diff --git a/rtdata/languages/default b/rtdata/languages/default
index 307417524..069c87050 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -249,7 +249,7 @@ HISTOGRAM_TOOLTIP_L;Show/Hide CIELab luminance histogram.
 HISTOGRAM_TOOLTIP_MODE;Toggle between linear, log-linear and log-log scaling of the histogram.
 HISTOGRAM_TOOLTIP_R;Show/Hide red histogram.
 HISTOGRAM_TOOLTIP_RAW;Show/Hide raw histogram.
-HISTOGRAM_TOOLTIP_TYPE;Toggle between histogram and waveform.
+HISTOGRAM_TOOLTIP_TYPE;Toggle between histogram, waveform, Hue-Saturation vectorscope, and Hue-Chroma vectorscope.
 HISTORY_CHANGED;Changed
 HISTORY_CUSTOMCURVE;Custom curve
 HISTORY_FROMCLIPBOARD;From clipboard
diff --git a/rtengine/improccoordinator.cc b/rtengine/improccoordinator.cc
index 4927c4e1f..f19eff54d 100644
--- a/rtengine/improccoordinator.cc
+++ b/rtengine/improccoordinator.cc
@@ -1643,6 +1643,9 @@ void ImProcCoordinator::updatePreviewImage(int todo, bool panningRelatedChange)
             if (hListener->updateHistogram()) {
                 updateLRGBHistograms();
             }
+            if (hListener->updateVectorscope()) {
+                updateVectorscope();
+            }
             if (hListener->updateWaveform()) {
                 updateWaveforms();
             }
@@ -1765,6 +1768,8 @@ void ImProcCoordinator::notifyHistogramChanged()
             histBlueRaw,
             histChroma,
             histLRETI,
+            vectorscopeScale,
+            vectorscope,
             waveformScale,
             waveformWidth,
             waveformRed.get(),
@@ -1835,6 +1840,55 @@ void ImProcCoordinator::updateLRGBHistograms()
 
 }
 
+void ImProcCoordinator::updateVectorscope()
+{
+    if (!workimg) {
+        return;
+    }
+
+    int x1, y1, x2, y2;
+    params->crop.mapToResized(pW, pH, scale, x1, x2, y1, y2);
+
+    constexpr int size = HistogramListener::vectorscope_size;
+    memset(vectorscope, 0, size * size * sizeof(vectorscope[0][0]));
+
+    for (int i = y1; i < y2; i++) {
+        int ofs = (i * pW + x1) * 3;
+
+        for (int j = x1; j < x2; j++) {
+            switch (hListener->vectorscopeType()) {
+                case 0: {
+                    // HS
+                    int r = 256 * workimg->data[ofs++];
+                    int g = 256 * workimg->data[ofs++];
+                    int b = 256 * workimg->data[ofs++];
+                    float h, s, l;
+                    Color::rgb2hsl(r, g, b, h, s, l);
+                    const int col = s * cos(2 * RT_PI * h) * (size / 2) + size / 2;
+                    const int row = s * sin(2 * RT_PI * h) * (size / 2) + size / 2;
+                    if (col >= 0 && col < size && row >= 0 && row < size) {
+                        vectorscope[row][col]++;
+                    }
+                    break;
+                }
+
+                case 1: {
+                    // CH
+                    const int col = (size / 96000.0) * nprevl->a[i][j] + size / 2;
+                    const int row = (size / 96000.0) * nprevl->b[i][j] + size / 2;
+
+                    if (col >= 0 && col < size && row >= 0 && row < size) {
+                        vectorscope[row][col]++;
+                    }
+                    break;
+                }
+            }
+        }
+    }
+
+    vectorscopeScale = workimg->getWidth() * workimg->getHeight();
+}
+
 void ImProcCoordinator::updateWaveforms()
 {
     if (!workimg) {
@@ -2314,7 +2368,7 @@ void ImProcCoordinator::setHighQualComputed()
     highQualityComputed = true;
 }
 
