MonoStep: monophonic 2-oscillator step-sequencer synth

Source/ui/SequencerMatrix.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <JuceHeader.h>
+
+class MonoStepAudioProcessor;
+
+class SequencerMatrix final : public juce::Component
+{
+public:
+    explicit SequencerMatrix (MonoStepAudioProcessor& processor);
+    ~SequencerMatrix() override = default;
+
+    std::function<void (int stepIdx)>      onStepSelected;
+    std::function<void (int stepIdx, bool gate)> onGateChanged;
+    std::function<void (int stepIdx, int semitone)> onNoteChanged;
+    std::function<void (int stepIdx, float cents)> onFineChanged;
+    std::function<void (int stepIdx, bool slide)> onSlideChanged;
+
+    void setSelectedStep (int stepIdx);
+    int getSelectedStep() const { return selectedStep; }
+
+    void setPlayPosition (int stepIdx);
+
+    void paint (juce::Graphics&) override;
+    void mouseDown (const juce::MouseEvent&) override;
+    void mouseDrag (const juce::MouseEvent&) override;
+    void mouseUp (const juce::MouseEvent&) override;
+
+private:
+    struct CellRect
+    {
+        int step;
+        int row;
+        bool hit;
+    };
+
+    CellRect cellAt (const juce::MouseEvent&) const;
+    juce::Rectangle<int> matrixBounds() const;
+    int rowForSemitone (int semitone) const;
+    int semitoneForRow (int row) const;
+
+    MonoStepAudioProcessor& processor;
+
+    float cellW = 24.0f;
+    float cellH = 17.0f;
+    float labelW = 40.0f;
+    float headerH = 24.0f;
+    float headerPad = 10.0f;
+
+    int selectedStep = 0;
+    int playPos = -1;
+
+    bool dragging = false;
+    bool startedActive = false;
+    bool moved = false;
+    int lastRow = 0;
+    int dragStep = 0;
+
+    bool fineDragging = false;
+    int fineRefRow = 0;
+    float fineStartCents = 0.0f;
+    float fineLastCents = -1000.0f;
+
+    bool slideDragging = false;
+    bool startedSlideActive = false;
+    int slideLastStep = -1;
+};