Golang Context.Stroke方法代码示例

func drawDropDown(ctx *nanovgo.Context, text string, x, y, w, h float32) {

	var cornerRadius float32 = 4.0

	bg := nanovgo.LinearGradient(x, y, x, y+h, nanovgo.RGBA(255, 255, 255, 16), nanovgo.RGBA(0, 0, 0, 16))
	ctx.BeginPath()
	ctx.RoundedRect(x+1, y+1, w-2, h-2, cornerRadius-1)
	ctx.SetFillPaint(bg)
	ctx.Fill()

	ctx.BeginPath()
	ctx.RoundedRect(x+0.5, y+0.5, w-1, h-1, cornerRadius-0.5)
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 48))
	ctx.Stroke()

	ctx.SetFontSize(20.0)
	ctx.SetFontFace("sans")
	ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 160))
	ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignMiddle)
	ctx.Text(x+h*0.3, y+h*0.5, text)

	ctx.SetFontSize(h * 1.3)
	ctx.SetFontFace("icons")
	ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 64))
	ctx.SetTextAlign(nanovgo.AlignCenter | nanovgo.AlignMiddle)
	ctx.Text(x+w-h*0.5, y+h*0.5, cpToUTF8(IconCHEVRONRIGHT))
}

func drawCaps(ctx *nanovgo.Context, x, y, width float32) {
	caps := []nanovgo.LineCap{nanovgo.Butt, nanovgo.Round, nanovgo.Square}
	var lineWidth float32 = 8.0

	ctx.Save()
	defer ctx.Restore()

	ctx.BeginPath()
	ctx.Rect(x-lineWidth/2, y, width+lineWidth, 40)
	ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 32))
	ctx.Fill()

	ctx.BeginPath()
	ctx.Rect(x, y, width, 40)
	ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 32))
	ctx.Fill()

	ctx.SetStrokeWidth(lineWidth)

	for i, cap := range caps {
		ctx.SetLineCap(cap)
		ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 255))
		ctx.BeginPath()
		ctx.MoveTo(x, y+float32(i)*10+5)
		ctx.LineTo(x+width, y+float32(i)*10+5)
		ctx.Stroke()
	}
}

func (g *Graph) Draw(self Widget, ctx *nanovgo.Context) {
	g.WidgetImplement.Draw(self, ctx)

	x := float32(g.x)
	y := float32(g.y)
	w := float32(g.w)
	h := float32(g.h)

	ctx.BeginPath()
	ctx.Rect(x, y, w, h)
	ctx.SetFillColor(g.backgroundColor)
	ctx.Fill()

	if len(g.values) < 2 {
		return
	}

	ctx.BeginPath()
	ctx.MoveTo(x, y+h)
	dx := float32(len(g.values) - 1)
	for i, v := range g.values {
		vx := x + float32(i)*w/dx
		vy := y + (1.0-v)*h
		ctx.LineTo(vx, vy)
	}

	ctx.LineTo(x+w, y+h)
	ctx.SetStrokeColor(nanovgo.MONO(100, 255))
	ctx.Stroke()
	ctx.SetFillColor(g.foregroundColor)
	ctx.Fill()

	ctx.SetFontFace(g.theme.FontNormal)
	ctx.SetFillColor(g.textColor)
	if g.caption != "" {
		ctx.SetFontSize(14)
		ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignTop)
		ctx.Text(x+3, y+1, g.caption)
	}

	if g.header != "" {
		ctx.SetFontSize(18)
		ctx.SetTextAlign(nanovgo.AlignRight | nanovgo.AlignTop)
		ctx.Text(x+w-3, y+1, g.header)
	}

	if g.footer != "" {
		ctx.SetFontSize(15)
		ctx.SetTextAlign(nanovgo.AlignRight | nanovgo.AlignBottom)
		ctx.Text(x+w-3, y+h-1, g.footer)
	}

