Rewrite of Gimp Color Wheel in C++.

8 files changed, 786 insertions, 1634 deletions

diff --git a/src/ui/CMakeLists.txt b/src/ui/CMakeLists.txt
index 47ff6884e..96658b2a1 100644
--- a/src/ui/CMakeLists.txt
+++ b/src/ui/CMakeLists.txt
@@ -170,6 +170,7 @@ set(ui_SRC
 	widget/frame.cpp
 	widget/highlight-picker.cpp
 	widget/imagetoggler.cpp
+        widget/ink-color-wheel.cpp
 	widget/ink-select-one-action.cpp
 	widget/ink-spinscale.cpp
 	widget/insertordericon.cpp
@@ -394,6 +395,7 @@ set(ui_SRC
 	widget/highlight-picker.h
 	widget/insertordericon.h
 	widget/imagetoggler.h
+        widget/ink-color-wheel.h
 	widget/ink-select-one-action.h
 	widget/ink-spinscale.h
 	widget/labelled.h
diff --git a/src/ui/widget/color-wheel-selector.cpp b/src/ui/widget/color-wheel-selector.cpp
index c0a27a552..1c2660876 100644
--- a/src/ui/widget/color-wheel-selector.cpp
+++ b/src/ui/widget/color-wheel-selector.cpp
@@ -17,7 +17,7 @@
 #include "ui/dialog-events.h"
 #include "ui/widget/color-scales.h"
 #include "ui/widget/color-slider.h"
-#include "widgets/gimp/gimpcolorwheel.h"
+#include "ui/widget/ink-color-wheel.h"
 
 namespace Inkscape {
 namespace UI {
@@ -46,8 +46,6 @@ ColorWheelSelector::ColorWheelSelector(SelectedColor &color)
 
 ColorWheelSelector::~ColorWheelSelector()
 {
-    _wheel = nullptr;
-
     _color_changed_connection.disconnect();
     _color_dragged_connection.disconnect();
 }
@@ -57,14 +55,12 @@ void ColorWheelSelector::_initUI()
     /* Create components */
     gint row = 0;
 
-    _wheel = gimp_color_wheel_new();
-    gtk_widget_show(_wheel);
-
-    gtk_widget_set_halign(_wheel, GTK_ALIGN_FILL);
-    gtk_widget_set_valign(_wheel, GTK_ALIGN_FILL);
-    gtk_widget_set_hexpand(_wheel, TRUE);
-    gtk_widget_set_vexpand(_wheel, TRUE);
-    gtk_grid_attach(GTK_GRID(gobj()), _wheel, 0, row, 3, 1);
+    _wheel = Gtk::manage(new Inkscape::UI::Widget::ColorWheel());
+    _wheel->set_halign(Gtk::ALIGN_FILL);
+    _wheel->set_valign(Gtk::ALIGN_FILL);
+    _wheel->set_hexpand(true);
+    _wheel->set_vexpand(true);
+    attach(*_wheel, 0, row, 3, 1);
 
     row++;
 
@@ -72,15 +68,9 @@ void ColorWheelSelector::_initUI()
     Gtk::Label *label = Gtk::manage(new Gtk::Label(_("_A:"), true));
     label->set_halign(Gtk::ALIGN_END);
     label->set_valign(Gtk::ALIGN_CENTER);
-    label->show();
 
-  #if GTK_CHECK_VERSION(3, 12, 0)
     label->set_margin_start(XPAD);
     label->set_margin_end(XPAD);
-  #else
-    label->set_margin_left(XPAD);
-    label->set_margin_right(XPAD);
-  #endif
     label->set_margin_top(YPAD);
     label->set_margin_bottom(YPAD);
     label->set_halign(Gtk::ALIGN_FILL);
@@ -93,15 +83,9 @@ void ColorWheelSelector::_initUI()
     /* Slider */
     _slider = Gtk::manage(new Inkscape::UI::Widget::ColorSlider(_alpha_adjustment));
     _slider->set_tooltip_text(_("Alpha (opacity)"));
-    _slider->show();
 
-  #if GTK_CHECK_VERSION(3, 12, 0)
     _slider->set_margin_start(XPAD);
     _slider->set_margin_end(XPAD);
-  #else
-    _slider->set_margin_left(XPAD);
-    _slider->set_margin_right(XPAD);
-  #endif
     _slider->set_margin_top(YPAD);
     _slider->set_margin_bottom(YPAD);
     _slider->set_hexpand(true);
@@ -117,15 +101,9 @@ void ColorWheelSelector::_initUI()
     spin_button->set_tooltip_text(_("Alpha (opacity)"));
     sp_dialog_defocus_on_enter(GTK_WIDGET(spin_button->gobj()));
     label->set_mnemonic_widget(*spin_button);
-    spin_button->show();
 
-  #if GTK_CHECK_VERSION(3, 12, 0)
     spin_button->set_margin_start(XPAD);
     spin_button->set_margin_end(XPAD);
-  #else
-    spin_button->set_margin_left(XPAD);
-    spin_button->set_margin_right(XPAD);
-  #endif
     spin_button->set_margin_top(YPAD);
     spin_button->set_margin_bottom(YPAD);
     spin_button->set_halign(Gtk::ALIGN_CENTER);
@@ -137,8 +115,9 @@ void ColorWheelSelector::_initUI()
     _slider->signal_grabbed.connect(sigc::mem_fun(*this, &ColorWheelSelector::_sliderGrabbed));
     _slider->signal_released.connect(sigc::mem_fun(*this, &ColorWheelSelector::_sliderReleased));
     _slider->signal_value_changed.connect(sigc::mem_fun(*this, &ColorWheelSelector::_sliderChanged));
+    _wheel->signal_color_changed().connect(sigc::mem_fun(*this, &ColorWheelSelector::_wheelChanged));
 
-    g_signal_connect(G_OBJECT(_wheel), "changed", G_CALLBACK(_wheelChanged), this);
+    show_all();
 }
 
 void ColorWheelSelector::on_show()
@@ -192,19 +171,14 @@ void ColorWheelSelector::_sliderChanged()
     _color.setAlpha(ColorScales::getScaled(_alpha_adjustment->gobj()));
 }
 
-void ColorWheelSelector::_wheelChanged(GimpColorWheel *wheel, ColorWheelSelector *wheelSelector)
+void ColorWheelSelector::_wheelChanged()
 {
-    if (wheelSelector->_updating) {
+    if (_updating) {
         return;
     }
 
-    gdouble h = 0;
-    gdouble s = 0;
-    gdouble v = 0;
-    gimp_color_wheel_get_color(wheel, &h, &s, &v);
-
-    float rgb[3] = { 0, 0, 0 };
-    SPColor::hsv_to_rgb_floatv(rgb, h, s, v);
+    double rgb[3] = { 0, 0, 0 };
+    _wheel->get_rgb(rgb[0], rgb[1], rgb[2]);
 
     SPColor color(rgb[0], rgb[1], rgb[2]);
 
@@ -212,13 +186,13 @@ void ColorWheelSelector::_wheelChanged(GimpColorWheel *wheel, ColorWheelSelector
     guint32 mid = color.toRGBA32(0x7f);
     guint32 end = color.toRGBA32(0xff);
 
-    wheelSelector->_updating = true;
-    wheelSelector->_slider->setColors(start, mid, end);
-    wheelSelector->_color.preserveICC();
+    _updating = true;
+    _slider->setColors(start, mid, end);
+    _color.preserveICC();
 
-    wheelSelector->_color.setHeld(gimp_color_wheel_is_adjusting(wheel));
-    wheelSelector->_color.setColor(color);
-    wheelSelector->_updating = false;
+    _color.setHeld(_wheel->is_adjusting());
+    _color.setColor(color);
+    _updating = false;
 }
 
 void ColorWheelSelector::_updateDisplay()
@@ -234,7 +208,7 @@ void ColorWheelSelector::_updateDisplay()
     {
         float hsv[3] = { 0, 0, 0 };
         SPColor::rgb_to_hsv_floatv(hsv, _color.color().v.c[0], _color.color().v.c[1], _color.color().v.c[2]);
-        gimp_color_wheel_set_color(GIMP_COLOR_WHEEL(_wheel), hsv[0], hsv[1], hsv[2]);
+        _wheel->set_rgb(_color.color().v.c[0], _color.color().v.c[1], _color.color().v.c[2]);
     }
 
     guint32 start = _color.color().toRGBA32(0x00);
diff --git a/src/ui/widget/color-wheel-selector.h b/src/ui/widget/color-wheel-selector.h
index a5e492f4b..59cf6b626 100644
--- a/src/ui/widget/color-wheel-selector.h
+++ b/src/ui/widget/color-wheel-selector.h
@@ -16,14 +16,12 @@
 
 #include "ui/selected-color.h"
 
-typedef struct _GimpColorWheel GimpColorWheel;
-
 namespace Inkscape {
 namespace UI {
 namespace Widget {
 
 class ColorSlider;
-
+class ColorWheel;
 class ColorWheelSelector
     : public Gtk::Grid
 {
@@ -43,14 +41,14 @@ protected:
     void _sliderGrabbed();
     void _sliderReleased();
     void _sliderChanged();
-    static void _wheelChanged(GimpColorWheel *wheel, ColorWheelSelector *cs);
+    void _wheelChanged();
 
     void _updateDisplay();
 
