CameraConnectionFragment.java 文件源码

/**
 * Configures the necessary {@link android.graphics.Matrix} transformation to `mTextureView`.
 * This method should be called after the camera preview size is determined in
 * setUpCameraOutputs and also the size of `mTextureView` is fixed.
 *
 * @param viewWidth  The width of `mTextureView`
 * @param viewHeight The height of `mTextureView`
 */
private void configureTransform(final int viewWidth, final int viewHeight) {
  final Activity activity = getActivity();
  if (null == textureView || null == previewSize || null == activity) {
    return;
  }
  final int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
  final Matrix matrix = new Matrix();
  final RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
  final RectF bufferRect = new RectF(0, 0, previewSize.getHeight(), previewSize.getWidth());
  final float centerX = viewRect.centerX();
  final float centerY = viewRect.centerY();
  if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
    bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
    matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
    final float scale =
        Math.max(
            (float) viewHeight / previewSize.getHeight(),
            (float) viewWidth / previewSize.getWidth());
    matrix.postScale(scale, scale, centerX, centerY);
    matrix.postRotate(90 * (rotation - 2), centerX, centerY);
  } else if (Surface.ROTATION_180 == rotation) {
    matrix.postRotate(180, centerX, centerY);
  }
  textureView.setTransform(matrix);
}