func buildMoon(theme gxui.Theme, center math.Point, radius float32) gxui.Image {
c := 40
p := make(gxui.Polygon, c*2)
for i := 0; i < c; i++ {
frac := float32(i) / float32(c)
α := math.Lerpf(math.Pi*1.2, math.Pi*-0.2, frac)
p[i] = gxui.PolygonVertex{
Position: math.Point{
X: center.X + int(radius*math.Sinf(α)),
Y: center.Y + int(radius*math.Cosf(α)),
},
RoundedRadius: 0,
}
}
for i := 0; i < c; i++ {
frac := float32(i) / float32(c)
α := math.Lerpf(math.Pi*-0.2, math.Pi*1.2, frac)
r := math.Lerpf(radius, radius*0.5, math.Sinf(frac*math.Pi))
p[i+c] = gxui.PolygonVertex{
Position: math.Point{
X: center.X + int(r*math.Sinf(α)),
Y: center.Y + int(r*math.Cosf(α)),
},
RoundedRadius: 0,
}
}
image := theme.CreateImage()
image.SetPolygon(p, gxui.CreatePen(3, gxui.Gray80), gxui.CreateBrush(gxui.Gray40))
return image
}
func buildStar(theme gxui.Theme, center math.Point, radius, rotation float32, points int) gxui.Image {
p := make(gxui.Polygon, points*2)
for i := 0; i < points*2; i++ {
frac := float32(i) / float32(points*2)
α := frac*math.TwoPi + rotation
r := []float32{radius, radius / 2}[i&1]
p[i] = gxui.PolygonVertex{
Position: math.Point{
X: center.X + int(r*math.Cosf(α)),
Y: center.Y + int(r*math.Sinf(α)),
},
RoundedRadius: []float32{0, 50}[i&1],
}
}
image := theme.CreateImage()
image.SetPolygon(p, gxui.CreatePen(3, gxui.Red), gxui.CreateBrush(gxui.Yellow))
return image
}
