improve vst refresh rate on windows

plugin/Source/PluginEditor.cpp

@@ -6,6 +6,7 @@
 #include "VectorscopeEngine.h"
 #include "SpectrogramEngine.h"
 #include "WaveformEngine.h"
+#include <cmath>
 #include <cstring>
 
 #if ! PRISM_USE_DEV_SERVER
@@ -19,7 +20,24 @@
 namespace
 {
     const juce::Identifier kRestoreSettingsEvent { "prismRestoreSettings" };
-    constexpr int kDrainCapacity = 16384;
+    constexpr int kDrainCapacity = 1 << 16;
+#if JUCE_WINDOWS
+    constexpr int kFallbackWindowsFrameRateHz = 60;
+    constexpr int kMaxWindowsFrameRateHz = 240;
+
+    int resolveWindowsFrameRateHz(const juce::Component& component)
+    {
+        const auto& displays = juce::Desktop::getInstance().getDisplays();
+        if (const auto* display = displays.getDisplayForRect(component.getScreenBounds()))
+        {
+            const auto frequency = display->verticalFrequencyHz;
+            if (frequency.has_value() && std::isfinite(*frequency) && *frequency > 0.0)
+                return juce::jlimit(30, kMaxWindowsFrameRateHz, (int) std::lround(*frequency));
+        }
+
+        return kFallbackWindowsFrameRateHz;
+    }
+#endif
 
     std::unique_ptr<ScopeEngine> makeEngine()
     {
@@ -128,9 +146,22 @@ PrismSpectrumEditor::PrismSpectrumEditor(PrismSpectrumProcessor& p)
     setResizeLimits(pref.minWidth, pref.minHeight, 4096, 4096);
     setSize(pref.defaultWidth, pref.defaultHeight);
 
-    // Drive frames at the display's refresh rate (adapts to 60/120/144 Hz).
     if (webView != nullptr)
+    {
+#if JUCE_WINDOWS
+        startTimerHz(resolveWindowsFrameRateHz(*this));
+#else
+        // Drive frames at the display's refresh rate (adapts to 60/120/144 Hz).
         vblank = juce::VBlankAttachment(this, [this] { renderFrame(); });
+#endif
+    }
+}
+
+PrismSpectrumEditor::~PrismSpectrumEditor()
+{
+#if JUCE_WINDOWS
+    stopTimer();
+#endif
 }
 
 void PrismSpectrumEditor::resized()
@@ -176,6 +207,13 @@ void PrismSpectrumEditor::showWebViewFallback()
     addAndMakeVisible(webViewFallback);
 }
 
+#if JUCE_WINDOWS
+void PrismSpectrumEditor::timerCallback()
+{
+    renderFrame();
+}
+#endif
+
 void PrismSpectrumEditor::onSettingsPanel(juce::var payload)
 {
     const int height = juce::jmax(0, (int) payload.getProperty("height", 0));

plugin/Source/PluginEditor.h

@@ -9,20 +9,26 @@
 /**
  * Hosts the React webview UI and bridges the reused Prism spectrum DSP to it.
  *
- * Driven by a VBlankAttachment (message thread, synced to the display's refresh
- * rate). Each vblank it drains stereo audio buffered by the processor, runs
- * Visualizer::Spectrum, and emits mid + side magnitudes to the webview as a
- * "spectrumFrame" event. Receives "prismConfig" (settings + fftSize/smoothing)
- * and "prismReady" events from the UI.
+ * Drains stereo audio buffered by the processor, feeds the selected scope engine,
+ * and emits frame payloads to the webview. macOS uses display vblank; Windows uses
+ * a steady message-thread timer because some DAW/WebView2 embeddings deliver
+ * vblank callbacks too slowly for data-driven scopes.
  */
 class PrismSpectrumEditor : public juce::AudioProcessorEditor
+#if JUCE_WINDOWS
+    , private juce::Timer
+#endif
 {
 public:
     explicit PrismSpectrumEditor(PrismSpectrumProcessor&);
-    ~PrismSpectrumEditor() override = default;
+    ~PrismSpectrumEditor() override;
 
     void resized() override;
 
