Golang Context.Save方法代碼示例

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 drawScissor(ctx *nanovgo.Context, x, y, t float32) {
	ctx.Save()

	// Draw first rect and set scissor to it's area.
	ctx.Translate(x, y)
	ctx.Rotate(nanovgo.DegToRad(5))
	ctx.BeginPath()
	ctx.Rect(-20, -20, 60, 40)
	ctx.SetFillColor(nanovgo.RGBA(255, 0, 0, 255))
	ctx.Fill()
	ctx.Scissor(-20, -20, 60, 40)

	// Draw second rectangle with offset and rotation.
	ctx.Translate(40, 0)
	ctx.Rotate(t)

	// Draw the intended second rectangle without any scissoring.
	ctx.Save()
	ctx.ResetScissor()
	ctx.BeginPath()
	ctx.Rect(-20, -10, 60, 30)
	ctx.SetFillColor(nanovgo.RGBA(255, 128, 0, 64))
	ctx.Fill()
	ctx.Restore()

	// Draw second rectangle with combined scissoring.
	ctx.IntersectScissor(-20, -10, 60, 30)
	ctx.BeginPath()
	ctx.Rect(-20, -10, 60, 30)
	ctx.SetFillColor(nanovgo.RGBA(255, 128, 0, 255))
	ctx.Fill()

	ctx.Restore()
}

func RenderDemo(ctx *nanovgo.Context, mx, my, width, height, t float32, blowup bool, data *DemoData) {
	drawEyes(ctx, width-250, 50, 150, 100, mx, my, t)
	drawParagraph(ctx, width-450, 50, 150, 100, mx, my)
	drawGraph(ctx, 0, height/2, width, height/2, t)
	drawColorWheel(ctx, width-300, height-300, 250.0, 250.0, t)

	// Line joints
	drawLines(ctx, 120, height-50, 600, 50, t)

	// Line widths
	drawWidths(ctx, 10, 50, 30)

	// Line caps
	drawCaps(ctx, 10, 300, 30)

	drawScissor(ctx, 50, height-80, t)

	ctx.Save()
	defer ctx.Restore()

	if blowup {
		ctx.Rotate(sinF(t*0.3) * 5.0 / 180.0 * nanovgo.PI)
		ctx.Scale(2.0, 2.0)
	}

	// Widgets
	drawWindow(ctx, "Widgets `n Stuff", 50, 50, 300, 400)
	var x float32 = 60.0
	var y float32 = 95.0
	drawSearchBox(ctx, "Search", x, y, 280, 25)
	y += 40
	drawDropDown(ctx, "Effects", x, y, 280, 28)
	popy := y + 14
	y += 45

	// Form
	drawLabel(ctx, "Login", x, y, 280, 20)
	y += 25
	drawEditBox(ctx, "Email", x, y, 280, 28)
	y += 35
	drawEditBox(ctx, "Password", x, y, 280, 28)
	y += 38
	drawCheckBox(ctx, "Remember me", x, y, 140, 28)
	drawButton(ctx, IconLOGIN, "Sign in", x+138, y, 140, 28, nanovgo.RGBA(0, 96, 128, 255))
	y += 45

	// Slider
	drawLabel(ctx, "Diameter", x, y, 280, 20)
	y += 25
	drawEditBoxNum(ctx, "123.00", "px", x+180, y, 100, 28)
	drawSlider(ctx, 0.4, x, y, 170, 28)
	y += 55

	drawButton(ctx, IconTRASH, "Delete", x, y, 160, 28, nanovgo.RGBA(128, 16, 8, 255))
	drawButton(ctx, 0, "Cancel", x+170, y, 110, 28, nanovgo.RGBA(0, 0, 0, 0))

	// Thumbnails box
	drawThumbnails(ctx, 365, popy-30, 160, 300, data.Images, t)
}

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 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 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 (v *VScrollPanel) Draw(self Widget, ctx *nanovgo.Context) {
	if len(v.children) == 0 {
		return
	}
	x := float32(v.x)
	y := float32(v.y)
	w := float32(v.w)
	h := float32(v.h)

	child := v.children[0]
	layout := self.Layout()
	if layout != nil {
		_, v.childPreferredHeight = layout.PreferredSize(self, ctx)
	} else {
		_, v.childPreferredHeight = child.PreferredSize(child, ctx)
	}

