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

feedback/spinner.go

@@ -0,0 +1,44 @@
+package feedback
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type SpinnerOptions struct {
+	// Scale is 1–4; zero means 1.
+	Scale int
+}
+
+// ring is where the spinner's eight beads sit, by hand.
+var ring = [8][2]int{{5, 1}, {8, 2}, {9, 5}, {8, 8}, {5, 9}, {2, 8}, {1, 5}, {2, 2}}
+
+// Spinner turns through eight frames, even under Reduce Motion.
+func Spinner(c *ui.Context, text string, o SpinnerOptions) *ui.Element {
+	k := pixel.K(c)
+	s := pixel.Or("Spinner Scale", o.Scale, 1)
+	if s > 4 {
+		panic("feedback: Spinner Scale past 4")
+	}
+	return ui.Box(c).Role(ui.RoleProgress).Label(text).Size(k.D(12*s), k.D(12*s)).Draw(func(p *ui.Painter, r ui.Rect) {
+		beads(k.Canvas(p, r), 0, 0, s)
+	})
+}
+
+// beads draws the spinner ring at x, y, scaled s.
+func beads(g pixel.Canvas, x, y, s int) {
+	head := g.Busy(10) % 8
+	for i, at := range ring {
+		ink := pixel.Shade
+		switch (head - i + 8) % 8 {
+		case 0:
+			ink = pixel.Accent
+		case 1:
+			ink = pixel.AccentLit
+		case 2:
+			ink = pixel.Faint
+		}
+		g.Rect(x+at[0]*s, y+at[1]*s, 2*s, 2*s, ink)
+	}
+}