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

feedback/skeleton.go

@@ -0,0 +1,44 @@
+package feedback
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type SkeletonOptions struct {
+	// Lines is the text lines; zero means 3.
+	Lines int
+	// Avatar puts a square before the lines.
+	Avatar bool
+	// Width is in dots; zero means 160.
+	Width int
+}
+
+// Skeleton stands in for content; a dithered shine sweeps it.
+func Skeleton(c *ui.Context, o SkeletonOptions) *ui.Element {
+	k := pixel.K(c)
+	n := pixel.Or("Skeleton Lines", o.Lines, 3)
+	w := pixel.Or("Skeleton Width", o.Width, 160)
+	h := n*12 - 4
+	return ui.Box(c).Role(ui.RoleStatus).Label(k.Msg("loading")).Size(k.D(w), k.D(max(h, 24))).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		x := 0
+		var shapes [][4]int
+		if o.Avatar {
+			shapes, x = append(shapes, [4]int{0, 0, 24, 24}), 30
+		}
+		for i := range n {
+			lw := w - x
+			if i == n-1 && n > 1 {
+				lw = lw * 3 / 5
+			}
+			shapes = append(shapes, [4]int{x, i * 12, lw, 8})
+		}
+		shine := g.Step(8)*6%(w+48) - 24
+		for _, s := range shapes {
+			g.Dither(s[0], s[1], s[2], s[3], pixel.Shade, pixel.Face, 4)
+			g.Clip(s[0], s[1], s[2], s[3], func() { g.Veil(shine, s[1], 16, s[3], pixel.Lit, 6) })
+		}
+	})
+}