docs: Turtle.get_Pattern OutputType and docs ( Fixes #266 )

Author: StartAutomating

Types/Turtle/get_Pattern.ps1

@@ -1,23 +1,121 @@
+<#
+.SYNOPSIS
+    Gets a Turtle Pattern
+.DESCRIPTION
+    Gets the current turtle as a pattern that stretches off to infinity.    
+.EXAMPLE
+    turtle star 42 4 | Save-Turtle "./GridPattern.svg"
+.EXAMPLE
+    turtle star 42 6 | Save-Turtle "./StarPattern6.svg"
+.EXAMPLE
+    turtle star 42 8 | Save-Turtle "./StarPattern8.svg"
+.EXAMPLE
+    turtle star 42 5 | Save-Turtle "./StarPattern5.svg"
+.EXAMPLE
+    turtle star 42 7 | Save-Turtle "./Star7Pattern.svg"
+.EXAMPLE
+    turtle viewbox 100 start 25 25 square 50 | Save-Turtle "./WindowPattern.svg" Pattern
+.EXAMPLE
+    turtle star 100 4 morph @(
+        turtle star 100 4
+        turtle rotate 90 star 100 4
+        turtle rotate 180 star 100 4
+        turtle rotate 270 star 100 4
+        turtle star 100 4
+    ) | Save-Turtle "./GridPatternMorph.svg"
+.EXAMPLE
+    turtle star 100 3 morph @(
+        turtle star 100 3
+        turtle rotate 90 star 100 3
+        turtle rotate 180 star 100 3
+        turtle rotate 270 star 100 3
+        turtle star 100 3
+    ) | Save-Turtle "./TriPatternMorph.svg"
+.EXAMPLE
+    turtle star 100 6 morph @(
+        turtle star 100 6
+        turtle rotate 90 star 100 6
+        turtle rotate 180 star 100 6
+        turtle rotate 270 star 100 6
+        turtle star 100 6
+    ) | Save-Turtle "./Star6PatternMorph.svg" | Show-Turtle
+.EXAMPLE
+    # We can use a pattern transform to scale the pattern
+    turtle sierpinskiTriangle PatternTransform @{
+        scale = 0.25
+        rotate = 120
+    } | 
+        Save-Turtle "./SierpinskiTrianglePattern.svg" Pattern | 
+        show-Turtle
+.EXAMPLE
+    # We can use pattern animations to change the pattern
+    # Animations are relative to initial transforms
+    turtle sierpinskiTriangle PatternTransform @{
+        scale = 0.25
+        rotate = 120
+    } PatternAnimation ([Ordered]@{
+        type = 'scale'    ; values = 1.33,0.66, 1.33 ; repeatCount = 'indefinite' ;dur = "23s"; additive = 'sum'
+    }) | 
+        Save-Turtle "./SierpinskiTrianglePattern.svg" Pattern | 
+        Show-Turtle
+#>
+[OutputType([xml])]
 param()
-$segments = @(
+
+# Get our viewbox
 $viewBox = $this.ViewBox
+# and get the width and height
 $null, $null, $viewX, $viewY = $viewBox
+
+# Initialize our core attributes.
+# These may be overwritten by user request.
+$coreAttributes = [Ordered]@{
+    'id'                = "$($this.ID)-pattern"
+    'patternUnits'      = 'userSpaceOnUse'
+    'width'             = $ViewX
+    'height'            = $viewY
+    'transform-origin'  = '50% 50%'
+}
+
+# If we have specified any transforms
+if ($this.PatternTransform) {    
+    $coreAttributes."patternTransform" = 
+        # Then generate a transform expression
+        @(foreach ($key in $this.PatternTransform.Keys) {
+            # transforms are a name, followed by parameters in paranthesis
+            "$key($($this.PatternTransform[$key]))"
+        }) -join ' '
+}
+
+# Pattern attributes can be defined within .SVGAttribute or .Attribute
+# provided they have the appropriate prefix
+$prefix = [Regex]::new('^/?pattern/', 'IgnoreCase')
+# (slashes are invalid markup, and thus a fine way to target nested instances)
+
+foreach ($collection in $this.SVGAttribute, $this.Attribute) {
+    # If the connection does not exist, continue.
+    if (-not $collection) { continue }
+    # For each key that matches the prefix
+    foreach ($key in $collection.Keys -match $prefix) {
+        # add it to the attributes after stripping the prefix.
+        $coreAttributes[$attributeName -replace $prefix] = $collection[$attributeName]
+    }
+}
+
+$segments = @(
 "<svg xmlns='http://www.w3.org/2000/svg' width='100%' height='100%'>"
 "<defs>"
-    "<pattern id='$($this.ID)-pattern' patternUnits='userSpaceOnUse' width='$viewX' height='$viewY' transform-origin='50% 50%'$(
-        if ($this.PatternTransform) {
-            " patternTransform='" + (
-                @(foreach ($key in $this.PatternTransform.Keys) {
-                    "$key($($this.PatternTransform[$key]))"
-                }) -join ' '
-            ) + "'"
-        }
-    )>"        
+    "<pattern$(
+    foreach ($attributeName in $coreAttributes.Keys) {
+        " $attributeName='$($coreAttributes[$attributeName])'"
+    }
+)>"
         $(if ($this.PatternAnimation) { $this.PatternAnimation })
         $($this.SVG.SVG.InnerXML)
     "</pattern>"
 "</defs>"
 "<rect width='10000%' height='10000%' x='-5000%' y='-5000%' fill='url(#$($this.ID)-pattern)' transform-origin='50% 50%' />"
-"</svg>") 
+"</svg>"
+) 
 
-$segments -join '' -as [xml]
+[xml]$segments