examples: animation example

examples/animation/main.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"flag"
+	"image"
+	"time"
+
+	"github.com/fogleman/gg"
+	"github.com/mcuadros/go-rpi-rgb-led-matrix"
+)
+
+var (
+	rows       = flag.Int("led-rows", 32, "number of rows supported")
+	parallel   = flag.Int("led-parallel", 1, "number of daisy-chained panels")
+	chain      = flag.Int("led-chain", 2, "number of displays daisy-chained")
+	brightness = flag.Int("brightness", 100, "brightness (0-100)")
+)
+
+func main() {
+	config := &rgbmatrix.DefaultConfig
+	config.Rows = *rows
+	config.Parallel = *parallel
+	config.ChainLength = *chain
+	config.Brightness = *brightness
+
+	m, err := rgbmatrix.NewRGBLedMatrix(config)
+	fatal(err)
+
+	tk := rgbmatrix.NewToolKit(m)
+	defer tk.Close()
+
+	tk.PlayAnimation(NewAnimation(image.Point{64, 32}))
+}
+
+func init() {
+	flag.Parse()
+}
+
+func fatal(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+type Animation struct {
+	ctx      *gg.Context
+	position image.Point
+	dir      image.Point
+	stroke   int
+}
+
+func NewAnimation(sz image.Point) *Animation {
+	return &Animation{
+		ctx:    gg.NewContext(sz.X, sz.Y),
+		dir:    image.Point{1, 1},
+		stroke: 5,
+	}
+}
+
+func (a *Animation) Next() (image.Image, time.Duration, error) {
+	defer a.updatePosition()
+
+	a.ctx.SetRGB(0, 0, 0)
+	a.ctx.Clear()
+
+	a.ctx.DrawCircle(float64(a.position.X), float64(a.position.Y), float64(a.stroke))
+	a.ctx.SetRGB(1, 0, 0)
+	a.ctx.Fill()
+	return a.ctx.Image(), time.Millisecond * 50, nil
+}
+
+func (a *Animation) updatePosition() {
+	a.position.X += 1 * a.dir.X
+	a.position.Y += 1 * a.dir.Y
+
+	if a.position.Y+a.stroke > a.ctx.Height() {
+		a.dir.Y = -1
+	} else if a.position.Y-a.stroke < 0 {
+		a.dir.Y = 1
+	}
+
+	if a.position.X+a.stroke > a.ctx.Width() {
+		a.dir.X = -1
+	} else if a.position.X-a.stroke < 0 {
+		a.dir.X = 1
+	}
+}