Golang draw2d.GraphicContext类代码示例

// Main draws "Hello World" and returns the filename. This should only be
// used during testing.
func Main(gc draw2d.GraphicContext, ext string) (string, error) {
	// Draw hello world
	Draw(gc, fmt.Sprintf("Hello World %d dpi", gc.GetDPI()))

	// Return the output filename
	return samples.Output("helloworld", ext), nil
}

// UseImageWithContext specifies both an image
// and a graphic context to create the canvas from.
// The minimum point of the given image
// should probably be 0,0.
func UseImageWithContext(img draw.Image, gc draw2d.GraphicContext) option {
	return func(c *Canvas) uint32 {
		c.img = img
		c.gc = gc
		c.dpi = gc.GetDPI()
		return setsDPI | setsSize
	}
}

// Draw "Hello World"
func Draw(gc draw2d.GraphicContext, text string) {
	// Draw a rounded rectangle using default colors
	draw2dkit.RoundedRectangle(gc, 5, 5, 135, 95, 10, 10)
	gc.FillStroke()

	// Set the font luximbi.ttf
	gc.SetFontData(draw2d.FontData{Name: "luxi", Family: draw2d.FontFamilyMono, Style: draw2d.FontStyleBold | draw2d.FontStyleItalic})
	// Set the fill text color to black
	gc.SetFillColor(image.Black)
	gc.SetFontSize(14)
	// Display Hello World
	gc.FillStringAt("Hello World", 8, 52)
}

// Main draws the tiger
func Main(gc draw2d.GraphicContext, ext string) (string, error) {
	gc.Save()

	// flip the image
	gc.Translate(0, 200)
	gc.Scale(0.35, -0.35)
	gc.Translate(70, -200)

	// Tiger postscript drawing
	tiger := samples.Resource("image", "tiger.ps", ext)

	// Draw tiger
	Draw(gc, tiger)
	gc.Restore()

	// Return the output filename
	return samples.Output("postscript", ext), nil
}

// Main draws a left hand and ear of a gopher. Afterwards it returns
// the filename. This should only be used during testing.
func Main(gc draw2d.GraphicContext, ext string) (string, error) {
	gc.Save()
	gc.Scale(0.5, 0.5)
	// Draw a (partial) gopher
	Draw(gc)
	gc.Restore()

	// Return the output filename
	return samples.Output("gopher", ext), nil
}

// Draw the droid on a certain position.
func Draw(gc draw2d.GraphicContext, x, y float64) {
	// set the fill and stroke color of the droid
	gc.SetFillColor(color.RGBA{0x44, 0xff, 0x44, 0xff})
	gc.SetStrokeColor(color.RGBA{0x44, 0x44, 0x44, 0xff})

	// set line properties
	gc.SetLineCap(draw2d.RoundCap)
	gc.SetLineWidth(5)

	// head
	gc.MoveTo(x+30, y+70)
	gc.ArcTo(x+80, y+70, 50, 50, 180*(math.Pi/180), 180*(math.Pi/180))
	gc.Close()
	gc.FillStroke()
	gc.MoveTo(x+60, y+25)
	gc.LineTo(x+50, y+10)
	gc.MoveTo(x+100, y+25)
	gc.LineTo(x+110, y+10)
	gc.Stroke()

	// left eye
	draw2dkit.Circle(gc, x+60, y+45, 5)
	gc.FillStroke()

	// right eye
	draw2dkit.Circle(gc, x+100, y+45, 5)
	gc.FillStroke()

	// body
	draw2dkit.RoundedRectangle(gc, x+30, y+75, x+30+100, y+75+90, 10, 10)
	gc.FillStroke()
	draw2dkit.Rectangle(gc, x+30, y+75, x+30+100, y+75+80)
	gc.FillStroke()

	// left arm
	draw2dkit.RoundedRectangle(gc, x+5, y+80, x+5+20, y+80+70, 10, 10)
	gc.FillStroke()

	// right arm
	draw2dkit.RoundedRectangle(gc, x+135, y+80, x+135+20, y+80+70, 10, 10)
	gc.FillStroke()

	// left leg
	draw2dkit.RoundedRectangle(gc, x+50, y+150, x+50+20, y+150+50, 10, 10)
	gc.FillStroke()

	// right leg
	draw2dkit.RoundedRectangle(gc, x+90, y+150, x+90+20, y+150+50, 10, 10)
	gc.FillStroke()
}

