/
main.go
165 lines (145 loc) · 3.31 KB
/
main.go
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package main
import (
"bytes"
"fmt"
"github.com/golang/freetype"
"github.com/golang/freetype/truetype"
"golang.org/x/image/math/fixed"
"image"
"image/color"
"image/draw"
"image/jpeg"
"io/ioutil"
"log"
"net/http"
"os"
"os/exec"
"sync"
"time"
)
var font *truetype.Font
var imageBytes []byte
var imageMutex sync.Mutex
func init() {
// Read the font data.
fontBytes, err := ioutil.ReadFile("luxisr.ttf")
if err != nil {
log.Fatal(err)
}
font, err = freetype.ParseFont(fontBytes)
if err != nil {
log.Fatal(err)
}
// To work around bug in image capture vgrabbj that sometimes
// returns a green screen (RasPi specific library location).
os.Setenv("LD_PRELOAD", "/usr/lib/arm-linux-gnueabihf/libv4l/v4l1compat.so")
}
func main() {
log.Println("River Starting.")
go makeImages(30)
http.HandleFunc("/", handler)
http.ListenAndServe(":8080", nil)
}
func handler(w http.ResponseWriter, r *http.Request) {
if r.URL.Path != "/" {
http.NotFound(w, r)
return
}
image := getImage()
if image == nil {
fmt.Fprintf(w, "Could not obtain image")
} else {
w.Write(image)
}
}
func getVideo() string {
if _, err := os.Stat("/dev/video0"); err == nil {
return "/dev/video0"
}
if _, err := os.Stat("/dev/video1"); err == nil {
return "/dev/video1"
}
if _, err := os.Stat("/dev/video2"); err == nil {
return "/dev/video2"
}
if _, err := os.Stat("/dev/video3"); err == nil {
return "/dev/video3"
}
if _, err := os.Stat("/dev/video4"); err == nil {
return "/dev/video4"
}
if _, err := os.Stat("/dev/video5"); err == nil {
return "/dev/video5"
}
if _, err := os.Stat("/dev/video6"); err == nil {
return "/dev/video6"
}
if _, err := os.Stat("/dev/video7"); err == nil {
return "/dev/video7"
}
if _, err := os.Stat("/dev/video8"); err == nil {
return "/dev/video8"
}
return "/dev/video9"
}
func getImage() []byte {
imageMutex.Lock()
defer imageMutex.Unlock()
return imageBytes
}
func PointToInt26_6(x, dpi float64) fixed.Int26_6 {
return fixed.Int26_6(x * dpi * (64.0 / 72.0))
}
func makeImages(secondsDelay int) {
delay := 0
for {
// Delay between making an image
time.Sleep(time.Duration(delay) * time.Second)
delay = secondsDelay
// Generate new image.
now := time.Now()
out, err := exec.Command("/usr/bin/vgrabbj", "-d", getVideo(), "-i", "svga", "-q", "90").Output()
if err != nil {
log.Println(err)
continue
}
// Decode the image.
src, _, err := image.Decode(bytes.NewReader(out))
if err != nil {
log.Println(err)
continue
}
// Time
label := now.Format("2/1/2006 3:04PM")
// Colour of text
fg := image.NewUniform(color.RGBA{255, 255, 0, 255})
// Copy in original image
rgba := image.NewRGBA(src.Bounds())
draw.Draw(rgba, rgba.Bounds(), src, image.ZP, draw.Src)
// Draw the text.
size := 24.0
c := freetype.NewContext()
c.SetDPI(72)
c.SetFont(font)
c.SetFontSize(size)
c.SetClip(rgba.Bounds())
c.SetDst(rgba)
c.SetSrc(fg)
pt := freetype.Pt(10, 10+int(PointToInt26_6(size, 72)>>6))
_, err = c.DrawString(label, pt)
if err != nil {
log.Println(err)
continue
}
// Produce jpeg of new image.
newImage := new(bytes.Buffer)
err = jpeg.Encode(newImage, rgba, &jpeg.Options{Quality: 90})
if err != nil {
log.Println(err)
continue
}
imageMutex.Lock()
imageBytes = newImage.Bytes()
imageMutex.Unlock()
}
}