-void ImProcCoordinator::updateWaveform()
+void ImProcCoordinator::requestUpdateWaveform()
 {
     if (hListener) {
         updateWaveforms();
@@ -2322,7 +2376,7 @@ void ImProcCoordinator::updateWaveform()
     }
 }
 
-void ImProcCoordinator::updateHistogram()
+void ImProcCoordinator::requestUpdateHistogram()
 {
     if (hListener) {
         updateLRGBHistograms();
@@ -2330,4 +2384,12 @@ void ImProcCoordinator::updateHistogram()
     }
 }
 
+void ImProcCoordinator::requestUpdateVectorscope()
+{
+    if (hListener) {
+        updateVectorscope();
+        notifyHistogramChanged();
+    }
+}
+
 }
diff --git a/rtengine/improccoordinator.h b/rtengine/improccoordinator.h
index 92b5e9346..14ee81934 100644
--- a/rtengine/improccoordinator.h
+++ b/rtengine/improccoordinator.h
@@ -126,6 +126,8 @@ protected:
     LUTu histBlue, histBlueRaw;
     LUTu histLuma, histToneCurve, histToneCurveBW, histLCurve, histCCurve;
     LUTu histLLCurve, histLCAM, histCCAM, histClad, bcabhist, histChroma, histLRETI;
+    int vectorscopeScale;
+    int vectorscope[HistogramListener::vectorscope_size][HistogramListener::vectorscope_size];
     /// Waveform's intensity. Same as height of reference image.
     int waveformScale;
     int waveformWidth;
@@ -202,6 +204,7 @@ protected:
     void notifyHistogramChanged();
     void reallocAll();
     void updateLRGBHistograms();
+    void updateVectorscope();
     void updateWaveforms();
     void setScale(int prevscale);
     void updatePreviewImage (int todo, bool panningRelatedChange);
@@ -560,8 +563,9 @@ public:
 
     } denoiseInfoStore;
 
-    void updateHistogram() override;
-    void updateWaveform() override;
+    void requestUpdateHistogram() override;
+    void requestUpdateVectorscope() override;
+    void requestUpdateWaveform() override;
 };
 
 }
diff --git a/rtengine/rtengine.h b/rtengine/rtengine.h
index 4121b4f49..49f858cdc 100644
--- a/rtengine/rtengine.h
+++ b/rtengine/rtengine.h
@@ -308,6 +308,8 @@ class HistogramObservable;
 class HistogramListener
 {
 public:
+    static constexpr int vectorscope_size = 128;
+
     virtual ~HistogramListener() = default;
     /** This member function is called when the histogram of the final image has changed.
       * @param histRed is the array of size 256 containing the histogram of the red channel
@@ -330,6 +332,8 @@ public:
         const LUTu& histBlueRaw,
         const LUTu& histChroma,
         const LUTu& histLRETI,
+        int vectorscopeScale,
+        const int vectorscope[vectorscope_size][vectorscope_size],
         int waveformScale,
         int waveformWidth,
         const int waveformRed[][256],
@@ -340,17 +344,23 @@ public:
     virtual void setObservable(HistogramObservable* observable) = 0;
     /** Returns if the listener wants the histogram to be updated. */
     virtual bool updateHistogram(void) = 0;
+    /** Returns if the listener wants the vectorscope to be updated. */
+    virtual bool updateVectorscope(void) = 0;
     /** Returns if the listener wants the waveform to be updated. */
     virtual bool updateWaveform(void) = 0;
+    /** Returns the vectorscope type: 0 for H-S and 1 for H-C. */
+    virtual int vectorscopeType(void) = 0;
 };
 
 class HistogramObservable
 {
 public:
     /** Tells the observable to update the histogram data. */
-    virtual void updateHistogram() = 0;
+    virtual void requestUpdateHistogram() = 0;
+    /** Tells the observable to update the vectorscope data. */
+    virtual void requestUpdateVectorscope() = 0;
     /** Tells the observable to update the waveform data. */
-    virtual void updateWaveform() = 0;
+    virtual void requestUpdateWaveform() = 0;
 };
 
