initial concept

src/types/spectrogram.ts

@@ -0,0 +1,38 @@
+export type SpectrogramClarityMode = 'classic' | 'sharp' | 'sharper'
+export type SpectrogramScaleMode = 'mel' | 'log' | 'linear'
+
+export const SPECTROGRAM_CLARITY_MODES: readonly SpectrogramClarityMode[] = [
+  'classic',
+  'sharp',
+  'sharper',
+]
+export const SPECTROGRAM_SCALE_MODES: readonly SpectrogramScaleMode[] = [
+  'mel',
+  'log',
+  'linear',
+]
+
+export const DEFAULT_SPECTROGRAM_CLARITY_MODE: SpectrogramClarityMode = 'sharper'
+export const DEFAULT_SPECTROGRAM_SCALE_MODE: SpectrogramScaleMode = 'log'
+export const MIN_SPECTROGRAM_SCROLL_SPEED = 0.5
+export const MAX_SPECTROGRAM_SCROLL_SPEED = 4
+export const SPECTROGRAM_SCROLL_SPEED_STEP = 0.5
+export const DEFAULT_SPECTROGRAM_SCROLL_SPEED = 2
+
+export function isSpectrogramClarityMode(value: unknown): value is SpectrogramClarityMode {
+  return typeof value === 'string' && SPECTROGRAM_CLARITY_MODES.includes(value as SpectrogramClarityMode)
+}
+
+export function isSpectrogramScaleMode(value: unknown): value is SpectrogramScaleMode {
+  return typeof value === 'string' && SPECTROGRAM_SCALE_MODES.includes(value as SpectrogramScaleMode)
+}
+
+export function clampSpectrogramScrollSpeed(value: unknown): number {
+  const numeric = Number(value)
+  if (!Number.isFinite(numeric)) {
+    return DEFAULT_SPECTROGRAM_SCROLL_SPEED
+  }
+
+  const snapped = Math.round(numeric / SPECTROGRAM_SCROLL_SPEED_STEP) * SPECTROGRAM_SCROLL_SPEED_STEP
+  return Math.min(MAX_SPECTROGRAM_SCROLL_SPEED, Math.max(MIN_SPECTROGRAM_SCROLL_SPEED, snapped))
+}