+{
+public:
+    Annotation annotation;
+
+    AnnotationLocation(Annotation annotation, int x, int y, int width, int height)
+        : annotation(annotation), x(x), y(y), width(width), height(height) {}
+
+    bool isInside(int pos_x, int pos_y) {
+        return (x <= pos_x) && (pos_x <= x + width)
+            && (y <= pos_y) && (pos_y <= y + height);
+    }
+
+private:
+    int x;
+    int y;
+    int width;
+    int height;
+};