     SelectedColor &_color;
     bool _updating;
     Glib::RefPtr<Gtk::Adjustment> _alpha_adjustment;
-    GtkWidget *_wheel;
+    Inkscape::UI::Widget::ColorWheel *_wheel;
     Inkscape::UI::Widget::ColorSlider *_slider;
 
 private:
diff --git a/src/ui/widget/ink-color-wheel.cpp b/src/ui/widget/ink-color-wheel.cpp
new file mode 100644
index 000000000..09688eca9
--- /dev/null
+++ b/src/ui/widget/ink-color-wheel.cpp
@@ -0,0 +1,675 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Color wheel widget. Outer ring for Hue. Inner triangle for Saturation and Value.
+ *
+ * Copyright (C) 2018 Tavmjong Bah
+ *
+ * The contents of this file may be used under the GNU General Public License Version 2 or later.
+ *
+ */
+
+#include "ink-color-wheel.h"
+
+// A point with a color value.
+class color_point {
+public:
+    color_point() : x(0), y(0), r(0), g(0), b(0) {};
+    color_point(double x, double y, double r, double g, double b) : x(x), y(y), r(r), g(g), b(b) {};
+    color_point(double x, double y, guint32 color) : x(x), y(y),
+                                                     r(((color & 0xff0000) >> 16)/255.0),
+                                                     g(((color &   0xff00) >>  8)/255.0),
+                                                     b(((color &     0xff)      )/255.0) {};
+    guint32 get_color() { return (int(r*255) << 16 | int(g*255) << 8 | int(b*255)); };
+    double x;
+    double y;
+    double r;
+    double g;
+    double b;
+};
+
+inline double lerp(const double& v0, const double& v1, const double& t0, const double&t1, const double& t) {
+    double s = 0;
+    if (t0 != t1) {
+        s = (t - t0)/(t1 - t0);
+    }
+    return (1.0 - s) * v0 + s * v1;
+}
+
+inline color_point lerp(const color_point& v0, const color_point& v1, const double &t0, const double &t1, const double& t) {
+    double x = lerp(v0.x, v1.x, t0, t1, t);
+    double y = lerp(v0.y, v1.y, t0, t1, t);
+    double r = lerp(v0.r, v1.r, t0, t1, t);
+    double g = lerp(v0.g, v1.g, t0, t1, t);
+    double b = lerp(v0.b, v1.b, t0, t1, t);
+    return (color_point(x, y, r, g, b));
+}
+
+inline double clamp(const double& value, const double& min, const double& max) {
+    if (value < min) return min;
+    if (value > max) return max;
+    return value;
+}
+
+// h, s, and v in range 0 to 1. Returns rgb value useful for use in Cairo.
+guint32 hsv_to_rgb(double h, double s, double v) {
+
+    if (h < 0.0 || h > 1.0 ||
+        s < 0.0 || s > 1.0 ||
+        v < 0.0 || v > 1.0) {
+        std::cerr << "ColorWheel: hsv_to_rgb: input out of bounds: (0-1)"
+                  << " h: " << h << " s: " << s << " v: " << v << std::endl;
+        return 0x0;
+    }
+
+    double r = v;
+    double g = v;
+    double b = v;
+
+    if (s != 0.0) {
+        double c = s * v;
+        if (h == 1.0) h = 0.0;
+        h *= 6.0;
+
+        double f = h - (int)h;
+        double p = v * (1.0 - s);
+        double q = v * (1.0 - s * f);
+        double t = v * (1.0 - s * (1.0 - f));
+
+        switch ((int)h) {
+            case 0: r = v; g = t; b = p; break;
+            case 1: r = q; g = v; b = p; break;
+            case 2: r = p; g = v; b = t; break;
+            case 3: r = p; g = q; b = v; break;
+            case 4: r = t; g = p; b = v; break;
+            case 5: r = v; g = p; b = q; break;
+            default: g_assert_not_reached();
+        }
+    }
+    guint32 rgb = (((int)floor (r*255 + 0.5) << 16) |
+                   ((int)floor (g*255 + 0.5) <<  8) |
+                   ((int)floor (b*255 + 0.5)      ));
+    return rgb;
+}
+
+double luminance(guint32 color)
+{
+    double r(((color & 0xff0000) >> 16)/255.0);
+    double g(((color &   0xff00) >>  8)/255.0);
+    double b(((color &     0xff)      )/255.0);
+    return (r * 0.2125 + g * 0.7154 + b * 0.0721);
+}
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+
+ColorWheel::ColorWheel()
+    : _hue(0.0)
+    , _saturation(1.0)
+    , _value(1.0)
+    , _ring_width(0.2)
+    , _mode(DRAG_NONE)
+    , _focus_on_ring(true)
+{
+    set_name("ColorWheel");
+    add_events(Gdk::BUTTON_PRESS_MASK   |
+               Gdk::BUTTON_RELEASE_MASK |
+               Gdk::BUTTON_MOTION_MASK  |
+               Gdk::KEY_PRESS_MASK      );
+    set_can_focus();
+}
+
+void
+ColorWheel::set_rgb(const double& r, const double&g, const double&b, bool override_hue)
+{
+    double Min = std::min({r, g, b});
+    double Max = std::max({r, g, b});
+    _value = Max;
+    if (Min == Max) {
+        if (override_hue) {
+            _hue = 0.0;
+        }
+    } else {
+        if (Max == r) {
+            _hue = ((g-b)/(Max-Min)    )/6.0;
+        } else if (Max == g) {
+            _hue = ((b-r)/(Max-Min) + 2)/6.0;
+        } else {
+            _hue = ((r-g)/(Max-Min) + 4)/6.0;
+        }
+        if (_hue < 0.0) {
+            _hue += 1.0;
+        }
+    }
+    if (Max == 0) {
+        _saturation = 0;
+    } else {
+        _saturation = (Max - Min)/Max;
+    }
+}
+
+void
+ColorWheel::get_rgb(double& r, double& g, double& b)
+{
+    guint32 color = get_rgb();
+    r = ((color & 0xff0000) >> 16)/255.0;
+    g = ((color & 0x00ff00) >>  8)/255.0;
+    b = ((color & 0x0000ff)      )/255.0;
+}
+
+guint32
+ColorWheel::get_rgb()
+{
+    return hsv_to_rgb(_hue, _saturation, _value);
+}
+
+bool
+ColorWheel::on_draw(const::Cairo::RefPtr<::Cairo::Context>& cr) {
+
+    Cairo::RefPtr<Cairo::Surface> surface = cr->get_target();
+    Cairo::RefPtr<Cairo::ImageSurface> image_surface =
+        Cairo::RefPtr<Cairo::ImageSurface>::cast_dynamic(surface);
+    if (!image_surface) {
+        std::cerr << "ColorWheel::on_draw: Failed Cast!" << std::endl;
+        return false;
+    }
+
+    Gtk::Allocation allocation = get_allocation();
+    const int width  = allocation.get_width();
+    const int height = allocation.get_height();
+
+    Cairo::Format format = image_surface->get_format();
+    const int stride = Cairo::ImageSurface::format_stride_for_width(format, width);
+
+    int cx = width/2;
+    int cy = height/2;
+
+    int focus_line_width;
+    int focus_padding;
+    get_style_property("focus-line-width", focus_line_width);
+    get_style_property("focus-padding",    focus_padding);
+
+    // Paint ring
+    guint32* buffer_ring = g_new (guint32, height * stride / 4);
+    double r_max = std::min( width, height)/2.0 - 2 * (focus_line_width + focus_padding);
+    double r_min = r_max * (1.0 - _ring_width);
+    double r2_max = (r_max+1) * (r_max+1); // Must expand a bit to avoid edge effects.
+    double r2_min = (r_min-1) * (r_min-1); // Must shrink a bit to avoid edge effects.
+
+    for (int i = 0; i < height; ++i) {
+        guint32* p = buffer_ring + i * width;
+        double dy = (cy - i);
+        for (int j = 0; j < width; ++j) {
+            double dx = (j - cx);
+            double r2 = dx * dx + dy * dy;
+            if (r2 < r2_min || r2 > r2_max) {
+                *p++ = 0; // Save calculation time.
+            } else {
+                double angle = atan2 (dy, dx);
+                if (angle < 0.0) {
+                    angle += 2.0 * M_PI;
+                }
+                double hue = angle/(2.0 * M_PI);
+
+                *p++ = hsv_to_rgb(hue, 1.0, 1.0);
+            }
+        }
+    }
+
+    Cairo::RefPtr<::Cairo::ImageSurface> source_ring =
+        ::Cairo::ImageSurface::create((unsigned char *)buffer_ring,
+                                      Cairo::FORMAT_RGB24,
+                                      width, height, stride);
+
+    cr->set_antialias(Cairo::ANTIALIAS_SUBPIXEL);
+
+    // Paint line on ring in source (so it gets clipped by stroke).
+    double l = 0.0;
+    guint32 color_on_ring = hsv_to_rgb(_hue, 1.0, 1.0);
+    if (luminance(color_on_ring) < 0.5) l = 1.0;
+
+    Cairo::RefPtr<::Cairo::Context> cr_source_ring = ::Cairo::Context::create(source_ring);
+    cr_source_ring->set_source_rgb(l, l, l);
+
+    cr_source_ring->move_to (cx, cy);
+    cr_source_ring->line_to (cx + cos(_hue * M_PI * 2.0) * r_max+1,
+                             cy - sin(_hue * M_PI * 2.0) * r_max+1);
+    cr_source_ring->stroke();
+
+    // Paint with ring surface, clipping to ring.
+    cr->save();
+    cr->set_source(source_ring, 0, 0);
+    cr->set_line_width (r_max - r_min);
+    cr->begin_new_path();
+    cr->arc(cx, cy, (r_max + r_min)/2.0, 0, 2.0 * M_PI);
+    cr->stroke();
+    cr->restore();
+
+    // Draw focus
+    if (has_focus() && _focus_on_ring) {
+        Glib::RefPtr<Gtk::StyleContext> style_context = get_style_context();
+        style_context->render_focus(cr, 0, 0, width, height);
+    }
+  
+    // Paint triangle.
+    /* The triangle is painted by first finding color points on the
+     * edges of the triangle at the same y value via linearly
+     * interpolating between corner values, and then interpolating along
+     * x between the those edge points. The interpolation is in sRGB
+     * space which leads to a complicated mapping between x/y and
+     * saturation/value. This was probably done to remove the need to
+     * convert between HSV and RGB for each pixel.
+     * Black corner: v = 0, s = 1
+     * White corner: v = 1, s = 0
+     * Color corner; v = 1, s = 1
+     */
+    const int padding = 3; // Avoid edge artifacts (only needed in y).
+    double x0, y0, x1, y1, x2, y2;
+    triangle_corners(x0, y0, x1, y1, x2, y2);
+    guint32 color0 = hsv_to_rgb(_hue, 1.0, 1.0);
+    guint32 color1 = hsv_to_rgb(_hue, 1.0, 0.0);
+    guint32 color2 = hsv_to_rgb(_hue, 0.0, 1.0);
+
+    color_point p0 (x0, y0, color0);
+    color_point p1 (x1, y1, color1);
+    color_point p2 (x2, y2, color2);
+
+    // Reorder so we paint from top down.
+    if (p1.y > p2.y) {
+        std::swap(p1, p2);
+    }
+
+    if (p0.y > p2.y) {
+        std::swap(p0, p2);
+    }
+
+    if (p0.y > p1.y) {
+        std::swap(p0, p1);
+    }
+
+    guint32* buffer_triangle = g_new (guint32, height * stride / 4);
+  
+    for (int y = 0; y < height; ++y) {
+        guint32* p = buffer_triangle + y * width;
+
+        if (p0.y <= y+padding && y-padding < p2.y) {
+
+            // Get values on side at position y.
+            color_point side0;
+            if (y < p1.y) {
+                side0 = lerp(p0, p1, p0.y, p1.y, y);
+            } else {
+                side0 = lerp(p1, p2, p1.y, p2.y, y);
+            }
+            color_point side1 = lerp(p0, p2, p0.y, p2.y, y);
+
+            // side0 should be on left
+            if (side0.x > side1.x) {
+                std::swap (side0, side1);
+            }
+
+            int x_start = std::max(0, int(side0.x));
+            int x_end   = std::min(int(side1.x), width);
+
+            for (int x = 0; x < width; ++x) {
+                if (x < x_start) {
+                    *p++ = side0.get_color();
+                } else if (x < x_end) {
+                    *p++ = lerp(side0, side1, side0.x, side1.x, x).get_color();
+                } else {
+                    *p++ = side1.get_color();
+                }
+            }
+        }
+    }
+
+    Cairo::RefPtr<::Cairo::ImageSurface> source_triangle =
+        ::Cairo::ImageSurface::create((unsigned char *)buffer_triangle,
+                                      Cairo::FORMAT_RGB24,
+                                      width, height, stride);
+
+    // Paint with triangle surface, clipping to triangle.
+    cr->save();
+    cr->set_source(source_triangle, 0, 0);
+    cr->move_to(p0.x, p0.y);
+    cr->line_to(p1.x, p1.y);
+    cr->line_to(p2.x, p2.y);
+    cr->close_path();
+    cr->fill();
