Golang Context.Scissor方法代码示例

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 (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 (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 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()
//.........这里部分代码省略.........

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.........