message: Fix pixel weights and naming mistakes
  Weights for left/right were based on wrong fractions, only incorporating
  the left fraction instead of the average.  Some sample references were
  wrong in the case of weighting four samples.
diff: @@ -375,7 +375,7 @@ where
  debug_assert!(left > 0 && right > 0,
  "First output column must have corresponding pixels");
  - let fract = (leftf.fract() + leftf.fract())/2.;
  + let fract = (leftf.fract() + rightf.fract())/2.;
  let mut sum_left = zero_sum();
  let mut sum_right = zero_sum();
  @@ -387,7 +387,7 @@ where
  add_pixel(&mut sum_right, k_right);
  }
  - // Now we approximate: bot/n*fract + top/n*(1-fract)
  + // Now we approximate: left/n*(1-fract) + right/n*fract
  let fact_right = fract /((top - bottom) as f32);
  let fact_left = (1. - fract)/((top - bottom) as f32);
  @@ -439,13 +439,13 @@ where
  )
  } else { // bottom == top && left == right
  - let k_br = image.get_pixel(right - 1, top - 1).channels4();
  - let k_tr = image.get_pixel(right - 1, top ).channels4();
  - let k_bl = image.get_pixel(right, top - 1).channels4();
  - let k_tl = image.get_pixel(right, top ).channels4();
  + let k_bl = image.get_pixel(right - 1, top - 1).channels4();
  + let k_tl = image.get_pixel(right - 1, top ).channels4();
  + let k_br = image.get_pixel(right, top - 1).channels4();
  + let k_tr = image.get_pixel(right, top ).channels4();
  let frac_v = (topf.fract() + bottomf.fract())/2.;
  - let frac_h = (rightf.fract() + rightf.fract())/2.;
  + let frac_h = (leftf.fract() + rightf.fract())/2.;
  let fact_tr = frac_v * frac_h;
  let fact_tl = frac_v * (1. - frac_h);
  @@ -466,6 +466,7 @@ where
  mix(k_br.2, k_tr.2, k_bl.2, k_tl.2),
  mix(k_br.3, k_tr.3, k_bl.3, k_tl.3),
  )
  + // (<S as NumCast>::from(0).unwrap(),<S as NumCast>::from(0).unwrap(),<S as NumCast>::from(0).unwrap(),<S as NumCast>::from(0).unwrap(),)
  };
  let pixel = Pixel::from_channels(avg.0, avg.1, avg.2, avg.3);
  