Move icon generation into dedicated files

colors.go

@@ -1,90 +0,0 @@
-package main
-
-import "image/color"
-
-func colorV1(hash [16]byte) color.RGBA {
-	r := 32 + (hash[0]%16)/2<<4
-	g := 32 + (hash[2]%16)/2<<4
-	b := 32 + (hash[len(hash)-1]%16)/2<<4
-
-	if r > g && r > b {
-		r += 48
-	} else if g > r && g > b {
-		g += 48
-	} else if b > r && b > g {
-		b += 48
-	}
-	return color.RGBA{r, g, b, 255}
-}
-
-func colorV2(hash [16]byte) color.RGBA {
-	var palette = []color.RGBA{
-		{0x3c, 0x38, 0x36, 0xff},
-		{0xcc, 0x24, 0x1d, 0xff},
-		{0x98, 0x97, 0x1a, 0xff},
-		{0xd7, 0x99, 0x21, 0xff},
-		{0x45, 0x85, 0x88, 0xff},
-		{0xb1, 0x62, 0x86, 0xff},
-		{0x68, 0x9d, 0x6a, 0xff},
-		{0xa8, 0x99, 0x84, 0xff},
-	}
-	return palette[hash[15]%8]
-}
-
-func colorGh(hash [16]byte) color.RGBA {
-	h1 := (uint16(hash[12]) & 0x0f) << 8
-	h2 := uint16(hash[13])
-
-	h := uint32(h1 | h2)
-	s := uint32(hash[14])
-	l := uint32(hash[15])
-
-	return hslToRgba(
-		remap(h, 0, 4096, 0, 360),
-		65.0-remap(s, 0, 255, 0, 20),
-		75.0-remap(l, 0, 255, 0, 20),
-	)
-}
-
-// http://www.w3.org/TR/css3-color/#hsl-color
-func hslToRgba(hue float32, sat float32, lum float32) color.RGBA {
-	hue = hue / 360.0
-	sat = sat / 100.0
-	lum = lum / 100.0
-
-	t2 := lum + sat - (lum * sat)
-	if lum <= 0.5 {
-		t2 = lum * (sat + 1.0)
-	}
-
-	t1 := lum*2.0 - t2
-
-	return color.RGBA{
-		uint8(hueToRgb(t1, t2, hue+1.0/3.0) * 255),
-		uint8(hueToRgb(t1, t2, hue) * 255),
-		uint8(hueToRgb(t1, t2, hue-1.0/3.0) * 255),
-		0xff,
-	}
-}
-
-func hueToRgb(t1 float32, t2 float32, hue float32) float32 {
-	if hue < 0.0 {
-		hue = hue + 1.0
-	} else if hue >= 1.0 {
-		hue = hue - 1.0
-	}
-
-	if hue < 1.0/6.0 {
-		return t1 + (t2-t1)*6.0*hue
-	}
-
-	if hue < 1.0/2.0 {
-		return t2
-	}
-
-	if hue < 2.0/3.0 {
-		return t1 + (t2-t1)*(2.0/3.0-hue)*6.0
-	}
-
-	return t1
-}

