terion/Source/VectorScope.cpp

#include "VectorScope.h"

VectorScope::VectorScope(TerionProcessor& p)
    : processor(p)
{
    startTimerHz(30);
}

VectorScope::~VectorScope()
{
    stopTimer();
}

void VectorScope::timerCallback()
{
    // Refresh the numeric readouts at kMetricsRateHz while keeping the trail
    // animation running at the full 30 Hz.
    const float frozen = processor.apvts.getRawParameterValue("freeze")->load();
    if (frozen < 0.5f && ++metricFrame >= 30 / kMetricsRateHz)
    {
        metricFrame = 0;
        cachedMetrics = processor.getMetrics();
    }
    repaint();
}

float VectorScope::getRadius() const
{
    auto bounds = getLocalBounds();
    return juce::jmin(bounds.getWidth(), bounds.getHeight()) * 0.5f * 0.85f;
}

void VectorScope::resized()
{
    auto bounds = getLocalBounds();
    trail = juce::Image(juce::Image::ARGB, bounds.getWidth(), bounds.getHeight(), true);
}

void VectorScope::paint(juce::Graphics& g)
{
    auto bounds = getLocalBounds();
    const int w = bounds.getWidth();
    const int h = bounds.getHeight();
    const float cx = w * 0.5f;
    const float cy = h * 0.5f;
    const float radius = getRadius();
    const float dotSize = processor.apvts.getRawParameterValue("dotSize")->load();
    const float frozen = processor.apvts.getRawParameterValue("freeze")->load();

    // Persistent glow trail: each frame the image itself is faded by a
    // decay factor (so it keeps dying off even after audio stops), then the
    // dots captured since the last frame are stamped in at full brightness.
    // Older history is retained purely in the image, so lowering the level
    // never erases the trail prematurely.
    if (trail.isValid())
    {
        if (frozen < 0.5f)
        {
            const float fadeTime = processor.apvts.getRawParameterValue("fadeTime")->load();
            const float afterglow = processor.apvts.getRawParameterValue("afterglow")->load();
            const float totalLife = fadeTime + afterglow;
            const float fps = 30.0f;

            if (totalLife > 0.0f)
            {
                // Per-frame alpha multiplier: the trail falls to ~0.1% of its
                // brightness over fadeTime + afterglow seconds.
                const float decay = std::exp(-6.9f / (totalLife * fps));
                trail.multiplyAllAlphas(decay);
            }

            // Stamp only points captured within roughly the last frame and a
            // half; everything older lives on in the decaying image above.
            const float newAge = 1.5f / (fps * fadeTime);
            const float newAlpha = 0.9f;
            const auto& points = processor.getPoints();

            juce::Graphics trailG(trail);

            for (const auto& pt : points)
            {
                if (pt.age > newAge)
                    continue;

                float x = cx + pt.side * radius * 2.0f;
                float y = cy - pt.mid * radius * 2.0f;

                float phase = std::abs(pt.side) / (std::abs(pt.mid) + 0.0001f);
                phase = juce::jmin(phase, 1.0f);

                juce::Colour color = juce::Colour::fromFloatRGBA(
                    0.2f + phase * 0.8f,
                    1.0f - phase * 0.4f,
                    1.0f - phase * 0.6f,
                    newAlpha);

                trailG.setColour(color);
                trailG.fillRect(x - dotSize * 0.5f, y - dotSize * 0.5f, dotSize, dotSize);
            }
        }
    }

    // Draw background
    g.fillAll(juce::Colour(0xff0a0a0f));

    // Draw the trail
    if (trail.isValid())
        g.drawImageAt(trail, 0, 0);

    // Concentric circles with dB labels
    g.setColour(juce::Colour(0xff1a1a25));
    const float dBValues[] = { -12.0f, -6.0f, 0.0f };
    const float dBFactors[] = { 0.25f, 0.5f, 1.0f };
    for (int i = 0; i < 3; ++i)
    {
        float r = radius * dBFactors[i];
        g.drawEllipse(cx - r, cy - r, r * 2.0f, r * 2.0f, 0.5f);

        // dB label at top-right of each circle
        g.setColour(juce::Colour(0xff444455));
        g.setFont(juce::Font(juce::FontOptions(9.0f * currentScale)));
        juce::String dbLabel = juce::String(dBValues[i], 0) + "dB";
        g.drawText(dbLabel, cx + r + 3.0f * currentScale, cy - r - 2.0f * currentScale,
                   40.0f * currentScale, 14.0f * currentScale, juce::Justification::centredLeft);
        g.setColour(juce::Colour(0xff1a1a25));
    }

    // 45-degree lines (L=R and L=-R)
    g.setColour(juce::Colour(0xff181822));
    g.drawLine(cx - radius, cy - radius, cx + radius, cy + radius, 0.5f);
    g.drawLine(cx - radius, cy + radius, cx + radius, cy - radius, 0.5f);

