diff --git a/icons/ghicons.go b/icons/ghicons.go
index bd49c23..61235a2 100644
--- a/icons/ghicons.go
+++ b/icons/ghicons.go
@@ -6,10 +6,20 @@ import (
 )
 
 type GhIconGenerator struct {
+	colorGenerator func([16]byte) color.RGBA
+}
+
+func NewGhIconGenerator() *GhIconGenerator {
+	return &GhIconGenerator{}
+}
+
+func (generator *GhIconGenerator) WithColorGenerator(colorGenerator func([16]byte) color.RGBA) *GhIconGenerator {
+	generator.colorGenerator = colorGenerator
+	return generator
 }
 
 // Based on https://github.com/dgraham/identicon
-func (generator *GhIconGenerator) GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA {
+func (generator *GhIconGenerator) GenIcon(id string, size int) *image.NRGBA {
 	if size > 512 {
 		size = 512
 	}
@@ -29,7 +39,7 @@ func (generator *GhIconGenerator) GenIcon(id string, size int, f func([16]byte)
 		}
 	}
 
-	return drawImage(mirrorData(data, blocks), blocks, size, f(hash))
+	return drawImage(mirrorData(data, blocks), blocks, size, generator.colorGenerator(hash))
 }
 
 // https://processing.org/reference/map_.html
diff --git a/icons/icons.go b/icons/icons.go
index ea37922..d1d4b01 100644
--- a/icons/icons.go
+++ b/icons/icons.go
@@ -10,7 +10,7 @@ import (
 )
 
 type IconGenerator interface {
-	GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA
+	GenIcon(id string, size int) *image.NRGBA
 }
 
 func HashBytes(id string) [16]byte {
diff --git a/icons/idicons.go b/icons/idicons.go
index c287bb9..9d8ab0d 100644
--- a/icons/idicons.go
+++ b/icons/idicons.go
@@ -7,9 +7,19 @@ import (
 )
 
 type IdIconGenerator struct {
+	colorGenerator func([16]byte) color.RGBA
 }
 
-func (generator *IdIconGenerator) GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA {
+func NewIdIconGenerator() *IdIconGenerator {
+	return &IdIconGenerator{}
+}
+
+func (generator *IdIconGenerator) WithColorGenerator(colorGenerator func([16]byte) color.RGBA) *IdIconGenerator {
+	generator.colorGenerator = colorGenerator
+	return generator
+}
+
+func (generator *IdIconGenerator) GenIcon(id string, size int) *image.NRGBA {
 	id = strings.ToLower(id)
 	blocks := 5
 	if size > 512 {
@@ -21,7 +31,7 @@ func (generator *IdIconGenerator) GenIcon(id string, size int, f func([16]byte)
 	for i := 0; i < len(hash)-1; i++ {
 		data[i] = hash[i]%2 != hash[i+1]%2
 	}
-	return drawImage(mirrorData(data, blocks), blocks, size, f(hash))
+	return drawImage(mirrorData(data, blocks), blocks, size, generator.colorGenerator(hash))
 }
 
 func ColorV1(hash [16]byte) color.RGBA {
diff --git a/icons/idicons_test.go b/icons/idicons_test.go
index 255d7c4..30e8f4c 100644
--- a/icons/idicons_test.go
+++ b/icons/idicons_test.go
@@ -7,13 +7,13 @@ import (
 )
 
 func TestIgnoreCase(t *testing.T) {
-	iconGenerator := IdIconGenerator{}
-
 	w1 := bytes.NewBuffer([]byte{})
-	png.Encode(w1, iconGenerator.GenIcon("example", 80, ColorV1))
+	ig1 := NewIdIconGenerator().WithColorGenerator(ColorV1)
+	png.Encode(w1, ig1.GenIcon("example", 80))
 
 	w2 := bytes.NewBuffer([]byte{})
-	png.Encode(w2, iconGenerator.GenIcon("Example", 80, ColorV1))
+	ig2 := NewIdIconGenerator().WithColorGenerator(ColorV1)
+	png.Encode(w2, ig2.GenIcon("Example", 80))
 
 	if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 {
 		t.Errorf("resulting images do not match")
@@ -21,14 +21,14 @@ func TestIgnoreCase(t *testing.T) {
 }
 
 func TestStringMatchesHash(t *testing.T) {
-	iconGenerator := IdIconGenerator{}
-
 	w1 := bytes.NewBuffer([]byte{})
+	ig1 := NewIdIconGenerator().WithColorGenerator(ColorV2)
 	// MD5 of lowercase 'example'
-	png.Encode(w1, iconGenerator.GenIcon("1a79a4d60de6718e8e5b326e338ae533", 80, ColorV2))
+	png.Encode(w1, ig1.GenIcon("1a79a4d60de6718e8e5b326e338ae533", 80))
 
 	w2 := bytes.NewBuffer([]byte{})
-	png.Encode(w2, iconGenerator.GenIcon("Example", 80, ColorV2))
+	ig2 := NewIdIconGenerator().WithColorGenerator(ColorV2)
+	png.Encode(w2, ig2.GenIcon("Example", 80))
 
 	if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 {
 		t.Errorf("resulting images do not match")
diff --git a/idicon.go b/idicon.go
index a79b9b1..d180ef3 100644
--- a/idicon.go
+++ b/idicon.go
@@ -53,13 +53,12 @@ func requestHandler(w http.ResponseWriter, r *http.Request) {
 
 	var iconGenerator icons.IconGenerator
 	if pattern == "github" {
-		iconGenerator = &icons.GhIconGenerator{}
-
+		iconGenerator = icons.NewGhIconGenerator().WithColorGenerator(cFunc)
 	} else {
-		iconGenerator = &icons.IdIconGenerator{}
+		iconGenerator = icons.NewIdIconGenerator().WithColorGenerator(cFunc)
 	}
 
-	err = png.Encode(w, iconGenerator.GenIcon(id, size, cFunc))
+	err = png.Encode(w, iconGenerator.GenIcon(id, size))
 }
 
 var (