Reworked return value structure by making the diff image mandatory. B…

…umped version to RC1

src/colorization.rs

@@ -89,7 +89,7 @@ pub struct Similarity {
     /// - RMS will be between 0. for all-white vs all-black and 1.0 for identical
     /// - SSIM usually is near 1. for similar, near 0. for different but can take on negative values for negative covariances
     /// - Hybrid mode will be inverse: 0. means no difference, 1.0 is maximum difference. For details see [`crate::hybrid::rgb_hybrid_compare`]    
-    pub image: Option<SimilarityImage>,
+    pub image: SimilarityImage,
     /// the average score of the image
     pub score: f64,
 }

src/hybrid.rs

@@ -59,7 +59,7 @@ fn merge_similarity_channels_yuva(
 
     let score = deviation.iter().sum::<f32>() as f64 / deviation.len() as f64;
     Similarity {
-        image: Some(image.into()),
+        image: image.into(),
         score,
     }
 }
@@ -87,7 +87,7 @@ fn merge_similarity_channels_yuv(input: &[GraySimilarityImage; 3]) -> Similarity
 
     let score = deviation.iter().sum::<f32>() as f64 / deviation.len() as f64;
     Similarity {
-        image: Some(image.into()),
+        image: image.into(),
         score,
     }
 }

src/lib.rs

@@ -63,8 +63,7 @@
 //! let image_two = image::open("image2.png").expect("Could not find test-image").into_rgba8();
 //! let result = image_compare::rgba_hybrid_compare(&image_one, &image_two).expect("Images had different dimensions");
 //! if result.score < 0.95 {
-//!   //we can unwrap here since hybrid compare always produces the result image
-//!   let diff_img = result.image.unwrap().to_color_map();
+//!   let diff_img = result.image.to_color_map();
 //!   diff_img.save("diff_image.png").expect("Could not save diff image");
 //! }
 //! ```
@@ -101,6 +100,9 @@ pub mod prelude {
         CalculationFailed(String),
     }
 
+    pub use crate::colorization::GraySimilarityImage;
+    pub use crate::colorization::RGBASimilarityImage;
+    pub use crate::colorization::RGBSimilarityImage;
     pub use crate::colorization::Similarity;
 }
 
@@ -138,7 +140,7 @@ pub fn gray_similarity_structure(
         Algorithm::MSSIMSimple => ssim_simple(first, second),
     }
     .map(|(score, i)| Similarity {
-        image: Some(i.into()),
+        image: i.into(),
         score,
     })
 }
@@ -189,7 +191,7 @@ pub fn rgb_similarity_structure(
     let image = utils::merge_similarity_channels(&input.try_into().unwrap());
     let score = results.iter().map(|(s, _)| *s).fold(1., f64::min);
     Ok(Similarity {
-        image: Some(image.into()),
+        image: image.into(),
         score,
     })
 }

tests/compare.rs

@@ -62,7 +62,7 @@ fn compare_hist_corr(world: &mut CompareWorld, metric: String) {
             &world.second.as_ref().unwrap().clone().into_luma8(),
         )
         .expect("Error comparing the two images!"),
-        image: None,
+        image: GraySimilarityImage::new(0, 0).into(),
     });
 }
 
@@ -149,8 +149,6 @@ fn check_result_image(world: &mut CompareWorld, reference: String) {
         .as_ref()
         .unwrap()
         .image
-        .as_ref()
-        .unwrap()
         .to_color_map()
         .into_luma8();
     let image_one = image::open(reference)
@@ -171,8 +169,6 @@ fn check_result_image_rgba(world: &mut CompareWorld, reference: String) {
         .as_ref()
         .unwrap()
         .image
-        .as_ref()
-        .unwrap()
         .to_color_map()
         .into_rgba8();
     let image_one = image::open(reference)
@@ -193,8 +189,6 @@ fn check_result_image_rgb(world: &mut CompareWorld, reference: String) {
         .as_ref()
         .unwrap()
         .image
-        .as_ref()
-        .unwrap()
         .to_color_map()
         .into_rgb8();
     let image_one = image::open(reference)