 /** This listener is used when the auto exposure has been recomputed (e.g. when the clipping ratio changed). */
diff --git a/rtgui/editorpanel.cc b/rtgui/editorpanel.cc
index 5bf3e54d8..e52c9f47a 100644
--- a/rtgui/editorpanel.cc
+++ b/rtgui/editorpanel.cc
@@ -2247,6 +2247,8 @@ void EditorPanel::histogramChanged(
     const LUTu& histBlueRaw,
     const LUTu& histChroma,
     const LUTu& histLRETI,
+    int vectorscopeScale,
+    const int vectorscope[HistogramListener::vectorscope_size][HistogramListener::vectorscope_size],
     int waveformScale,
     int waveformWidth,
     const int waveformRed[][256],
@@ -2255,7 +2257,7 @@ void EditorPanel::histogramChanged(
 )
 {
     if (histogramPanel) {
-        histogramPanel->histogramChanged(histRed, histGreen, histBlue, histLuma, histChroma, histRedRaw, histGreenRaw, histBlueRaw, waveformScale, waveformWidth, waveformRed, waveformGreen, waveformBlue);
+        histogramPanel->histogramChanged(histRed, histGreen, histBlue, histLuma, histChroma, histRedRaw, histGreenRaw, histBlueRaw, vectorscopeScale, vectorscope, waveformScale, waveformWidth, waveformRed, waveformGreen, waveformBlue);
     }
 
     tpc->updateCurveBackgroundHistogram(histToneCurve, histLCurve, histCCurve, histLCAM, histCCAM, histRed, histGreen, histBlue, histLuma, histLRETI);
@@ -2272,12 +2274,32 @@ bool EditorPanel::updateHistogram(void)
         || histogram_scope_type == HistogramPanelListener::NONE;
 }
 
+bool EditorPanel::updateVectorscope(void)
+{
+    return
+        histogram_scope_type == HistogramPanelListener::VECTORSCOPE_HS
+        || histogram_scope_type == HistogramPanelListener::VECTORSCOPE_CH
+        || histogram_scope_type == HistogramPanelListener::NONE;
+}
+
 bool EditorPanel::updateWaveform(void)
 {
     return histogram_scope_type == HistogramPanelListener::WAVEFORM
         || histogram_scope_type == HistogramPanelListener::NONE;
 }
 
+int EditorPanel::vectorscopeType(void)
+{
+    switch (histogram_scope_type) {
+        case HistogramPanelListener::VECTORSCOPE_HS:
+            return 0;
+        case HistogramPanelListener::VECTORSCOPE_CH:
+            return 1;
+        default:
+            return -1;
+    }
+}
+
 void EditorPanel::scopeTypeChanged(ScopeType new_type)
 {
     histogram_scope_type = new_type;
@@ -2289,9 +2311,13 @@ void EditorPanel::scopeTypeChanged(ScopeType new_type)
     // Make sure the new scope is updated since we only actively update the
     // current scope.
     if (new_type == HistogramPanelListener::HISTOGRAM) {
-        histogram_observable->updateHistogram();
+        histogram_observable->requestUpdateHistogram();
+    } else if (new_type == HistogramPanelListener::VECTORSCOPE_HS) {
+        histogram_observable->requestUpdateVectorscope();
+    } else if (new_type == HistogramPanelListener::VECTORSCOPE_CH) {
+        histogram_observable->requestUpdateVectorscope();
     } else if (new_type == HistogramPanelListener::WAVEFORM) {
-        histogram_observable->updateWaveform();
+        histogram_observable->requestUpdateWaveform();
     }
 }
 