// Draw the image frame with certain parameters.
func Draw(gc draw2d.GraphicContext, png string,
	dw, dh, margin, lineWidth float64) error {
	// Draw frame
	draw2dkit.RoundedRectangle(gc, lineWidth, lineWidth, dw-lineWidth, dh-lineWidth, 100, 100)
	gc.SetLineWidth(lineWidth)
	gc.FillStroke()

	// load the source image
	source, err := draw2dimg.LoadFromPngFile(png)
	if err != nil {
		return err
	}
	// Size of source image
	sw, sh := float64(source.Bounds().Dx()), float64(source.Bounds().Dy())
	// Draw image to fit in the frame
	// TODO Seems to have a transform bug here on draw image
	scale := math.Min((dw-margin*2)/sw, (dh-margin*2)/sh)
	gc.Save()
	gc.Translate((dw-sw*scale)/2, (dh-sh*scale)/2)
	gc.Scale(scale, scale)
	gc.Rotate(0.2)

	gc.DrawImage(source)
	gc.Restore()
	return nil
}

// Draw a left hand and ear of a gopher using a gc thanks to
// https://github.com/golang-samples/gopher-vector/
func Draw(gc draw2d.GraphicContext) {
	// Initialize Stroke Attribute
	gc.SetLineWidth(3)
	gc.SetLineCap(draw2d.RoundCap)
	gc.SetStrokeColor(color.Black)

	// Left hand
	// <path fill-rule="evenodd" clip-rule="evenodd" fill="#F6D2A2" stroke="#000000" stroke-width="3" stroke-linecap="round" d="
	// M10.634,300.493c0.764,15.751,16.499,8.463,23.626,3.539c6.765-4.675,8.743-0.789,9.337-10.015
	// c0.389-6.064,1.088-12.128,0.744-18.216c-10.23-0.927-21.357,1.509-29.744,7.602C10.277,286.542,2.177,296.561,10.634,300.493"/>
	gc.SetFillColor(color.RGBA{0xF6, 0xD2, 0xA2, 0xff})
	gc.MoveTo(10.634, 300.493)
	rCubicCurveTo(gc, 0.764, 15.751, 16.499, 8.463, 23.626, 3.539)
	rCubicCurveTo(gc, 6.765, -4.675, 8.743, -0.789, 9.337, -10.015)
	rCubicCurveTo(gc, 0.389, -6.064, 1.088, -12.128, 0.744, -18.216)
	rCubicCurveTo(gc, -10.23, -0.927, -21.357, 1.509, -29.744, 7.602)
	gc.CubicCurveTo(10.277, 286.542, 2.177, 296.561, 10.634, 300.493)
	gc.FillStroke()

	// <path fill-rule="evenodd" clip-rule="evenodd" fill="#C6B198" stroke="#000000" stroke-width="3" stroke-linecap="round" d="
	// M10.634,300.493c2.29-0.852,4.717-1.457,6.271-3.528"/>
	gc.MoveTo(10.634, 300.493)
	rCubicCurveTo(gc, 2.29, -0.852, 4.717, -1.457, 6.271, -3.528)
	gc.Stroke()

	// Left Ear
	// <path fill-rule="evenodd" clip-rule="evenodd" fill="#6AD7E5" stroke="#000000" stroke-width="3" stroke-linecap="round" d="
	// M46.997,112.853C-13.3,95.897,31.536,19.189,79.956,50.74L46.997,112.853z"/>
	gc.MoveTo(46.997, 112.853)
	gc.CubicCurveTo(-13.3, 95.897, 31.536, 19.189, 79.956, 50.74)
	gc.LineTo(46.997, 112.853)
	gc.Close()
	gc.Stroke()
}

// Draw a line with an angle with specified line cap and join
func Draw(gc draw2d.GraphicContext, cap draw2d.LineCap, join draw2d.LineJoin,
	x0, y0, x1, y1, offset float64) {
	gc.SetLineCap(cap)
	gc.SetLineJoin(join)

	// Draw thick line
	gc.SetStrokeColor(color.NRGBA{0x33, 0x33, 0x33, 0xFF})
	gc.SetLineWidth(30.0)
	gc.MoveTo(x0, y0)
	gc.LineTo((x0+x1)/2+offset, (y0+y1)/2)
	gc.LineTo(x1, y1)
	gc.Stroke()

