Generating the Gophercises certificate

gcert.go

package main

import (
	"github.com/ajstarks/deck/generate"
	"os"
	"time"
)

type certdata struct {
	student    string
	instructor string
	date       time.Time
}

const (
	color1  = "rgb(122,84,102)"
	color2  = "rgb(102,61,79)"
	mid     = 50.0
	linelen = 30.0
	top     = 75.0
	midy    = 50.0
	infoy   = midy - 30
	imy     = 20.0
	ll      = 5.0
	rl      = ll + 60.0
	ly      = 18.0
)

func headfoot(deck *generate.Deck, hy, fy float64) {
	xc := []float64{0, 100, 0}
	yc := []float64{100, 100, hy}

	// header
	deck.Polygon(xc, yc, color1)
	xc[2] = 100
	deck.Polygon(xc, yc, color2)

	// footer
	xc[2] = 0
	yc[0] = 0
	yc[1] = 0
	yc[2] = fy
	deck.Polygon(xc, yc, color2)
	xc[2] = 100
	deck.Polygon(xc, yc, color1)
}

func makecert(deck *generate.Deck, data []certdata) {
	for _, d := range data {
		deck.StartSlide()
		headfoot(deck, 90, 10)
		body(deck, d)
		deck.EndSlide()
	}
}

func body(deck *generate.Deck, d certdata) {
	deck.TextMid(mid, top, "Certificate of Completion", "serif", 6, "black")
	deck.TextMid(mid, top-15, "This certificate is awarded to", "sans", 3, "black")
	deck.TextMid(mid, midy, d.student, "serif", 4, color1)
	deck.TextMid(mid, midy-10, "For successfully completing all twenty exercises in the\nGophercises Go programming course.", "sans", 3, "black")
	deck.TextMid(20, infoy, d.date.Format("Jan _2, 2006"), "serif", 3, "gray")
	deck.TextMid(20, infoy-5, "Date", "sans", 2, "gray")
	deck.TextMid(80, infoy-5, "Instructor", "sans", 2, "gray")
	deck.TextMid(80, midy-30, d.instructor, "serif", 3, "gray")
	deck.Line(ll, ly, ll+linelen, ly, 0.1, "gray")
	deck.Line(rl, ly, rl+linelen, ly, 0.1, "gray")
	deck.Image(mid, imy, 125, 130, "gophercises_jumping.png", "https://gophercises.com/")
}

func main() {

	today := time.Now()
	data := []certdata{
		{"Jon Calhoun", "Jonathan Calhoun", today},
		{"Anthony Starks", "Jonathan Calhoun", today},
	}

	deck := generate.NewSlides(os.Stdout, 0, 0)
	deck.StartDeck()
	makecert(deck, data)
	deck.EndDeck()
}