    // Hair cross (brighter, thin)
    drawHairCross(g, cx, cy);

    // Legends
    drawLegends(g, cx, cy, radius);

    // Metrics overlay
    drawMetricsOverlay(g, bounds);

    // Border
    g.setColour(juce::Colour(0xff333340));
    g.drawRect(bounds, 1);
}

void VectorScope::drawHairCross(juce::Graphics& g, float cx, float cy)
{
    auto bounds = getLocalBounds().toFloat();

    // Bright center cross — two short, bright strokes
    g.setColour(juce::Colour(0xff9999b3));

    // Horizontal
    g.drawLine(bounds.getX() + 8.0f, cy, bounds.getRight() - 8.0f, cy, 0.5f);
    // Vertical
    g.drawLine(cx, bounds.getY() + 8.0f, cx, bounds.getBottom() - 8.0f, 0.5f);

    // Tiny center dot
    g.setColour(juce::Colour(0xff8888aa));
    g.fillEllipse(cx - 2.0f, cy - 2.0f, 4.0f, 4.0f);
}

void VectorScope::drawLegends(juce::Graphics& g, float cx, float cy, float radius)
{
    const float s = currentScale;
    g.setColour(juce::Colour(0xff666677));
    g.setFont(juce::Font(juce::FontOptions(10.0f * s)));

    // Side label (X axis, right side)
    g.drawText("Side", cx + radius + 4.0f * s, cy + 4.0f * s, 40.0f * s, 14.0f * s,
               juce::Justification::centredLeft);

    // Mid label (Y axis, top)
    g.drawText("Mid", cx + 4.0f * s, cy - radius - 16.0f * s, 40.0f * s, 14.0f * s,
               juce::Justification::centredLeft);

    // Diagonal labels: in M/S space these are the pure-channel loci
    g.setColour(juce::Colour(0xff444455));
    g.setFont(juce::Font(juce::FontOptions(8.0f * s)));

    // L = 0 (right channel only): line y = x through centre
    float diagX = cx + radius * 0.71f;
    g.drawText("R only", diagX + 4.0f * s, cy + radius * 0.71f, 30.0f * s, 12.0f * s,
               juce::Justification::centredLeft);

    // R = 0 (left channel only): line y = -x through centre
    g.drawText("L only", diagX + 4.0f * s, cy - radius * 0.71f - 12.0f * s, 30.0f * s, 12.0f * s,
               juce::Justification::centredLeft);
}

void VectorScope::drawMetricsOverlay(juce::Graphics& g, const juce::Rectangle<int>& bounds)
{
    const auto& metrics = cachedMetrics;
    const float s = currentScale;
    const int margin = static_cast<int>(10.0f * s);
    const int lineHeight = static_cast<int>(14.0f * s);
    const int startY = bounds.getBottom() - margin - (7 * lineHeight);

    // Background panel
    juce::Rectangle<int> panelRect(bounds.getX() + margin, startY - static_cast<int>(5.0f * s),
                                   static_cast<int>(120.0f * s), 7 * lineHeight + static_cast<int>(10.0f * s));
    g.setColour(juce::Colour(0xff0a0a0f).withAlpha(0.8f));
    g.fillRect(panelRect);
    g.setColour(juce::Colour(0xff333340));
    g.drawRect(panelRect, 1);

    // Metrics text
    g.setFont(juce::Font(juce::FontOptions(9.0f * s)));
    g.setColour(juce::Colour(0xff888899));

    auto drawMetric = [&](const juce::String& label, float value, const juce::String& unit, int y)
    {
        g.drawText(label, panelRect.getX() + static_cast<int>(5.0f * s), y,
                   static_cast<int>(50.0f * s), lineHeight, juce::Justification::centredLeft);
        g.setColour(juce::Colour(0xffccccdd));
        g.drawText(juce::String(value, 1) + unit, panelRect.getX() + static_cast<int>(55.0f * s), y,
                   static_cast<int>(60.0f * s), lineHeight, juce::Justification::centredRight);
        g.setColour(juce::Colour(0xff888899));
    };

    int y = startY;
    drawMetric("Corr", metrics.correlation, "", y); y += lineHeight;
    drawMetric("Width", metrics.stereoWidth, "dB", y); y += lineHeight;
    drawMetric("Mid", metrics.midLevel, "dB", y); y += lineHeight;
    drawMetric("Side", metrics.sideLevel, "dB", y); y += lineHeight;
    drawMetric("Balance", metrics.balance, "dB", y); y += lineHeight;
    drawMetric("Phase", metrics.phaseAngle, "deg", y); y += lineHeight;
    drawMetric("Crest", metrics.crestFactor, "dB", y); y += lineHeight;
}