Types/Turtle/CircleArc.ps1
|
<# .SYNOPSIS Draws a Circle Arc .DESCRIPTION Draws a Circular Arc. The Turtle heading will not change, and the Turtle will end up at it's original position. .EXAMPLE Turtle CircleArc .EXAMPLE Turtle @( 'CircleArc',42, 90, 'Rotate', 90 * 4 ) save ./Quadrants.svg .EXAMPLE Turtle @( 'CircleArc',42, 60, 'Rotate', 60 * 6 ) save ./Sextants.svg .EXAMPLE Turtle @( 'CircleArc',42, 45, 'Rotate', 45 * 8 ) save ./Octants.svg #> param( # The radius of the circle [double] $Radius = 42, # The angle of the arc [double] $Angle = 30 ) # If we wanted an angle that was a multiple of 360 # we actually want to just draw a circle if ([Math]::Round($Angle % 360, $this.Precision) -eq 0) { # We start at the center $centerX = $this.X $centerY = $this.Y # Jump to an edge $this = $this.Jump($Radius) # and track the delta $DeltaX = $this.X - $centerX $DeltaY = $this.Y - $centerY return $this. # Arcing to the opposite of that delta (*2) takes us to the far edge Arc($Radius, $Radius, 0, $false, $false, $DeltaX * -2, $DeltaY * -2). # And Arcing back takes us to our original position along the edge Arc($Radius, $Radius, 0, $false, $false, $DeltaX * 2, $DeltaY * 2). # Jump back and we are back in the center of the circle. Jump(-$radius) } # For a normal circular arc, start by pushing our location onto the stack $this = $this.Push() # Draw a line to the edge of the circle $null = $this.Forward($Radius) # This will be the wedge end $WedgeEndX = $this.Position.X $WedgeEndY = $this.Position.Y # Go back to the center, rotate, and move forward by the radius. $null = $this.Forward(-$radius) $null = $this.Rotate($Angle).Forward($radius) # now we can compute the distance to the end of the wedge $DeltaX = $WedgeEndX - $this.Position.X $DeltaY = $WedgeEndY - $this.Position.Y # and draw an arc to this location $this = $this.Arc($Radius, $Radius, 0, ($Angle -gt 180), $false, $DeltaX, $DeltaY) # and then pop our position back $null = $this.Pop() # and return this $null = $this.ResizeViewBox($Radius) return $this |