	ctx.BeginPath()
	ctx.Rect(x, y, w, h)
	ctx.SetStrokeColor(nanovgo.MONO(100, 255))
	ctx.Stroke()
}

func (sf *SpinnerFilter) Draw(self nanogui.Widget, ctx *nanovgo.Context) {
	if sf.isActive() {
		var py int
		fw, fh := sf.Parent().Size()
		if window, ok := sf.Parent().(*nanogui.Window); ok {
			hh := window.Theme().WindowHeaderHeight
			py += hh
			fh -= hh
		}
		sf.SetPosition(0, py)
		sf.SetSize(fw, fh)

		currentTime := nanogui.GetTime() - sf.startTime

		var alpha float32
		var showSpinner bool
		if sf.state == SpinnerFadeIn {
			if currentTime > 1 {
				alpha = 0.7
				showSpinner = true
			} else {
				alpha = currentTime * 0.7
			}
		} else {
			if currentTime > 1 {
				alpha = 0.7
			} else {
				alpha = (1.0 - currentTime) * 0.7
			}
		}
		ctx.Save()
		ctx.BeginPath()
		ctx.SetFillColor(nanovgo.MONOf(0, alpha))
		ctx.Rect(0, float32(py), float32(fw), float32(fh))
		ctx.Fill()
		if showSpinner {
			cx := float32(fw / 2)
			cy := float32(py + fh/2)
			rotation := 2 * math.Pi * float64(currentTime*float32(sf.speed)*float32(sf.num)) / float64(sf.num)
			dr := float64(2 * math.Pi / float64(sf.num))
			ctx.SetStrokeWidth(sf.lineWidth)
			for i := 0; i < sf.num; i++ {
				ctx.BeginPath()
				ctx.MoveTo(cx+float32(math.Cos(rotation))*sf.c1, cy+float32(math.Sin(rotation))*sf.c1)
				ctx.LineTo(cx+float32(math.Cos(rotation))*sf.c2, cy+float32(math.Sin(rotation))*sf.c2)
				ctx.SetStrokeColor(nanovgo.MONOf(1.0, float32(i)/float32(sf.num)))
				ctx.Stroke()
				rotation += dr
			}
		}
		ctx.Restore()
	} else {
		sf.SetSize(0, 0)
		sf.SetVisible(false)
		return
	}
}

func drawEditBoxBase(ctx *nanovgo.Context, x, y, w, h float32) {
	// Edit
	bg := nanovgo.BoxGradient(x+1, y+1+1.5, w-2, h-2, 3, 4, nanovgo.RGBA(255, 255, 255, 32), nanovgo.RGBA(32, 32, 32, 32))
	ctx.BeginPath()
	ctx.RoundedRect(x+1, y+1, w-2, h-2, 4-1)
	ctx.SetFillPaint(bg)
	ctx.Fill()

	ctx.BeginPath()
	ctx.RoundedRect(x+0.5, y+0.5, w-1, h-1, 4-0.5)
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 48))
	ctx.Stroke()
}

func drawLines(ctx *nanovgo.Context, x, y, w, h, t float32) {
	var pad float32 = 5.0
	s := w/9.0 - pad*2
	joins := []nanovgo.LineCap{nanovgo.Miter, nanovgo.Round, nanovgo.Bevel}
	caps := []nanovgo.LineCap{nanovgo.Butt, nanovgo.Round, nanovgo.Square}

	ctx.Save()
	defer ctx.Restore()

	pts := []float32{
		-s*0.25 + cosF(t*0.3)*s*0.5,
		sinF(t*0.3) * s * 0.5,
		-s * 0.25,
		0,
		s * 0.25,
		0,
		s*0.25 + cosF(-t*0.3)*s*0.5,
		sinF(-t*0.3) * s * 0.5,
	}
	for i, cap := range caps {
		for j, join := range joins {
			fx := x + s*0.5 + float32(i*3+j)/9.0*w + pad
			fy := y - s*0.5 + pad