	ctx.Save()
	ctx.Translate(x, y)
	ctx.Scissor(0, 0, w, h)
	ctx.Translate(0, -v.scroll*(float32(v.childPreferredHeight)-h))
	if child.Visible() {
		child.Draw(child, ctx)
	}
	ctx.Restore()
	if v.childPreferredHeight > v.h {
		scrollH := h * minF(1.0, h/float32(v.childPreferredHeight))
		scrollH = minF(maxF(20.0, scrollH), h)
		paint := nanovgo.BoxGradient(x+w-12+1, y+4+1, 8, h-8, 3, 4, nanovgo.MONO(0, 32), nanovgo.MONO(0, 92))
		ctx.BeginPath()
		ctx.RoundedRect(x+w-12, y+4, 8, h-8, 3)
		ctx.SetFillPaint(paint)
		ctx.Fill()

		barPaint := nanovgo.BoxGradient(x+y-12-1, y+4+1+(h-8-scrollH)*v.scroll-1, 8, scrollH, 3, 4, nanovgo.MONO(220, 100), nanovgo.MONO(128, 100))
		ctx.BeginPath()
		ctx.RoundedRect(x+w-12+1, y+4+1+(h-8-scrollH)*v.scroll, 8-2, scrollH-2, 2)
		ctx.SetFillPaint(barPaint)
		ctx.Fill()
	}
}

func drawSpinner(ctx *nanovgo.Context, cx, cy, r, t float32) {
	a0 := 0.0 + t*6
	a1 := nanovgo.PI + t*6
	r0 := r
	r1 := r * 0.75

	ctx.Save()
	defer ctx.Restore()

	ctx.BeginPath()
	ctx.Arc(cx, cy, r0, a0, a1, nanovgo.Clockwise)
	ctx.Arc(cx, cy, r1, a1, a0, nanovgo.CounterClockwise)
	ctx.ClosePath()
	ax := cx + cosF(a0)*(r0+r1)*0.5
	ay := cy + sinF(a0)*(r0+r1)*0.5
	bx := cx + cosF(a1)*(r0+r1)*0.5
	by := cy + sinF(a1)*(r0+r1)*0.5
	paint := nanovgo.LinearGradient(ax, ay, bx, by, nanovgo.RGBA(0, 0, 0, 0), nanovgo.RGBA(0, 0, 0, 128))
	ctx.SetFillPaint(paint)
	ctx.Fill()
}

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 (w *Window) Draw(self Widget, ctx *nanovgo.Context) {
	ds := float32(w.theme.WindowDropShadowSize)
	cr := float32(w.theme.WindowCornerRadius)
	hh := float32(w.theme.WindowHeaderHeight)

	// Draw window
	wx := float32(w.x)
	wy := float32(w.y)
	ww := float32(w.w)
	wh := float32(w.h)
	ctx.Save()
	ctx.BeginPath()
	ctx.RoundedRect(wx, wy, ww, wh, cr)
	if w.mouseFocus {
		ctx.SetFillColor(w.theme.WindowFillFocused)
	} else {
		ctx.SetFillColor(w.theme.WindowFillUnfocused)
	}
	ctx.Fill()

	// Draw a drop shadow
	shadowPaint := nanovgo.BoxGradient(wx, wy, ww, wh, cr*2, ds*2, w.theme.DropShadow, w.theme.Transparent)
	ctx.BeginPath()
	ctx.Rect(wx-ds, wy-ds, ww+ds*2, wh+ds*2)
	ctx.RoundedRect(wx, wy, ww, wh, cr)
	ctx.PathWinding(nanovgo.Hole)
	ctx.SetFillPaint(shadowPaint)
	ctx.Fill()

	if w.title != "" {
		headerPaint := nanovgo.LinearGradient(wx, wy, ww, wh+hh, w.theme.WindowHeaderGradientTop, w.theme.WindowHeaderGradientBot)

		ctx.BeginPath()
		ctx.RoundedRect(wx, wy, ww, hh, cr)
		ctx.SetFillPaint(headerPaint)
		ctx.Fill()

		ctx.BeginPath()
		ctx.RoundedRect(wx, wy, ww, wh, cr)
		ctx.SetStrokeColor(w.theme.WindowHeaderSepTop)
		ctx.Scissor(wx, wy, ww, 0.5)
		ctx.Stroke()
		ctx.ResetScissor()

