From 664146fd69352ada2380de1e3223d40a70725c6e Mon Sep 17 00:00:00 2001
From: Alexy <Alexy@DESKTOP-JI2TJNL>
Date: Sun, 31 Oct 2021 15:35:30 -0400
Subject: [PATCH 1/3] Applying colormap on color images (like ultrasounds)

---
 .../storedPixelDataToCanvasImageDataPseudocolorLUT.js     | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js b/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
index 8f60b193..d7222e80 100644
--- a/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
+++ b/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
@@ -35,7 +35,10 @@ function storedPixelDataToCanvasImageDataPseudocolorLUT (image, grayscaleLut, co
 
   if (minPixelValue < 0) {
     while (storedPixelDataIndex < numPixels) {
-      grayscale = grayscaleLut[pixelData[storedPixelDataIndex++] + (-minPixelValue)];
+      grayscale = grayscaleLut[pixelData[storedPixelDataIndex] - minPixelValue];
+      //Incrementing by 1 pixel only works with original black and white images. RGBA comes in groups of 4 pixels
+      //(same for the else condition below)
+      storedPixelDataIndex += (image.color ? 4 : 1);
       rgba = clut[grayscale];
       canvasImageDataData[canvasImageDataIndex++] = rgba[0];
       canvasImageDataData[canvasImageDataIndex++] = rgba[1];
@@ -44,7 +47,8 @@ function storedPixelDataToCanvasImageDataPseudocolorLUT (image, grayscaleLut, co
     }
   } else {
     while (storedPixelDataIndex < numPixels) {
-      grayscale = grayscaleLut[pixelData[storedPixelDataIndex++]];
+      grayscale = grayscaleLut[pixelData[storedPixelDataIndex]];
+      storedPixelDataIndex += (image.color ? 4 : 1);
       rgba = clut[grayscale];
       canvasImageDataData[canvasImageDataIndex++] = rgba[0];
       canvasImageDataData[canvasImageDataIndex++] = rgba[1];

From 0cc3583652d1db91fade0fab718866aa0035d7ed Mon Sep 17 00:00:00 2001
From: Alexy <Alexy@DESKTOP-JI2TJNL>
Date: Fri, 12 Nov 2021 15:58:26 -0500
Subject: [PATCH 2/3] Applying color LUT to RGBA images. For RGBA images, it
 calculates the grayscale pixel value using the luminosity method.

---
 ...ixelDataToCanvasImageDataPseudocolorLUT.js | 22 ++++++++++++++-----
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js b/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
index d7222e80..79c30161 100644
--- a/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
+++ b/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
@@ -33,12 +33,23 @@ function storedPixelDataToCanvasImageDataPseudocolorLUT (image, grayscaleLut, co
     clut = colorLut;
   }
 
+  const grayscalePixelByDefault = () => {
+    return pixelData[storedPixelDataIndex++];
+  };
+  var grayscalePixelByLuminosityMethod = () => {
+    var r = pixelData[storedPixelDataIndex++];
+    var g = pixelData[storedPixelDataIndex++];
+    var b = pixelData[storedPixelDataIndex++];
+    storedPixelDataIndex++;//skip alpha channel
+    return Math.round(0.299 * r + 0.587 * g + 0.114 * b);
+  };
+  var grayscalePixel = image.color
+    ? grayscalePixelByLuminosityMethod
+    : grayscalePixelByDefault;
+
   if (minPixelValue < 0) {
     while (storedPixelDataIndex < numPixels) {
-      grayscale = grayscaleLut[pixelData[storedPixelDataIndex] - minPixelValue];
-      //Incrementing by 1 pixel only works with original black and white images. RGBA comes in groups of 4 pixels
-      //(same for the else condition below)
-      storedPixelDataIndex += (image.color ? 4 : 1);
+      grayscale = grayscaleLut[grayscalePixel() - minPixelValue];
       rgba = clut[grayscale];
       canvasImageDataData[canvasImageDataIndex++] = rgba[0];
       canvasImageDataData[canvasImageDataIndex++] = rgba[1];
@@ -47,8 +58,7 @@ function storedPixelDataToCanvasImageDataPseudocolorLUT (image, grayscaleLut, co
     }
   } else {
     while (storedPixelDataIndex < numPixels) {
-      grayscale = grayscaleLut[pixelData[storedPixelDataIndex]];
-      storedPixelDataIndex += (image.color ? 4 : 1);
+      grayscale = grayscaleLut[grayscalePixel()];
       rgba = clut[grayscale];
       canvasImageDataData[canvasImageDataIndex++] = rgba[0];
       canvasImageDataData[canvasImageDataIndex++] = rgba[1];

From 4728410bd15ca3b6c8c80a06de793d5548e7cfb4 Mon Sep 17 00:00:00 2001
From: Alexy <Alexy@DESKTOP-JI2TJNL>
Date: Fri, 12 Nov 2021 16:16:47 -0500
Subject: [PATCH 3/3] Some refactoring

---
 .../storedPixelDataToCanvasImageDataPseudocolorLUT.js  | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js b/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
index 79c30161..a0cdb2fe 100644
--- a/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
+++ b/src/internal/storedPixelDataToCanvasImageDataPseudocolorLUT.js
@@ -36,14 +36,14 @@ function storedPixelDataToCanvasImageDataPseudocolorLUT (image, grayscaleLut, co
   const grayscalePixelByDefault = () => {
     return pixelData[storedPixelDataIndex++];
   };
-  var grayscalePixelByLuminosityMethod = () => {
-    var r = pixelData[storedPixelDataIndex++];
-    var g = pixelData[storedPixelDataIndex++];
-    var b = pixelData[storedPixelDataIndex++];
+  const grayscalePixelByLuminosityMethod = () => {
+    const r = pixelData[storedPixelDataIndex++];
+    const g = pixelData[storedPixelDataIndex++];
+    const b = pixelData[storedPixelDataIndex++];
     storedPixelDataIndex++;//skip alpha channel
     return Math.round(0.299 * r + 0.587 * g + 0.114 * b);
   };
-  var grayscalePixel = image.color
+  const grayscalePixel = image.color
     ? grayscalePixelByLuminosityMethod
     : grayscalePixelByDefault;