diff --git a/rtgui/editorpanel.h b/rtgui/editorpanel.h
index 1794de11b..b9d196ccd 100644
--- a/rtgui/editorpanel.h
+++ b/rtgui/editorpanel.h
@@ -128,6 +128,8 @@ public:
         const LUTu& histBlueRaw,
         const LUTu& histChroma,
         const LUTu& histLRETI,
+        int vectorscopeScale,
+        const int vectorscope[HistogramListener::vectorscope_size][HistogramListener::vectorscope_size],
         int waveformScale,
         int waveformWidth,
         const int waveformRed[][256],
@@ -136,7 +138,9 @@ public:
     ) override;
     void setObservable(rtengine::HistogramObservable* observable) override;
     bool updateHistogram(void) override;
+    bool updateVectorscope(void) override;
     bool updateWaveform(void) override;
+    int vectorscopeType(void) override;
 
     // HistogramPanelListener
     void scopeTypeChanged(ScopeType new_type) override;
diff --git a/rtgui/histogrampanel.cc b/rtgui/histogrampanel.cc
index d3d92880d..0967212d0 100644
--- a/rtgui/histogrampanel.cc
+++ b/rtgui/histogrampanel.cc
@@ -163,8 +163,12 @@ HistogramPanel::HistogramPanel () : panel_listener(nullptr)
         showMode->set_image(*mode2Image);
     if (options.histogramScopeType == 0) {
         // TODO: scopeType->set_image(*histImage);
-    } else {
+    } else if (options.histogramScopeType == 1) {
         // TODO: scopeType->set_image(*waveImage);
+    } else if (options.histogramScopeType == 2) {
+        // TODO: scopeType->set_image(*vectHsImage);
+    } else if (options.histogramScopeType == 3) {
+        // TODO: scopeType->set_image(*vectHcImage);
     }
     showBAR->set_image   (showBAR->get_active()   ? *barImage   : *barImage_g);
     
@@ -254,7 +258,7 @@ void HistogramPanel::showRGBBar()
 
     gfxGrid->attach_next_to(*histogramRGBArea, *histogramArea, pos);
     setHistRGBInvalid();
-    histogramRGBArea->setShow(true);
+    histogramRGBArea->setShow(options.histogramScopeType < 2);
 }
 
 void HistogramPanel::resized (Gtk::Allocation& req)
@@ -331,12 +335,16 @@ void HistogramPanel::mode_released ()
 
 void HistogramPanel::type_pressed()
 {
-    constexpr int TYPE_COUNT = 2; // Histogram and waveform.
+    constexpr int TYPE_COUNT = 4; // Histogram, waveform, and 2 vectorscopes.
     options.histogramScopeType = (options.histogramScopeType + 1) % TYPE_COUNT;
     if (options.histogramScopeType == 0) {
         // TODO: showMode->set_image(*histImage);
-    } else {
+    } else if (options.histogramScopeType == 1) {
         // TODO: showMode->set_image(*waveImage);
+    } else if (options.histogramScopeType == 2) {
+        // TODO: showMode->set_image(*vectHsImage);
+    } else if (options.histogramScopeType == 3) {
+        // TODO: showMode->set_image(*vectHcImage);
     }
     type_changed();
     rgbv_toggled();
@@ -350,6 +358,9 @@ void HistogramPanel::type_changed()
     }
 
