1 files changed, 42 insertions, 0 deletions
diff --git a/gui/widget/output.go b/gui/widget/output.go
new file mode 100644
index 0000000..0d03c0c
--- /dev/null
+++ b/gui/widget/output.go
@@ -0,0 +1,42 @@
+package widget
+
+import (
+	"fmt"
+	"sync"
+
+	"image"
+	"image/draw"
+
+	"volute/gui"
+	"volute/gui/text"
+	"volute/gui/win"
+)
+
+func Output(val <-chan float64, r image.Rectangle, env gui.Env, wg *sync.WaitGroup) {
+	defer wg.Done()
+	defer close(env.Draw())
+
+	var v float64 = 0.0
+	env.Draw() <- outputDraw(v, r)
+Loop:
+	for {
+		select {
+		case v = <-val:
+			env.Draw() <- outputDraw(v, r)
+		case event, ok := <-env.Events():
+			if !ok { // channel closed
+				break Loop
+			}
+			if event, ok := event.(win.WiFocus); ok && event.Focused {
+				env.Draw() <- outputDraw(v, r)
+			}
+		}
+	}
+}
+
+func outputDraw(v float64, r image.Rectangle) func(draw.Image) image.Rectangle {
+	return func(drw draw.Image) image.Rectangle {
+		text.Draw([]byte(fmt.Sprintf("%.3f", v)), drw, r, BLACK, WHITE)
+		return r
+	}
+}