Draw* helpers
This commit is contained in:
Michael Fogleman
parent
d2a761c38b
commit
80ced376d0
160
context.go
160
context.go
@ -4,6 +4,7 @@ import (
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"image"
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"image/color"
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"image/draw"
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"math"
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"github.com/golang/freetype/raster"
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"golang.org/x/image/math/fixed"
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@ -56,28 +57,28 @@ func NewContext(width, height int) *Context {
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}
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}
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func (c *Context) Image() image.Image {
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return c.im
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func (dc *Context) Image() image.Image {
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return dc.im
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}
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func (c *Context) Width() int {
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return c.width
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func (dc *Context) Width() int {
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return dc.width
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}
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func (c *Context) Height() int {
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return c.height
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func (dc *Context) Height() int {
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return dc.height
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}
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func (c *Context) WriteToPNG(path string) error {
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return writeToPNG(path, c.im)
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func (dc *Context) WriteToPNG(path string) error {
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return writeToPNG(path, dc.im)
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}
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func (c *Context) Paint() {
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draw.Draw(c.im, c.im.Bounds(), image.NewUniform(c.color), image.ZP, draw.Src)
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func (dc *Context) Paint() {
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draw.Draw(dc.im, dc.im.Bounds(), image.NewUniform(dc.color), image.ZP, draw.Src)
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}
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func (c *Context) SetSourceRGBA(r, g, b, a float64) {
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c.color = color.NRGBA{
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func (dc *Context) SetSourceRGBA(r, g, b, a float64) {
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dc.color = color.NRGBA{
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uint8(r * 255),
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uint8(g * 255),
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uint8(b * 255),
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@ -85,97 +86,136 @@ func (c *Context) SetSourceRGBA(r, g, b, a float64) {
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}
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}
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func (c *Context) SetSourceRGB(r, g, b float64) {
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c.SetSourceRGBA(r, g, b, 1)
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func (dc *Context) SetSourceRGB(r, g, b float64) {
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dc.SetSourceRGBA(r, g, b, 1)
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}
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func (c *Context) SetLineWidth(lineWidth float64) {
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c.lineWidth = lineWidth
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func (dc *Context) SetLineWidth(lineWidth float64) {
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dc.lineWidth = lineWidth
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}
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func (c *Context) SetLineCap(lineCap LineCap) {
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func (dc *Context) SetLineCap(lineCap LineCap) {
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switch lineCap {
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case LineCapButt:
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c.capper = raster.ButtCapper
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dc.capper = raster.ButtCapper
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case LineCapRound:
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c.capper = raster.RoundCapper
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dc.capper = raster.RoundCapper
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case LineCapSquare:
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c.capper = raster.SquareCapper
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dc.capper = raster.SquareCapper
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}
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}
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func (c *Context) SetLineJoin(lineJoin LineJoin) {
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func (dc *Context) SetLineJoin(lineJoin LineJoin) {
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switch lineJoin {
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case LineJoinBevel:
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c.joiner = raster.BevelJoiner
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dc.joiner = raster.BevelJoiner
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case LineJoinRound:
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c.joiner = raster.RoundJoiner
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dc.joiner = raster.RoundJoiner
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}
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}
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func (c *Context) SetFillRule(fillRule FillRule) {
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c.fillRule = fillRule
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func (dc *Context) SetFillRule(fillRule FillRule) {
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dc.fillRule = fillRule
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}
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func (c *Context) MoveTo(x, y float64) {
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c.start = fp(x, y)
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c.path.Start(c.start)
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func (dc *Context) MoveTo(x, y float64) {
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dc.start = fp(x, y)
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dc.path.Start(dc.start)
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}
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func (c *Context) LineTo(x, y float64) {
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if len(c.path) == 0 {
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c.MoveTo(x, y)
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func (dc *Context) LineTo(x, y float64) {
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if len(dc.path) == 0 {
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dc.MoveTo(x, y)
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} else {
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c.path.Add1(fp(x, y))
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dc.path.Add1(fp(x, y))
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}
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}
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func (c *Context) QuadraticTo(x1, y1, x2, y2 float64) {
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if len(c.path) == 0 {
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c.MoveTo(x1, y1)
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func (dc *Context) QuadraticTo(x1, y1, x2, y2 float64) {
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if len(dc.path) == 0 {
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dc.MoveTo(x1, y1)
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} else {
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c.path.Add2(fp(x1, y1), fp(x2, y2))
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dc.path.Add2(fp(x1, y1), fp(x2, y2))
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}
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}
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func (c *Context) ClosePath() {
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if len(c.path) > 0 {
