Add display components 041-065; move Icon into display; QR via rsc.io/qr

display/stamp.go

@@ -0,0 +1,49 @@
+package display
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type StampOptions struct {
+	// Slot is the ink; zero means Bad.
+	Slot pixel.Slot
+	Seed int
+}
+
+// Stamp is a rubber-stamp mark whose border wears unevenly.
+func Stamp(c *ui.Context, s string, o StampOptions) *ui.Element {
+	k := pixel.K(c)
+	ink := slotOr(o.Slot, pixel.Bad)
+	w, h := pixel.Measure(s)+12, pixel.LineHeight+8
+	return art(c, k, s, w, h, func(g pixel.Canvas) {
+		ring := func(in int) {
+			for i := in; i < w-in; i++ {
+				worn(g, o.Seed, i, in, ink)
+				worn(g, o.Seed, i, h-1-in, ink)
+			}
+			for j := in + 1; j < h-1-in; j++ {
+				worn(g, o.Seed, in, j, ink)
+				worn(g, o.Seed, w-1-in, j, ink)
+			}
+		}
+		ring(0)
+		ring(2)
+		g.Text(6, 4, s, ink, 1)
+	})
+}
+
+// worn inks a border dot unless seeded wear skips it.
+func worn(g pixel.Canvas, seed, x, y int, ink pixel.Slot) {
+	if hash(seed, x, y)%7 != 0 {
+		g.Dot(x, y, ink)
+	}
+}
+
+func hash(seed, x, y int) uint32 {
+	n := uint32(seed*73856093 ^ x*19349663 ^ y*83492791)
+	n ^= n >> 13
+	n *= 0x5bd1e995
+	return n ^ n>>15
+}