First worked example

spinclock/main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"fmt"
+	"log/slog"
+	"math/rand"
+	"sync"
+	"time"
+
+	"github.com/tardisx/streamdeck-plugin"
+	"github.com/tardisx/streamdeck-plugin/events"
+	"github.com/tardisx/streamdeck-plugin/tools"
+)
+
+// keep track of instances we've seen, each one has a different
+// colour
+type clocks struct {
+	contextColour map[string]string
+	lock          sync.Mutex
+}
+
+// template for making a clock image in SVG
+const svgClock = `
+<svg width="144" height="144" xmlns="http://www.w3.org/2000/svg">
+  <rect width="144" height="144" fill="black"/>
+  <text x="72" y="108"
+        font-family="Arial, sans-serif"
+        font-size="96"
+        font-weight="bold"
+        fill="%s"
+        text-anchor="middle"
+        dominant-baseline="central"
+		transform="rotate(%d, 72, 72)">
+    %02d
+  </text>
+</svg>`
+
+func main() {
+	clocks := clocks{
+		contextColour: map[string]string{},
+		lock:          sync.Mutex{},
+	}
+	slog.Info("Starting up")
+	c := streamdeck.NewWithLogger(slog.Default())
+
+	slog.Info("Registering handlers")
+	c.RegisterHandler(func(e events.ERWillAppear) {
+		// clock appeared, give it a random colour
+		slog.Info("appearing " + e.Context)
+		clocks.lock.Lock()
+		defer clocks.lock.Unlock()
+		clocks.contextColour[e.Context] = randRGB()
+	})
+	c.RegisterHandler(func(e events.ERWillDisappear) {
+		// Stop updating this clock by simply removing it from our struct.
+		// Note that this is not required, and in this case it means that
+		// when it gets re-instantiated it will get a new colour.
+		// But it is good practice to not spend CPU on updating things that
+		// are not currently being displayed.
+		slog.Info("disappearing " + e.Context)
+		clocks.lock.Lock()
+		defer clocks.lock.Unlock()
+		delete(clocks.contextColour, e.Context)
+	})
+	c.RegisterHandler(func(e events.ERKeyDown) {
+		// button pressed, change its colour
+		slog.Info("keyDown " + e.Context)
+		clocks.lock.Lock()
+		defer clocks.lock.Unlock()
+		clocks.contextColour[e.Context] = randRGB()
+		drawClock(c, e.Context, clocks.contextColour[e.Context])
+	})
+
+	slog.Info("Connecting web socket")
+	err := c.Connect()
+	if err != nil {
+		panic(err)
+	}
+
+	// update all clocks, continuously
+	go func() {
+		for {
+			clocks.lock.Lock()
+			for context, colour := range clocks.contextColour {
+				drawClock(c, context, colour)
+			}
+			clocks.lock.Unlock()
+			time.Sleep(time.Second)
+		}
+	}()
+
+	slog.Info("waiting for the end")
+	c.WaitForPluginExit()
+}
+
+func drawClock(c streamdeck.Connection, context string, colour string) {
+	// rotation for this minute of the hour
+	rot := int(360.0 * (float64(time.Now().Minute()) / 60.0))
+	// generate the SVG
+	svg := fmt.Sprintf(svgClock, colour, rot, time.Now().Hour())
+
+	// create the event
+	newImage := events.NewESSetImage(
+		context,
+		tools.SVGToPayload(svg),
+		events.EventTargetBoth,
+		nil)
+
+	// send it
+	c.Send(newImage)
+}
+
+// randRGB creates a random colour
+func randRGB() string {
+	return fmt.Sprintf("#%02x%02x%02x", rand.Intn(256), rand.Intn(256), rand.Intn(256))
+}