+    cr->restore();
+
+  
+    // Draw marker
+    double mx = x1 + (x2-x1) * _value + (x0-x2) * _saturation * _value;
+    double my = y1 + (y2-y1) * _value + (y0-y2) * _saturation * _value;
+
+    double a = 0.0;
+    guint32 color_at_marker = get_rgb();
+    if (luminance(color_at_marker) < 0.5) a = 1.0;
+
+    cr->set_source_rgb(a, a, a);
+    cr->begin_new_path();
+    cr->arc(mx, my, 4, 0, 2 * M_PI);
+    cr->stroke();
+
+    // Draw focus
+    if (has_focus() && !_focus_on_ring) {
+        Glib::RefPtr<Gtk::StyleContext> style_context = get_style_context();
+        style_context->render_focus(cr, mx-4, my-4, 8, 8); // This doesn't seem to work.
+        cr->set_line_width(0.5);
+        cr->set_source_rgb(1-a, 1-a, 1-a);
+        cr->begin_new_path();
+        cr->arc(mx, my, 7, 0, 2 * M_PI);
+        cr->stroke();
+    }
+
+    return true;
+}
+
+// Find triangle corners given hue and radius.
+void
+ColorWheel::triangle_corners(double &x0, double &y0,
+                             double &x1, double &y1,
+                             double &x2, double &y2)
+{
+    Gtk::Allocation allocation = get_allocation();
+    const int width  = allocation.get_width();
+    const int height = allocation.get_height();
+
+    int cx = width/2;
+    int cy = height/2;
+
+    int focus_line_width;
+    int focus_padding;
+    get_style_property("focus-line-width", focus_line_width);
+    get_style_property("focus-padding",    focus_padding);
+
+    double r_max = std::min( width, height)/2.0 - 2 * (focus_line_width + focus_padding);
+    double r_min = r_max * (1.0 - _ring_width);
+
+    double angle = _hue * 2.0 * M_PI;
+
+    x0 = cx + cos(angle) * r_min;
+    y0 = cy - sin(angle) * r_min;
+    x1 = cx + cos(angle + 2.0 * M_PI / 3.0) * r_min;
+    y1 = cy - sin(angle + 2.0 * M_PI / 3.0) * r_min;
+    x2 = cx + cos(angle + 4.0 * M_PI / 3.0) * r_min;
+    y2 = cy - sin(angle + 4.0 * M_PI / 3.0) * r_min;
+}
+
+void
+ColorWheel::set_from_xy(const double& x, const double& y)
+{
+    Gtk::Allocation allocation = get_allocation();
+    const int width  = allocation.get_width();
+    const int height = allocation.get_height();
+    double cx = width/2.0;
+    double cy = height/2.0;
+    double r = std::min(cx, cy) * (1 - _ring_width);
+
+    // We calculate RGB value under the cursor by rotating the cursor
+    // and triangle by the hue value and looking at position in the
+    // now right pointing triangle.
+    double angle = _hue  * 2 * M_PI;
+    double Sin = sin(angle);
+    double Cos = cos(angle);
+    double xp =  ((x-cx) * Cos - (y-cy) * Sin) / r;
+    double yp =  ((x-cx) * Sin + (y-cy) * Cos) / r;
+
+    double xt = lerp(0.0, 1.0, -0.5, 1.0, xp);
+    xt = clamp(xt, 0, 1);
+
+    double dy = (1-xt) * cos(M_PI/6.0);
+    double yt = lerp(0.0, 1.0, -dy, dy, yp);
+    yt = clamp(yt, 0, 1);
+
+    color_point c0(0, 0, yt, yt, yt);              // Grey point along base.
+    color_point c1(0, 0, hsv_to_rgb(_hue, 1, 1));  // Hue point at apex
+    color_point c = lerp(c0, c1, 0, 1, xt);
+
+    set_rgb(c.r, c.g, c.b, false); // Don't override previous hue.
+}
+
+bool
+ColorWheel::is_in_ring(const double& x, const double& y)
+{
+    Gtk::Allocation allocation = get_allocation();
+    const int width  = allocation.get_width();
+    const int height = allocation.get_height();
+
+    int cx = width/2;
+    int cy = height/2;
+
+    int focus_line_width;
+    int focus_padding;
+    get_style_property("focus-line-width", focus_line_width);
+    get_style_property("focus-padding",    focus_padding);
+
+    double r_max = std::min( width, height)/2.0 - 2 * (focus_line_width + focus_padding);
+    double r_min = r_max * (1.0 - _ring_width);
+    double r2_max = r_max * r_max;
+    double r2_min = r_min * r_min;
+
+    double dx = x - cx;
+    double dy = y - cy;
+    double r2 = dx * dx + dy * dy;
+  
+    return (r2_min < r2 && r2 < r2_max);
+}
+
+bool
+ColorWheel::is_in_triangle(const double& x, const double& y)
+{
+    double x0, y0, x1, y1, x2, y2;
+    triangle_corners(x0, y0, x1, y1, x2, y2);
+
+    double det = (x2-x1) * (y0-y1) - (y2-y1) * (x0-x1);
+    double s = ((x -x1) * (y0-y1) - (y -y1) * (x0-x1)) / det; 
+    double t = ((x2-x1) * (y -y1) - (y2-y1) * (x -x1)) / det; 
+
+    return (s >= 0.0 && t >= 0.0 && s+t <= 1.0);
+}
+
+bool
+ColorWheel::on_focus(Gtk::DirectionType direction)
+{
+    // In forward direction, focus passes from no focus to ring focus to triangle focus to no focus.
+    if (!has_focus()) {
+        _focus_on_ring = (direction == Gtk::DIR_TAB_FORWARD);
+        grab_focus();
+        return true;
+    }
+
+    // Already have focus
+    bool keep_focus = false;
+
+    switch (direction) {
+        case Gtk::DIR_UP:
+        case Gtk::DIR_LEFT:
+        case Gtk::DIR_TAB_BACKWARD:
+            if (!_focus_on_ring) {
+                _focus_on_ring = true;
+                keep_focus = true;
+            }
+            break;
+
+        case Gtk::DIR_DOWN:
+        case Gtk::DIR_RIGHT:
+        case Gtk::DIR_TAB_FORWARD:
+            if (_focus_on_ring) {
+                _focus_on_ring = false;
+                keep_focus = true;
+            }
+            break;
+    }
+
+    queue_draw();  // Update focus indicators.
+
+    return keep_focus;
+}
+
+bool
+ColorWheel::on_button_press_event(GdkEventButton* event)
+{
+    // Seat is automatically grabbed.
+    double x = event->x;
+    double y = event->y;
+
+    if (is_in_ring(x, y) ) {
+        _mode = DRAG_H;
+        grab_focus();
+        _focus_on_ring = true;
+        return true;
+    }
+
+    if (is_in_triangle(x, y)) {
+        _mode = DRAG_SV;
+        grab_focus();
+        _focus_on_ring = false;
+        return true;
+    }
+
+    return false;
+}
+
+bool
+ColorWheel::on_button_release_event(GdkEventButton* event)
+{
+    _mode == DRAG_NONE;
+    return true;
+}
+
+bool
+ColorWheel::on_motion_notify_event(GdkEventMotion* event)
+{
+    double x = event->x;
+    double y = event->y;
+
+    Gtk::Allocation allocation = get_allocation();
+    const int width  = allocation.get_width();
+    const int height = allocation.get_height();
+    double cx = width/2.0;
+    double cy = height/2.0;
+    double r = std::min(cx, cy) * (1 - _ring_width);
+
+    if (_mode == DRAG_H) {
+
+        double angle = -atan2(y-cy, x-cx);
+        if (angle < 0) angle += 2.0 * M_PI;
+        _hue = angle / (2.0 * M_PI);
+
+        queue_draw();
+        _signal_color_changed.emit();
+        return true;
+    }
+
+    if (_mode == DRAG_SV) {
+
+        set_from_xy(x, y);
+        _signal_color_changed.emit();
+        queue_draw();
+        return true;
+    }
+
+    return false;
+}
+
+bool
+ColorWheel::on_key_press_event(GdkEventKey* key_event)
+{
+    bool consumed = false;
+
+    unsigned int key = 0;
+    gdk_keymap_translate_keyboard_state( Gdk::Display::get_default()->get_keymap(),
+                                         key_event->hardware_keycode,
+                                         (GdkModifierType)key_event->state,
+                                         0, &key, nullptr, nullptr, nullptr );
+
+    double x0, y0, x1, y1, x2, y2;
+    triangle_corners(x0, y0, x1, y1, x2, y2);
+
+    // Marker position
+    double mx = x1 + (x2-x1) * _value + (x0-x2) * _saturation * _value;
+    double my = y1 + (y2-y1) * _value + (y0-y2) * _saturation * _value;
+
+
+    const double delta_hue = 2.0/360.0;
+
+    switch (key) {
+
+        case GDK_KEY_Up:
+        case GDK_KEY_KP_Up:
+            if (_focus_on_ring) {
+                _hue += delta_hue;
+            } else {
+                my -= 1.0;
+                set_from_xy(mx, my);
+            }
+            consumed = true;
+            break;
+
+        case GDK_KEY_Down:
+        case GDK_KEY_KP_Down:
+            if (_focus_on_ring) {
+                _hue -= delta_hue;
+            } else {
+                my += 1.0;
+                set_from_xy(mx, my);
+            }
+            consumed = true;
+            break;
+
+        case GDK_KEY_Left:
+        case GDK_KEY_KP_Left:
+            if (_focus_on_ring) {
+                _hue += delta_hue;
+            } else {
+                mx -= 1.0;
+                set_from_xy(mx, my);
+            }
+            consumed = true;
+            break;
+
+        case GDK_KEY_Right:
+        case GDK_KEY_KP_Right:
+            if (_focus_on_ring) {
+                _hue -= delta_hue;
+            } else {
+                mx += 1.0;
+                set_from_xy(mx, my);
+            }
+            consumed = true;
+            break;
+
+    }
+
+    if (consumed) {
+        if (_hue >= 1.0) _hue -= 1.0;
+        if (_hue <  0.0) _hue += 1.0;
+        _signal_color_changed.emit();
+        queue_draw();
+    }
+
+    return consumed;
+}
+
+sigc::signal<void>
+ColorWheel::signal_color_changed()
+{
+    return _signal_color_changed;
+}
+
+} // Namespace Inkscape
+}
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
diff --git a/src/ui/widget/ink-color-wheel.h b/src/ui/widget/ink-color-wheel.h
new file mode 100644
index 000000000..c6333b702
--- /dev/null
+++ b/src/ui/widget/ink-color-wheel.h
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Color wheel widget. Outer ring for Hue. Inner triangle for Saturation and Value.
+ *
+ * Copyright (C) 2018 Tavmjong Bah
+ *
+ * The contents of this file may be used under the GNU General Public License Version 2 or later.
+ *
+ */
+
+#ifndef INK_COLORWHEEL_H
+#define INK_COLORWHEEL_H
+
+/* Rewrite of the C Gimp ColorWheel which came originally from GTK2. */
+
+#include <gtkmm.h>
+#include <iostream>
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+  
+class ColorWheel : public Gtk::DrawingArea
+{
+public:
+    ColorWheel();
+    void set_rgb(const double& r, const double& g, const double& b, bool override_hue = true);
+    void get_rgb(double& r, double& g, double& b);
+    guint32 get_rgb();
+    bool is_adjusting() {return _mode != DRAG_NONE;}
+
+protected:
+    bool on_draw(const::Cairo::RefPtr<::Cairo::Context>& cr) override;
+
+private:
+    void triangle_corners(double& x0, double& y0,
+                          double& x1, double& y1,
+                          double& x2, double& y2);
+    void set_from_xy(const double& x, const double& y);
+    bool is_in_ring(    const double& x, const double& y);
+    bool is_in_triangle(const double& x, const double& y);
+
+    enum DragMode {
+        DRAG_NONE,
+        DRAG_H,
+        DRAG_SV
+    };
+
+    double _hue;  // Range [0,1)
+    double _saturation;
+    double _value;
+    double _ring_width;
+    DragMode _mode;
+    bool   _focus_on_ring;
+
+    // Callbacks
+    bool on_focus(Gtk::DirectionType direction) override;
+    bool on_button_press_event(GdkEventButton* event) override;
+    bool on_button_release_event(GdkEventButton* event) override;
+    bool on_motion_notify_event(GdkEventMotion* event) override;
+    bool on_key_press_event(GdkEventKey* key_event) override;
+
+    // Signals
+public:
+    sigc::signal<void> signal_color_changed();
+
+protected:
+    sigc::signal<void> _signal_color_changed;
+
+};
+
+} // Namespace Inkscape
+}
+}
+#endif // INK_COLOR_WHEEL_H
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
diff --git a/src/widgets/gimp/CMakeLists.txt b/src/widgets/gimp/CMakeLists.txt
index 0c8686cdd..c870b7528 100644
--- a/src/widgets/gimp/CMakeLists.txt
+++ b/src/widgets/gimp/CMakeLists.txt
@@ -1,11 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 set(gimpwidgets_SRC
-	gimpcolorwheel.c
 	ruler.cpp
 
