From 44b2c8604a92339afc898134115fb3bd5b6f3b33 Mon Sep 17 00:00:00 2001
From: tiffany1618 <tiffany9342@gmail.com>
Date: Mon, 8 Mar 2021 19:51:22 -0800
Subject: [PATCH] Fixed scale channels

---
 src/convert.rs       | 4 +++-
 src/filter/edge.rs   | 9 +++++----
 tests/filter_test.rs | 2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/convert.rs b/src/convert.rs
index 7e6a68c..c420ffb 100644
--- a/src/convert.rs
+++ b/src/convert.rs
@@ -5,7 +5,9 @@ use crate::error::ImgProcResult;
 
 /// Scales channels from range 0.0 to `current_max` to range 0.0 to `scaled_max`
 pub fn scale_channels(input: &Image<f64>, current_min: f64, scaled_min: f64, current_max: f64, scaled_max: f64) -> ImgProcResult<Image<f64>> {
-    Ok(input.map_channels(|channel| ((channel + (scaled_min - current_min)) / (current_max - current_min) * (scaled_max - scaled_min))))
+    Ok(input.map_channels(|channel| {
+        (channel - current_min) / (current_max - current_min) * (scaled_max - scaled_min) + scaled_min
+    }))
 }
 
 /// Converts an `Image<f64>` with channels in range 0 to `scale` to an `Image<u8>` with channels
diff --git a/src/filter/edge.rs b/src/filter/edge.rs
index ecdb07a..44050aa 100644
--- a/src/filter/edge.rs
+++ b/src/filter/edge.rs
@@ -4,7 +4,7 @@
 
 use crate::{filter, error, util, convert};
 use crate::image::{Image, BaseImage};
-use crate::error::{ImgProcResult, check_grayscale};
+use crate::error::ImgProcResult;
 use crate::util::constants::{K_PREWITT_1D_VERT, K_PREWITT_1D_HORZ, K_SOBEL_1D_VERT, K_SOBEL_1D_HORZ, K_LAPLACIAN};
 
 /// Applies a separable derivative mask to a grayscale image
@@ -45,8 +45,9 @@ pub fn laplacian(input: &Image<f64>) -> ImgProcResult<Image<f64>> {
     Ok(filter::unseparable_filter(input, &K_LAPLACIAN)?)
 }
 
-/// Applies the Laplacian of Gaussian operator to a grayscale image. Output contains positive
-/// and negative values - use [`normalize_laplacian()`](fn.normalize_laplacian.html) for visualization
+/// Applies the Laplacian of Gaussian operator using a `size x size` kernel to a grayscale image.
+/// Output contains positive and negative values - use
+/// [`normalize_laplacian()`](fn.normalize_laplacian.html) for visualization
 pub fn laplacian_of_gaussian(input: &Image<f64>, size: u32, sigma: f64) -> ImgProcResult<Image<f64>> {
     let kernel = util::generate_log_kernel(size, sigma)?;
     Ok(filter::unseparable_filter(input, &kernel)?)
@@ -54,7 +55,7 @@ pub fn laplacian_of_gaussian(input: &Image<f64>, size: u32, sigma: f64) -> ImgPr
 
 /// Normalizes the result of a Laplacian or Laplacian of Gaussian operator to the range [0, 255]
 pub fn normalize_laplacian(input: &Image<f64>) -> ImgProcResult<Image<u8>> {
-    check_grayscale(input)?;
+    error::check_grayscale(input)?;
 
     let min = *input.data().iter().min_by(|x, y| x.partial_cmp(y).unwrap()).unwrap();
     let max = *input.data().iter().max_by(|x, y| x.partial_cmp(y).unwrap()).unwrap();
diff --git a/tests/filter_test.rs b/tests/filter_test.rs
index 39b111d..ad3a817 100644
--- a/tests/filter_test.rs
+++ b/tests/filter_test.rs
@@ -144,7 +144,7 @@ fn laplacian() {
     write(&filter::normalize_laplacian(&filtered).unwrap(), "images/tests/filter/laplacian.png").unwrap();
 }
 
-#[test]
+// #[test]
 fn laplacian_of_gaussian() {
     let img: Image<f64> = colorspace::rgb_to_grayscale(&setup("images/scaled.png").unwrap()).into();