Function toggleListViewColumnsPopover

renderer.js:14787–14831

(anchorBtn)

    maxDim > 0 && tanHalfFov > 0
      ? Math.abs(maxDim / 2 / tanHalfFov) * 1.5
      : 5;
  if (!Number.isFinite(cameraZ) || cameraZ <= 0) cameraZ = 5;

  // Camera sits on the (z,z,z) diagonal — keep far plane beyond that distance.
  const cameraDistance = cameraZ * Math.sqrt(3);
  camera.near = Math.max(0.01, cameraDistance / 1000);
  camera.far = Math.max(10000, cameraDistance * 20);
  camera.updateProjectionMatrix();

  camera.position.set(cameraZ, cameraZ, cameraZ);
  camera.lookAt(0, 0, 0);

  renderer.render(scene, camera);
}

/** True when a thumbnail data-URL is effectively empty (transparent / clipped render). */
function isMostlyEmptyThumbnailDataUrl(dataUrl) {
  return new Promise((resolve) => {
    if (!dataUrl || typeof dataUrl !== 'string' || !dataUrl.startsWith('data:image')) {
      resolve(true);
      return;
    }
    const img = new Image();
    img.onload = () => {
      try {
        const w = Math.min(64, img.width || 64);
        const h = Math.min(64, img.height || 64);
        const canvas = document.createElement('canvas');
        canvas.width = w;
        canvas.height = h;
        const ctx = canvas.getContext('2d', { willReadFrequently: true });
        if (!ctx) {
          resolve(false);
          return;
        }
        ctx.drawImage(img, 0, 0, w, h);
        const pixels = ctx.getImageData(0, 0, w, h).data;
        let opaque = 0;
        for (let i = 0; i < pixels.length; i += 4) {
          if (pixels[i + 3] > 12) opaque += 1;
        }
        // Less than 0.5% opaque pixels ≈ blank (model clipped or failed).
        resolve(opaque < w * h * 0.005);
      } catch (error) {
        resolve(false);
      }
    };
    img.onerror = () => resolve(true);