 	# -------
 	# Headers
-	gimpcolorwheel.h
 	ruler.h
 )
 
diff --git a/src/widgets/gimp/gimpcolorwheel.c b/src/widgets/gimp/gimpcolorwheel.c
deleted file mode 100644
index 87f17eac6..000000000
--- a/src/widgets/gimp/gimpcolorwheel.c
+++ /dev/null
@@ -1,1484 +0,0 @@
-// SPDX-License-Identifier: LGPL-3.0-or-later
-/* HSV color selector for GTK+
- *
- * Copyright (C) 1999 The Free Software Foundation
- *
- * Authors: Simon Budig <Simon.Budig@unix-ag.org> (original code)
- *          Federico Mena-Quintero <federico@gimp.org> (cleanup for GTK+)
- *          Jonathan Blandford <jrb@redhat.com> (cleanup for GTK+)
- *          Michael Natterer <mitch@gimp.org> (ported back to GIMP)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation; either version 3 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, see <http://www.gnu.org/licenses/>.
- */
-
-/*
- * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
- * file for a list of people on the GTK+ Team.  See the ChangeLog
- * files for a list of changes.  These files are distributed with
- * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
- */
-
-/*
- * This widget was adopted by Inkscape by Alex Valavanis <valavanisalex@gmail.com>
- * on 2013-01-08.  Last merges with GIMP code were applied using the following
- * commits from the GIMP git repository at 
- * http://git.gnome.org/browse/gimp/tree/modules/gimpcolorwheel.c
- *
- * Gtk+ 2 code merge: commit 632c5 (2013-01-06)
- * Gtk+ 3 code merge: commit bcfc6, gtk3-port branch (2013-01-06)
- */
-
-#include <gtk/gtk.h>
-#include <gdk/gdkkeysyms.h>
-
-#include "gimpcolorwheel.h"
-#include <math.h>
-
-
-/* Default ring fraction */
-#define DEFAULT_FRACTION 0.1
-
-/* Default width/height */
-#define DEFAULT_SIZE 100
-
-/* Default ring width */
-#define DEFAULT_RING_WIDTH 10
-
-
-/* Dragging modes */
-typedef enum
-{
-  DRAG_NONE,
-  DRAG_H,
-  DRAG_SV
-} DragMode;
-
-/* Private part of the GimpColorWheel structure */
-typedef struct
-{
-  /* Color value */
-  gdouble h;
-  gdouble s;
-  gdouble v;
-
-  /* ring_width is this fraction of size */
-  gdouble ring_fraction;
-
-  /* Size and ring width */
-  gint size;
-  gint ring_width;
-
-  /* Window for capturing events */
-  GdkWindow *window;
-
-  /* Dragging mode */
-  DragMode mode;
-
-  guint focus_on_ring : 1;
-} GimpColorWheelPrivate;
-
-enum
-{
-  CHANGED,
-  MOVE,
-  LAST_SIGNAL
-};
-
-static void     gimp_color_wheel_map            (GtkWidget          *widget);
-static void     gimp_color_wheel_unmap          (GtkWidget          *widget);
-static void     gimp_color_wheel_realize        (GtkWidget          *widget);
-static void     gimp_color_wheel_unrealize      (GtkWidget          *widget);
-static void     gimp_color_wheel_size_allocate  (GtkWidget          *widget,
-                                                 GtkAllocation      *allocation);
-static gboolean gimp_color_wheel_button_press   (GtkWidget          *widget,
-                                                 GdkEventButton     *event);
-static gboolean gimp_color_wheel_button_release (GtkWidget          *widget,
-                                                 GdkEventButton     *event);
-static gboolean gimp_color_wheel_motion         (GtkWidget          *widget,
-                                                 GdkEventMotion     *event);
-static gboolean gimp_color_wheel_draw           (GtkWidget          *widget,
-                                                 cairo_t            *cr);
-static void     gimp_color_wheel_get_preferred_width (GtkWidget     *widget,
-		                                 gint               *minimum_width,
-						 gint               *natural_width);
-static void     gimp_color_wheel_get_preferred_height (GtkWidget    *widget,
-		                                 gint               *minimum_height,
-						 gint               *natural_height);
-static gboolean gimp_color_wheel_grab_broken    (GtkWidget          *widget,
-                                                 GdkEventGrabBroken *event);
-static gboolean gimp_color_wheel_focus          (GtkWidget          *widget,
-                                                 GtkDirectionType    direction);
-static void     gimp_color_wheel_move           (GimpColorWheel     *wheel,
-                                                 GtkDirectionType    dir);
-
-
-static guint wheel_signals[LAST_SIGNAL];
-
-G_DEFINE_TYPE (GimpColorWheel, gimp_color_wheel, GTK_TYPE_WIDGET)
-
-#define parent_class gimp_color_wheel_parent_class
-
-
-static void
-gimp_color_wheel_class_init (GimpColorWheelClass *class)
-{
-  GObjectClass        *object_class = G_OBJECT_CLASS (class);
-  GtkWidgetClass      *widget_class = GTK_WIDGET_CLASS (class);
-  GimpColorWheelClass *wheel_class  = GIMP_COLOR_WHEEL_CLASS (class);
-  GtkBindingSet       *binding_set;
-
-  widget_class->map                  = gimp_color_wheel_map;
-  widget_class->unmap                = gimp_color_wheel_unmap;
-  widget_class->realize              = gimp_color_wheel_realize;
-  widget_class->unrealize            = gimp_color_wheel_unrealize;
-  widget_class->size_allocate        = gimp_color_wheel_size_allocate;
-  widget_class->button_press_event   = gimp_color_wheel_button_press;
-  widget_class->button_release_event = gimp_color_wheel_button_release;
-  widget_class->motion_notify_event  = gimp_color_wheel_motion;
-  widget_class->get_preferred_width  = gimp_color_wheel_get_preferred_width;
-  widget_class->get_preferred_height = gimp_color_wheel_get_preferred_height;
-  widget_class->draw                 = gimp_color_wheel_draw;
-  widget_class->focus                = gimp_color_wheel_focus;
-  widget_class->grab_broken_event    = gimp_color_wheel_grab_broken;
-
-  wheel_class->move                  = gimp_color_wheel_move;
-
-  wheel_signals[CHANGED] =
-    g_signal_new ("changed",
-                  G_OBJECT_CLASS_TYPE (object_class),
-                  G_SIGNAL_RUN_FIRST,
-                  G_STRUCT_OFFSET (GimpColorWheelClass, changed),
-                  NULL, NULL,
-                  g_cclosure_marshal_VOID__VOID,
-                  G_TYPE_NONE, 0);
-
-  wheel_signals[MOVE] =
-    g_signal_new ("move",
-                  G_OBJECT_CLASS_TYPE (object_class),
-                  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
-                  G_STRUCT_OFFSET (GimpColorWheelClass, move),
-                  NULL, NULL,
-                  g_cclosure_marshal_VOID__ENUM,
-                  G_TYPE_NONE, 1,
-                  GTK_TYPE_DIRECTION_TYPE);
-
-  binding_set = gtk_binding_set_by_class (class);
-
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Up, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_UP);
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Up, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_UP);
-
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Down, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_DOWN);
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Down, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_DOWN);
-
-
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Right, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_RIGHT);
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Right, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_RIGHT);
-
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_Left, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_LEFT);
-  gtk_binding_entry_add_signal (binding_set, GDK_KEY_KP_Left, 0,
-                                "move", 1,
-                                G_TYPE_ENUM, GTK_DIR_LEFT);
-
-  g_type_class_add_private (object_class, sizeof (GimpColorWheelPrivate));
-}
-
-static void
-gimp_color_wheel_init (GimpColorWheel *wheel)
-{
-  GimpColorWheelPrivate *priv;
-
-  priv = G_TYPE_INSTANCE_GET_PRIVATE (wheel, GIMP_TYPE_COLOR_WHEEL,
-                                      GimpColorWheelPrivate);
-
-  wheel->priv = priv;
-
-  gtk_widget_set_has_window (GTK_WIDGET (wheel), FALSE);
-  gtk_widget_set_can_focus (GTK_WIDGET (wheel), TRUE);
-
-  priv->ring_fraction = DEFAULT_FRACTION;
-  priv->size          = DEFAULT_SIZE;
-  priv->ring_width    = DEFAULT_RING_WIDTH;
-}
-
-static void
-gimp_color_wheel_map (GtkWidget *widget)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-
-  GTK_WIDGET_CLASS (parent_class)->map (widget);
-
-  gdk_window_show (priv->window);
-}
-
-static void
-gimp_color_wheel_unmap (GtkWidget *widget)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-
-  gdk_window_hide (priv->window);
-
-  GTK_WIDGET_CLASS (parent_class)->unmap (widget);
-}
-
-static void
-gimp_color_wheel_realize (GtkWidget *widget)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-  GtkAllocation          allocation;