     if (options.histogramScopeType == 0) {
+        showRed->set_sensitive();
+        showGreen->set_sensitive();
+        showBlue->set_sensitive();
         showValue->set_sensitive(!showRAW->get_active());
         showChro->set_sensitive(!showRAW->get_active());
         showRAW->set_sensitive();
@@ -359,7 +370,10 @@ void HistogramPanel::type_changed()
             updateHistAreaOptions();
             panel_listener->scopeTypeChanged(HistogramPanelListener::HISTOGRAM);
         }
-    } else {
+    } else if (options.histogramScopeType == 1) {
+        showRed->set_sensitive();
+        showGreen->set_sensitive();
+        showBlue->set_sensitive();
         showValue->set_sensitive(false);
         showChro->set_sensitive(false);
         showRAW->set_sensitive(false);
@@ -369,6 +383,28 @@ void HistogramPanel::type_changed()
             updateHistAreaOptions();
             panel_listener->scopeTypeChanged(HistogramPanelListener::WAVEFORM);
         }
+    } else {
+        showRed->set_sensitive(false);
+        showGreen->set_sensitive(false);
+        showBlue->set_sensitive(false);
+        showValue->set_sensitive(false);
+        showChro->set_sensitive(false);
+        showRAW->set_sensitive(false);
+        showMode->set_sensitive(false);
+        histogramRGBArea = histogramRGBAreaHori.get();
+        if (panel_listener) {
+            updateHistAreaOptions();
+            HistogramPanelListener::ScopeType type;
+            switch (options.histogramScopeType) {
+                case 2:
+                    type = HistogramPanelListener::VECTORSCOPE_HS;
+                    break;
+                case 3:
+                    type = HistogramPanelListener::VECTORSCOPE_CH;
+                    break;
+            }
+            panel_listener->scopeTypeChanged(type);
+        }
     }
 
     if (showBAR->get_active()) {
@@ -395,7 +431,7 @@ void HistogramPanel::rgbv_toggled ()
     histogramArea->updateBackBuffer ();
     histogramArea->queue_draw ();
 
-    histogramRGBArea->updateOptions (showRed->get_active(), showGreen->get_active(), showBlue->get_active(), showValue->get_active(), showChro->get_active(), showRAW->get_active(), showBAR->get_active());
+    histogramRGBArea->updateOptions (showRed->get_active(), showGreen->get_active(), showBlue->get_active(), showValue->get_active(), showChro->get_active(), showRAW->get_active(), showBAR->get_active() && options.histogramScopeType < 2);
     histogramRGBArea->updateBackBuffer (0, 0, 0);
     histogramRGBArea->queue_draw ();
 }
@@ -458,8 +494,14 @@ void HistogramPanel::setPanelListener(HistogramPanelListener* listener)
         HistogramPanelListener::ScopeType type;
         if (options.histogramScopeType == 0) {
             type = HistogramPanelListener::HISTOGRAM;
-        } else {
+        } else if (options.histogramScopeType == 1) {
             type = HistogramPanelListener::WAVEFORM;
+        } else if (options.histogramScopeType == 2) {
+            type = HistogramPanelListener::VECTORSCOPE_HS;
+        } else if (options.histogramScopeType == 3) {
+            type = HistogramPanelListener::VECTORSCOPE_CH;
+        } else {
+            type = HistogramPanelListener::NONE;
         }
         listener->scopeTypeChanged(type);
     }
@@ -616,7 +658,7 @@ void HistogramRGBArea::updateBackBuffer (int r, int g, int b, const Glib::ustrin
                 drawBar(cc, b, 255.0, winw, winh, s);
             }
 
-            if((needLuma || needChroma) && options.histogramScopeType != 1) {
+            if((needLuma || needChroma) && options.histogramScopeType == 0) {
                 float Lab_L, Lab_a, Lab_b;
                 rtengine::Color::rgb2lab01(profile, profileW, r / 255.f, g / 255.f, b / 255.f, Lab_L, Lab_a, Lab_b, options.rtSettings.HistogramWorking);
 
@@ -828,6 +870,9 @@ HistogramArea::HistogramArea (DrawModeListener *fml) :
     lhist(256);
     chist(256);
 
+    const int vect_size = VECTORSCOPE_SIZE * Cairo::ImageSurface::format_stride_for_width(Cairo::FORMAT_ARGB32, VECTORSCOPE_SIZE);
+    vect_buffer.reset(new unsigned char[vect_size]);
+
     get_style_context()->add_class("drawingarea");
     set_name("HistogramArea");
 
