init

Source/ArcKnob.cpp

@@ -0,0 +1,50 @@
+#include "ArcKnob.h"
+
+ArcKnob::ArcKnob(juce::RangedAudioParameter& param)
+    : juce::Slider(juce::Slider::RotaryHorizontalVerticalDrag,
+                   juce::Slider::NoTextBox),
+      parameter(param)
+{
+}
+
+void ArcKnob::paint(juce::Graphics& g)
+{
+    auto bounds = getLocalBounds().toFloat();
+    float diameter = juce::jmin(bounds.getWidth(), bounds.getHeight());
+    float radius = diameter * 0.42f;
+    float cx = bounds.getCentreX();
+    float cy = bounds.getCentreY();
+
+    const float startAngle = juce::MathConstants<float>::pi * 1.25f;
+    const float endAngle = juce::MathConstants<float>::pi * 2.75f;
+    const float angleRange = endAngle - startAngle;
+
+    float rangeMin = static_cast<float>(getMinimum());
+    float rangeMax = static_cast<float>(getMaximum());
+    float value = static_cast<float>(getValue());
+    float normalizedValue = (rangeMax > rangeMin)
+                                ? juce::jlimit(0.0f, 1.0f, (value - rangeMin) / (rangeMax - rangeMin))
+                                : 0.0f;
+    float valueAngle = startAngle + normalizedValue * angleRange;
+
+    // Background arc (dim)
+    juce::Path bgArc;
+    bgArc.addArc(cx - radius, cy - radius, radius * 2.0f, radius * 2.0f,
+                 startAngle, endAngle, true);
+    g.setColour(juce::Colour(0xff333340));
+    g.strokePath(bgArc, juce::PathStrokeType(1.5f));
+
+    // Value arc
+    if (normalizedValue > 0.001f)
+    {
+        juce::Path valueArc;
+        valueArc.addArc(cx - radius, cy - radius, radius * 2.0f, radius * 2.0f,
+                         startAngle, valueAngle, true);
+        g.setColour(juce::Colour(0xff7ecfcf));
+        g.strokePath(valueArc, juce::PathStrokeType(1.5f));
+    }
+
+    // Center dot
+    g.setColour(juce::Colour(0xff7ecfcf));
+    g.fillEllipse(cx - 2.0f, cy - 2.0f, 4.0f, 4.0f);
+}