-  GdkWindowAttr          attr;
-  gint                   attr_mask;
-  GdkWindow             *parent_window;
-
-  gtk_widget_get_allocation (widget, &allocation);
-
-  gtk_widget_set_realized (widget, TRUE);
-
-  attr.window_type = GDK_WINDOW_CHILD;
-  attr.x           = allocation.x;
-  attr.y           = allocation.y;
-  attr.width       = allocation.width;
-  attr.height      = allocation.height;
-  attr.wclass      = GDK_INPUT_ONLY;
-  attr.event_mask  = (gtk_widget_get_events (widget) |
-                      GDK_KEY_PRESS_MASK      |
-                      GDK_BUTTON_PRESS_MASK   |
-                      GDK_BUTTON_RELEASE_MASK |
-                      GDK_POINTER_MOTION_MASK |
-                      GDK_ENTER_NOTIFY_MASK   |
-                      GDK_LEAVE_NOTIFY_MASK);
-
-  attr_mask = GDK_WA_X | GDK_WA_Y;
-
-  parent_window = gtk_widget_get_parent_window (widget);
-
-  gtk_widget_set_window (widget, parent_window);
-  g_object_ref (parent_window);
-
-  priv->window = gdk_window_new (parent_window, &attr, attr_mask);
-  gdk_window_set_user_data (priv->window, wheel);
-}
-
-static void
-gimp_color_wheel_unrealize (GtkWidget *widget)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-
-  gdk_window_set_user_data (priv->window, NULL);
-  gdk_window_destroy (priv->window);
-  priv->window = NULL;
-
-  GTK_WIDGET_CLASS (parent_class)->unrealize (widget);
-}
-
-static void
-gimp_color_wheel_get_preferred_width (GtkWidget *widget,
-                                      gint      *minimum_width,
-				      gint      *natural_width)
-{
-  gint focus_width;
-  gint focus_pad;
-
-  gtk_widget_style_get (widget,
-                        "focus-line-width", &focus_width,
-                        "focus-padding", &focus_pad,
-                        NULL);
-  
-  *minimum_width = *natural_width = DEFAULT_SIZE + 2 * (focus_width + focus_pad);
-}
-
-static void
-gimp_color_wheel_get_preferred_height (GtkWidget *widget,
-                                       gint      *minimum_height,
-				       gint      *natural_height)
-{
-  gint focus_width;
-  gint focus_pad;
-
-  gtk_widget_style_get (widget,
-                        "focus-line-width", &focus_width,
-                        "focus-padding", &focus_pad,
-                        NULL);
-  
-  *minimum_height = *natural_height = DEFAULT_SIZE + 2 * (focus_width + focus_pad);
-}
-
-static void
-gimp_color_wheel_size_allocate (GtkWidget     *widget,
-                                GtkAllocation *allocation)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-  gint                   focus_width;
-  gint                   focus_pad;
-
-  gtk_widget_set_allocation (widget, allocation);
-
-  gtk_widget_style_get (widget,
-                        "focus-line-width", &focus_width,
-                        "focus-padding",    &focus_pad,
-                        NULL);
-
-  priv->size = MIN (allocation->width  - 2 * (focus_width + focus_pad),
-                    allocation->height - 2 * (focus_width + focus_pad));
-
-  priv->ring_width = priv->size * priv->ring_fraction;
-
-  if (gtk_widget_get_realized (widget))
-    gdk_window_move_resize (priv->window,
-                            allocation->x,
-                            allocation->y,
-                            allocation->width,
-                            allocation->height);
-}
-
-
-/* Utility functions */
-
-#define INTENSITY(r, g, b) ((r) * 0.30 + (g) * 0.59 + (b) * 0.11)
-
-/* Converts from HSV to RGB */
-static void
-hsv_to_rgb (gdouble *h,
-            gdouble *s,
-            gdouble *v)
-{
-  gdouble hue, saturation, value;
-  gdouble f, p, q, t;
-
-  if (*s == 0.0)
-    {
-      *h = *v;
-      *s = *v;
-   /* *v = *v; -- heh */
-    }
-  else
-    {
-      hue = *h * 6.0;
-      saturation = *s;
-      value = *v;
-
-      if (hue == 6.0)
-        hue = 0.0;
-
-      f = hue - (int) hue;
-      p = value * (1.0 - saturation);
-      q = value * (1.0 - saturation * f);
-      t = value * (1.0 - saturation * (1.0 - f));
-
-      switch ((int) hue)
-        {
-        case 0:
-          *h = value;
-          *s = t;
-          *v = p;
-          break;
-
-        case 1:
-          *h = q;
-          *s = value;
-          *v = p;
-          break;
-
-        case 2:
-          *h = p;
-          *s = value;
-          *v = t;
-          break;
-
-        case 3:
-          *h = p;
-          *s = q;
-          *v = value;
-          break;
-
-        case 4:
-          *h = t;
-          *s = p;
-          *v = value;
-          break;
-
-        case 5:
-          *h = value;
-          *s = p;
-          *v = q;
-          break;
-
-        default:
-          g_assert_not_reached ();
-        }
-    }
-}
-
-/* Computes the vertices of the saturation/value triangle */
-static void
-compute_triangle (GimpColorWheel *wheel,
-                  gint           *hx,
-                  gint           *hy,
-                  gint           *sx,
-                  gint           *sy,
-                  gint           *vx,
-                  gint           *vy)
-{
-  GimpColorWheelPrivate *priv = wheel->priv;
-  GtkAllocation          allocation;
-  gdouble                center_x;
-  gdouble                center_y;
-  gdouble                inner, outer;
-  gdouble                angle;
-
-  gtk_widget_get_allocation (GTK_WIDGET (wheel), &allocation);
-
-  center_x = allocation.width / 2.0;
-  center_y = allocation.height / 2.0;
-
-  outer = priv->size / 2.0;
-  inner = outer - priv->ring_width;
-  angle = priv->h * 2.0 * G_PI;
-
-  *hx = floor (center_x + cos (angle) * inner + 0.5);
-  *hy = floor (center_y - sin (angle) * inner + 0.5);
-  *sx = floor (center_x + cos (angle + 2.0 * G_PI / 3.0) * inner + 0.5);
-  *sy = floor (center_y - sin (angle + 2.0 * G_PI / 3.0) * inner + 0.5);
-  *vx = floor (center_x + cos (angle + 4.0 * G_PI / 3.0) * inner + 0.5);
-  *vy = floor (center_y - sin (angle + 4.0 * G_PI / 3.0) * inner + 0.5);
-}
-
-/* Computes whether a point is inside the hue ring */
-static gboolean
-is_in_ring (GimpColorWheel *wheel,
-            gdouble         x,
-            gdouble         y)
-{
-  GimpColorWheelPrivate *priv = wheel->priv;
-  GtkAllocation          allocation;
-  gdouble                dx, dy, dist;
-  gdouble                center_x;
-  gdouble                center_y;
-  gdouble                inner, outer;
-
-  gtk_widget_get_allocation (GTK_WIDGET (wheel), &allocation);
-
-  center_x = allocation.width / 2.0;
-  center_y = allocation.height / 2.0;
-
-  outer = priv->size / 2.0;
-  inner = outer - priv->ring_width;
-
-  dx = x - center_x;
-  dy = center_y - y;
-  dist = dx * dx + dy * dy;
-
-  return (dist >= inner * inner && dist <= outer * outer);
-}
-
-/* Computes a saturation/value pair based on the mouse coordinates */
-static void
-compute_sv (GimpColorWheel *wheel,
-            gdouble         x,
-            gdouble         y,
-            gdouble        *s,
-            gdouble        *v)
-{
-  GtkAllocation allocation;
-  gint          ihx, ihy, isx, isy, ivx, ivy;
-  gdouble       hx, hy, sx, sy, vx, vy;
-  gdouble       center_x;
-  gdouble       center_y;
-
-  gtk_widget_get_allocation (GTK_WIDGET (wheel), &allocation);
-
-  compute_triangle (wheel, &ihx, &ihy, &isx, &isy, &ivx, &ivy);
-
-  center_x = allocation.width / 2.0;
-  center_y = allocation.height / 2.0;
-
-  hx = ihx - center_x;
-  hy = center_y - ihy;
-  sx = isx - center_x;
-  sy = center_y - isy;
-  vx = ivx - center_x;
-  vy = center_y - ivy;
-  x -= center_x;
-  y = center_y - y;
-
-  if (vx * (x - sx) + vy * (y - sy) < 0.0)
-    {
-      *s = 1.0;
-      *v = (((x - sx) * (hx - sx) + (y - sy) * (hy-sy))
-            / ((hx - sx) * (hx - sx) + (hy - sy) * (hy - sy)));
-
-      if (*v < 0.0)
-        *v = 0.0;
-      else if (*v > 1.0)
-        *v = 1.0;
-    }
-  else if (hx * (x - sx) + hy * (y - sy) < 0.0)
-    {
-      *s = 0.0;
-      *v = (((x - sx) * (vx - sx) + (y - sy) * (vy - sy))
-            / ((vx - sx) * (vx - sx) + (vy - sy) * (vy - sy)));
-
-      if (*v < 0.0)
-        *v = 0.0;
-      else if (*v > 1.0)
-        *v = 1.0;
-    }
-  else if (sx * (x - hx) + sy * (y - hy) < 0.0)
-    {
-      *v = 1.0;
-      *s = (((x - vx) * (hx - vx) + (y - vy) * (hy - vy)) /
-            ((hx - vx) * (hx - vx) + (hy - vy) * (hy - vy)));
-
-      if (*s < 0.0)
-        *s = 0.0;
-      else if (*s > 1.0)
-        *s = 1.0;
-    }
-  else
-    {
-      *v = (((x - sx) * (hy - vy) - (y - sy) * (hx - vx))
-            / ((vx - sx) * (hy - vy) - (vy - sy) * (hx - vx)));
-
-      if (*v<= 0.0)
-        {
-          *v = 0.0;
-          *s = 0.0;
-        }
-      else
-        {
-          if (*v > 1.0)
-            *v = 1.0;
-
-          if (fabs (hy - vy) < fabs (hx - vx))