		ctx.BeginPath()
		ctx.MoveTo(wx+0.5, wy+hh-1.5)
		ctx.LineTo(wx+ww-0.5, wy+hh-1.5)
		ctx.SetStrokeColor(w.theme.WindowHeaderSepTop)
		ctx.Stroke()

		ctx.SetFontSize(18.0)
		ctx.SetFontFace(w.theme.FontBold)
		ctx.SetTextAlign(nanovgo.AlignCenter | nanovgo.AlignMiddle)
		ctx.SetFontBlur(2.0)
		ctx.SetFillColor(w.theme.DropShadow)
		ctx.Text(wx+ww*0.5, wy+hh*0.5, w.title)
		ctx.SetFontBlur(0.0)
		if w.focused {
			ctx.SetFillColor(w.theme.WindowTitleFocused)
		} else {
			ctx.SetFillColor(w.theme.WindowTitleUnfocused)
		}
		ctx.Text(wx+ww*0.5, wy+hh*0.5-1, w.title)
	}
	ctx.Restore()
	w.WidgetImplement.Draw(self, ctx)
}

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 drawParagraph(ctx *nanovgo.Context, x, y, width, height, mx, my float32) {
	text := "This is longer chunk of text.\n  \n  Would have used lorem ipsum but she    was busy jumping over the lazy dog with the fox and all the men who came to the aid of the party."

	ctx.Save()
	defer ctx.Restore()

	ctx.SetFontSize(18.0)
	ctx.SetFontFace("sans")
	ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignTop)
	_, _, lineh := ctx.TextMetrics()
	// The text break API can be used to fill a large buffer of rows,
	// or to iterate over the text just few lines (or just one) at a time.
	// The "next" variable of the last returned item tells where to continue.
	runes := []rune(text)

	var gx, gy float32
	var gutter int
	lnum := 0

	for _, row := range ctx.TextBreakLinesRune(runes, width) {
		hit := mx > x && mx < (x+width) && my >= y && my < (y+lineh)

		ctx.BeginPath()
		var alpha uint8
		if hit {
			alpha = 64
		} else {
			alpha = 16
		}
		ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, alpha))
		ctx.Rect(x, y, row.Width, lineh)
		ctx.Fill()

		ctx.SetFillColor(nanovgo.RGBA(255, 255, 255, 255))
		ctx.TextRune(x, y, runes[row.StartIndex:row.EndIndex])

		if hit {
			var caretX float32
			if mx < x+row.Width/2 {
				caretX = x
			} else {
				caretX = x + row.Width
			}
			px := x
			lineRune := runes[row.StartIndex:row.EndIndex]
			glyphs := ctx.TextGlyphPositionsRune(x, y, lineRune)
			for j, glyph := range glyphs {
				x0 := glyph.X
				var x1 float32
				if j+1 < len(glyphs) {
					x1 = glyphs[j+1].X
				} else {
					x1 = x + row.Width
				}
				gx = x0*0.3 + x1*0.7
				if mx >= px && mx < gx {
					caretX = glyph.X
				}
				px = gx
			}
			ctx.BeginPath()
			ctx.SetFillColor(nanovgo.RGBA(255, 192, 0, 255))
			ctx.Rect(caretX, y, 1, lineh)
			ctx.Fill()

			gutter = lnum + 1
			gx = x - 10
			gy = y + lineh/2
		}
		lnum++
		y += lineh
	}

	if gutter > 0 {
		txt := strconv.Itoa(gutter)

		ctx.SetFontSize(13.0)
		ctx.SetTextAlign(nanovgo.AlignRight | nanovgo.AlignMiddle)

		_, bounds := ctx.TextBounds(gx, gy, txt)

		ctx.BeginPath()
		ctx.SetFillColor(nanovgo.RGBA(255, 192, 0, 255))
		ctx.RoundedRect(
			float32(int(bounds[0]-4)),
			float32(int(bounds[1]-2)),
			float32(int(bounds[2]-bounds[0])+8),
			float32(int(bounds[3]-bounds[1])+4),
			float32(int(bounds[3]-bounds[1])+4)/2.0-1.0)
		ctx.Fill()

		ctx.SetFillColor(nanovgo.RGBA(32, 32, 32, 255))
		ctx.Text(gx, gy, txt)
	}

	y += 20.0

	ctx.SetFontSize(13.0)
	ctx.SetTextAlign(nanovgo.AlignLeft | nanovgo.AlignTop)
	ctx.SetTextLineHeight(1.2)
//.........這裏部分代碼省略.........