@@ -904,6 +949,8 @@ void HistogramArea::update(
     const LUTu& histRedRaw,
     const LUTu& histGreenRaw,
     const LUTu& histBlueRaw,
+    int vectorscopeScale,
+    const int vectorscope[VECTORSCOPE_SIZE][VECTORSCOPE_SIZE],
     int waveformScale,
     int waveformWidth,
     const int waveformRed[][256],
@@ -936,6 +983,11 @@ void HistogramArea::update(
             memcpy(gw, waveformGreen, 256 * waveformWidth * sizeof(gw[0][0]));
             memcpy(bw, waveformBlue, 256 * waveformWidth * sizeof(bw[0][0]));
             wave_buffer_dirty = true;
+        } else if (scopeType >= 2) {
+            vectorscope_scale = vectorscopeScale;
+            memcpy(vect, vectorscope, VECTORSCOPE_SIZE * VECTORSCOPE_SIZE *
+                sizeof(vect[0][0]));
+            vect_buffer_dirty = true;
         }
         valid = true;
     } else {
@@ -1009,7 +1061,7 @@ void HistogramArea::updateBackBuffer ()
     int nrOfVGridPartitions = 8; // always show 8 stops (lines at 1,3,7,15,31,63,127)
 
     // draw vertical gridlines
-    if (options.histogramScopeType != 1) {
+    if (options.histogramScopeType == 0) {
         for (int i = 0; i <= nrOfVGridPartitions; i++) {
             double xpos = padding + 0.5;
             if (options.histogramDrawMode < 2) {
@@ -1031,6 +1083,8 @@ void HistogramArea::updateBackBuffer ()
             cr->line_to(w, ypos);
             cr->stroke();
         }
+    } else if (options.histogramScopeType >= 2) {
+        // Vectorscope has no gridlines.
     } else if (options.histogramDrawMode == 0) {
         for (int i = 1; i < nrOfHGridPartitions; i++) {            
             cr->move_to (padding, i * (double)h / nrOfHGridPartitions + 0.5);
@@ -1156,6 +1210,8 @@ void HistogramArea::updateBackBuffer ()
 
     } else if (scopeType == 1 && waveform_width > 0) {
         drawWaveform(cr, w, h);
+    } else if (scopeType >= 2) {
+        drawVectorscope(cr, w, h);
     }
 
     // Draw the frame's border
@@ -1220,6 +1276,107 @@ void HistogramArea::drawMarks(Cairo::RefPtr<Cairo::Context> &cr,
     cr->fill();
 }
 