icons/ghicons.go

@@ -0,0 +1,107 @@
+package icons
+
+import (
+	"image"
+	"image/color"
+)
+
+type GhIconGenerator struct {
+}
+
+// Based on https://github.com/dgraham/identicon
+func (generator *GhIconGenerator) GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA {
+	if size > 512 {
+		size = 512
+	}
+	blocks := 5
+
+	hash := HashBytes(id)
+	nibbles := nibbles(hash)
+	data := make([]bool, blocks*blocks)
+
+	for x := 0; x < blocks; x++ {
+		for y := 0; y < blocks; y++ {
+			ni := x + blocks*(blocks-y-1)
+			if x+blocks*y > 2*blocks {
+				di := (x + blocks*y) - 2*blocks
+				data[di] = nibbles[ni%32]%2 == 0
+			}
+		}
+	}
+
+	return drawImage(mirrorData(data, blocks), blocks, size, f(hash))
+}
+
+// https://processing.org/reference/map_.html
+func remap(value uint32, vmin uint32, vmax uint32, dmin uint32, dmax uint32) float32 {
+	return float32((value-vmin)*(dmax-dmin)) / float32((vmax-vmin)+dmin)
+}
+
+func nibbles(hash [16]byte) []byte {
+	nibbles := make([]byte, 32)
+
+	for i := 0; i <= 15; i++ {
+		nibbles[i*2+1] = hash[i] & 0x0f
+		nibbles[i*2] = hash[i] & 0xf0 >> 4
+	}
+
+	return nibbles
+}
+
+func ColorGh(hash [16]byte) color.RGBA {
+	h1 := (uint16(hash[12]) & 0x0f) << 8
+	h2 := uint16(hash[13])
+
+	h := uint32(h1 | h2)
+	s := uint32(hash[14])
+	l := uint32(hash[15])
+
+	return hslToRgba(
+		remap(h, 0, 4096, 0, 360),
+		65.0-remap(s, 0, 255, 0, 20),
+		75.0-remap(l, 0, 255, 0, 20),
+	)
+}
+
+// http://www.w3.org/TR/css3-color/#hsl-color
+func hslToRgba(hue float32, sat float32, lum float32) color.RGBA {
+	hue = hue / 360.0
+	sat = sat / 100.0
+	lum = lum / 100.0
+
+	t2 := lum + sat - (lum * sat)
+	if lum <= 0.5 {
+		t2 = lum * (sat + 1.0)
+	}
+
+	t1 := lum*2.0 - t2
+
+	return color.RGBA{
+		uint8(hueToRgb(t1, t2, hue+1.0/3.0) * 255),
+		uint8(hueToRgb(t1, t2, hue) * 255),
+		uint8(hueToRgb(t1, t2, hue-1.0/3.0) * 255),
+		0xff,
+	}
+}
+
+func hueToRgb(t1 float32, t2 float32, hue float32) float32 {
+	if hue < 0.0 {
+		hue = hue + 1.0
+	} else if hue >= 1.0 {
+		hue = hue - 1.0
+	}
+
+	if hue < 1.0/6.0 {
+		return t1 + (t2-t1)*6.0*hue
+	}
+
+	if hue < 1.0/2.0 {
+		return t2
+	}
+
+	if hue < 2.0/3.0 {
+		return t1 + (t2-t1)*(2.0/3.0-hue)*6.0
+	}
+
+	return t1
+}

icons/ghicons_test.go

@@ -0,0 +1,30 @@
+package icons
+
+import "testing"
+
+func TestHSLtoRGB(t *testing.T) {
+	red := hslToRgba(0, 100, 50)
+	if red.R != 255 || red.G != 0 || red.B != 0 {
+		t.Errorf("Color red not as required")
+	}
+
+	green := hslToRgba(120, 100, 50)
+	if green.R != 0 || green.G != 255 || green.B != 0 {
+		t.Errorf("Color green not as required")
+	}
+
+	blue := hslToRgba(240, 100, 50)
+	if blue.R != 0 || blue.G != 0 || blue.B != 255 {
+		t.Errorf("Color blue not as required")
+	}
+}
+
+func TestShouldCreateNibbles(t *testing.T) {
+	hash := [16]byte{}
+	hash[0] = 0x12
+	nibbles := nibbles(hash)
+
+	if nibbles[0] != 0x01 || nibbles[1] != 02 {
+		t.Errorf("Nibbles not extracted as expected")
+	}
+}