func drawColorWheel(ctx *nanovgo.Context, x, y, w, h, t float32) {
	var r0, r1, ax, ay, bx, by, aeps, r float32
	hue := sinF(t * 0.12)

	ctx.Save()
	defer ctx.Restore()
	/*      ctx.BeginPath()
	ctx.Rect(x,y,w,h)
	ctx.FillColor(nanovgo.RGBA(255,0,0,128))
	ctx.Fill()*/

	cx := x + w*0.5
	cy := y + h*0.5
	if w < h {
		r1 = w*0.5 - 5.0
	} else {
		r1 = h*0.5 - 5.0
	}
	r0 = r1 - 20.0
	aeps = 0.5 / 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+1.0)/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()
		ax = cx + cosF(a0)*(r0+r1)*0.5
		ay = cy + sinF(a0)*(r0+r1)*0.5
		bx = cx + cosF(a1)*(r0+r1)*0.5
		by = cy + sinF(a1)*(r0+r1)*0.5
		paint := nanovgo.LinearGradient(ax, ay, bx, by, nanovgo.HSLA(a0/(nanovgo.PI*2), 1.0, 0.55, 255), nanovgo.HSLA(a1/(nanovgo.PI*2), 1.0, 0.55, 255))
		ctx.SetFillPaint(paint)
		ctx.Fill()
	}

	ctx.BeginPath()
	ctx.Circle(cx, cy, r0-0.5)
	ctx.Circle(cx, cy, r1+0.5)
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 64))
	ctx.SetStrokeWidth(1.0)
	ctx.Stroke()

	// Selector
	ctx.Translate(cx, cy)
	ctx.Rotate(hue * nanovgo.PI * 2)

	// Marker on
	ctx.SetStrokeWidth(2.0)
	ctx.BeginPath()
	ctx.Rect(r0-1, -3, r1-r0+2, 6)
	ctx.SetStrokeColor(nanovgo.RGBA(255, 255, 255, 192))
	ctx.Stroke()

	paint := nanovgo.BoxGradient(r0-3, -5, r1-r0+6, 10, 2, 4, nanovgo.RGBA(0, 0, 0, 128), nanovgo.RGBA(0, 0, 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
	ax = cosF(120.0/180.0*nanovgo.PI) * r
	ay = sinF(120.0/180.0*nanovgo.PI) * r
	bx = cosF(-120.0/180.0*nanovgo.PI) * r
	by = sinF(-120.0/180.0*nanovgo.PI) * r
	ctx.BeginPath()
	ctx.MoveTo(r, 0)
	ctx.LineTo(ax, ay)
	ctx.LineTo(bx, by)
	ctx.ClosePath()
	paint = nanovgo.LinearGradient(r, 0, ax, ay, nanovgo.HSLA(hue, 1.0, 0.5, 255), nanovgo.RGBA(255, 255, 255, 255))
	ctx.SetFillPaint(paint)
	ctx.Fill()
	paint = nanovgo.LinearGradient((r+ax)*0.5, (0+ay)*0.5, bx, by, nanovgo.RGBA(0, 0, 0, 0), nanovgo.RGBA(0, 0, 0, 255))
	ctx.SetFillPaint(paint)
	ctx.Fill()
	ctx.SetStrokeColor(nanovgo.RGBA(0, 0, 0, 64))
	ctx.Stroke()

	// Select circle on triangle
	ax = cosF(120.0/180.0*nanovgo.PI) * r * 0.3
	ay = sinF(120.0/180.0*nanovgo.PI) * r * 0.4
	ctx.SetStrokeWidth(2.0)
	ctx.BeginPath()
	ctx.Circle(ax, ay, 5)
	ctx.SetStrokeColor(nanovgo.RGBA(255, 255, 255, 192))
	ctx.Stroke()

	paint = nanovgo.RadialGradient(ax, ay, 7, 9, nanovgo.RGBA(0, 0, 0, 64), nanovgo.RGBA(0, 0, 0, 0))
	ctx.BeginPath()
	ctx.Rect(ax-20, ay-20, 40, 40)
	ctx.Circle(ax, ay, 7)
	ctx.PathWinding(nanovgo.Hole)
	ctx.SetFillPaint(paint)
	ctx.Fill()
}

func drawThumbnails(ctx *nanovgo.Context, x, y, w, h float32, images []int, t float32) {
	var cornerRadius float32 = 3.0

	var thumb float32 = 60.0
	var arry float32 = 30.5
	stackh := float32(len(images)/2)*(thumb+10) + 10
	u := (1 + cosF(t*0.5)) * 0.5
	u2 := (1 - cosF(t*0.2)) * 0.5

	ctx.Save()
	defer ctx.Restore()