+void HistogramArea::drawVectorscope(Cairo::RefPtr<Cairo::Context> &cr, int w, int h)
+{
+    // Arbitrary scale factor multiplied by vectorscope area and divided by
+    // current scale.
+    const float scale = 16.f * VECTORSCOPE_SIZE * VECTORSCOPE_SIZE / vectorscope_scale;
+
+    // See Cairo documentation on stride.
+    const int cairo_stride = Cairo::ImageSurface::format_stride_for_width(Cairo::FORMAT_ARGB32, VECTORSCOPE_SIZE);
+
+    if (vect_buffer_dirty && vectorscope_scale > 0) {
+        // TODO: Optimize.
+        for (int u = 0; u < VECTORSCOPE_SIZE; u++) {
+            for (int v = 0; v < VECTORSCOPE_SIZE; v++) {
+                const unsigned char value = LIM<float>(scale * vect[u][v], 0, 0xff);
+                *(uint32_t*)&(vect_buffer[(VECTORSCOPE_SIZE - 1 - u) * cairo_stride + v * 4]) =
+                    value | (value << 8) | (value << 16) | (value << 24);
+            }
+        }
+
+        vect_buffer_dirty = false;
+    }
+
+    const float scope_size = min<float>(w, h) - 2 * padding;
+    const float o_x = (w - scope_size) / 2;
+    const float o_y = (h - scope_size) / 2;
+    const double s = RTScalable::getScale();
+    auto orig_matrix = cr->get_matrix();
+    const double line_spacing = 4.0 * s;
+    const double line_length = scope_size / 2.0 - 2.0 * line_spacing;
+    std::valarray<double> ch_ds(1);
+
+    cr->translate(w / 2.0, h / 2.0);
+    cr->set_source_rgba (1., 1., 1., 0.25);
+    cr->set_line_width (1.0 * s);
+    cr->set_antialias(Cairo::ANTIALIAS_SUBPIXEL);
+    ch_ds[0] = 4;
+
+    if (scopeType == 2) { // Hue-Saturation.
+        // RYGCBM lines.
+        for (int i = 0; i < 6; i++) {
+            cr->move_to(line_spacing, 0);
+            cr->line_to(line_spacing + line_length, 0);
+            cr->rotate_degrees(60);
+        }
+        cr->stroke();
+        // 100% saturation circle.
+        cr->arc(0, 0, scope_size / 2.0, 0, 2 * RT_PI);
+        cr->stroke();
+        // 25%, 50%, and 75% saturation.
+        cr->set_dash(ch_ds, 0);
+        for (int i = 1; i < 4; i++) {
+            cr->arc(0, 0, i * scope_size / 8.0, 0, 2 * RT_PI);
+            cr->stroke();
+        }
+        // HSV skin tone line derived from -I axis of YIQ.
+        cr->rotate(-0.134900 * RT_PI);
+        cr->move_to(line_spacing, 0);
+        cr->line_to(line_spacing + line_length, 0);
+        cr->stroke();
+        cr->unset_dash();
+    } else if (scopeType == 3) { // Hue-Chroma.
+        // a and b axes.
+        cr->move_to(0, line_spacing);
+        cr->line_to(0, line_spacing + line_length);
+        cr->move_to(0, -line_spacing);
+        cr->line_to(0, -line_spacing - line_length);
+        cr->move_to(line_spacing, 0);
+        cr->line_to(line_spacing + line_length, 0);
+        cr->move_to(-line_spacing, 0);
+        cr->line_to(-line_spacing - line_length, 0);
+        cr->stroke();
+        // 25%, 50%, 75%, and 100% of standard chroma range.
+        cr->set_dash(ch_ds, 0);
+        for (int i = 1; i <= 4; i++) {
+            cr->arc(0, 0, i * scope_size / 8.0, 0, 2 * RT_PI);
+            cr->stroke();
+        }
+        // CIELAB skin tone line, approximated by 50% saturation and
+        // value along the HSV skin tone line.
+        cr->rotate(-0.321713 * RT_PI);
+        cr->move_to(line_spacing, 0);
+        cr->line_to(line_spacing + line_length, 0);
+        cr->stroke();
+        cr->unset_dash();
+    }
+    cr->set_matrix(orig_matrix);
+
+    // Vectorscope trace.
+    if (vectorscope_scale > 0) {
+        Cairo::RefPtr<Cairo::ImageSurface> surface = Cairo::ImageSurface::create(
+            vect_buffer.get(), Cairo::FORMAT_ARGB32, VECTORSCOPE_SIZE, VECTORSCOPE_SIZE, cairo_stride);
+        cr->translate(o_x, o_y);
+        cr->scale(scope_size / VECTORSCOPE_SIZE, scope_size / VECTORSCOPE_SIZE);
+        cr->set_source(surface, 0, 0);
+        cr->set_operator(Cairo::OPERATOR_OVER);
+        cr->paint();
+        surface->finish();
+        cr->set_matrix(orig_matrix);
+    }
+}
+
 void HistogramArea::drawWaveform(Cairo::RefPtr<Cairo::Context> &cr, int w, int h)
 {
     // Arbitrary scale factor divided by current scale.
@@ -1310,7 +1467,7 @@ bool HistogramArea::on_button_release_event (GdkEventButton* event)
 
 bool HistogramArea::on_motion_notify_event (GdkEventMotion* event)
 {
-    if (drawMode == 0 || scopeType == 1) {
+    if (drawMode == 0 || scopeType >= 1) {
         return false;
     }
 
diff --git a/rtgui/histogrampanel.h b/rtgui/histogrampanel.h
index 83099c68e..a3d29bdd3 100644
--- a/rtgui/histogrampanel.h
+++ b/rtgui/histogrampanel.h
@@ -32,6 +32,11 @@
 
 class HistogramArea;
 