			ctx.SetLineCap(cap)
			ctx.SetLineJoin(join)

			ctx.SetStrokeWidth(s * 0.3)
			ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 160))
			ctx.BeginPath()
			ctx.MoveTo(fx+pts[0], fy+pts[1])
			ctx.LineTo(fx+pts[2], fy+pts[3])
			ctx.LineTo(fx+pts[4], fy+pts[5])
			ctx.LineTo(fx+pts[6], fy+pts[7])
			ctx.Stroke()

			ctx.SetLineCap(nanovgo.Butt)
			ctx.SetLineJoin(nanovgo.Bevel)

			ctx.SetStrokeWidth(1.0)
			ctx.SetStrokeColor(nanovgo.RGBA(0, 192, 255, 255))
			ctx.BeginPath()
			ctx.MoveTo(fx+pts[0], fy+pts[1])
			ctx.LineTo(fx+pts[2], fy+pts[3])
			ctx.LineTo(fx+pts[4], fy+pts[5])
			ctx.LineTo(fx+pts[6], fy+pts[7])
			ctx.Stroke()

		}
	}
}

func drawWidths(ctx *nanovgo.Context, x, y, width float32) {
	ctx.Save()
	defer ctx.Restore()

	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 255))
	for i := 0; i < 20; i++ {
		w := (float32(i) + 0.5) * 0.1
		ctx.SetStrokeWidth(w)
		ctx.BeginPath()
		ctx.MoveTo(x, y)
		ctx.LineTo(x+width, y+width*0.3)
		ctx.Stroke()
		y += 10
	}
}

func drawButton(ctx *nanovgo.Context, preicon int, text string, x, y, w, h float32, col nanovgo.Color) {
	var cornerRadius float32 = 4.0
	var iw float32

	var alpha uint8
	if isBlack(col) {
		alpha = 16
	} else {
		alpha = 32
	}
	bg := nanovgo.LinearGradient(x, y, x, y+h, nanovgo.RGBA(255, 255, 255, alpha), nanovgo.RGBA(0, 0, 0, alpha))
	ctx.BeginPath()
	ctx.RoundedRect(x+1, y+1, w-2, h-2, cornerRadius-1)
	if !isBlack(col) {
		ctx.SetFillColor(col)
		ctx.Fill()
	}
	ctx.SetFillPaint(bg)
	ctx.Fill()

	ctx.BeginPath()
	ctx.RoundedRect(x+0.5, y+0.5, w-1, h-1, cornerRadius-0.5)
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 48))
	ctx.Stroke()

	ctx.SetFontSize(20.0)
	ctx.SetFontFace("sans-bold")
	tw, _ := ctx.TextBounds(0, 0, text)
	if preicon != 0 {
		ctx.SetFontSize(h * 1.3)
		ctx.SetFontFace("icons")
		iw, _ = ctx.TextBounds(0, 0, cpToUTF8(preicon))
		iw += h * 0.15

		ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 96))
		ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignMiddle)
		ctx.Text(x+w*0.5-tw*0.5-iw*0.75, y+h*0.5, cpToUTF8(preicon))
	}

	ctx.SetFontSize(20.0)
	ctx.SetFontFace("sans-bold")
	ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignMiddle)
	ctx.SetFillColor(nanovgo.RGBA(0, 0, 0, 160))
	ctx.Text(x+w*0.5-tw*0.5+iw*0.25, y+h*0.5-1, text)
	ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 160))
	ctx.Text(x+w*0.5-tw*0.5+iw*0.25, y+h*0.5, text)
}

func drawWindow(ctx *nanovgo.Context, title string, x, y, w, h float32) {
	var cornerRadius float32 = 3.0

	ctx.Save()
	defer ctx.Restore()
	//      ctx.Reset();

