♻️ (clockfare): refactor with test

Author: yuanyu90221

clockface_sample/clock.svg

@@ -20,21 +20,11 @@ type Point struct {
 	Y float64
 }
 
-// SecondHand is the unit vector of the second hand of an analogue clock at time `t`
-// represented as a Point.
-func SecondHand(t time.Time) Point {
-	p := secondHandPoint(t)
-	p = Point{p.X * secondHandLength, p.Y * secondHandLength}
-	p = Point{p.X, -p.Y}
-	p = Point{p.X + clockCentreX, p.Y + clockCentreY} //translate
-	return p
-}
-
 func secondsInRadians(t time.Time) float64 {
 	return (math.Pi / (secondsInHalfClock / (float64(t.Second()))))
 }
 
-func secondHandPoint(t time.Time) Point {
+func SecondHandPoint(t time.Time) Point {
 	return angleToPoint(secondsInRadians(t))
 }
 
@@ -50,7 +40,7 @@ func angleToPoint(angle float64) Point {
 	return Point{x, y}
 }
 
-func minuteHandPoint(t time.Time) Point {
+func MinuteHandPoint(t time.Time) Point {
 	return angleToPoint(minutesInRadians(t))
 }
 
@@ -59,6 +49,6 @@ func hoursInRadians(t time.Time) float64 {
 		(math.Pi / (hoursInHalfClock / float64(t.Hour()%hoursInClock)))
 }
 
-func hourHandPoint(t time.Time) Point {
+func HourHandPoint(t time.Time) Point {
 	return angleToPoint(hoursInRadians(t))
 }

clockface_sample/clockface/clockface.go

@@ -45,7 +45,7 @@ func TestSecondHandPoint(t *testing.T) {
 
 	for _, c := range cases {
 		t.Run(testName(c.time), func(t *testing.T) {
-			got := secondHandPoint(c.time)
+			got := SecondHandPoint(c.time)
 			if !roughlyEqualPoint(got, c.point) {
 				t.Fatalf("Wanted %v Point, but got %v", c.point, got)
 			}
@@ -93,7 +93,7 @@ func TestMinuteHandPoint(t *testing.T) {
 
 	for _, c := range cases {
 		t.Run(testName(c.time), func(t *testing.T) {
-			got := minuteHandPoint(c.time)
+			got := MinuteHandPoint(c.time)
 			if !roughlyEqualPoint(got, c.point) {
 				t.Fatalf("Wanted %v Point, but got %v", c.point, got)
 			}
@@ -133,7 +133,7 @@ func TestHourHandPoint(t *testing.T) {
 
 	for _, c := range cases {
 		t.Run(testName(c.time), func(t *testing.T) {
-			got := hourHandPoint(c.time)
+			got := HourHandPoint(c.time)
 			if !roughlyEqualPoint(got, c.point) {
 				t.Fatalf("Wanted %v Point, but got %v", c.point, got)
 			}

clockface_sample/clockface/clockface_test.go

@@ -4,10 +4,10 @@ import (
 	"os"
 	"time"
 
-	"github.com/leetcode-golang-classroom/learn-golang-with-tests/clockface_sample/clockface"
+	"github.com/leetcode-golang-classroom/learn-golang-with-tests/clockface_sample/svg"
 )
 
 func main() {
 	t := time.Now()
-	clockface.SVGWriter(os.Stdout, t)
+	svg.Write(os.Stdout, t)
 }

clockface_sample/clockface/svgWriter.go

@@ -0,0 +1,86 @@
+package svg
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io"
+	"time"
+
+	"github.com/leetcode-golang-classroom/learn-golang-with-tests/clockface_sample/clockface"
+)
+
+type SVG struct {
+	XMLName xml.Name `xml:"svg"`
+	Xmlns   string   `xml:"xmlns,attr"`
+	Width   string   `xml:"width,attr"`
+	Height  string   `xml:"height,attr"`
+	ViewBox string   `xml:"viewBox,attr"`
+	Version string   `xml:"version,attr"`
+	Circle  Circle   `xml:"circle"`
+	Line    []Line   `xml:"line"`
+}
+
+type Circle struct {
+	Cx float64 `xml:"cx,attr"`
+	Cy float64 `xml:"cy,attr"`
+	R  float64 `xml:"r,attr"`
+}
+
+type Line struct {
+	X1 float64 `xml:"x1,attr"`
+	Y1 float64 `xml:"y1,attr"`
+	X2 float64 `xml:"x2,attr"`
+	Y2 float64 `xml:"y2,attr"`
+}
+
+const (
+	secondHandLength = 90
+	minuteHandLength = 80
+	hourHandLength   = 50
+	clockCentreX     = 150
+	clockCentreY     = 150
+)
+
+// Write writes an SVG representation of an analogue clock, showing the time t, to the writer w.
+func Write(w io.Writer, t time.Time) {
+	io.WriteString(w, svgStart)
+	io.WriteString(w, bezel)
+	secondHand(w, t)
+	minuteHand(w, t)
+	hourHand(w, t)
+	io.WriteString(w, svgEnd)
+}
+
+func secondHand(w io.Writer, t time.Time) {
+	p := makeHand(clockface.SecondHandPoint(t), secondHandLength)
+	fmt.Fprintf(w, `<line x1="150" y1="150" x2="%.3f" y2="%.3f" style="fill:none;stroke:#f00;stroke-width:3px;"/>`, p.X, p.Y)
+}
+
+func minuteHand(w io.Writer, t time.Time) {
+	p := makeHand(clockface.MinuteHandPoint(t), minuteHandLength)
+	fmt.Fprintf(w, `<line x1="150" y1="150" x2="%.3f" y2="%.3f" style="fill:none;stroke:#000;stroke-width:3px;"/>`, p.X, p.Y)
+}
+
+func makeHand(p clockface.Point, length float64) clockface.Point {
+	p = clockface.Point{X: p.X * length, Y: p.Y * length} // scale
+	p = clockface.Point{X: p.X, Y: -p.Y}                  // flip
+	// transition
+	return clockface.Point{X: p.X + clockCentreX, Y: p.Y + clockCentreY}
+}
+
+const svgStart = `<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg xmlns="http://www.w3.org/2000/svg"
+     width="100%"
+     height="100%"
+     viewBox="0 0 300 300"
+     version="2.0">`
+
+const bezel = `<circle cx="150" cy="150" r="100" style="fill:#fff;stroke:#000;stroke-width:5px;"/>`
+
+const svgEnd = `</svg>`
+
+func hourHand(w io.Writer, t time.Time) {
+	p := makeHand(clockface.HourHandPoint(t), hourHandLength)
+	fmt.Fprintf(w, `<line x1="150" y1="150" x2="%.3f" y2="%.3f" style="fill:none;stroke:#000;stroke-width:3px;"/>`, p.X, p.Y)
+}