diff --git a/CHANGELOG.md b/CHANGELOG.md
index 26fb99743..63623f23d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 ### Fixed
 * Load images from Node.js object URLs (#2525)
+* Fix off-by-one RGB values from `getImageData` on semi-transparent pixels (#1933)
 
 3.2.3
 ==================
diff --git a/src/CanvasRenderingContext2d.cc b/src/CanvasRenderingContext2d.cc
index 6183837c0..a203455df 100644
--- a/src/CanvasRenderingContext2d.cc
+++ b/src/CanvasRenderingContext2d.cc
@@ -1079,10 +1079,9 @@ Context2d::GetImageData(const Napi::CallbackInfo& info) {
           dst[bx + 2] = b;
         } else {
           // Undo alpha pre-multiplication
-          float alphaR = (float)255 / a;
-          dst[bx + 0] = (int)((float)r * alphaR);
-          dst[bx + 1] = (int)((float)g * alphaR);
-          dst[bx + 2] = (int)((float)b * alphaR);
+          dst[bx + 0] = (r * 255 + a / 2) / a;
+          dst[bx + 1] = (g * 255 + a / 2) / a;
+          dst[bx + 2] = (b * 255 + a / 2) / a;
         }
 
       }
diff --git a/test/canvas.test.js b/test/canvas.test.js
index b8c50b979..60e44e205 100644
--- a/test/canvas.test.js
+++ b/test/canvas.test.js
@@ -2224,6 +2224,15 @@ describe('Canvas', function () {
       assert.equal(result.data[255], 255) // not black or junk data
       assert.equal(result.data[255 * 256], 255) // not black or junk data
     })
+
+    it('round-trips semi-transparent pixels through getImageData (#1933)', function () {
+      const canvas = createCanvas(1, 1)
+      const ctx = canvas.getContext('2d')
+      ctx.putImageData(createImageData(new Uint8ClampedArray([252, 252, 252, 252]), 1), 0, 0)
+      assert.deepEqual(Array.from(ctx.getImageData(0, 0, 1, 1).data), [252, 252, 252, 252])
+      ctx.putImageData(createImageData(new Uint8ClampedArray([255, 128, 1, 2]), 1), 0, 0)
+      assert.deepEqual(Array.from(ctx.getImageData(0, 0, 1, 1).data), [255, 128, 0, 2])
+    })
   })
 
   it('Canvas#createPNGStream()', function (done) {