增加和修改了非常多的功能

src/ui/SpectrumWidget.cpp

@@ -0,0 +1,65 @@
+#include "SpectrumWidget.h"
+#include <QPainter>
+#include <QLinearGradient>
+
+SpectrumWidget::SpectrumWidget(int barCount, QWidget* parent)
+    : QWidget(parent), _barCount(barCount), _current(barCount, 0), _peak(barCount, 0)
+{
+    setFixedSize(100, 26);
+    _decayTimer = new QTimer(this);
+    _decayTimer->setInterval(33);
+    connect(_decayTimer, &QTimer::timeout, this, [this]() {
+        bool anyActive = false;
+        for (int i = 0; i < _barCount; ++i) {
+            _peak[i] *= 0.88f;
+            if (_peak[i] < 0.01f) _peak[i] = 0;
+            else anyActive = true;
+        }
+        if (!anyActive) _decayTimer->stop();
+        update();
+    });
+}
+
+void SpectrumWidget::updateLevels(const QVector<float>& levels) {
+    for (int i = 0; i < _barCount && i < levels.size(); ++i) {
+        _current[i] = levels[i];
+        if (levels[i] > _peak[i]) _peak[i] = levels[i];
+    }
+    if (!_decayTimer->isActive()) _decayTimer->start();
+    update();
+}
+
+void SpectrumWidget::reset() {
+    _current.fill(0);
+    _peak.fill(0);
+    _decayTimer->stop();
+    update();
+}
+
+void SpectrumWidget::paintEvent(QPaintEvent*) {
+    QPainter p(this);
+    p.setRenderHint(QPainter::Antialiasing);
+
+    int w = width(), h = height();
+    qreal gap = 1.5;
+    qreal barW = (w - (_barCount - 1) * gap) / _barCount;
+
+    for (int i = 0; i < _barCount; ++i) {
+        qreal x = i * (barW + gap);
+        qreal level = qMin(1.0f, _peak[i]);
+        qreal barH = qMax(2.0, level * h);
+
+        QLinearGradient grad(0, h, 0, h - barH);
+        if (level > 0.01) {
+            grad.setColorAt(0, QColor(94, 179, 230, 200));
+            grad.setColorAt(1, QColor(92, 184, 92, 240));
+        } else {
+            grad.setColorAt(0, QColor(42, 48, 64, 100));
+            grad.setColorAt(1, QColor(42, 48, 64, 60));
+        }
+
+        p.setPen(Qt::NoPen);
+        p.setBrush(grad);
+        p.drawRoundedRect(QRectF(x, h - barH, barW, barH), 1.5, 1.5);
+    }
+}