Camera Raw panel docked beside the canvas: scope, Light, Color, Effects, canvas tools (12.8b1)

src/UI/CameraRawSlider.h

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+#pragma once
+#include <QColor>
+#include <QSlider>
+#include <functional>
+#include <optional>
+#include <utility>
+
+// Swift's CameraRawSliderTrack: a coloured track, or the system's.
+struct CameraRawSliderTrack {
+    enum class Kind { plain, temperature, tint, chroma, hue, saturation, luminance };
+    Kind kind = Kind::plain;
+    // A family's centre, for hue, saturation and luminance.
+    double degrees = 0;
+    // Left and right colours; none keeps the system track.
+    std::optional<std::pair<QColor, QColor>> colors() const;
+};
+
+// Swift's CameraRawSlider: a double click on the knob resets.
+class CameraRawSlider : public QSlider {
+    Q_OBJECT
+public:
+    CameraRawSlider(double low, double high, CameraRawSliderTrack track, const QString &help, std::function<void(double)> change,
+                    std::function<void()> reset, QWidget *parent = nullptr);
+    // Shows a value, unless a drag holds the knob.
+    void display(double value);
+    double shown() const;
+    bool isOnKnob(QPoint point) const;
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+    void mouseDoubleClickEvent(QMouseEvent *event) override;
+
+private:
+    const double m_low;
+    const double m_high;
+    const CameraRawSliderTrack m_track;
+    const std::function<void(double)> m_change;
+    const std::function<void()> m_reset;
+};