-            *s = (x - sx - *v * (vx - sx)) / (*v * (hx - vx));
-          else
-            *s = (y - sy - *v * (vy - sy)) / (*v * (hy - vy));
-
-          if (*s < 0.0)
-            *s = 0.0;
-          else if (*s > 1.0)
-            *s = 1.0;
-        }
-    }
-}
-
-/* Computes whether a point is inside the saturation/value triangle */
-static gboolean
-is_in_triangle (GimpColorWheel *wheel,
-                gdouble         x,
-                gdouble         y)
-{
-  gint    hx, hy, sx, sy, vx, vy;
-  gdouble det, s, v;
-
-  compute_triangle (wheel, &hx, &hy, &sx, &sy, &vx, &vy);
-
-  det = (vx - sx) * (hy - sy) - (vy - sy) * (hx - sx);
-
-  s = ((x - sx) * (hy - sy) - (y - sy) * (hx - sx)) / det;
-  v = ((vx - sx) * (y - sy) - (vy - sy) * (x - sx)) / det;
-
-  return (s >= 0.0 && v >= 0.0 && s + v <= 1.0);
-}
-
-/* Computes a value based on the mouse coordinates */
-static double
-compute_v (GimpColorWheel *wheel,
-           gdouble         x,
-           gdouble         y)
-{
-  GtkAllocation allocation;
-  gdouble       center_x;
-  gdouble       center_y;
-  gdouble       dx, dy;
-  gdouble       angle;
-
-  gtk_widget_get_allocation (GTK_WIDGET (wheel), &allocation);
-
-  center_x = allocation.width / 2.0;
-  center_y = allocation.height / 2.0;
-
-  dx = x - center_x;
-  dy = center_y - y;
-
-  angle = atan2 (dy, dx);
-  if (angle < 0.0)
-    angle += 2.0 * G_PI;
-
-  return angle / (2.0 * G_PI);
-}
-
-static void
-set_cross_grab (GimpColorWheel *wheel,
-                GdkEvent       *event)
-{
-  GimpColorWheelPrivate *priv = wheel->priv;
-  GdkCursor             *cursor;
-
-  cursor =
-    gdk_cursor_new_for_display (gtk_widget_get_display (GTK_WIDGET (wheel)),
-                                GDK_CROSSHAIR);
-
-  GdkDevice *device = gtk_get_current_event_device();
-#if GTK_CHECK_VERSION(3,20,0)
-  GdkSeat *seat = gdk_device_get_seat(device);
-  gdk_seat_grab (seat,
-                 priv->window,
-                 GDK_SEAT_CAPABILITY_ALL_POINTING,
-		 FALSE,
-		 cursor,
-		 event,
-		 NULL,
-		 NULL);
-#else
-  gdk_device_grab (device,
-		   priv->window,
-		   GDK_OWNERSHIP_NONE,
-		   FALSE,
-		   GDK_POINTER_MOTION_MASK      |
-		   GDK_POINTER_MOTION_HINT_MASK |
-		   GDK_BUTTON_RELEASE_MASK,
-		   cursor, gtk_get_current_event_time());
-#endif
-
-  g_object_unref (cursor);
-}
-
-static gboolean gimp_color_wheel_grab_broken(GtkWidget *widget, GdkEventGrabBroken *event)
-{
-    (void)event;
-    GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-    GimpColorWheelPrivate *priv  = wheel->priv;
-
-    priv->mode = DRAG_NONE;
-
-    return TRUE;
-}
-
-static gboolean
-gimp_color_wheel_button_press (GtkWidget      *widget,
-                               GdkEventButton *event)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-  gdouble                x, y;
-
-  if (priv->mode != DRAG_NONE || event->button != 1)
-    return FALSE;
-
-  x = event->x;
-  y = event->y;
-
-  if (is_in_ring (wheel, x, y))
-    {
-      priv->mode = DRAG_H;
-      set_cross_grab (wheel, (GdkEvent *)event);
-
-      gimp_color_wheel_set_color (wheel,
-                                  compute_v (wheel, x, y),
-                                  priv->s,
-                                  priv->v);
-
-      gtk_widget_grab_focus (widget);
-      priv->focus_on_ring = TRUE;
-
-      return TRUE;
-    }
-
-  if (is_in_triangle (wheel, x, y))
-    {
-      gdouble s, v;
-
-      priv->mode = DRAG_SV;
-      set_cross_grab (wheel, (GdkEvent *)event);
-
-      compute_sv (wheel, x, y, &s, &v);
-      gimp_color_wheel_set_color (wheel, priv->h, s, v);
-
-      gtk_widget_grab_focus (widget);
-      priv->focus_on_ring = FALSE;
-
-      return TRUE;
-    }
-
-  return FALSE;
-}
-
-static gboolean
-gimp_color_wheel_button_release (GtkWidget      *widget,
-                                 GdkEventButton *event)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-  DragMode               mode;
-  gdouble                x, y;
-
-  if (priv->mode == DRAG_NONE || event->button != 1)
-    return FALSE;
-
-  /* Set the drag mode to DRAG_NONE so that signal handlers for "catched"
-   * can see that this is the final color state.
-   */
-
-  mode = priv->mode;
-  priv->mode = DRAG_NONE;
-
-  x = event->x;
-  y = event->y;
-
-  if (mode == DRAG_H)
-    {
-      gimp_color_wheel_set_color (wheel,
-                                  compute_v (wheel, x, y), priv->s, priv->v);
-    }
-  else if (mode == DRAG_SV)
-    {
-      gdouble s, v;
-
-      compute_sv (wheel, x, y, &s, &v);
-      gimp_color_wheel_set_color (wheel, priv->h, s, v);
-    }
-  else
-    g_assert_not_reached ();
-
-  GdkDevice *device = gtk_get_current_event_device();
-#if GTK_CHECK_VERSION(3,20,0)
-  GdkSeat *seat = gdk_device_get_seat(device);
-  gdk_seat_ungrab (seat);
-#else
-  gdk_device_ungrab (device,
-                     (GdkEvent *)event);
-#endif
-
-  return TRUE;
-}
-
-static gboolean
-gimp_color_wheel_motion (GtkWidget      *widget,
-                         GdkEventMotion *event)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-  gdouble                x, y;
-
-  if (priv->mode == DRAG_NONE)
-    return FALSE;
-
-  gdk_event_request_motions (event);
-  x = event->x;
-  y = event->y;
-
-  if (priv->mode == DRAG_H)
-    {
-      gimp_color_wheel_set_color (wheel,
-                                  compute_v (wheel, x, y), priv->s, priv->v);
-      return TRUE;
-    }
-  else if (priv->mode == DRAG_SV)
-    {
-      gdouble s, v;
-
-      compute_sv (wheel, x, y, &s, &v);
-      gimp_color_wheel_set_color (wheel, priv->h, s, v);
-      return TRUE;
-    }
-
-  g_assert_not_reached ();
-
-  return FALSE;
-}
-
-
-/* Redrawing */
-
-/* Paints the hue ring */
-static void
-paint_ring (GimpColorWheel *wheel,
-            cairo_t        *cr)
-{
-  GtkWidget             *widget = GTK_WIDGET (wheel);
-  GimpColorWheelPrivate *priv   = wheel->priv;
-  gint                   width, height;
-  gint                   xx, yy;
-  gdouble                dx, dy, dist;
-  gdouble                center_x;
-  gdouble                center_y;
-  gdouble                inner, outer;
-  guint32               *buf, *p;
-  gdouble                angle;
-  gdouble                hue;
-  gdouble                r, g, b;
-  cairo_surface_t       *source;
-  cairo_t               *source_cr;
-  gint                   stride;
-
-  width  = gtk_widget_get_allocated_width  (widget);
-  height = gtk_widget_get_allocated_height (widget);
-
-  center_x = width  / 2.0;
-  center_y = height / 2.0;
-
-  outer = priv->size / 2.0;
-  inner = outer - priv->ring_width;
-
-  /* Create an image initialized with the ring colors */
-
-  stride = cairo_format_stride_for_width (CAIRO_FORMAT_RGB24, width);
-  buf = g_new (guint32, height * stride / 4);
-
-  for (yy = 0; yy < height; yy++)
-    {
-      p = buf + yy * width;
-      dy = -(yy - center_y);
-
-      for (xx = 0; xx < width; xx++)
-        {
-          dx = xx - center_x;
-
-          dist = dx * dx + dy * dy;
-          if (dist < ((inner-1) * (inner-1)) || dist > ((outer+1) * (outer+1)))
-            {
-              *p++ = 0;
-              continue;
-            }
-
-          angle = atan2 (dy, dx);
-          if (angle < 0.0)
-            angle += 2.0 * G_PI;
-
-          hue = angle / (2.0 * G_PI);
-
-          r = hue;
-          g = 1.0;
-          b = 1.0;
-          hsv_to_rgb (&r, &g, &b);
-
-          *p++ = (((int)floor (r * 255 + 0.5) << 16) |
-                  ((int)floor (g * 255 + 0.5) << 8) |
-                  (int)floor (b * 255 + 0.5));
-        }
-    }
-
-  source = cairo_image_surface_create_for_data ((unsigned char *)buf,
-                                                CAIRO_FORMAT_RGB24,
-                                                width, height, stride);
-
-  /* Now draw the value marker onto the source image, so that it
-   * will get properly clipped at the edges of the ring
-   */
-  source_cr = cairo_create (source);
-
-  r = priv->h;
-  g = 1.0;
-  b = 1.0;
-  hsv_to_rgb (&r, &g, &b);
-
-  if (INTENSITY (r, g, b) > 0.5)
-    cairo_set_source_rgb (source_cr, 0.0, 0.0, 0.0);
-  else
-    cairo_set_source_rgb (source_cr, 1.0, 1.0, 1.0);
-
-  cairo_move_to (source_cr, center_x, center_y);
-  cairo_line_to (source_cr,
-                 center_x + cos (priv->h * 2.0 * G_PI) * priv->size / 2,
-                 center_y - sin (priv->h * 2.0 * G_PI) * priv->size / 2);
-  cairo_stroke (source_cr);
-  cairo_destroy (source_cr);
-
-  /* Draw the ring using the source image */
-
-  cairo_save (cr);
-
-  cairo_set_source_surface (cr, source, 0, 0);
-  cairo_surface_destroy (source);
-
-  cairo_set_line_width (cr, priv->ring_width);
-  cairo_new_path (cr);
-  cairo_arc (cr,
