func (c *ColorWheel) Draw(self Widget, ctx *nanovgo.Context) {
c.WidgetImplement.Draw(self, ctx)
if !c.visible {
return
}
x := float32(c.x)
y := float32(c.y)
w := float32(c.w)
h := float32(c.h)
ctx.Save()
defer ctx.Restore()
cx := x + w*0.5
cy := y + h*0.5
r1 := toF(w < h, w, h)*0.5 - 5.0
r0 := r1 * 0.75
aeps := 0.7 / r1 // half a pixel arc length in radians (2pi cancels out).
for i := 0; i < 6; i++ {
a0 := float32(i)/6.0*nanovgo.PI*2.0 - aeps
a1 := float32(i+1)/6.0*nanovgo.PI*2.0 + aeps
ctx.BeginPath()
ctx.Arc(cx, cy, r0, a0, a1, nanovgo.Clockwise)
ctx.Arc(cx, cy, r1, a1, a0, nanovgo.CounterClockwise)
ctx.ClosePath()
sin1, cos1 := sinCosF(a0)
sin2, cos2 := sinCosF(a1)
ax := cx + cos1*(r0+r1)*0.5
ay := cy + sin1*(r0+r1)*0.5
bx := cx + cos2*(r0+r1)*0.5
by := cy + sin2*(r0+r1)*0.5
color1 := nanovgo.HSLA(a0/(nanovgo.PI*2), 1.0, 0.55, 255)
color2 := nanovgo.HSLA(a1/(nanovgo.PI*2), 1.0, 0.55, 255)
paint := nanovgo.LinearGradient(ax, ay, bx, by, color1, color2)
ctx.SetFillPaint(paint)
ctx.Fill()
}
ctx.BeginPath()
ctx.Circle(cx, cy, r0-0.5)
ctx.Circle(cx, cy, r1+0.5)
ctx.SetStrokeColor(nanovgo.MONO(0, 64))
ctx.Stroke()
// Selector
ctx.Save()
defer ctx.Restore()
ctx.Translate(cx, cy)
ctx.Rotate(c.hue * nanovgo.PI * 2)
// Marker on
u := clampF(r1/50, 1.5, 4.0)
ctx.SetStrokeWidth(u)
ctx.BeginPath()
ctx.Rect(r0-1, -2*u, r1-r0+2, 4*u)
ctx.SetStrokeColor(nanovgo.MONO(255, 192))
ctx.Stroke()
paint := nanovgo.BoxGradient(r0-3, -5, r1-r0+6, 10, 2, 4, nanovgo.MONO(0, 128), nanovgo.MONO(0, 0))
ctx.BeginPath()
ctx.Rect(r0-2-10, -4-10, r1-r0+4+20, 8+20)
ctx.Rect(r0-2, -4, r1-r0+4, 8)
ctx.PathWinding(nanovgo.Hole)
ctx.SetFillPaint(paint)
ctx.Fill()
// Center triangle
r := r0 - 6
sin1, cos1 := sinCosF(120.0 / 180.0 * nanovgo.PI)
sin2, cos2 := sinCosF(-120.0 / 180.0 * nanovgo.PI)
ax := cos1 * r
ay := sin1 * r
bx := cos2 * r
by := sin2 * r
ctx.BeginPath()
ctx.MoveTo(r, 0)
ctx.LineTo(ax, ay)
ctx.LineTo(bx, by)
ctx.ClosePath()
triPaint1 := nanovgo.LinearGradient(r, 0, ax, ay, nanovgo.HSL(c.hue, 1.0, 0.5), nanovgo.MONO(255, 255))
ctx.SetFillPaint(triPaint1)
ctx.Fill()
triPaint2 := nanovgo.LinearGradient((r+ax)*0.5, ay*0.5, bx, by, nanovgo.MONO(0, 0), nanovgo.MONO(0, 255))
ctx.SetFillPaint(triPaint2)
ctx.Fill()
// selector circle on triangle
px, py := c.calculatePosition()
ctx.SetStrokeWidth(u)
ctx.BeginPath()
ctx.Circle(px, py, 2*u)
ctx.SetStrokeColor(nanovgo.MONO(255, 192))
ctx.Stroke()
}
func (c *ColorWheel) Color() nanovgo.Color {
return nanovgo.HSL(c.hue, c.saturation, c.lightness)
}