+#if JUCE_WINDOWS
+    void timerCallback() override;
+#endif
+
     // Called by the webview event listeners (message thread).
     void onPrismConfig(juce::var payload);
     void onPrismReady();
@@ -64,9 +70,11 @@ private:
     std::unique_ptr<juce::WebBrowserComponent> webView;
     juce::Label webViewFallback;
 
-    // Declared last so it is destroyed first — no vblank callback can fire into
-    // a partially-destroyed editor.
+    // Declared last so it is destroyed first; no vblank callback can fire into a
+    // partially-destroyed editor. Windows uses juce::Timer instead.
+#if ! JUCE_WINDOWS
     juce::VBlankAttachment vblank;
+#endif
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PrismSpectrumEditor)
 };

src/plugin-ui/ScopeApp.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useState, type JSX, type ReactNode } from 'react'
+import { useEffect, useRef, useState, type CSSProperties, type JSX, type ReactNode } from 'react'
 import type { ScopeKind } from '../types/scope'
 import type { ScopeSettings } from '../types/settings'
 import type { PrismResolvedTheme } from '../types/theme'
@@ -26,20 +26,38 @@ interface ScopeAppProps<K extends ScopeKind> {
 export default function ScopeApp<K extends ScopeKind>({ kind, renderScope }: ScopeAppProps<K>): JSX.Element {
   const { settings, resolvedTheme, handleUpdate } = useScopeHostSync(kind)
   const [settingsOpen, setSettingsOpen] = useState(false)
+  const [lockedViewportHeight, setLockedViewportHeight] = useState<number | null>(null)
+  const viewportRef = useRef<HTMLDivElement>(null)
 
   useEffect(() => {
     emitToHost('prismSettingsPanel', { height: settingsOpen ? PANEL_HEIGHT : 0 })
   }, [settingsOpen])
 
+  const toggleSettings = (): void => {
+    if (settingsOpen) {
+      setSettingsOpen(false)
+      setLockedViewportHeight(null)
+      return
+    }
+
+    const rect = viewportRef.current?.getBoundingClientRect()
+    setLockedViewportHeight(rect && rect.height > 0 ? Math.ceil(rect.height) : null)
+    setSettingsOpen(true)
+  }
+
+  const appStyle = lockedViewportHeight === null
+    ? undefined
+    : ({ '--spectrum-viewport-height': `${lockedViewportHeight}px` } as CSSProperties)
+
   return (
-    <div className="spectrum-app">
-      <div className="spectrum-app__viewport">
+    <div className={`spectrum-app ${settingsOpen ? 'has-settings' : ''}`.trim()} style={appStyle}>
+      <div ref={viewportRef} className="spectrum-app__viewport">
         {renderScope(settings, resolvedTheme)}
 
         <button
           type="button"
           className={`spectrum-app__gear ${settingsOpen ? 'is-active' : ''}`.trim()}
-          onClick={() => setSettingsOpen((open) => !open)}
+          onClick={toggleSettings}
           aria-label="Settings"
           title="Settings"
         >

src/plugin-ui/styles.css

@@ -26,6 +26,11 @@ body {
   flex-direction: column;
   width: 100%;
   height: 100%;
+  overflow: hidden;
+}
+
+.spectrum-app.has-settings {
+  overflow-y: auto;
 }
 
 /* The scope fills everything above the (optional) bottom settings panel. */
@@ -35,6 +40,11 @@ body {
   min-height: 0;
 }
 
+.spectrum-app.has-settings .spectrum-app__viewport {
+  flex: 0 0 var(--spectrum-viewport-height, 100%);
+  height: var(--spectrum-viewport-height, 100%);
+}
+
 .spectrum-scope {
   position: absolute;
   inset: 0;
@@ -84,10 +94,9 @@ body {
   border-color: var(--control-border-active, rgba(56, 189, 248, 0.4));
 }
 
-/* Settings panel along the bottom (like the app). The editor window grows by exactly
-   this height when it opens, so the scope viewport above keeps its size. The fixed
-   basis MUST match PANEL_HEIGHT in ScopeApp.tsx (the grow delta), or the scope would
-   shift. Content taller than this scrolls. */
+/* Settings panel along the bottom. The editor asks the host to grow by this height,
+   but Windows DAWs may delay or constrain that resize, so the viewport locks to its
+   previous height and this panel overflows instead of shrinking the scope. */
 .spectrum-app__panel {
   flex: 0 0 280px;
   width: 100%;