Update Laplacian kernel, fix color calculation

processing/laplasian-filter.go

@@ -2,24 +2,23 @@ package processing
 
 import (
 	"image/color"
-	"math"
 
 	"github.com/julyskies/brille/constants"
 	"github.com/julyskies/brille/utilities"
 )
 
-var laplasianKernel = [3][3]int{
-	{0, -1, 0},
-	{-1, 4, -1},
-	{0, -1, 0},
+var laplacianKernel = [3][3]int{
+	{-1, -1, -1},
+	{-1, 8, -1},
+	{-1, -1, -1},
 }
 
 func LaplasianFilter(source [][]color.Color) [][]color.Color {
 	width, height := len(source), len(source[0])
 	destination := utilities.CreateGrid(width, height)
 	for x := 0; x < width; x += 1 {
 		for y := 0; y < height; y += 1 {
-			gradientX := 0
+			averageSum := 0
 			for i := 0; i < 3; i += 1 {
 				for j := 0; j < 3; j += 1 {
 					k := utilities.GradientPoint(x, i, width)
@@ -28,13 +27,11 @@ func LaplasianFilter(source [][]color.Color) [][]color.Color {
 						source[x+k][y+l],
 						constants.GRAYSCALE_AVERAGE,
 					)
-					gradientX += int(grayColor) * laplasianKernel[i][j]
+					averageSum += int(grayColor) * laplacianKernel[i][j]
 				}
 			}
-			colorCode := 255 - uint8(int(math.Sqrt(
-				float64((gradientX * gradientX)),
-			)))
-			destination[x][y] = color.RGBA{colorCode, colorCode, colorCode, 255}
+			channel := 255 - uint8(utilities.MaxMin(averageSum, 255, 0))
+			destination[x][y] = color.RGBA{channel, channel, channel, 255}
 		}
 	}
 	return destination