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c.path.Add1(c.start)
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func (dc *Context) ClosePath() {
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if len(dc.path) > 0 {
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dc.path.Add1(dc.start)
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}
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}
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func (c *Context) NewPath() {
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c.path.Clear()
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func (dc *Context) NewPath() {
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dc.path.Clear()
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}
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func (c *Context) StrokePreserve() {
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painter := raster.NewRGBAPainter(c.im)
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painter.SetColor(c.color)
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r := raster.NewRasterizer(c.width, c.height)
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func (dc *Context) StrokePreserve() {
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painter := raster.NewRGBAPainter(dc.im)
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painter.SetColor(dc.color)
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r := raster.NewRasterizer(dc.width, dc.height)
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r.UseNonZeroWinding = true
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r.AddStroke(c.path, fi(c.lineWidth), c.capper, c.joiner)
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r.AddStroke(dc.path, fi(dc.lineWidth), dc.capper, dc.joiner)
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r.Rasterize(painter)
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}
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func (c *Context) Stroke() {
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c.StrokePreserve()
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c.NewPath()
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func (dc *Context) Stroke() {
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dc.StrokePreserve()
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dc.NewPath()
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}
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func (c *Context) FillPreserve() {
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func (dc *Context) FillPreserve() {
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// make sure the path is closed
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path := make(raster.Path, len(c.path))
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copy(path, c.path)
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path.Add1(c.start)
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painter := raster.NewRGBAPainter(c.im)
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painter.SetColor(c.color)
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r := raster.NewRasterizer(c.width, c.height)
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r.UseNonZeroWinding = c.fillRule == FillRuleWinding
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path := make(raster.Path, len(dc.path))
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copy(path, dc.path)
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path.Add1(dc.start)
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painter := raster.NewRGBAPainter(dc.im)
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painter.SetColor(dc.color)
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r := raster.NewRasterizer(dc.width, dc.height)
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r.UseNonZeroWinding = dc.fillRule == FillRuleWinding
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r.AddPath(path)
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r.Rasterize(painter)
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}
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func (c *Context) Fill() {
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c.FillPreserve()
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c.NewPath()
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func (dc *Context) Fill() {
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dc.FillPreserve()
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dc.NewPath()
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}
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func (dc *Context) DrawLine(x1, y1, x2, y2 float64) {
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dc.MoveTo(x1, y1)
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dc.LineTo(x2, y2)
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}
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func (dc *Context) DrawEllipseArc(x, y, rx, ry, angle1, angle2 float64) {
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const n = 16
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for i := 0; i <= n; i++ {
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p1 := float64(i+0) / n
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p2 := float64(i+1) / n
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a1 := angle1 + (angle2-angle1)*p1
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a2 := angle1 + (angle2-angle1)*p2
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x0 := x + rx*math.Cos(a1)
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y0 := y + ry*math.Sin(a1)
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x1 := x + rx*math.Cos(a1+(a2-a1)/2)
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y1 := y + ry*math.Sin(a1+(a2-a1)/2)
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x2 := x + rx*math.Cos(a2)
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y2 := y + ry*math.Sin(a2)
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cx := 2*x1 - x0/2 - x2/2
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cy := 2*y1 - y0/2 - y2/2
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if i == 0 {
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dc.MoveTo(x0, y0)
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}
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dc.QuadraticTo(cx, cy, x2, y2)
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}
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}
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func (dc *Context) DrawEllipse(x, y, rx, ry float64) {
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dc.DrawEllipseArc(x, y, rx, ry, 0, 2*math.Pi)
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}
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func (dc *Context) DrawArc(x, y, r, angle1, angle2 float64) {
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dc.DrawEllipseArc(x, y, r, r, angle1, angle2)
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}
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func (dc *Context) DrawCircle(x, y, r float64) {
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dc.DrawEllipseArc(x, y, r, r, 0, 2*math.Pi)
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}
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16
examples/circle.go
Normal file
16
examples/circle.go
Normal file
@ -0,0 +1,16 @@
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package main
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import "github.com/fogleman/dd"
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func main() {
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dc := dd.NewContext(1000, 1000)
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dc.SetSourceRGB(1, 1, 1)
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dc.Paint()
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dc.DrawCircle(500, 500, 400)
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dc.SetSourceRGBA(0, 0, 0, 0.25)
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dc.FillPreserve()
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dc.SetSourceRGB(0, 0, 0.5)
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dc.SetLineWidth(8)
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dc.Stroke()
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dc.WriteToPNG("out.png")
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}
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@ -15,8 +15,6 @@ func main() {
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dc.FillPreserve()
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dc.SetSourceRGB(0, 0, 0)
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dc.SetLineWidth(8)
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// dc.SetLineCap(dd.LineCapButt)
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// dc.SetLineJoin(dd.LineJoinBevel)
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dc.Stroke()
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dc.WriteToPNG("out.png")
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}
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