Initial BEAMGRID VST3/AU spectrum analyzer

Source/AnalyserComponent.h

@@ -0,0 +1,129 @@
+#pragma once
+
+#include "JuceHeader.h"
+#include "Analyser.h"
+#include "BeamgridLookAndFeel.h"
+
+// Black spectrum visualizer: teal analyzer bands and peak-colored markers.
+class AnalyserComponent : public juce::Component,
+                          public juce::Timer
+{
+public:
+    AnalyserComponent (Analyser& analyserToUse,
+                       juce::AudioProcessorValueTreeState& paramsToUse,
+                       BeamgridLookAndFeel& lookAndFeelToUse)
+        : analyser (analyserToUse), params (paramsToUse), lf (lookAndFeelToUse)
+    {
+        startTimerHz (60);
+    }
+
+    ~AnalyserComponent() override
+    {
+        stopTimer();
+    }
+
+    void timerCallback() override
+    {
+        const double graceMs  = *params.getRawParameterValue ("grace");
+        const double falloff  = *params.getRawParameterValue ("falloff");
+        const double barfall  = *params.getRawParameterValue ("barfalloff");
+        const int    bars     = juce::roundToInt (params.getRawParameterValue ("bars")->load());
+        const double hue      = *params.getRawParameterValue ("hue");
+
+        analyser.setGraceSeconds (graceMs / 1000.0);
+        analyser.setFalloffRate (0.1 + falloff * 5.0);
+        // Bar falloff: higher knob -> faster bar descent (smaller release tau).
+        analyser.setBarReleaseTau (2.0 - barfall * 1.98);
+        analyser.setNumBands (bars);
+
+        // HUE knob: 12 o'clock (0.5) = no rotation; left/right rotate +/- 180 deg.
+        lf.setHueTurns (static_cast<float> (hue - 0.5));
+
+        analyser.update (1.0 / 60.0);
+        repaint();
+    }
+
+    void paint (juce::Graphics& g) override
+    {
+        const auto area = getLocalBounds().toFloat().reduced (8.0f);
+        const int n = analyser.getNumBands();
+
+        // Reserve margins for the axis legends.
+        juce::Rectangle<float> plot = area;
+        plot.setLeft (area.getX() + 40.0f);
+        plot.setBottom (area.getBottom() - 20.0f);
+
+        const float gap = 2.0f;
+        const float bandWidth = (plot.getWidth() - gap * (n + 1)) / static_cast<float> (n);
+        const float baseY = plot.getBottom();
+
+        const juce::Colour gridColour = lf.transform (juce::Colours::grey.brighter (0.2f)).withAlpha (0.32f);
+        const juce::Colour labelColour = lf.transform (juce::Colours::grey);
+
+        // Frequency gridlines + labels (log spaced).
+        const double freqTicks[] = { 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000, 20000 };
+        g.setFont (juce::FontOptions (10.0f));
+        for (double f : freqTicks)
+        {
+            if (f < analyser.getMinFreq() || f > analyser.getMaxFreq())
+                continue;
+
+            const float frac = analyser.freqToFraction (f);
+            const float x = plot.getX() + gap + frac * (plot.getWidth() - 2.0f * gap);
+
+            g.setColour (gridColour);
+            g.drawVerticalLine (static_cast<int> (x), plot.getY(), plot.getBottom());
+
+            g.setColour (labelColour);
+            g.drawText (formatFreq (f), x - 18.0f, plot.getBottom() + 3.0f, 36.0f, 14.0f,
+                        juce::Justification::centredTop, false);
+        }
+
+        // Level gridlines + labels (dB).
+        const double dbTicks[] = { 0.0, -6.0, -12.0, -24.0, -36.0, -48.0 };
+        for (double db : dbTicks)
+        {
+            const float frac = analyser.dbToFraction (db);
+            const float y = baseY - frac * plot.getHeight();
+
+            g.setColour (gridColour);
+            g.drawHorizontalLine (static_cast<int> (y), plot.getX(), plot.getRight());
+
+            g.setColour (labelColour);
+            g.drawText (juce::String (db, 0), area.getX(), y - 7.0f, 36.0f, 14.0f,
+                        juce::Justification::centredRight, false);
+        }
+
+        // Analyzer bands (teal) and peak markers (peak color).
+        for (int i = 0; i < n; ++i)
+        {
+            const float level = analyser.getLevel (i);
+            const float peak  = analyser.getPeak (i);
+
+            const float x = plot.getX() + gap + i * (bandWidth + gap);
+            const float h = level * plot.getHeight();
+            const float y = baseY - h;
+
+            g.setColour (lf.getTeal());
+            g.fillRect (x, y, bandWidth, h);
+
+            const float peakY = baseY - peak * plot.getHeight();
+            g.setColour (lf.getPeak());
+            g.fillRect (x, peakY - 2.0f, bandWidth, 3.0f);
+        }
+    }
+
+    static juce::String formatFreq (double f)
+    {
+        if (f >= 1000.0)
+            return juce::String (f / 1000.0, 1, false) + "k";
+        return juce::String (static_cast<int> (f));
+    }
+
+private:
+    Analyser& analyser;
+    juce::AudioProcessorValueTreeState& params;
+    BeamgridLookAndFeel& lf;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AnalyserComponent)
+};