-             center_x, center_y,
-             priv->size / 2.0 - priv->ring_width / 2.0,
-             0, 2 * G_PI);
-  cairo_stroke (cr);
-
-  cairo_restore (cr);
-
-  g_free (buf);
-}
-
-/* Converts an HSV triplet to an integer RGB triplet */
-static void
-get_color (gdouble  h,
-           gdouble  s,
-           gdouble  v,
-           gint    *r,
-           gint    *g,
-           gint    *b)
-{
-  hsv_to_rgb (&h, &s, &v);
-
-  *r = floor (h * 255 + 0.5);
-  *g = floor (s * 255 + 0.5);
-  *b = floor (v * 255 + 0.5);
-}
-
-#define SWAP(a, b, t) ((t) = (a), (a) = (b), (b) = (t))
-
-#define LERP(a, b, v1, v2, i) (((v2) - (v1) != 0)                                       \
-                               ? ((a) + ((b) - (a)) * ((i) - (v1)) / ((v2) - (v1)))     \
-                               : (a))
-
-/* Number of pixels we extend out from the edges when creating
- * color source to avoid artifacts
- */
-#define PAD 3
-
-/* Paints the HSV triangle */
-static void
-paint_triangle (GimpColorWheel *wheel,
-                cairo_t        *cr,
-                gboolean        draw_focus)
-{
-  GtkWidget             *widget = GTK_WIDGET (wheel);
-  GimpColorWheelPrivate *priv   = wheel->priv;
-  gint                   hx, hy, sx, sy, vx, vy; /* HSV vertices */
-  gint                   x1, y1, r1, g1, b1; /* First vertex in scanline order */
-  gint                   x2, y2, r2, g2, b2; /* Second vertex */
-  gint                   x3, y3, r3, g3, b3; /* Third vertex */
-  gint                   t;
-  guint32               *buf, *p, c;
-  gint                   xl, xr, rl, rr, gl, gr, bl, br; /* Scanline data */
-  gint                   xx, yy;
-  gint                   x_interp, y_interp;
-  gint                   x_start, x_end;
-  cairo_surface_t       *source;
-  gdouble                r, g, b;
-  gint                   stride;
-  gint                   width, height;
-  GtkStyleContext       *context;
-
-  width  = gtk_widget_get_allocated_width  (widget);
-  height = gtk_widget_get_allocated_height (widget);
-
-  /* Compute triangle's vertices */
-
-  compute_triangle (wheel, &hx, &hy, &sx, &sy, &vx, &vy);
-
-  x1 = hx;
-  y1 = hy;
-  get_color (priv->h, 1.0, 1.0, &r1, &g1, &b1);
-
-  x2 = sx;
-  y2 = sy;
-  get_color (priv->h, 1.0, 0.0, &r2, &g2, &b2);
-
-  x3 = vx;
-  y3 = vy;
-  get_color (priv->h, 0.0, 1.0, &r3, &g3, &b3);
-
-  if (y2 > y3)
-    {
-      SWAP (x2, x3, t);
-      SWAP (y2, y3, t);
-      SWAP (r2, r3, t);
-      SWAP (g2, g3, t);
-      SWAP (b2, b3, t);
-    }
-
-  if (y1 > y3)
-    {
-      SWAP (x1, x3, t);
-      SWAP (y1, y3, t);
-      SWAP (r1, r3, t);
-      SWAP (g1, g3, t);
-      SWAP (b1, b3, t);
-    }
-
-  if (y1 > y2)
-    {
-      SWAP (x1, x2, t);
-      SWAP (y1, y2, t);
-      SWAP (r1, r2, t);
-      SWAP (g1, g2, t);
-      SWAP (b1, b2, t);
-    }
-
-  /* Shade the triangle */
-
-  stride = cairo_format_stride_for_width (CAIRO_FORMAT_RGB24, width);
-  buf = g_new (guint32, height * stride / 4);
-
-  for (yy = 0; yy < height; yy++)
-    {
-      p = buf + yy * width;
-
-      if (yy >= y1 - PAD && yy < y3 + PAD)
-        {
-          y_interp = CLAMP (yy, y1, y3);
-
-          if (y_interp < y2)
-            {
-              xl = LERP (x1, x2, y1, y2, y_interp);
-
-              rl = LERP (r1, r2, y1, y2, y_interp);
-              gl = LERP (g1, g2, y1, y2, y_interp);
-              bl = LERP (b1, b2, y1, y2, y_interp);
-            }
-          else
-            {
-              xl = LERP (x2, x3, y2, y3, y_interp);
-
-              rl = LERP (r2, r3, y2, y3, y_interp);
-              gl = LERP (g2, g3, y2, y3, y_interp);
-              bl = LERP (b2, b3, y2, y3, y_interp);
-            }
-
-          xr = LERP (x1, x3, y1, y3, y_interp);
-
-          rr = LERP (r1, r3, y1, y3, y_interp);
-          gr = LERP (g1, g3, y1, y3, y_interp);
-          br = LERP (b1, b3, y1, y3, y_interp);
-
-          if (xl > xr)
-            {
-              SWAP (xl, xr, t);
-              SWAP (rl, rr, t);
-              SWAP (gl, gr, t);
-              SWAP (bl, br, t);
-            }
-
-          x_start = MAX (xl - PAD, 0);
-          x_end = MIN (xr + PAD, width);
-          x_start = MIN (x_start, x_end);
-
-          c = (rl << 16) | (gl << 8) | bl;
-
-          for (xx = 0; xx < x_start; xx++)
-            *p++ = c;
-
-          for (; xx < x_end; xx++)
-            {
-              x_interp = CLAMP (xx, xl, xr);
-
-              *p++ = ((LERP (rl, rr, xl, xr, x_interp) << 16) |
-                      (LERP (gl, gr, xl, xr, x_interp) << 8) |
-                      LERP (bl, br, xl, xr, x_interp));
-            }
-
-          c = (rr << 16) | (gr << 8) | br;
-
-          for (; xx < width; xx++)
-            *p++ = c;
-        }
-    }
-
-  source = cairo_image_surface_create_for_data ((unsigned char *)buf,
-                                                CAIRO_FORMAT_RGB24,
-                                                width, height, stride);
-
-  /* Draw a triangle with the image as a source */
-
-  cairo_set_source_surface (cr, source, 0, 0);
-  cairo_surface_destroy (source);
-
-  cairo_move_to (cr, x1, y1);
-  cairo_line_to (cr, x2, y2);
-  cairo_line_to (cr, x3, y3);
-  cairo_close_path (cr);
-  cairo_fill (cr);
-
-  g_free (buf);
-
-  /* Draw value marker */
-
-  xx = floor (sx + (vx - sx) * priv->v + (hx - vx) * priv->s * priv->v + 0.5);
-  yy = floor (sy + (vy - sy) * priv->v + (hy - vy) * priv->s * priv->v + 0.5);
-
-  r = priv->h;
-  g = priv->s;
-  b = priv->v;
-  hsv_to_rgb (&r, &g, &b);
-
-  context = gtk_widget_get_style_context (widget);
-
-  gtk_style_context_save (context);
-
-  if (INTENSITY (r, g, b) > 0.5)
-    {
-      gtk_style_context_add_class (context, "light-area-focus");
-      cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
-    }
-  else
-    {
-      gtk_style_context_add_class (context, "dark-area-focus");
-      cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
-    }
-
-#define RADIUS 4
-#define FOCUS_RADIUS 6
-
-  cairo_new_path (cr);
-  cairo_arc (cr, xx, yy, RADIUS, 0, 2 * G_PI);
-  cairo_stroke (cr);
-
-  /* Draw focus outline */
-
-  if (draw_focus && ! priv->focus_on_ring)
-    {
-      gint focus_width;
-      gint focus_pad;
-
-      gtk_widget_style_get (widget,
-                            "focus-line-width", &focus_width,
-                            "focus-padding",    &focus_pad,
-                            NULL);
-
-      gtk_render_focus (context, cr,
-                        xx - FOCUS_RADIUS - focus_width - focus_pad,
-                        yy - FOCUS_RADIUS - focus_width - focus_pad,
-                        2 * (FOCUS_RADIUS + focus_width + focus_pad),
-                        2 * (FOCUS_RADIUS + focus_width + focus_pad));
-    }
-
-  gtk_style_context_restore (context);
-}
-
-static gboolean
-gimp_color_wheel_draw (GtkWidget *widget,
-                       cairo_t   *cr)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-  gboolean               draw_focus;
-
-  draw_focus = gtk_widget_has_visible_focus (widget);
-
-  paint_ring (wheel, cr);
-  paint_triangle (wheel, cr, draw_focus);
-
-  if (draw_focus && priv->focus_on_ring)
-    {
-      GtkStyleContext *context = gtk_widget_get_style_context (widget);
-
-      gtk_render_focus (context, cr, 0, 0,
-                        gtk_widget_get_allocated_width (widget),
-                        gtk_widget_get_allocated_height (widget));
-    }
-
-  return FALSE;
-}
-
-static gboolean
-gimp_color_wheel_focus (GtkWidget        *widget,
-                        GtkDirectionType  dir)
-{
-  GimpColorWheel        *wheel = GIMP_COLOR_WHEEL (widget);
-  GimpColorWheelPrivate *priv  = wheel->priv;
-
-  if (!gtk_widget_has_focus (widget))
-    {
-      if (dir == GTK_DIR_TAB_BACKWARD)
-        priv->focus_on_ring = FALSE;
-      else
-        priv->focus_on_ring = TRUE;
-
-      gtk_widget_grab_focus (widget);
-      return TRUE;
-    }
-
-  switch (dir)
-    {
-    case GTK_DIR_UP:
-      if (priv->focus_on_ring)
-        return FALSE;
-      else
-        priv->focus_on_ring = TRUE;
-      break;
-
-    case GTK_DIR_DOWN:
-      if (priv->focus_on_ring)
-        priv->focus_on_ring = FALSE;
-      else
-        return FALSE;
-      break;
-
-    case GTK_DIR_LEFT:
-    case GTK_DIR_TAB_BACKWARD:
-      if (priv->focus_on_ring)
-        return FALSE;
-      else
-        priv->focus_on_ring = TRUE;
-      break;
-
-    case GTK_DIR_RIGHT:
-    case GTK_DIR_TAB_FORWARD:
-      if (priv->focus_on_ring)
-        priv->focus_on_ring = FALSE;
-      else
-        return FALSE;
-      break;
-    }
-
-  gtk_widget_queue_draw (widget);
-
-  return TRUE;
-}
-
-/**
- * gimp_color_wheel_new:
- *
- * Creates a new HSV color selector.
