// 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()
}
// 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 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()
}
// 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()
}