Add text components 021-040 with demos and behavior tests

text/shadowtext.go

@@ -0,0 +1,21 @@
+package text
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type ShadowTextOptions struct {
+	Slot  pixel.Slot
+	Scale int
+}
+
+// ShadowText drops a 1-dot Shade shadow behind s.
+func ShadowText(c *ui.Context, s string, o ShadowTextOptions) *ui.Element {
+	k, sc := pixel.K(c), scale(o.Scale)
+	return block(c, k, s, pixel.Measure(s)*sc+1, pixel.LineHeight*sc+1, func(g pixel.Canvas) {
+		g.Text(1, 1, s, pixel.Shade, sc)
+		g.Text(0, 0, s, o.Slot, sc)
+	})
+}