Types/Turtle/Circle.ps1
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<# .SYNOPSIS Draws a circle. .DESCRIPTION Draws a whole or partial circle using turtle graphics. That is, it draws a circle by moving the turtle forward and rotating it. To draw a semicircle, use an extent of 0.5. To draw a quarter circle, use an extent of 0.25. To draw a half hexagon, use an extent of 0.5 and step count of 6. .EXAMPLE $turtle = New-Turtle $turtle.Circle(10).Pattern.Save("$pwd/CirclePattern.svg") .EXAMPLE Move-Turtle Circle 10 | Save-Turtle "$pwd/CirclePattern.svg" -Property Pattern .EXAMPLE $turtle = New-Turtle | Move-Turtle Forward 10 | Move-Turtle Rotate -90 | Move-Turtle Circle 5 | Move-Turtle Circle 5 .5 | Move-Turtle Rotate -90 | Move-Turtle Forward 10 | Save-Turtle .\DashDotDash.svg .EXAMPLE $turtle = New-Turtle | Move-Turtle Forward 20 | Move-Turtle Circle 5 .75 | Move-Turtle Forward 20 | Move-Turtle Circle 5 .75 | Move-Turtle Forward 20 | Move-Turtle Circle 5 .75 | Move-Turtle Forward 20 | Move-Turtle Circle 5 .75 | Save-Turtle .\CommandSymbol.svg #> param( [double]$Radius = 10, [double]$Extent = 1, [int]$StepCount = 180 ) $circumference = 2 * [math]::PI * $Radius $circumferenceStep = $circumference / $StepCount if ($extent -eq 0) { return $this} $extentMultiplier = if ($extent -gt 0) { 1 } else { -1 } $currentExtent = 0 $maxExtent = [math]::Abs($extent) $extentStep = 1/$StepCount $null = foreach ($n in 1..$StepCount) { $this.Forward($circumferenceStep) $currentExtent += $extentStep if ($n -le $StepCount -and $currentExtent -le $maxExtent) { $this.Rotate( (360 / $StepCount) * $extentMultiplier) } if ($currentExtent -gt $maxExtent) { break } } return $this |