icons/icons.go

@@ -0,0 +1,64 @@
+package icons
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"image"
+	"image/color"
+	"image/draw"
+	"regexp"
+)
+
+type IconGenerator interface {
+	GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA
+}
+
+func HashBytes(id string) [16]byte {
+	hash := [16]byte{}
+	md5RegExp := regexp.MustCompile("[a-f0-9]{32}")
+	if !md5RegExp.Match([]byte(id)) {
+		hash = md5.Sum([]byte(id))
+	} else {
+		dec, _ := hex.DecodeString(id)
+		for idx, b := range dec {
+			hash[idx] = b
+		}
+	}
+	return hash
+}
+
+func mirrorData(data []bool, blocks int) []bool {
+	for x := 0; x < blocks; x++ {
+		min := x*blocks + 1
+		for y := 0; y < blocks; y++ {
+			a := ((blocks - x - 1) * blocks) + y
+			b := min + y - 1
+			if data[a] {
+				data[b] = true
+			}
+		}
+	}
+	return data
+}
+
+func drawImage(data []bool, blocks int, size int, c color.Color) *image.NRGBA {
+	img := image.NewNRGBA(image.Rect(0, 0, size, size))
+
+	draw.Draw(img, img.Bounds(), &image.Uniform{color.Gray{240}}, image.Point{0, 0}, draw.Src)
+
+	blockSize := size / (blocks + 1)
+	border := (size - (blocks * blockSize)) / 2
+
+	for x := border; x < blockSize*blocks+border; x++ {
+		bx := (x - border) / blockSize
+		for y := border; y < blockSize*blocks+border; y++ {
+			by := (y - border) / blockSize
+			idx := bx*blocks + by
+			if data[idx] && (bx < blocks || by < blocks) {
+				img.Set(x, y, c)
+			}
+		}
+	}
+
+	return img
+}

icons/idicons.go

@@ -0,0 +1,54 @@
+package icons
+
+import (
+	"image"
+	"image/color"
+	"strings"
+)
+
+type IdIconGenerator struct {
+}
+
+func (generator *IdIconGenerator) GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA {
+	id = strings.ToLower(id)
+	blocks := 5
+	if size > 512 {
+		size = 512
+	}
+
+	hash := HashBytes(id)
+	data := make([]bool, blocks*blocks)
+	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))
+}
+
+func ColorV1(hash [16]byte) color.RGBA {
+	r := 32 + (hash[0]%16)/2<<4
+	g := 32 + (hash[2]%16)/2<<4
+	b := 32 + (hash[len(hash)-1]%16)/2<<4
+
+	if r > g && r > b {
+		r += 48
+	} else if g > r && g > b {
+		g += 48
+	} else if b > r && b > g {
+		b += 48
+	}
+	return color.RGBA{r, g, b, 255}
+}
+
+func ColorV2(hash [16]byte) color.RGBA {
+	var palette = []color.RGBA{
+		{0x3c, 0x38, 0x36, 0xff},
+		{0xcc, 0x24, 0x1d, 0xff},
+		{0x98, 0x97, 0x1a, 0xff},
+		{0xd7, 0x99, 0x21, 0xff},
+		{0x45, 0x85, 0x88, 0xff},
+		{0xb1, 0x62, 0x86, 0xff},
+		{0x68, 0x9d, 0x6a, 0xff},
+		{0xa8, 0x99, 0x84, 0xff},
+	}
+	return palette[hash[15]%8]
+}

icons/idicons_test.go

@@ -0,0 +1,36 @@
+package icons
+
+import (
+	"bytes"
+	"image/png"
+	"testing"
+)
+
+func TestIgnoreCase(t *testing.T) {
+	iconGenerator := IdIconGenerator{}
+
+	w1 := bytes.NewBuffer([]byte{})
+	png.Encode(w1, iconGenerator.GenIcon("example", 80, ColorV1))
+
+	w2 := bytes.NewBuffer([]byte{})
+	png.Encode(w2, iconGenerator.GenIcon("Example", 80, ColorV1))
+
+	if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 {
+		t.Errorf("resulting images do not match")
+	}
+}
+
+func TestStringMatchesHash(t *testing.T) {
+	iconGenerator := IdIconGenerator{}
+
+	w1 := bytes.NewBuffer([]byte{})
+	// MD5 of lowercase 'example'
+	png.Encode(w1, iconGenerator.GenIcon("1a79a4d60de6718e8e5b326e338ae533", 80, ColorV2))
+
+	w2 := bytes.NewBuffer([]byte{})
+	png.Encode(w2, iconGenerator.GenIcon("Example", 80, ColorV2))
+
+	if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 {
+		t.Errorf("resulting images do not match")
+	}
+}

