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PhotoCapabilities - Web APIs 编辑

The PhotoCapabilities interface of the MediaStream Image Capture API provides available configuration options for an attached photographic device. A PhotoCapabilities object is retrieved by calling ImageCapture.getPhotoCapabilities().

Properties

PhotoCapabilities.redEyeReduction Read only: Returns one of "never", "always", or "controllable". The "controllable" value means the device's red-eye reduction is controllable by the user.
PhotoCapabilities.imageHeight Read only: Returns a MediaSettingsRange object indicating the image height range supported by the user agent.
PhotoCapabilities.imageWidth Read only: Returns a MediaSettingsRange object indicating the image width range supported by the user agent.
PhotoCapabilities.fillLightMode Read only: Returns an array of available fill light options. Options may include auto, off, or flash.

Example

The following example, extracted from Chrome's Image Capture / Photo Resolution Sample, uses the results from getPhotoCapabilities() to modify the size of an input range. This example also shows how the ImageCapture object is created using a MediaStreamTrack retrieved from a device's MediaStream.

const input = document.querySelector('input[type="range"]');

var imageCapture;

navigator.mediaDevices.getUserMedia({video: true})
.then(mediaStream => {
  document.querySelector('video').srcObject = mediaStream;

  const track = mediaStream.getVideoTracks()[0];
  imageCapture = new ImageCapture(track);

  return imageCapture.getPhotoCapabilities();
})
.then(photoCapabilities => {
  const settings = imageCapture.track.getSettings();

  input.min = photoCapabilities.imageWidth.min;
  input.max = photoCapabilities.imageWidth.max;
  input.step = photoCapabilities.imageWidth.step;

  return imageCapture.getPhotoSettings();
})
.then(photoSettings => {
  input.value = photoSettings.imageWidth;
})
.catch(error => console.log('Argh!', error.name || error));