Expose convolution function (#46)

lib/index.js

@@ -26,12 +26,12 @@ export { default as prewittHorizontal } from './filters/prewittHorizontal'
 export { default as sharpen } from './filters/sharpen'
 export { default as sobelVertical } from './filters/sobelVertical'
 export { default as sobelHorizontal } from './filters/sobelHorizontal'
-
 export { default as gaussian } from './filters/gaussian'
 export { default as bigGaussian } from './filters/bigGaussian'
 export { default as canny } from './filters/canny'
 
 // utils
+export { default as convolution } from './operations/convolution'
 export { default as printCanvas } from './utils/printCanvas'
 export { default as getImage } from './utils/getImage'
 export { default as filterImage } from './utils/filterImage'

lib/operations/convolution.js

@@ -1,12 +1,12 @@
-const convolution = function (pixels, weights) {
-  let side = Math.round(Math.sqrt(weights.length)),
-    halfSide = Math.floor(side / 2),
-    src = pixels.data,
-    canvasWidth = pixels.width,
-    canvasHeight = pixels.height,
-    temporaryCanvas = document.createElement('canvas'),
-    temporaryCtx = temporaryCanvas.getContext('2d'),
-    outputData = temporaryCtx.createImageData(canvasWidth, canvasHeight)
+const convolution = function (pixels, kernel) {
+  let side = Math.round(Math.sqrt(kernel.length))
+  let halfSide = Math.floor(side / 2)
+  let src = pixels.data
+  let canvasWidth = pixels.width
+  let canvasHeight = pixels.height
+  let temporaryCanvas = document.createElement('canvas')
+  let temporaryCtx = temporaryCanvas.getContext('2d')
+  let outputData = temporaryCtx.createImageData(canvasWidth, canvasHeight)
 
   for (let y = 0; y < canvasHeight; y++) {
     for (let x = 0; x < canvasWidth; x++) {
@@ -27,7 +27,7 @@ const convolution = function (pixels, weights) {
             currentKernelX < canvasWidth
           ) {
             let offset = (currentKernelY * canvasWidth + currentKernelX) * 4,
-              weight = weights[kernelY * side + kernelX]
+              weight = kernel[kernelY * side + kernelX]
 
             sumReds += src[offset] * weight
             sumGreens += src[offset + 1] * weight