command line argument and a config register

blend.go

@@ -11,13 +11,15 @@ import (
 	"sync"
 )
 
+// job passed to goroutines. blend color from img1 and img2 at position (x, y)
 type blendColorJob struct {
-	X    int
-	Y    int
-	Img1 image.Image
-	Img2 image.Image
+	X      int
+	Y      int
+	Img1   image.Image
+	Img2   image.Image
 }
 
+// new color after blend, to apply at position (x, y)
 type blendColorResult struct {
 	X     int
 	Y     int
@@ -98,7 +100,8 @@ func (p *blendWorkerPool) BlendImages(img1 image.Image, img2 image.Image) {
 
 // encode the image
 func encodeImage(imgData *image.RGBA) {
-	out, _ := os.Create("output.jpg")
+	outputFile := fmt.Sprintf("%s/%s", ConfigRegister.OutputDir, "output.jpg")
+	out, _ := os.Create(outputFile)
 	defer out.Close()
 	fmt.Print("Encoding the image...")
 	jpeg.Encode(out, imgData, nil)
@@ -117,19 +120,33 @@ func grayscale(pixel color.Color) color.Color {
 	}
 }
 
-// alpha blending RGBA pixels
-func blend(fc uint8, bc uint8, fa uint8, ba uint8) float64 {
-	// fc : foreground color
-	// bc : background color
-	// fa : foreground alpha
-	// ba : background alpha
-	// all values are alpha-premultiplied
-
-	// darken only
+func darken(fc uint8, bc uint8, fa uint8) float64 {
 	return math.Min(float64(fc), float64(bc))
+}
 
-	// fucky fucky fun
-	// return float64((fc * fa) + (bc * (fa * 2)))
+func lighten(fc uint8, bc uint8, fa uint8) float64 {
+	return math.Max(float64(fc), float64(bc))
+}
+
+// produce absolute garbage
+func fuckyfun(fc uint8, bc uint8, fa uint8) float64 {
+	return float64((fc * fa) + (bc * (fa * 2)))
+}
+
+// get the blending method from the config register
+func blend(fc uint8, bc uint8, fa uint8, ba uint8) float64 {
+	var newValue float64
+	switch ConfigRegister.Method {
+	case "darken":
+		newValue = darken(fc, bc, fa)
+	case "ligten":
+		newValue = lighten(fc, bc, fa)
+	case "fuckyfun":
+		newValue = fuckyfun(fc, bc, fa)
+	default:
+		newValue = darken(fc, bc, fa)
+	}
+	return newValue
 }
 
 // blend two RGBA colors/pixels and returns a new one