feat: publish av-tools 0.1.0

tests/unit/waveform-runtime-canvas.test.ts

@@ -0,0 +1,114 @@
+import { describe, expect, it, vi } from 'vitest';
+import {
+  aggregatePcmPeaks,
+  describeWaveform,
+  renderWaveformToCanvas,
+} from '../../src/waveform';
+
+describe('waveform canvas rendering', () => {
+  it('renders bounded columns and supplies a text alternative', () => {
+    const peaks = aggregatePcmPeaks(
+      {
+        container: 'raw',
+        data: new Int16Array([-32_768, 0, 16_384, 32_767]),
+        encoding: 's16le',
+        sampleRate: 2,
+      },
+      { bucketCount: 4 }
+    );
+    const { canvas, context, attributes } = createCanvas(200, 80);
+
+    const rendered = renderWaveformToCanvas(canvas, peaks, {
+      devicePixelRatio: 2,
+      startBucket: 1,
+      endBucket: 4,
+      selection: { startFraction: 0.25, endFraction: 0.75 },
+    });
+
+    expect(canvas.width).toBe(400);
+    expect(canvas.height).toBe(160);
+    expect(rendered.startBucket).toBe(1);
+    expect(rendered.endBucket).toBe(4);
+    expect(rendered.accessibleLabel).toContain('Audio waveform');
+    expect(attributes.get('role')).toBe('img');
+    expect(attributes.get('aria-label')).toBe(rendered.accessibleLabel);
+    expect(context.moveTo).toHaveBeenCalled();
+    expect(context.lineTo).toHaveBeenCalled();
+    expect(context.fillRect).toHaveBeenCalledWith(50, 0, 100, 80);
+  });
+
+  it('describes empty waveforms and respects an explicit accessible label', () => {
+    const empty = aggregatePcmPeaks(
+      {
+        container: 'raw',
+        data: new Uint8Array(),
+        encoding: 's16le',
+        sampleRate: 8_000,
+      },
+      { bucketCount: 1 }
+    );
+    const { canvas, attributes } = createCanvas(100, 40);
+    const result = renderWaveformToCanvas(canvas, empty, {
+      accessibleLabel: 'No audible content',
+    });
+
+    expect(describeWaveform(empty)).toBe('Empty audio waveform.');
+    expect(result.accessibleLabel).toBe('No audible content');
+    expect(attributes.get('aria-label')).toBe('No audible content');
+  });
+
+  it('rejects unsafe dimensions, ranges, and selections', () => {
+    const peaks = aggregatePcmPeaks(
+      {
+        container: 'raw',
+        data: new Int16Array([1, 2]),
+        encoding: 's16le',
+        sampleRate: 8_000,
+      },
+      { bucketCount: 2 }
+    );
+    const { canvas } = createCanvas(100, 40);
+
+    expect(() =>
+      renderWaveformToCanvas(canvas, peaks, { width: 100_000 })
+    ).toThrow(/safe limits/u);
+    expect(() =>
+      renderWaveformToCanvas(canvas, peaks, {
+        startBucket: 2,
+        endBucket: 1,
+      })
+    ).toThrow(/bucket range/u);
+    expect(() =>
+      renderWaveformToCanvas(canvas, peaks, {
+        selection: { startFraction: -1, endFraction: 0.5 },
+      })
+    ).toThrow(/selection/u);
+  });
+});
+
+function createCanvas(width: number, height: number) {
+  const attributes = new Map<string, string>();
+  const context = {
+    setTransform: vi.fn(),
+    clearRect: vi.fn(),
+    fillRect: vi.fn(),
+    beginPath: vi.fn(),
+    moveTo: vi.fn(),
+    lineTo: vi.fn(),
+    stroke: vi.fn(),
+    fillStyle: '',
+    strokeStyle: '',
+    lineWidth: 1,
+  };
+  const canvas = {
+    width,
+    height,
+    clientWidth: width,
+    clientHeight: height,
+    getContext: vi.fn(() => context),
+    setAttribute: vi.fn((name: string, value: string) => {
+      attributes.set(name, value);
+    }),
+  } as unknown as HTMLCanvasElement;
+  return { canvas, context, attributes };
+}