root.psm1
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# make sure all required assemblies are loaded BEFORE any class definitions use them: try { Add-Type -AssemblyName System.Runtime.WindowsRuntime # WinRT assemblies are loaded indirectly: $null = [Windows.Storage.StorageFile, Windows.Storage, ContentType = WindowsRuntime] $null = [Windows.Media.Ocr.OcrEngine, Windows.Foundation, ContentType = WindowsRuntime] $null = [Windows.Foundation.IAsyncOperation`1, Windows.Foundation, ContentType = WindowsRuntime] $null = [Windows.Graphics.Imaging.SoftwareBitmap, Windows.Foundation, ContentType = WindowsRuntime] $null = [Windows.Storage.Streams.RandomAccessStream, Windows.Storage.Streams, ContentType = WindowsRuntime] $null = [WindowsRuntimeSystemExtensions] # some WinRT assemblies such as [Windows.Globalization.Language] are loaded indirectly by returning # the object types: $null = [Windows.Media.Ocr.OcrEngine]::AvailableRecognizerLanguages # grab the async awaiter method: Add-Type -AssemblyName System.Runtime.WindowsRuntime # find the awaiter method $awaiter = [WindowsRuntimeSystemExtensions].GetMember('GetAwaiter', 'Method', 'Public,Static') | Where-Object { $_.GetParameters()[0].ParameterType.Name -eq 'IAsyncOperation`1' } | Select-Object -First 1 # define awaiter function function Invoke-Async([object]$AsyncTask, [Type]$As) { return $awaiter. MakeGenericMethod($As). Invoke($null, @($AsyncTask)). GetResult() } } catch { throw 'OCR requires Windows 10 and Windows PowerShell. You cannot use this module in PowerShell 7' } function Convert-PsoImageToText { <# .SYNOPSIS Converts an image file to text by using Windows 10 built-in OCR .DESCRIPTION Detailed Description .EXAMPLE Convert-ImageToText -Path c:\temp\image.png Converts the image in image.png to text #> [CmdletBinding()] param ( [Parameter(Mandatory,ValueFromPipeline,ValueFromPipelineByPropertyName)] [string] [Alias('FullName')] $Path, # dynamically create auto-completion from available OCR languages: [ArgumentCompleter({ # receive information about current state: param($commandName, $parameterName, $wordToComplete, $commandAst, $fakeBoundParameters) [Windows.Media.Ocr.OcrEngine]::AvailableRecognizerLanguages | Foreach-Object { # create completionresult items: $displayname = $_.DisplayName $id = $_.LanguageTag [System.Management.Automation.CompletionResult]::new($id, $displayname, "ParameterValue", "$displayName`r`n$id") } })] [Windows.Globalization.Language] $Language ) begin { Add-Type -AssemblyName System.Runtime.WindowsRuntime # [Windows.Media.Ocr.OcrEngine]::AvailableRecognizerLanguages if ($PSBoundParameters.ContainsKey('Language')) { $ocrEngine = [Windows.Media.Ocr.OcrEngine]::TryCreateFromLanguage($Language) } else { $ocrEngine = [Windows.Media.Ocr.OcrEngine]::TryCreateFromUserProfileLanguages() } # PowerShell doesn't have built-in support for Async operations, # but all the WinRT methods are Async. # This function wraps a way to call those methods, and wait for their results. } process { # all of these methods run asynchronously because they are tailored for responsive UIs # PowerShell is single-threaded and synchronous so a helper function is used to # run the async methods and wait for them to complete, essentially reversing the async # behavior # Invoke() requires the async method and the desired return type # get image file: $file = [Windows.Storage.StorageFile]::GetFileFromPathAsync($path) $storageFile = Invoke-Async $file -As ([Windows.Storage.StorageFile]) # read image content: $content = $storageFile.OpenAsync([Windows.Storage.FileAccessMode]::Read) $fileStream = Invoke-Async $content -As ([Windows.Storage.Streams.IRandomAccessStream]) # get bitmap decoder: $decoder = [Windows.Graphics.Imaging.BitmapDecoder]::CreateAsync($fileStream) $bitmapDecoder = Invoke-Async $decoder -As ([Windows.Graphics.Imaging.BitmapDecoder]) # decode bitmap: $bitmap = $bitmapDecoder.GetSoftwareBitmapAsync() $softwareBitmap = Invoke-Async $bitmap -As ([Windows.Graphics.Imaging.SoftwareBitmap]) # do optical text recognition (OCR) and return lines and words: $ocrResult = $ocrEngine.RecognizeAsync($softwareBitmap) (Invoke-Async $ocrResult -As ([Windows.Media.Ocr.OcrResult])).Lines | Select-Object -Property Text, @{Name='Words';Expression={$_.Words.Text}} } } |