beamgrid/Source/BeamgridLookAndFeel.h

#pragma once

#include "JuceHeader.h"

// Visual styling for BEAMGRID: black UI with teal accents. A single HUE knob
// rotates the hue of every saturated colour on the UI via a shared LookAndFeel.
class BeamgridLookAndFeel : public juce::LookAndFeel_V4
{
public:
    BeamgridLookAndFeel()
    {
        setColour (juce::Slider::rotarySliderFillColourId, tealBase);
        setColour (juce::Slider::rotarySliderOutlineColourId, juce::Colours::black.brighter (0.18f));
        setColour (juce::Slider::textBoxTextColourId, juce::Colours::lightgrey);
        setColour (juce::Slider::textBoxOutlineColourId, juce::Colours::transparentBlack);
        setColour (juce::Label::textColourId, juce::Colours::lightgrey);
    }

    // Base palette (used at 12 o'clock / zero hue rotation).
    static const juce::Colour tealBase;
    static const juce::Colour peakBase;

    // Hue rotation in turns (-0.5 .. +0.5); 0 = original colours.
    float hueTurns = 0.0f;

    void setHueTurns (float turns) noexcept { hueTurns = turns; }

    juce::Colour transform (juce::Colour c) const noexcept
    {
        return c.withRotatedHue (hueTurns);
    }

    juce::Colour getTeal() const noexcept { return transform (tealBase); }
    juce::Colour getPeak() const noexcept { return transform (peakBase); }

    void drawRotarySlider (juce::Graphics& g, int x, int y, int w, int h,
                           float pos, float startAngle, float endAngle,
                           juce::Slider& slider) override
    {
        const auto bounds = juce::Rectangle<int> (x, y, w, h).toFloat().reduced (6.0f);
        const auto centre = bounds.getCentre();
        const auto radius = juce::jmin (bounds.getWidth(), bounds.getHeight()) * 0.5f;
        const float thickness = 5.0f;

        // Background track arc.
        juce::Path track;
        track.addArc (centre.x - radius, centre.y - radius, radius * 2.0f, radius * 2.0f,
                      startAngle, endAngle, thickness);
        g.setColour (slider.findColour (juce::Slider::rotarySliderOutlineColourId));
        g.strokePath (track, juce::PathStrokeType (thickness));

        // Filled value arc (teal, hue-rotated).
        const float angle = startAngle + pos * (endAngle - startAngle);
        juce::Path value;
        value.addArc (centre.x - radius, centre.y - radius, radius * 2.0f, radius * 2.0f,
                      startAngle, angle, thickness);
        g.setColour (getTeal());
        g.strokePath (value, juce::PathStrokeType (thickness));

        // Pointer line.
        juce::Path pointer;
        const float pointerLen = radius * 0.78f;
        pointer.addLineSegment (juce::Line<float> (centre.x, centre.y,
                                                   centre.x + std::sin (angle) * pointerLen,
                                                   centre.y - std::cos (angle) * pointerLen), 2.0f);
        g.setColour (juce::Colours::white);
        g.strokePath (pointer, juce::PathStrokeType (2.5f));
    }
};