+namespace
+{
+constexpr int VECTORSCOPE_SIZE = 128;
+}
+
 struct HistogramAreaIdleHelper {
     HistogramArea* harea;
     bool destroyed;
@@ -156,6 +161,10 @@ private:
 protected:
     LUTu rhist, ghist, bhist, lhist, chist;
     LUTu rhistRaw, ghistRaw, bhistRaw, lhistRaw; //lhistRaw is unused?
+    int vectorscope_scale;
+    int vect[VECTORSCOPE_SIZE][VECTORSCOPE_SIZE];
+    std::unique_ptr<unsigned char[]> vect_buffer;
+    bool vect_buffer_dirty;
     int waveform_scale;
     int waveform_width;
     std::unique_ptr<int[][256]> rwave, gwave, bwave;
@@ -191,6 +200,8 @@ public:
         const LUTu& histRedRaw,
         const LUTu& histGreenRaw,
         const LUTu& histBlueRaw,
+        int vectorscopeScale,
+        const int vectorscope[VECTORSCOPE_SIZE][VECTORSCOPE_SIZE],
         int waveformScale,
         int waveformWidth,
         const int waveformRed[][256],
@@ -208,6 +219,7 @@ public:
 private:
     void drawCurve(Cairo::RefPtr<Cairo::Context> &cr, const LUTu & data, double scale, int hsize, int vsize);
     void drawMarks(Cairo::RefPtr<Cairo::Context> &cr, const LUTu & data, double scale, int hsize, int & ui, int & oi);
+    void drawVectorscope(Cairo::RefPtr<Cairo::Context> &cr, int hsize, int vsize);
     void drawWaveform(Cairo::RefPtr<Cairo::Context> &cr, int hsize, int vsize);
     Gtk::SizeRequestMode get_request_mode_vfunc () const override;
     void get_preferred_height_vfunc (int& minimum_height, int& natural_height) const override;
@@ -219,7 +231,7 @@ private:
 class HistogramPanelListener
 {
 public:
-    enum ScopeType {HISTOGRAM, WAVEFORM, NONE};
+    enum ScopeType {HISTOGRAM, VECTORSCOPE_CH, VECTORSCOPE_HS, WAVEFORM, NONE};
 
     virtual void scopeTypeChanged(ScopeType new_type) = 0;
 };
@@ -286,6 +298,8 @@ public:
         const LUTu& histRedRaw,
         const LUTu& histGreenRaw,
         const LUTu& histBlueRaw,
+        int vectorscopeScale,
+        const int vectorscope[VECTORSCOPE_SIZE][VECTORSCOPE_SIZE],
         int waveformScale,
         int waveformWidth,
         const int waveformRed[][256],
@@ -293,7 +307,7 @@ public:
         const int waveformBlue[][256]
     )
     {
-        histogramArea->update(histRed, histGreen, histBlue, histLuma, histChroma, histRedRaw, histGreenRaw, histBlueRaw, waveformScale, waveformWidth, waveformRed, waveformGreen, waveformBlue);
+        histogramArea->update(histRed, histGreen, histBlue, histLuma, histChroma, histRedRaw, histGreenRaw, histBlueRaw, vectorscopeScale, vectorscope, waveformScale, waveformWidth, waveformRed, waveformGreen, waveformBlue);
     }
     // pointermotionlistener interface
     void pointerMoved (bool validPos, const Glib::ustring &profile, const Glib::ustring &profileW, int x, int y, int r, int g, int b, bool isRaw = false) override;