	// Window
	ctx.BeginPath()
	ctx.RoundedRect(x, y, w, h, cornerRadius)
	ctx.SetFillColor(nanovgo.RGBA(28, 30, 34, 192))
	//      ctx.FillColor(nanovgo.RGBA(0,0,0,128));
	ctx.Fill()

	// Drop shadow
	shadowPaint := nanovgo.BoxGradient(x, y+2, w, h, cornerRadius*2, 10, nanovgo.RGBA(0, 0, 0, 128), nanovgo.RGBA(0, 0, 0, 0))
	ctx.BeginPath()
	ctx.Rect(x-10, y-10, w+20, h+30)
	ctx.RoundedRect(x, y, w, h, cornerRadius)
	ctx.PathWinding(nanovgo.Hole)
	ctx.SetFillPaint(shadowPaint)
	ctx.Fill()

	// Header
	headerPaint := nanovgo.LinearGradient(x, y, x, y+15, nanovgo.RGBA(255, 255, 255, 8), nanovgo.RGBA(0, 0, 0, 16))
	ctx.BeginPath()
	ctx.RoundedRect(x+1, y+1, w-2, 30, cornerRadius-1)
	ctx.SetFillPaint(headerPaint)
	ctx.Fill()
	ctx.BeginPath()
	ctx.MoveTo(x+0.5, y+0.5+30)
	ctx.LineTo(x+0.5+w-1, y+0.5+30)
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 32))
	ctx.Stroke()

	ctx.SetFontSize(18.0)
	ctx.SetFontFace("sans-bold")
	ctx.SetTextAlign(nanovgo.AlignCenter | nanovgo.AlignMiddle)

	ctx.SetFontBlur(2)
	ctx.SetFillColor(nanovgo.RGBA(0, 0, 0, 128))
	ctx.Text(x+w/2, y+16+1, title)

	ctx.SetFontBlur(0)
	ctx.SetFillColor(nanovgo.RGBA(220, 220, 220, 160))
	ctx.Text(x+w/2, y+16, title)
}

func (i *ImagePanel) Draw(self Widget, ctx *nanovgo.Context) {
	cols, _ := i.gridSize()

	x := float32(i.x)
	y := float32(i.y)
	thumbSize := float32(i.thumbSize)

	for j, image := range i.images {
		pX := x + float32(i.margin+(j%cols)*(i.thumbSize+i.spacing))
		pY := y + float32(i.margin+(j/cols)*(i.thumbSize+i.spacing))

		imgW, imgH, _ := ctx.ImageSize(image.ImageID)
		var iw, ih, ix, iy float32
		if imgW < imgH {
			iw = thumbSize
			ih = iw * float32(imgH) / float32(imgW)
			ix = 0
			iy = -(ih - thumbSize) * 0.5
		} else {
			ih = thumbSize
			iw = ih * float32(imgH) / float32(imgW)
			iy = 0
			ix = -(iw - thumbSize) * 0.5
		}
		imgPaint := nanovgo.ImagePattern(pX+ix, pY+iy, iw, ih, 0, image.ImageID, toF(i.mouseIndex == j, 1.0, 0.7))
		ctx.BeginPath()
		ctx.RoundedRect(pX, pY, thumbSize, thumbSize, 5)
		ctx.SetFillPaint(imgPaint)
		ctx.Fill()

		shadowPaint := nanovgo.BoxGradient(pX-1, pY, thumbSize+2, thumbSize+2, 5, 3, nanovgo.MONO(0, 128), nanovgo.MONO(0, 0))

		ctx.BeginPath()
		ctx.Rect(pX-5, pY-5, thumbSize+10, thumbSize+10)
		ctx.RoundedRect(pX, pY, thumbSize, thumbSize, 6)
		ctx.PathWinding(nanovgo.Hole)
		ctx.SetFillPaint(shadowPaint)
		ctx.Fill()

		ctx.BeginPath()
		ctx.RoundedRect(pX+0.5, pY+0.5, thumbSize-1, thumbSize-1, 4-0.5)
		ctx.SetStrokeWidth(1.0)
		ctx.SetStrokeColor(nanovgo.MONO(255, 80))
		ctx.Stroke()
	}
}