	// Draw thin helping line
	gc.SetStrokeColor(color.NRGBA{0xFF, 0x33, 0x33, 0xFF})
	gc.SetLineWidth(2.56)
	gc.MoveTo(x0, y0)
	gc.LineTo((x0+x1)/2+offset, (y0+y1)/2)
	gc.LineTo(x1, y1)
	gc.Stroke()
}

// Draw a gopher head (not rotated)
func Draw(gc draw2d.GraphicContext, x, y, w, h float64) {
	h23 := (h * 2) / 3

	blf := color.RGBA{0, 0, 0, 0xff}          // black
	wf := color.RGBA{0xff, 0xff, 0xff, 0xff}  // white
	nf := color.RGBA{0x8B, 0x45, 0x13, 0xff}  // brown opaque
	brf := color.RGBA{0x8B, 0x45, 0x13, 0x99} // brown transparant
	brb := color.RGBA{0x8B, 0x45, 0x13, 0xBB} // brown transparant

	// round head top
	gc.MoveTo(x, y+h*1.002)
	gc.CubicCurveTo(x+w/4, y-h/3, x+3*w/4, y-h/3, x+w, y+h*1.002)
	gc.Close()
	gc.SetFillColor(brb)
	gc.Fill()

	// rectangle head bottom
	draw2dkit.RoundedRectangle(gc, x, y+h, x+w, y+h+h, h/5, h/5)
	gc.Fill()

	// left ear outside
	draw2dkit.Circle(gc, x, y+h, w/12)
	gc.SetFillColor(brf)
	gc.Fill()

	// left ear inside
	draw2dkit.Circle(gc, x, y+h, 0.5*w/12)
	gc.SetFillColor(nf)
	gc.Fill()

	// right ear outside
	draw2dkit.Circle(gc, x+w, y+h, w/12)
	gc.SetFillColor(brf)
	gc.Fill()

	// right ear inside
	draw2dkit.Circle(gc, x+w, y+h, 0.5*w/12)
	gc.SetFillColor(nf)
	gc.Fill()

	// left eye outside white
	draw2dkit.Circle(gc, x+w/3, y+h23, w/9)
	gc.SetFillColor(wf)
	gc.Fill()

	// left eye black
	draw2dkit.Circle(gc, x+w/3+w/24, y+h23, 0.5*w/9)
	gc.SetFillColor(blf)
	gc.Fill()

	// left eye inside white
	draw2dkit.Circle(gc, x+w/3+w/24+w/48, y+h23, 0.2*w/9)
	gc.SetFillColor(wf)
	gc.Fill()

	// right eye outside white
	draw2dkit.Circle(gc, x+w-w/3, y+h23, w/9)
	gc.Fill()

	// right eye black
	draw2dkit.Circle(gc, x+w-w/3+w/24, y+h23, 0.5*w/9)
	gc.SetFillColor(blf)
	gc.Fill()

	// right eye inside white
	draw2dkit.Circle(gc, x+w-(w/3)+w/24+w/48, y+h23, 0.2*w/9)
	gc.SetFillColor(wf)
	gc.Fill()

	// left tooth
	gc.SetFillColor(wf)
	draw2dkit.RoundedRectangle(gc, x+w/2-w/8, y+h+h/2.5, x+w/2-w/8+w/8, y+h+h/2.5+w/6, w/10, w/10)
	gc.Fill()

	// right tooth
	draw2dkit.RoundedRectangle(gc, x+w/2, y+h+h/2.5, x+w/2+w/8, y+h+h/2.5+w/6, w/10, w/10)
	gc.Fill()

	// snout
	draw2dkit.Ellipse(gc, x+(w/2), y+h+h/2.5, w/6, w/12)
	gc.SetFillColor(nf)
	gc.Fill()

	// nose
	draw2dkit.Ellipse(gc, x+(w/2), y+h+h/7, w/10, w/12)
	gc.SetFillColor(blf)
	gc.Fill()
}

// Main draws a rotated face of the gopher. Afterwards it returns
// the filename. This should only be used during testing.
func Main(gc draw2d.GraphicContext, ext string) (string, error) {
	gc.SetStrokeColor(image.Black)
	gc.SetFillColor(image.White)
	gc.Save()
	// Draw a (partial) gopher
	gc.Translate(-60, 65)
	gc.Rotate(-30 * (math.Pi / 180.0))
	Draw(gc, 48, 48, 240, 72)
	gc.Restore()

	// Return the output filename
	return samples.Output("gopher2", ext), nil
}