performance updates

KJamsClone/DJLoopEditing.swift

@@ -180,7 +180,7 @@ final class DJNativeSpectrumView: DJWaveMouseView {
     private var hoverX: Double?
     private var tracking: NSTrackingArea?
     override init(frame: NSRect) {
-        super.init(frame:frame)
+        super.init(frame:frame);clipsToBounds = true
         freeze = { [weak self] start in self?.frozenViewport = start;self?.needsDisplay = true }
     }
     required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
@@ -223,6 +223,12 @@ final class DJNativeSpectrumView: DJWaveMouseView {
         super.mouseDown(with:event)
     }
     override func draw(_ dirtyRect: NSRect) {
+        guard let context = NSGraphicsContext.current?.cgContext else { return }
+        context.saveGState()
+        defer { context.restoreGState() }
+        // Cached sections extend beyond the viewport while scrolling. Neither
+        // those sections nor their markers may paint into adjacent deck controls.
+        context.clip(to:bounds)
         NSColor.black.setFill();bounds.fill()
         guard let player,player.duration > 0,span > 0,!player.waveform.isEmpty else { return }
         let time = player.displayTime,start = frozenViewport ?? (time-span/2),width = bounds.width,height = bounds.height