// Draw() draws the widget (and all child widgets)
func (w *WidgetImplement) Draw(self Widget, ctx *nanovgo.Context) {
	if debugFlag {
		ctx.SetStrokeWidth(1.0)
		ctx.BeginPath()
		ctx.Rect(float32(w.x)-0.5, float32(w.y)-0.5, float32(w.w)+1.0, float32(w.h)+1.0)
		ctx.SetStrokeColor(nanovgo.RGBA(255, 0, 0, 255))
		ctx.Stroke()
	}

	if len(w.children) == 0 {
		return
	}
	ctx.Translate(float32(w.x), float32(w.y))
	// draw depth 0 items
	var drawLater widgetsAsc = make([]Widget, 0, len(w.children))
	for _, child := range w.children {
		if child.Visible() {
			depth := child.Depth()
			if depth == 0 {
				cx, cy := child.Position()
				cw, ch := child.Size()
				if !self.IsClipped(cx, cy, cw, ch) {
					child.Draw(child, ctx)
				}
			} else {
				drawLater = append(drawLater, child)
			}
		}
	}
	// draw by depth order
	sort.Sort(drawLater)
	for _, child := range drawLater {
		cx, cy := child.Position()
		cw, ch := child.Size()
		if !self.IsClipped(cx, cy, cw, ch) {
			child.Draw(child, ctx)
		}
	}
	ctx.Translate(-float32(w.x), -float32(w.y))
}

func drawSlider(ctx *nanovgo.Context, pos, x, y, w, h float32) {
	cy := y + float32(int(h*0.5))
	kr := float32(int(h * 0.25))

	ctx.Save()
	defer ctx.Restore()
	//      ctx.ClearState(vg);

	// Slot
	bg := nanovgo.BoxGradient(x, cy-2+1, w, 4, 2, 2, nanovgo.RGBA(0, 0, 0, 32), nanovgo.RGBA(0, 0, 0, 128))
	ctx.BeginPath()
	ctx.RoundedRect(x, cy-2, w, 4, 2)
	ctx.SetFillPaint(bg)
	ctx.Fill()

	// Knob Shadow
	bg = nanovgo.RadialGradient(x+float32(int(pos*w)), cy+1, kr-3, kr+3, nanovgo.RGBA(0, 0, 0, 64), nanovgo.RGBA(0, 0, 0, 0))
	ctx.BeginPath()
	ctx.Rect(x+float32(int(pos*w))-kr-5, cy-kr-5, kr*2+5+5, kr*2+5+5+3)
	ctx.Circle(x+float32(int(pos*w)), cy, kr)
	ctx.PathWinding(nanovgo.Hole)
	ctx.SetFillPaint(bg)
	ctx.Fill()

	// Knob
	knob := nanovgo.LinearGradient(x, cy-kr, x, cy+kr, nanovgo.RGBA(255, 255, 255, 16), nanovgo.RGBA(0, 0, 0, 16))
	ctx.BeginPath()
	ctx.Circle(x+float32(int(pos*w)), cy, kr-1)
	ctx.SetFillColor(nanovgo.RGBA(40, 43, 48, 255))
	ctx.Fill()
	ctx.SetFillPaint(knob)
	ctx.Fill()

	ctx.BeginPath()
	ctx.Circle(x+float32(int(pos*w)), cy, kr-0.5)
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 92))
	ctx.Stroke()
}

func (t *TextBox) Draw(self Widget, ctx *nanovgo.Context) {
	t.WidgetImplement.Draw(self, ctx)

	x := float32(t.x)
	y := float32(t.y)
	w := float32(t.w)
	h := float32(t.h)