	// Drop shadow
	shadowPaint := nanovgo.BoxGradient(x, y+4, w, h, cornerRadius*2, 20, 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()

	// Window
	ctx.BeginPath()
	ctx.RoundedRect(x, y, w, h, cornerRadius)
	ctx.MoveTo(x-10, y+arry)
	ctx.LineTo(x+1, y+arry-11)
	ctx.LineTo(x+1, y+arry+11)
	ctx.SetFillColor(nanovgo.RGBA(200, 200, 200, 255))
	ctx.Fill()

	ctx.Block(func() {
		ctx.Scissor(x, y, w, h)
		ctx.Translate(0, -(stackh-h)*u)

		dv := 1.0 / float32(len(images)-1)

		for i, imageID := range images {
			tx := x + 10.0
			ty := y + 10.0
			tx += float32(i%2) * (thumb + 10.0)
			ty += float32(i/2) * (thumb + 10.0)
			imgW, imgH, _ := ctx.ImageSize(imageID)
			var iw, ih, ix, iy float32
			if imgW < imgH {
				iw = thumb
				ih = iw * float32(imgH) / float32(imgW)
				ix = 0
				iy = -(ih - thumb) * 0.5
			} else {
				ih = thumb
				iw = ih * float32(imgW) / float32(imgH)
				ix = -(iw - thumb) * 0.5
				iy = 0
			}

			v := float32(i) * dv
			a := clampF((u2-v)/dv, 0, 1)

			if a < 1.0 {
				drawSpinner(ctx, tx+thumb/2, ty+thumb/2, thumb*0.25, t)
			}

			imgPaint := nanovgo.ImagePattern(tx+ix, ty+iy, iw, ih, 0.0/180.0*nanovgo.PI, imageID, a)
			ctx.BeginPath()
			ctx.RoundedRect(tx, ty, thumb, thumb, 5)
			ctx.SetFillPaint(imgPaint)
			ctx.Fill()

			shadowPaint := nanovgo.BoxGradient(tx-1, ty, thumb+2, thumb+2, 5, 3, nanovgo.RGBA(0, 0, 0, 128), nanovgo.RGBA(0, 0, 0, 0))
			ctx.BeginPath()
			ctx.Rect(tx-5, ty-5, thumb+10, thumb+10)
			ctx.RoundedRect(tx, ty, thumb, thumb, 6)
			ctx.PathWinding(nanovgo.Hole)
			ctx.SetFillPaint(shadowPaint)
			ctx.Fill()

			ctx.BeginPath()
			ctx.RoundedRect(tx+0.5, ty+0.5, thumb-1, thumb-1, 4-0.5)
			ctx.SetStrokeWidth(1.0)
			ctx.SetStrokeColor(nanovgo.RGBA(255, 255, 255, 192))
			ctx.Stroke()
		}
	})

	// Hide fades
	fadePaint := nanovgo.LinearGradient(x, y, x, y+6, nanovgo.RGBA(200, 200, 200, 255), nanovgo.RGBA(200, 200, 200, 0))
	ctx.BeginPath()
	ctx.Rect(x+4, y, w-8, 6)
	ctx.SetFillPaint(fadePaint)
	ctx.Fill()

	fadePaint = nanovgo.LinearGradient(x, y+h, x, y+h-6, nanovgo.RGBA(200, 200, 200, 255), nanovgo.RGBA(200, 200, 200, 0))
	ctx.BeginPath()
	ctx.Rect(x+4, y+h-6, w-8, 6)
	ctx.SetFillPaint(fadePaint)
	ctx.Fill()

	// Scroll bar
	shadowPaint = nanovgo.BoxGradient(x+w-12+1, y+4+1, 8, h-8, 3, 4, nanovgo.RGBA(0, 0, 0, 32), nanovgo.RGBA(0, 0, 0, 92))
	ctx.BeginPath()
//.........這裏部分代碼省略.........