Add feedback components 106-130; inert scope, focus return, two-step deploy

feedback/meter.go

@@ -0,0 +1,41 @@
+package feedback
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type MeterOptions struct {
+	// Min and Max are zero for 0 to 1.
+	Min, Max float64
+	// Warning and Critical are levels; zero means none.
+	Warning, Critical float64
+	// Width is in dots; zero means 120.
+	Width int
+}
+
+// Meter shows a level in Good, Warn or Bad.
+func Meter(c *ui.Context, text string, value float64, o MeterOptions) *ui.Element {
+	k := pixel.K(c)
+	lo, hi := o.Min, o.Max
+	if lo == 0 && hi == 0 {
+		hi = 1
+	}
+	if hi <= lo {
+		panic("feedback: Meter range is empty")
+	}
+	w := pixel.Or("Meter Width", o.Width, 120)
+	at := func(v float64) int { return 2 + int(max(0, min(1, (v-lo)/(hi-lo)))*float64(w-4)) }
+	ink := level(value, o.Warning, o.Critical)
+	return ui.Box(c).Role(ui.RoleMeter).Label(text).Description(fmtNum(value)).Size(k.D(w), k.D(10)).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		g.Frame(0, 0, w, 10, pixel.Sunken, pixel.Well)
+		g.Rect(2, 2, at(value)-2, 6, ink)
+		for _, mark := range []float64{o.Warning, o.Critical} {
+			if mark != 0 {
+				g.VLine(at(mark), 1, 8, pixel.Edge)
+			}
+		}
+	})
+}