// ArcNegative draws an arc with a negative angle (anti clockwise). func ArcNegative(gc draw2d.GraphicContext, xc, yc, width, height float64) { xc += width / 2 yc += height / 2 radiusX, radiusY := width/2, height/2 startAngle := 45.0 * (math.Pi / 180.0) /* angles are specified */ angle := -225 * (math.Pi / 180.0) /* clockwise in radians */ gc.SetLineWidth(width / 10) gc.SetLineCap(draw2d.ButtCap) gc.SetStrokeColor(image.Black) gc.ArcTo(xc, yc, radiusX, radiusY, startAngle, angle) gc.Stroke() // fill a circle gc.SetStrokeColor(color.NRGBA{255, 0x33, 0x33, 0x80}) gc.SetFillColor(color.NRGBA{255, 0x33, 0x33, 0x80}) gc.SetLineWidth(width / 20) gc.MoveTo(xc+math.Cos(startAngle)*radiusX, yc+math.Sin(startAngle)*radiusY) gc.LineTo(xc, yc) gc.LineTo(xc-radiusX, yc) gc.Stroke() gc.ArcTo(xc, yc, width/10.0, height/10.0, 0, 2*math.Pi) gc.Fill() }
// 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() }
// Star draws many lines from a center. func Star(gc draw2d.GraphicContext, x, y, width, height float64) { gc.Save() gc.Translate(x+width/2, y+height/2) gc.SetLineWidth(width / 40) for i := 0.0; i < 360; i = i + 10 { // Go from 0 to 360 degrees in 10 degree steps gc.Save() // Keep rotations temporary gc.Rotate(i * (math.Pi / 180.0)) // Rotate by degrees on stack from 'for' gc.MoveTo(0, 0) gc.LineTo(width/2, 0) gc.Stroke() gc.Restore() } gc.Restore() }
// 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() }
// Dash draws a line with a dash pattern func Dash(gc draw2d.GraphicContext, x, y, width, height float64) { sx, sy := width/162, height/205 gc.SetStrokeColor(image.Black) gc.SetLineDash([]float64{height / 10, height / 50, height / 50, height / 50}, -50.0) gc.SetLineCap(draw2d.ButtCap) gc.SetLineJoin(draw2d.RoundJoin) gc.SetLineWidth(height / 50) gc.MoveTo(x+sx*60.0, y) gc.LineTo(x+sx*60.0, y) gc.LineTo(x+sx*162, y+sy*205) rLineTo(gc, sx*-102.4, 0) gc.CubicCurveTo(x+sx*-17, y+sy*205, x+sx*-17, y+sy*103, x+sx*60.0, y+sy*103.0) gc.Stroke() gc.SetLineDash(nil, 0.0) }
// FillStroke first fills and afterwards strokes a path. func FillStroke(gc draw2d.GraphicContext, x, y, width, height float64) { sx, sy := width/210, height/215 gc.MoveTo(x+sx*113.0, y) gc.LineTo(x+sx*215.0, y+sy*215) rLineTo(gc, sx*-100, 0) gc.CubicCurveTo(x+sx*35, y+sy*215, x+sx*35, y+sy*113, x+sx*113.0, y+sy*113) gc.Close() gc.MoveTo(x+sx*50.0, y) rLineTo(gc, sx*51.2, sy*51.2) rLineTo(gc, sx*-51.2, sy*51.2) rLineTo(gc, sx*-51.2, sy*-51.2) gc.Close() gc.SetLineWidth(width / 20.0) gc.SetFillColor(color.NRGBA{0, 0, 0xFF, 0xFF}) gc.SetStrokeColor(image.Black) gc.FillStroke() }
// CubicCurve draws a cubic curve with its control points. func CubicCurve(gc draw2d.GraphicContext, x, y, width, height float64) { sx, sy := width/162, height/205 x0, y0 := x, y+sy*100.0 x1, y1 := x+sx*75, y+sy*205 x2, y2 := x+sx*125, y x3, y3 := x+sx*205, y+sy*100 gc.SetStrokeColor(image.Black) gc.SetFillColor(color.NRGBA{0xAA, 0xAA, 0xAA, 0xFF}) gc.SetLineWidth(width / 10) gc.MoveTo(x0, y0) gc.CubicCurveTo(x1, y1, x2, y2, x3, y3) gc.Stroke() gc.SetStrokeColor(color.NRGBA{0xFF, 0x33, 0x33, 0x88}) gc.SetLineWidth(width / 20) // draw segment of curve gc.MoveTo(x0, y0) gc.LineTo(x1, y1) gc.LineTo(x2, y2) gc.LineTo(x3, y3) gc.Stroke() }
// CurveRectangle draws a rectangle with bezier curves (not rounded rectangle). func CurveRectangle(gc draw2d.GraphicContext, x0, y0, rectWidth, rectHeight float64, stroke, fill color.Color) { radius := (rectWidth + rectHeight) / 4 x1 := x0 + rectWidth y1 := y0 + rectHeight if rectWidth/2 < radius { if rectHeight/2 < radius { gc.MoveTo(x0, (y0+y1)/2) gc.CubicCurveTo(x0, y0, x0, y0, (x0+x1)/2, y0) gc.CubicCurveTo(x1, y0, x1, y0, x1, (y0+y1)/2) gc.CubicCurveTo(x1, y1, x1, y1, (x1+x0)/2, y1) gc.CubicCurveTo(x0, y1, x0, y1, x0, (y0+y1)/2) } else { gc.MoveTo(x0, y0+radius) gc.CubicCurveTo(x0, y0, x0, y0, (x0+x1)/2, y0) gc.CubicCurveTo(x1, y0, x1, y0, x1, y0+radius) gc.LineTo(x1, y1-radius) gc.CubicCurveTo(x1, y1, x1, y1, (x1+x0)/2, y1) gc.CubicCurveTo(x0, y1, x0, y1, x0, y1-radius) } } else { if rectHeight/2 < radius { gc.MoveTo(x0, (y0+y1)/2) gc.CubicCurveTo(x0, y0, x0, y0, x0+radius, y0) gc.LineTo(x1-radius, y0) gc.CubicCurveTo(x1, y0, x1, y0, x1, (y0+y1)/2) gc.CubicCurveTo(x1, y1, x1, y1, x1-radius, y1) gc.LineTo(x0+radius, y1) gc.CubicCurveTo(x0, y1, x0, y1, x0, (y0+y1)/2) } else { gc.MoveTo(x0, y0+radius) gc.CubicCurveTo(x0, y0, x0, y0, x0+radius, y0) gc.LineTo(x1-radius, y0) gc.CubicCurveTo(x1, y0, x1, y0, x1, y0+radius) gc.LineTo(x1, y1-radius) gc.CubicCurveTo(x1, y1, x1, y1, x1-radius, y1) gc.LineTo(x0+radius, y1) gc.CubicCurveTo(x0, y1, x0, y1, x0, y1-radius) } } gc.Close() gc.SetStrokeColor(stroke) gc.SetFillColor(fill) gc.SetLineWidth(10.0) gc.FillStroke() }
// Draw vertically spaced lines func Draw(gc draw2d.GraphicContext, x0, y0, x1, y1 float64) { // Draw a line gc.MoveTo(x0, y0) gc.LineTo(x1, y1) gc.Stroke() }