idicon.go

@@ -1,130 +1,18 @@
 package main
 
 import (
-	"crypto/md5"
-	"encoding/hex"
 	"flag"
 	"fmt"
-	"image"
-	"image/color"
-	"image/draw"
+	"github.com/BurntSushi/toml"
+	"github.com/gorilla/mux"
+	"idicon/icons"
 	"image/png"
 	"log"
 	"net/http"
 	"os"
-	"regexp"
 	"strconv"
-	"strings"
-
-	"github.com/BurntSushi/toml"
-	"github.com/gorilla/mux"
 )
 
-// https://processing.org/reference/map_.html
-func remap(value uint32, vmin uint32, vmax uint32, dmin uint32, dmax uint32) float32 {
-	return float32((value-vmin)*(dmax-dmin)) / float32((vmax-vmin)+dmin)
-}
-
-func nibbles(hash [16]byte) []byte {
-	nibbles := make([]byte, 32)
-
-	for i := 0; i <= 15; i++ {
-		nibbles[i*2+1] = hash[i] & 0x0f
-		nibbles[i*2] = hash[i] & 0xf0 >> 4
-	}
-
-	return nibbles
-}
-
-// Based on https://github.com/dgraham/identicon
-func genGhIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA {
-	if size > 512 {
-		size = 512
-	}
-	blocks := 5
-
-	hash := hashBytes(id)
-	nibbles := nibbles(hash)
-	data := make([]bool, blocks*blocks)
-
-	for x := 0; x < blocks; x++ {
-		for y := 0; y < blocks; y++ {
-			ni := x + blocks*(blocks-y-1)
-			if x+blocks*y > 2*blocks {
-				di := (x + blocks*y) - 2*blocks
-				data[di] = nibbles[ni%32]%2 == 0
-			}
-		}
-	}
-
-	return drawImage(mirrorData(data, blocks), blocks, size, f(hash))
-}
-
-func genIdIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA {
-	id = strings.ToLower(id)
-	blocks := 5
-	if size > 512 {
-		size = 512
-	}
-
-	hash := hashBytes(id)
-	data := make([]bool, blocks*blocks)
-	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))
-}
-
-func hashBytes(id string) [16]byte {
-	hash := [16]byte{}
-	md5RegExp := regexp.MustCompile("[a-f0-9]{32}")
-	if !md5RegExp.Match([]byte(id)) {
-		hash = md5.Sum([]byte(id))
-	} else {
-		dec, _ := hex.DecodeString(id)
-		for idx, b := range dec {
-			hash[idx] = b
-		}
-	}
-	return hash
-}
-
-func mirrorData(data []bool, blocks int) []bool {
-	for x := 0; x < blocks; x++ {
-		min := x*blocks + 1
-		for y := 0; y < blocks; y++ {
-			a := ((blocks - x - 1) * blocks) + y
-			b := min + y - 1
-			if data[a] {
-				data[b] = true
-			}
-		}
-	}
-	return data
-}
-
-func drawImage(data []bool, blocks int, size int, c color.Color) *image.NRGBA {
-	img := image.NewNRGBA(image.Rect(0, 0, size, size))
-
-	draw.Draw(img, img.Bounds(), &image.Uniform{color.Gray{240}}, image.Point{0, 0}, draw.Src)
-
-	blockSize := size / (blocks + 1)
-	border := (size - (blocks * blockSize)) / 2
-
-	for x := border; x < blockSize*blocks+border; x++ {
-		bx := (x - border) / blockSize
-		for y := border; y < blockSize*blocks+border; y++ {
-			by := (y - border) / blockSize
-			idx := bx*blocks + by
-			if data[idx] && (bx < blocks || by < blocks) {
-				img.Set(x, y, c)
-			}
-		}
-	}
-
-	return img
-}
-
 func requestHandler(w http.ResponseWriter, r *http.Request) {
 	id := mux.Vars(r)["id"]
 