	bg := nanovgo.BoxGradient(x+1, y+2, w-2, h-2, 3, 4, nanovgo.MONO(255, 32), nanovgo.MONO(32, 32))
	fg1 := nanovgo.BoxGradient(x+1, y+2, w-2, h-2, 3, 4, nanovgo.MONO(150, 32), nanovgo.MONO(32, 32))
	fg2 := nanovgo.BoxGradient(x+1, y+2, w-2, h-2, 3, 4, nanovgo.RGBA(255, 0, 0, 100), nanovgo.RGBA(255, 0, 0, 50))

	ctx.BeginPath()
	ctx.RoundedRect(x+1, y+2, w-2, h-2, 3)
	if t.editable && t.Focused() {
		if t.validFormat {
			ctx.SetFillPaint(fg1)
		} else {
			ctx.SetFillPaint(fg2)
		}
	} else {
		ctx.SetFillPaint(bg)
	}

	ctx.Fill()

	ctx.BeginPath()
	ctx.RoundedRect(x+0.5, y+0.5, w-1, h-1, 2.5)
	ctx.SetStrokeColor(nanovgo.MONO(0, 48))
	ctx.Stroke()

	ctx.SetFontSize(float32(t.FontSize()))
	ctx.SetFontFace(t.Font())
	drawPosX := x
	drawPosY := y + h*0.5 + 1

	xSpacing := h * 0.3
	var unitWidth float32

	if t.unitImage > 0 {
		iw, ih, _ := ctx.ImageSize(t.unitImage)
		unitHeight := float32(ih) * 0.4
		unitWidth = float32(iw) * unitHeight / float32(h)
		imgPaint := nanovgo.ImagePattern(x+w-xSpacing-unitWidth, drawPosY-unitHeight*0.5,
			unitWidth, unitHeight, 0, t.unitImage, toF(t.enabled, 0.7, 0.35))
		ctx.BeginPath()
		ctx.Rect(x+w-xSpacing-unitWidth, drawPosY-unitHeight*0.5, unitWidth, unitHeight)
		ctx.SetFillPaint(imgPaint)
		ctx.Fill()
		unitWidth += 2
	} else if t.units != "" {
		unitWidth, _ = ctx.TextBounds(0, 0, t.units)
		ctx.SetFillColor(nanovgo.MONO(255, toB(t.enabled, 64, 32)))
		ctx.SetTextAlign(nanovgo.AlignRight | nanovgo.AlignMiddle)
		ctx.Text(x+w-xSpacing, drawPosY, t.units)
	}

	switch t.alignment {
	case TextLeft:
		ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignMiddle)
		drawPosX += xSpacing
	case TextRight:
		ctx.SetTextAlign(nanovgo.AlignRight | nanovgo.AlignMiddle)
		drawPosX += w - unitWidth - xSpacing
	case TextCenter:
		ctx.SetTextAlign(nanovgo.AlignCenter | nanovgo.AlignMiddle)
		drawPosX += w * 0.5
	}
	if t.enabled {
		ctx.SetFillColor(t.theme.TextColor)
	} else {
		ctx.SetFillColor(t.theme.DisabledTextColor)
	}
	// clip visible text area
	clipX := x + xSpacing - 1
	clipY := y + 1.0
	clipWidth := w - unitWidth - 2.0*xSpacing + 2.0
	clipHeight := h - 3.0
	ctx.Scissor(clipX, clipY, clipWidth, clipHeight)
	oldDrawPosX := drawPosX
	drawPosX += t.textOffset

	if t.committed {
		ctx.Text(drawPosX, drawPosY, t.value)
	} else {
		text := t.editingText()
		textString := string(text)
		_, bounds := ctx.TextBounds(drawPosX, drawPosY, textString)
		lineH := bounds[3] - bounds[1]
		// find cursor positions
		glyphs := ctx.TextGlyphPositionsRune(drawPosX, drawPosY, text)
		t.updateCursor(ctx, bounds[2], glyphs)

		// compute text offset
		prevCPos := toI(t.cursorPos > 0, t.cursorPos-1, 0)
		nextCPos := toI(t.cursorPos < len(glyphs), t.cursorPos+1, len(glyphs))
		prevCX := t.textIndex2Position(prevCPos, bounds[2], glyphs)
		nextCX := t.textIndex2Position(nextCPos, bounds[2], glyphs)

		if nextCX > clipX+clipWidth {
//.........这里部分代码省略.........

