unicornpaint

A web-based painting app for raspberry PI and pimoroni Unicorn Hat HD
Log | Files | Refs | README

RealUnicorn2.go (1386B)

      1 // +build linux,arm linux,arm64
      2 
      3 package unicorn
      4 
      5 import (
      6 	"image"
      7 	"log"
      8 	"os"
      9 	"os/signal"
     10 	"syscall"
     11 
     12 	"github.com/ecc1/spi"
     13 )
     14 
     15 type RealUnicorn2 struct {
     16 	*BaseUnicorn2
     17 	device *spi.Device
     18 }
     19 
     20 func (u *RealUnicorn2) renderImage(im image.Image) {
     21 	b := im.Bounds()
     22 	width, height := b.Dx(), b.Dy()
     23 	sz := (width * height * 3) + 1
     24 	write := make([]byte, sz)
     25 
     26 	// Write leading bit
     27 	write[0] = 0x72
     28 
     29 	// Write color values
     30 	ix := 1
     31 	for x := 0; x < width; x++ {
     32 		for y := 0; y < height; y++ {
     33 			col := im.At(x, y)
     34 			r, g, b, _ := col.RGBA()
     35 			write[ix] = byte(r)
     36 			ix++
     37 			write[ix] = byte(g)
     38 			ix++
     39 			write[ix] = byte(b)
     40 			ix++
     41 		}
     42 	}
     43 	// Write to the device
     44 	err := u.device.Transfer(write)
     45 	if err != nil {
     46 		log.Printf("Error writing to SPI device %v", err)
     47 	}
     48 }
     49 
     50 // NewUnicorn2 ...
     51 // Constructs a new and improved unicorn from stuff and things
     52 func NewUnicorn2() (*RealUnicorn2, error) {
     53 	dev, err := spi.Open("/dev/spidev0.0", 9000000, 0)
     54 	if err != nil {
     55 		return nil, err
     56 	}
     57 	return &RealUnicorn2{
     58 		NewBaseUnicorn2(),
     59 		dev,
     60 	}, nil
     61 }
     62 
     63 // StartRender ...
     64 // Passes through to base to actually do the render
     65 func (u *RealUnicorn2) StartRender() chan bool {
     66 	return u.StartRenderBase(u.renderImage)
     67 }
     68 
     69 // MainLoop ...
     70 // Just blocks until sigterm
     71 func (u *RealUnicorn2) MainLoop() {
     72 	c := make(chan os.Signal, 2)
     73 	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
     74 	<-c
     75 }