feat: Turtle.get_WEBP ( Fixes #61 )

Author: James Brundage

Types/Turtle/get_WEBP.ps1

@@ -0,0 +1,45 @@
+$chromiumNames = 'chromium','chrome','msedge'
+foreach ($browserName in $chromiumNames) {
+    $chromiumCommand = 
+        $ExecutionContext.SessionState.InvokeCommand.GetCommand($browserName,'Application')
+    if (-not $chromiumCommand) { 
+        $chromiumCommand = 
+            Get-Process -Name $browserName -ErrorAction Ignore | 
+            Select-Object -First 1 -ExpandProperty Path
+    }
+    if ($chromiumCommand) { break }
+}
+if (-not $chromiumCommand) {
+    Write-Error "No Chromium-based browser found. Please install one of: $($chromiumNames -join ', ')"
+    return
+}
+
+$pngRasterizer = $this.Canvas -replace '/\*Insert-Post-Processing-Here\*/', @'
+    const dataUrl = await canvas.toDataURL('image/webp')
+    console.log(dataUrl)
+  
+    const newImage = document.createElement('img')
+    newImage.src = dataUrl
+    document.body.appendChild(newImage)
+'@
+
+
+$appDataRoot = [Environment]::GetFolderPath("ApplicationData")
+$appDataPath = Join-Path $appDataRoot 'Turtle'
+$filePath   = Join-Path $appDataPath 'Turtle.raster.html'
+$null = New-Item -ItemType File -Force -Path $filePath -Value (
+    $pngRasterizer -join [Environment]::NewLine
+)
+# $pngRasterizer > $filePath
+
+$headlessArguments = @(
+    '--headless', # run in headless mode
+    '--dump-dom', # dump the DOM to stdout
+    '--disable-gpu', # disable GPU acceleration
+    '--no-sandbox' # disable the sandbox if running in CI/CD            
+)
+
+$chromeOutput = & $chromiumCommand @headlessArguments "$filePath" | Out-String 
+if ($chromeOutput -match '<img\ssrc="data:image/\w+;base64,(?<b64>[^"]+)') {
+    ,[Convert]::FromBase64String($matches.b64)
+}