- *
- * Return value: A newly-created HSV color selector.
- *
- * Since: 2.10
- */
-GtkWidget*
-gimp_color_wheel_new (void)
-{
-  return g_object_new (GIMP_TYPE_COLOR_WHEEL, NULL);
-}
-
-/**
- * gimp_color_wheel_set_color:
- * @hsv: An HSV color selector
- * @h: Hue
- * @s: Saturation
- * @v: Value
- *
- * Sets the current color in an HSV color selector.
- * Color component values must be in the [0.0, 1.0] range.
- *
- * Since: 2.10
- */
-void
-gimp_color_wheel_set_color (GimpColorWheel *wheel,
-                            gdouble         h,
-                            gdouble         s,
-                            gdouble         v)
-{
-  GimpColorWheelPrivate *priv;
-
-  g_return_if_fail (GIMP_IS_COLOR_WHEEL (wheel));
-  g_return_if_fail (h >= 0.0 && h <= 1.0);
-  g_return_if_fail (s >= 0.0 && s <= 1.0);
-  g_return_if_fail (v >= 0.0 && v <= 1.0);
-
-  priv = wheel->priv;
-
-  if(h == 0.0 && s == 0.0) {
-    h = priv->h;
-  }
-
-  priv->h = h;
-  priv->s = s;
-  priv->v = v;
-
-  g_signal_emit (wheel, wheel_signals[CHANGED], 0);
-
-  gtk_widget_queue_draw (GTK_WIDGET (wheel));
-}
-
-/**
- * gimp_color_wheel_get_color:
- * @hsv: An HSV color selector
- * @h: (out): Return value for the hue
- * @s: (out): Return value for the saturation
- * @v: (out): Return value for the value
- *
- * Queries the current color in an HSV color selector.
- * Returned values will be in the [0.0, 1.0] range.
- *
- * Since: 2.10
- */
-void
-gimp_color_wheel_get_color (GimpColorWheel *wheel,
-                            gdouble        *h,
-                            gdouble        *s,
-                            gdouble        *v)
-{
-  GimpColorWheelPrivate *priv;
-
-  g_return_if_fail (GIMP_IS_COLOR_WHEEL (wheel));
-
-  priv = wheel->priv;
-
-  if (h) *h = priv->h;
-  if (s) *s = priv->s;
-  if (v) *v = priv->v;
-}
-
-/**
- * gimp_color_wheel_set_ring_fraction:
- * @ring: A wheel color selector
- * @fraction: Ring fraction
- *
- * Sets the ring fraction of a wheel color selector.
- *
- * Since: 2.10
- */
-void
-gimp_color_wheel_set_ring_fraction (GimpColorWheel *hsv,
-                                    gdouble         fraction)
-{
-  GimpColorWheelPrivate *priv;
-
-  g_return_if_fail (GIMP_IS_COLOR_WHEEL (hsv));
-
-  priv = hsv->priv;
-
-  priv->ring_fraction = CLAMP (fraction, 0.01, 0.99);
-
-  gtk_widget_queue_draw (GTK_WIDGET (hsv));
-}
-
-/**
- * gimp_color_wheel_get_ring_fraction:
- * @ring: A wheel color selector
- *
- * Returns value: The ring fraction of the wheel color selector.
- *
- * Since: 2.10
- */
-gdouble
-gimp_color_wheel_get_ring_fraction (GimpColorWheel *wheel)
-{
-  GimpColorWheelPrivate *priv;
-
-  g_return_val_if_fail (GIMP_IS_COLOR_WHEEL (wheel), DEFAULT_FRACTION);
-
-  priv = wheel->priv;
-
-  return priv->ring_fraction;
-}
-
-/**
- * gimp_color_wheel_is_adjusting:
- * @hsv: A #GimpColorWheel
- *
- * An HSV color selector can be said to be adjusting if multiple rapid
- * changes are being made to its value, for example, when the user is
- * adjusting the value with the mouse. This function queries whether
- * the HSV color selector is being adjusted or not.
- *
- * Return value: %TRUE if clients can ignore changes to the color value,
- *     since they may be transitory, or %FALSE if they should consider
- *     the color value status to be final.
- *
- * Since: 2.14
- */
-gboolean
-gimp_color_wheel_is_adjusting (GimpColorWheel *wheel)
-{
-  GimpColorWheelPrivate *priv;
-
-  g_return_val_if_fail (GIMP_IS_COLOR_WHEEL (wheel), FALSE);
-
-  priv = wheel->priv;
-
-  return priv->mode != DRAG_NONE;
-}
-
-static void
-gimp_color_wheel_move (GimpColorWheel   *wheel,
-                       GtkDirectionType  dir)
-{
-  GimpColorWheelPrivate *priv = wheel->priv;
-  gdouble                hue, sat, val;
-  gint                   hx, hy, sx, sy, vx, vy; /* HSV vertices */
-  gint                   x, y; /* position in triangle */
-
-  hue = priv->h;
-  sat = priv->s;
-  val = priv->v;
-
-  compute_triangle (wheel, &hx, &hy, &sx, &sy, &vx, &vy);
-
-  x = floor (sx + (vx - sx) * priv->v + (hx - vx) * priv->s * priv->v + 0.5);
-  y = floor (sy + (vy - sy) * priv->v + (hy - vy) * priv->s * priv->v + 0.5);
-
-#define HUE_DELTA 0.002
-  switch (dir)
-    {
-    case GTK_DIR_UP:
-      if (priv->focus_on_ring)
-        hue += HUE_DELTA;
-      else
-        {
-          y -= 1;
-          compute_sv (wheel, x, y, &sat, &val);
-        }
-      break;
-
-    case GTK_DIR_DOWN:
-      if (priv->focus_on_ring)
-        hue -= HUE_DELTA;
-      else
-        {
-          y += 1;
-          compute_sv (wheel, x, y, &sat, &val);
-        }
-      break;
-
-    case GTK_DIR_LEFT:
-      if (priv->focus_on_ring)
-        hue += HUE_DELTA;
-      else
-        {
-          x -= 1;
-          compute_sv (wheel, x, y, &sat, &val);
-        }
-      break;
-
-    case GTK_DIR_RIGHT:
-      if (priv->focus_on_ring)
-        hue -= HUE_DELTA
-          ;
-      else
-        {
-          x += 1;
-          compute_sv (wheel, x, y, &sat, &val);
-        }
-      break;
-
-    default:
-      /* we don't care about the tab directions */
-      break;
-    }
-
-  /* Wrap */
-  if (hue < 0.0)
-    hue = 1.0;
-  else if (hue > 1.0)
-    hue = 0.0;
-
-  gimp_color_wheel_set_color (wheel, hue, sat, val);
-}
diff --git a/src/widgets/gimp/gimpcolorwheel.h b/src/widgets/gimp/gimpcolorwheel.h
deleted file mode 100644
index e79fc1575..000000000
--- a/src/widgets/gimp/gimpcolorwheel.h
+++ /dev/null
@@ -1,97 +0,0 @@
-// SPDX-License-Identifier: LGPL-3.0-or-later
-/** @file
- * HSV color selector for GTK+
- */
-/* HSV color selector for GTK+
- *
- * Copyright (C) 1999 The Free Software Foundation
- *
- * Authors: Simon Budig <Simon.Budig@unix-ag.org> (original code)
- *          Federico Mena-Quintero <federico@gimp.org> (cleanup for GTK+)
- *          Jonathan Blandford <jrb@redhat.com> (cleanup for GTK+)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation; either version 3 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, see <http://www.gnu.org/licenses/>.
- */
-
-/*
- * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
- * file for a list of people on the GTK+ Team.  See the ChangeLog
- * files for a list of changes.  These files are distributed with
- * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
- */
-
-#ifndef __GIMP_COLOR_WHEEL_H__
-#define __GIMP_COLOR_WHEEL_H__
-
-G_BEGIN_DECLS
-
-#define GIMP_TYPE_COLOR_WHEEL            (gimp_color_wheel_get_type ())
-#define GIMP_COLOR_WHEEL(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GIMP_TYPE_COLOR_WHEEL, GimpColorWheel))
-#define GIMP_COLOR_WHEEL_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), GIMP_TYPE_COLOR_WHEEL, GimpColorWheelClass))
-#define GIMP_IS_COLOR_WHEEL(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GIMP_TYPE_COLOR_WHEEL))
-#define GIMP_IS_COLOR_WHEEL_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GIMP_TYPE_COLOR_WHEEL))
-#define GIMP_COLOR_WHEEL_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), GIMP_TYPE_COLOR_WHEEL, GimpColorWheelClass))
-
-
-typedef struct _GimpColorWheel      GimpColorWheel;
-typedef struct _GimpColorWheelClass GimpColorWheelClass;
-
-struct _GimpColorWheel
-{
-  GtkWidget parent_instance;
-
-  /* Private data */
-  gpointer priv;
-};
-
-struct _GimpColorWheelClass
-{
-  GtkWidgetClass parent_class;
-
-  /* Notification signals */
-  void (* changed) (GimpColorWheel   *wheel);
-
-  /* Keybindings */
-  void (* move)    (GimpColorWheel   *wheel,
-                    GtkDirectionType  type);
-
-  /* Padding for future expansion */
-  void (*_gimp_reserved1) ();
-  void (*_gimp_reserved2) ();
-  void (*_gimp_reserved3) ();
-  void (*_gimp_reserved4) ();
-};
-
-
-GType       gimp_color_wheel_get_type          (void) G_GNUC_CONST;
-GtkWidget * gimp_color_wheel_new               (void);
-
-void        gimp_color_wheel_set_color         (GimpColorWheel *wheel,
-                                                double          h,
-                                                double          s,
-                                                double          v);
-void        gimp_color_wheel_get_color         (GimpColorWheel *wheel,
-                                                gdouble        *h,
-                                                gdouble        *s,
-                                                gdouble        *v);
-
-void        gimp_color_wheel_set_ring_fraction (GimpColorWheel *wheel,
-                                                gdouble         fraction);
-gdouble     gimp_color_wheel_get_ring_fraction (GimpColorWheel *wheel);
-
-gboolean    gimp_color_wheel_is_adjusting      (GimpColorWheel *wheel);
-
-G_END_DECLS
-
-#endif /* __GIMP_COLOR_WHEEL_H__ */