@@ -144,7 +32,7 @@ func requestHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	for _, userConfig := range config.Users {
-		if hashBytes(id) == hashBytes(userConfig.ID) {
+		if icons.HashBytes(id) == icons.HashBytes(userConfig.ID) {
 			id = userConfig.Alias
 			if len(userConfig.ColorScheme) > 0 {
 				colorScheme = userConfig.ColorScheme
@@ -156,19 +44,22 @@ func requestHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Add("Content-Type", "image/png")
-	cFunc := colorV2
+	cFunc := icons.ColorV2
 	if colorScheme == "v1" {
-		cFunc = colorV1
+		cFunc = icons.ColorV1
 	} else if colorScheme == "gh" {
-		cFunc = colorGh
+		cFunc = icons.ColorGh
 	}
 
+	var iconGenerator icons.IconGenerator
 	if pattern == "github" {
-		err = png.Encode(w, genGhIcon(id, size, cFunc))
+		iconGenerator = &icons.GhIconGenerator{}
+
 	} else {
-		err = png.Encode(w, genIdIcon(id, size, cFunc))
+		iconGenerator = &icons.IdIconGenerator{}
 	}
 
+	err = png.Encode(w, iconGenerator.GenIcon(id, size, cFunc))
 }
 
 var (

idicon_test.go

@@ -1,9 +1,7 @@
 package main
 
 import (
-	"bytes"
 	_ "embed"
-	"image/png"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -87,31 +85,6 @@ func TestCorrectResponseForGHColorSchemeAndPattern(t *testing.T) {
 	}
 }
 
-func TestIgnoreCase(t *testing.T) {
-	w1 := bytes.NewBuffer([]byte{})
-	png.Encode(w1, genIdIcon("example", 80, colorV1))
-
-	w2 := bytes.NewBuffer([]byte{})
-	png.Encode(w2, genIdIcon("Example", 80, colorV1))
-
-	if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 {
-		t.Errorf("resulting images do not match")
-	}
-}
-
-func TestStringMatchesHash(t *testing.T) {
-	w1 := bytes.NewBuffer([]byte{})
-	// MD5 of lowercase 'example'
-	png.Encode(w1, genIdIcon("1a79a4d60de6718e8e5b326e338ae533", 80, colorV2))
-
-	w2 := bytes.NewBuffer([]byte{})
-	png.Encode(w2, genIdIcon("Example", 80, colorV2))
-
-	if bytes.Compare(w1.Bytes(), w2.Bytes()) != 0 {
-		t.Errorf("resulting images do not match")
-	}
-}
-
 func TestUsesConfig(t *testing.T) {
 	configure("./testdata/testconfig.toml")
 
@@ -154,30 +127,3 @@ func TestCorrectResponseForUserConfig(t *testing.T) {
 		t.Errorf("returned image does not match expected image for mapped alias '42'")
 	}
 }
-
-func TestHSLtoRGB(t *testing.T) {
-	red := hslToRgba(0, 100, 50)
-	if red.R != 255 || red.G != 0 || red.B != 0 {
-		t.Errorf("Color red not as required")
-	}
-
-	green := hslToRgba(120, 100, 50)
-	if green.R != 0 || green.G != 255 || green.B != 0 {
-		t.Errorf("Color green not as required")
-	}
-
-	blue := hslToRgba(240, 100, 50)
-	if blue.R != 0 || blue.G != 0 || blue.B != 255 {
-		t.Errorf("Color blue not as required")
-	}
-}
-
-func TestShouldCreateNibbles(t *testing.T) {
-	hash := [16]byte{}
-	hash[0] = 0x12
-	nibbles := nibbles(hash)
-
-	if nibbles[0] != 0x01 || nibbles[1] != 02 {
-		t.Errorf("Nibbles not extracted as expected")
-	}
-}