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 drawGraph(ctx *nanovgo.Context, x, y, w, h, t float32) {
	var sx, sy [6]float32
	dx := w / 5.0

	samples := []float32{
		(1 + sinF(t*1.2345+cosF(t*0.33457)*0.44)) * 0.5,
		(1 + sinF(t*0.68363+cosF(t*1.3)*1.55)) * 0.5,
		(1 + sinF(t*1.1642+cosF(t*0.33457)*1.24)) * 0.5,
		(1 + sinF(t*0.56345+cosF(t*1.63)*0.14)) * 0.5,
		(1 + sinF(t*1.6245+cosF(t*0.254)*0.3)) * 0.5,
		(1 + sinF(t*0.345+cosF(t*0.03)*0.6)) * 0.5,
	}

	for i := 0; i < 6; i++ {
		sx[i] = x + float32(i)*dx
		sy[i] = y + h*samples[i]*0.8
	}

	// Graph background
	bg := nanovgo.LinearGradient(x, y, x, y+h, nanovgo.RGBA(0, 160, 192, 0), nanovgo.RGBA(0, 160, 192, 64))
	ctx.BeginPath()
	ctx.MoveTo(sx[0], sy[0])
	for i := 1; i < 6; i++ {
		ctx.BezierTo(sx[i-1]+dx*0.5, sy[i-1], sx[i]-dx*0.5, sy[i], sx[i], sy[i])
	}
	ctx.LineTo(x+w, y+h)
	ctx.LineTo(x, y+h)
	ctx.SetFillPaint(bg)
	ctx.Fill()

	// Graph line
	ctx.BeginPath()
	ctx.MoveTo(sx[0], sy[0]+2)
	for i := 1; i < 6; i++ {
		ctx.BezierTo(sx[i-1]+dx*0.5, sy[i-1]+2, sx[i]-dx*0.5, sy[i]+2, sx[i], sy[i]+2)
	}
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 32))
	ctx.SetStrokeWidth(3.0)
	ctx.Stroke()

	ctx.BeginPath()
	ctx.MoveTo(sx[0], sy[0])
	for i := 1; i < 6; i++ {
		ctx.BezierTo(sx[i-1]+dx*0.5, sy[i-1], sx[i]-dx*0.5, sy[i], sx[i], sy[i])
	}
	ctx.SetStrokeColor(nanovgo.RGBA(0, 160, 192, 255))
	ctx.SetStrokeWidth(3.0)
	ctx.Stroke()

	// Graph sample pos
	for i := 0; i < 6; i++ {
		bg = nanovgo.RadialGradient(sx[i], sy[i]+2, 3.0, 8.0, nanovgo.RGBA(0, 0, 0, 32), nanovgo.RGBA(0, 0, 0, 0))
		ctx.BeginPath()
		ctx.Rect(sx[i]-10, sy[i]-10+2, 20, 20)
		ctx.SetFillPaint(bg)
		ctx.Fill()
	}

	ctx.BeginPath()
	for i := 0; i < 6; i++ {
		ctx.Circle(sx[i], sy[i], 4.0)
	}
	ctx.SetFillColor(nanovgo.RGBA(0, 160, 192, 255))
	ctx.Fill()
	ctx.BeginPath()
	for i := 0; i < 6; i++ {
		ctx.Circle(sx[i], sy[i], 2.0)
	}
	ctx.SetFillColor(nanovgo.RGBA(220, 220, 220, 255))
	ctx.Fill()

	ctx.SetStrokeWidth(1.0)
}